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  • 1. Affognon, Hippolyte
    et al.
    Mburu, Peter
    Hassan, Osama Ahmed
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Kingori, Sarah
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Sang, Rosemary
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ethnic groups' knowledge, attitude and practices and Rift Valley fever exposure in Isiolo County of Kenya2017In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 11, no 3, article id e0005405Article in journal (Refereed)
    Abstract [en]

    Rift Valley fever (RVF) is an emerging mosquito-borne viral hemorrhagic fever in Africa and the Arabian Peninsula, affecting humans and livestock. For spread of infectious diseases, including RVF, knowledge, attitude and practices play an important role, and the understanding of the influence of behavior is crucial to improve prevention and control efforts. The objective of the study was to assess RVF exposure, in a multiethnic region in Kenya known to experience RVF outbreaks, from the behavior perspective. We investigated how communities in Isiolo County, Kenya were affected, in relation to their knowledge, attitude and practices, by the RVF outbreak of 2006/2007. A cross-sectional study was conducted involving 698 households selected randomly from three different ethnic communities. Data were collected using a structured questionnaire regarding knowledge, attitudes and practices that could affect the spread of RVF. In addition, information was collected from the communities regarding the number of humans and livestock affected during the RVF outbreak. This study found that better knowledge about a specific disease does not always translate to better practices to avoid exposure to the disease. However, the high knowledge, attitude and practice score measured as a single index of the Maasai community may explain why they were less affected, compared to other investigated communities (Borana and Turkana), by RVF during the 2006/2007 outbreak. We conclude that RVF exposure in Isiolo County, Kenya during the outbreak was likely determined by the behavioral differences of different resident community groups. We then recommend that strategies to combat RVF should take into consideration behavioral differences among communities.

  • 2.
    Ahlm, Clas
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Eliasson, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Vapalahti, O.
    University of Helsinki and Helsinki University Central Hospital Laboratory, Finland.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Seroprevalence of Sindbis virus and associated risk factors in northern Sweden2014In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 142, no 7, p. 1559-1565Article in journal (Refereed)
    Abstract [en]

    Mosquito-borne Sindbis virus (SINV) cause disease characterized by rash, fever and arthritis which often leads to long-lasting arthralgia. To determine the seroprevalence of SINV and associated risk factors in northern Sweden, a randomly selected population aged between 25 and 74 years were invited to join the MONICA study. Serum from 1611 samples were analysed for specific IgG antibodies. Overall, 2·9% had IgG against SINV. More men (3·7%) than women (2·0%) were SINV seropositive (P = 0·047) and it was more common in subjects with a lower educational level (P = 0·013) and living in small, rural communities (P < 0·001). Seropositivity was associated with higher waist circumference (P = 0·1), elevated diastolic blood pressure (P = 0·037), and history of a previous stroke (P = 0·011). In a multiple logistic regression analysis, adjusting for known risk factors for stroke, seropositivity for SINV was an independent predictor of having had a stroke (odds ratio 4·3, 95% confidence interval 1·4–13·0,P = 0·011).

  • 3.
    Baudin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Hossain, Delowar
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Importance of charge interactions in Rift Valley fever virus attachment to host cellsManuscript (preprint) (Other academic)
    Abstract [en]

    The mosquito-borne Rift Valley fever virus (RVFV) cause disease in both humans and animals and can infect a large range of animals as well as humans. Many different cell types are infected both in vivo and in vitro. To enter a cell the virus needs to attach and enter, and this initial binding to the host cell surface could depend on both general mechanisms, and different specific receptors. Our aim was to characterize determinants for RVFV entry into its host cells.To examine RVFV attachment to host cells we based our experimental assay on RVF virus-like particles containing a reporter gene. The enveloped RVFV uses protruding glycoproteins (Gn and Gc) for attachment and entry and to investigate potential virus-cell surface interactions, the net surface charge of the glycoproteins was first calculated. The RVFV glycoprotein Gn had a predicted isoelectric point (pI) of 7.6 and a net positive charge of +6.9 at pH 7.0, suggesting a charge interaction between the Gn ectodomain and the negatively charged cell surface. RVFV Gc on the other hand, was highly negatively charged, -12.8 at neutral pH, most probably reflecting that Gc is not exposed until after receptor binding. To characterize the general conditions needed for RVFV attachment, cells or virus were treated with various compounds. Both sodium chloride and the negatively charged heparin inhibited RVF virus-like particle infection, strongly indicating that viral binding was charge-dependent. Treatment with sodium periodate pointed to a carbohydrate structure as a cellular interaction partner. Removal of sialic acid or heparan sulfate receptors on the cell surface by enzymatic treatment and blocking of the heparan sulfate receptor did not inhibit virus attachment.In conclusion, RVFV binding to host cells was charge dependent and the results point to a carbohydrate structure with negative charge as a potential attachment factor.

  • 4.
    Baudin, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Jumaa, Ammar M.
    Jomma, Huda J. E.
    Karsany, Mubarak S.
    Bucht, Göran
    Näslund, Jonas
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Mohamed, Nahla
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Association of Rift Valley fever virus infection with miscarriage in Sudanese women: a cross-sectional study2016In: The Lancet Global Health, E-ISSN 2214-109X, Vol. 4, no 11, p. e864-e871Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Rift Valley fever virus is an emerging mosquito-borne virus that causes infections in animals and human beings in Africa and the Arabian Peninsula. Outbreaks of Rift Valley fever lead to mass abortions in livestock, but such abortions have not been identified in human bezings. Our aim was to investigate the cause of miscarriages in febrile pregnant women in an area endemic for Rift Valley fever.

    METHODS: Pregnant women with fever of unknown origin who attended the governmental hospital of Port Sudan, Sudan, between June 30, 2011, and Nov 17, 2012, were sampled at admission and included in this cross-sectional study. Medical records were retrieved and haematological tests were done on patient samples. Presence of viral RNA as well as antibodies against a variety of viruses were analysed. Any association of viral infections, symptoms, and laboratory parameters to pregnancy outcome was investigated using Pearson's χ(2) test.

    FINDINGS: Of 130 pregnant women with febrile disease, 28 were infected with Rift Valley fever virus and 31 with chikungunya virus, with typical clinical and laboratory findings for the infection in question. 15 (54%) of 28 women with an acute Rift Valley fever virus infection had miscarriages compared with 12 (12%) of 102 women negative for Rift Valley fever virus (p<0·0001). In a multiple logistic regression analysis, adjusting for age, haemorrhagic disease, and chikungunya virus infection, an acute Rift Valley fever virus infection was an independent predictor of having a miscarriage (odds ratio 7·4, 95% CI 2·7-20·1; p<0·0001).

    INTERPRETATION: This study is the first to show an association between infection with Rift Valley fever virus and miscarriage in pregnant women. Further studies are warranted to investigate the possible mechanisms. Our findings have implications for implementation of preventive measures, and evidence-based information to the public in endemic countries should be strongly recommended during Rift Valley fever outbreaks.

    FUNDING: Schlumberger Faculty for the Future, CRDF Global (31141), the Swedish International Development Cooperation Agency, the County Council of Västerbotten, and the Faculty of Medicine, Umeå University.

  • 5.
    Bergqvist, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Forsman, Oscar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Larsson, Pär
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Näslund, Jonas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Lilja, Tobias
    Engdahl, Cecilia
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lindström, Anders
    Gylfe, Åsa
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Arctic Research Centre at Umeå University.
    Bucht, Göran
    [ 1 ] CBRN Def & Secur, Swedish Def Res Agcy, SE-90182 Umea, Sweden.
    Detection and Isolation of Sindbis Virus from Mosquitoes Captured During an Outbreak in Sweden, 20132015In: Vector Borne and Zoonotic Diseases, ISSN 1530-3667, E-ISSN 1557-7759, Vol. 15, no 2, p. 133-140Article in journal (Refereed)
    Abstract [en]

    Mosquito-borne alphaviruses have the potential to cause large outbreaks throughout the world. Here we investigated the causative agent of an unexpected Sindbis virus (SINV) outbreak during August-September, 2013, in a previously nonendemic region of Sweden. Mosquitoes were collected using carbon dioxide-baited CDC traps at locations close to human cases. The mosquitoes were initially screened as large pools by SINV-specific quantitative RT-PCR, and the SINV-positive mosquitoes were species determined by single-nucleotide polymorphism (SNP) analysis, followed by sequencing the barcoding region of the cytochrome oxidase I gene. The proportion of the collected mosquitoes was determined by a metabarcoding strategy. By using novel strategies for PCR screening and genetic typing, a new SINV strain, Lovanger, was isolated from a pool of 1600 mosquitoes composed of Culex, Culiseta, and Aedes mosquitoes as determined by metabarcoding. The SINV-positive mosquito Culiseta morsitans was identified by SNP analysis and sequencing. After whole-genome sequencing and phylogenetic analysis, the SINV Lovanger isolate was shown to be most closely similar to recent Finnish SINV isolates. In conclusion, within a few weeks, we were able to detect and isolate a novel SINV strain and identify the mosquito vector during a sudden SINV outbreak.

  • 6.
    Bergstedt Oscarsson, Kristina
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Brorstad, Alette
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Baudin, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forssén, Annika
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Eriksson, Marie
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Human Puumala hantavirus infection in northern Sweden: increased seroprevalence and association to risk and health factors2016In: BMC Infectious Diseases, ISSN 1471-2334, E-ISSN 1471-2334, Vol. 16, article id 566Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The rodent borne Puumala hantavirus (PUUV) causes haemorrhagic fever with renal syndrome in central and northern Europe. The number of cases has increased and northern Sweden has experienced large outbreaks in 1998 and 2006-2007 which raised questions regarding the level of immunity in the human population.

    METHODS: A randomly selected population aged between 25 and 74 years from northern Sweden were invited during 2009 to participate in a WHO project for monitoring of trends and determinants in cardiovascular disease. Health and risk factors were evaluated and sera from 1,600 participants were available for analysis for specific PUUV IgG antibodies using a recombinant PUUV nucleocapsid protein ELISA.

    RESULTS: The overall seroprevalence in the investigated population was 13.4 %, which is a 50 % increase compared to a similar study only two decades previously. The prevalence of PUUV IgG increased with age, and among 65-75 years it was 22 %. More men (15.3 %) than women (11.4 %) were seropositive (p < 0.05). The identified risk factors were smoking (OR = 1.67), living in rural areas (OR = 1.92), and owning farmland or forest (OR = 2.44). No associations were found between previous PUUV exposure and chronic lung disease, diabetes, hypertension, renal dysfunction, stroke or myocardial infarction.

    CONCLUSIONS: PUUV is a common infection in northern Sweden and there is a high life time risk to acquire PUUV infection in endemic areas. Certain risk factors as living in rural areas and smoking were identified. Groups with increased risk should be targeted for future vaccination when available, and should also be informed about appropriate protection from rodent secreta.

  • 7.
    Bergstedt-Oskarsson, Kristina
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Brorstad, Alette
    Baudin, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lindberg, Anne
    Forssén, Annika
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Seroepidemiology, comorbidity and riskfactors for Puumula hantavirus in a highly endemic area of Sweden2011Conference paper (Other academic)
  • 8. Björkström, Niklas K
    et al.
    Lindgren, Therese
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Stoltz, Malin
    Fauriat, Cyril
    Braun, Monika
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Michaëlsson, Jakob
    Malmberg, Karl-Johan
    Klingström, Jonas
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ljunggren, Hans-Gustaf
    Rapid expansion and long-term persistence of elevated NK cell numbers in humans infected with hantavirus2011In: Journal of Experimental Medicine, ISSN 0022-1007, E-ISSN 1540-9538, Vol. 208, no 1, p. 13-21Article in journal (Refereed)
    Abstract [en]

    Natural killer (NK) cells are known to mount a rapid response to several virus infections. In experimental models of acute viral infection, this response has been characterized by prompt NK cell activation and expansion followed by rapid contraction. In contrast to experimental model systems, much less is known about NK cell responses to acute viral infections in humans. We demonstrate that NK cells can rapidly expand and persist at highly elevated levels for >60 d after human hantavirus infection. A large part of the expanding NK cells expressed the activating receptor NKG2C and were functional in terms of expressing a licensing inhibitory killer cell immunoglobulin-like receptor (KIR) and ability to respond to target cell stimulation. These results demonstrate that NK cells can expand and remain elevated in numbers for a prolonged period of time in humans after a virus infection. In time, this response extends far beyond what is considered normal for an innate immune response.

  • 9.
    Bystrom, Julia Wigren
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Näslund, Jonas
    Umeå University, Faculty of Science and Technology, European CBRNE Center.
    Trulsson, Fredrik
    Umeå University, Faculty of Science and Technology, European CBRNE Center. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Wesula Lwande, Olivia
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Bucht, Göran
    Umeå University, Faculty of Science and Technology, European CBRNE Center.
    Quantification and kinetics of viral RNA transcripts produced in Orthohantavirus infected cells2018In: Virology Journal, ISSN 1743-422X, E-ISSN 1743-422X, Vol. 15, p. 1-7, article id 18Article in journal (Refereed)
    Abstract [en]

    Background: Rodent borne viruses of the Orthohantavirus genus cause hemorrhagic fever with renal syndrome among people in Eurasia, and hantavirus cardiopulmonary syndrome in the Americas. At present, there are no specific treatments or efficient vaccines against these diseases. Improved understanding of viral transcription and replication may instigate targeted treatment of Orthohantavirus infections. For this purpose, we investigated the kinetics and levels of viral RNA transcription during an ongoing infection in-vitro. Methods: Vero E6 cells were infected with Puumala Orthohantavirus (strain Kazan) before cells and supernatants were collected at different time points post infection for the detection of viral RNAs. A plasmid containing primer binding sites of the three Orthohantavirus segments small (S), medium (M) and large (L) was constructed and standard curves were generated to calculate the copy numbers of the individual transcripts in the collected samples. Results: Our results indicated a rapid increase in the copy number of viral RNAs after 9 h post infection. At peak days, 2-6 days after infection, the S- and M-segment transcripts became thousand and hundred-fold more abundant than the copy number of the L-segment RNA, respectively. The presence of viral RNA in the cell culture media was detected at later time-points. Conclusions: We have developed a method to follow RNA transcription in-vitro after synchronous infection of Vero cells. The obtained results may contribute to the understanding of the viral replication, and may have implications in the development of antiviral drugs targeting transcription or replication of negative stranded RNA viruses.

  • 10.
    Drobni, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Mistry, Nitesh
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    McMillan, Nigel
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Carboxy-fluorescein diacetate, succinimidyl ester labeled papillomavirus virus-like particles fluoresce after internalization and interact with heparan sulfate for binding and entry2003In: Virology, ISSN 0042-6822, E-ISSN 1096-0341, Vol. 310, no 1, p. 163-172Article in journal (Refereed)
    Abstract [en]

    Human papillomaviruses (HPVs) infect epithelial cells and are associated with genital carcinoma. Most epithelial cell lines express cell-surface glycosaminoglycans (GAGs) usually found attached to the protein core of proteoglycans. Our aim was to study how GAGs influenced HPV entry. Using a human keratinocyte cell line (HaCaT), preincubation of HPV virus-like particles (VLPs) with GAGs showed a dose-dependent inhibition of binding. The IC(50) (50% inhibition) was only 0.5 microg/ml for heparin, 1 microg/ml for dextran sulfate, and 5-10 microg/ml for heparan sulfate from mucosal origin. Mutated chinese hamster ovary (CHO) cell lines lacking heparan sulfate or all GAGs were unable to bind HPV VLPs. Here we also report a method to study internalization by using VLPs labeled with carboxy-fluorescein diacetate, succinimidyl ester, a fluorochrome that is only activated after cell entry. Pretreatment of labeled HPV VLPs with heparin inhibited uptake, suggesting a primary interaction between HPV and cell-surface heparan sulfate.

  • 11.
    Drobni, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Näslund, Jonas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lactoferrin inhibits human papillomavirus binding and uptake in vitro.2004In: Antiviral Research, ISSN 0166-3542, E-ISSN 1872-9096, Vol. 64, no 1, p. 63-68Article in journal (Refereed)
    Abstract [en]

    Lactoferrin (LF), a member of the transferrin family, is a bi-globular protein secreted in milk, saliva, tears, seminal fluid, endocervix and vaginal secretions. LF is an important player in the defence against pathogenic microorganisms and has also been shown to have activity against several viruses including herpesvirus, adenovirus, rotavirus and poliovirus. The antiviral activity of LF is directed against the early steps of viral infection and the LF antiviral effect against herpesvirus is mediated through LF binding to the herpesvirus receptor heparan sulfate. Human papillomavirus (HPV) causes genital warts and is a prerequisite for cervical cancer. HPV can also use heparan sulfate on the cell surface as a receptor. We studied the inhibition by LF on HPV entry by incubating HaCaT cells and HPV-16 virus-like particles (VLPs) with either human (HLF) or bovine lactoferrin (BLF). LF inhibited internalization of HPV-16 particles using CFDA-SE-labelled VLPs that only fluoresce after internalisation. By using a western blot assay we also found dose-dependent LF inhibition of HPV-16 VLP binding to the HaCaT cell surface. BLF was a more potent inhibitor of HPV entry than human LF. It was also clear that LF acted early in the HPV uptake process.

  • 12.
    Drobni, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Näslund, Jonas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Jenssen, Håvard
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    The anti-HPV activity of human and bovine lactoferricin.Manuscript (Other academic)
  • 13.
    Engdahl, Cecilia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Larsson, Pär
    Swedish Defense Research Agency, CBRN Defense and Security, Umeå, Sweden.
    Näslund, Jonas
    Swedish Defense Research Agency, CBRN Defense and Security, Umeå, Sweden.
    Bravo, Mayra
    Swedish Defense Research Agency, CBRN Defense and Security, Umeå, Sweden.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lundström, Jan O.
    Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Bucht, Göran
    Swedish Defense Research Agency, CBRN Defense and Security, Umeå, Sweden.
    Identification of Swedish mosquitoes based on molecular barcoding of the COI gene and SNP analysis2014In: Molecular Ecology Resources, ISSN 1755-098X, E-ISSN 1755-0998, Vol. 14, no 3, p. 478-488Article in journal (Refereed)
    Abstract [en]

    Mosquito-borne infectious diseases are emerging in many regions of the world. Consequently, surveillance of mosquitoes and concomitant infectious agents is of great importance for prediction and prevention of mosquito-borne infectious diseases. Currently, morphological identification of mosquitoes is the traditional procedure. However, sequencing of specified genes or standard genomic regions, DNA barcoding, has recently been suggested as a global standard for identification and classification of many different species. Our aim was to develop a genetic method to identify mosquitoes and to study their relationship. Mosquitoes were captured at collection sites in northern Sweden and identified morphologically before the cytochrome c oxidase subunit I (COI) gene sequences of 14 of the most common mosquito species were determined. The sequences obtained were then used for phylogenetic placement, for validation and benchmarking of phenetic classifications and finally to develop a hierarchical PCR-based typing scheme based on single nucleotide polymorphism sites (SNPs) to enable rapid genetic identification, circumventing the need for morphological characterization. The results showed that exact phylogenetic relationships between mosquito taxa were preserved at shorter evolutionary distances, but at deeper levels, they could not be inferred with confidence using COI gene sequence data alone. Fourteen of the most common mosquito species in Sweden were identified by the SNP/PCR-based typing scheme, demonstrating that genetic typing using SNPs of the COI gene is a useful method for identification of mosquitoes with potential for worldwide application.

  • 14.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Detection of human papillomavirus: a study of normal cells, cervical intraepithelial neoplasia and cancer of the uterine cervix1991Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human papillomavirus (HPV) infections of the genital tract are now recognized to be among the most prevalent sexually transmitted diseases and also a contributing factor to some cancers of the lower genital tract of women and men. Presence of HPV in a clinical specimen is confined to detection of the HPV genome by DNA hybridization techniques.

    In this thesis, the commonly used DNA hybridization techniques Southern blot and filter in situ hybridization (FISH), were first used for detection of genital HPV infection. In order to increase and simplify the detection of HPV in clinical specimens a more sensitive technique, the polymerase chain reaction (PCR) was subsequently utilized.

    For type-specific amplificaiton of HPV 6, 16, 18 and 33 by PCR, oligonucleotide primers located in the E6 and E7 regions of the HPV genome were selected. They were found to specifically amplify the four types. To be able to amplify a broad spectrum of genital HPV types, general primers located in the E7 and El region of the HPV genome, were designed and evaluated. They were found to amplify a wide range of genital HPV types. To further increase the sensitivity and specificity, a two-step PCR using general primers, was assembled and evaluated against a one-step PCR on cervical scrapes from young women in a population-based study. The two-step PCR increased the sensitivity about three-fold compared to the one-step PCR.

    By Southern blot and FISH, 46% of women with abnormal Papanicolaou (Pap) smears were shown to carry HPV DNA. Of the women analysed by Southern blot, 39 % harboured HPV DNA and 25 % proved HPV 16 positive. Of the samples analysed with FISH, 27 % contained HPV DNA, compared to 11 % of samples from a group of reference women with normal cytology. With the Southern blot technique, HPV DNA was detected in 66% of women with cervical intraepithelial neoplasia grade III (CIN III) lesions. Fifty-four percent of the women with CIN III lesions were positive for HPV 16 DNA.

    By type-specific PCR, 12 out of 13 women with cervical squamous carcinoma were shown to carry HPV 16 and/or 18. Among women with adenosquamous carcinoma of the cervix, HPV 18 was the most prevalent type (26%) but HPV 16 was also found in a proportion of the women(15 %). Nine of 13 premenopausal cases with cervical adenocarcinoma were HPV positive compared to only 2 of 13 postmenopausal cases (p< 0.015). HPV 16 DNA was detected in 48%of women with cervical intraepithelial neoplasia (CIN), by the use of type-specific PCR.

    Three different groups of women with normal cytology were studied. Among women attending a family planning clinic in Kenya, 19% were shown to carry HPV virus, by the use of general primers. HPV 16 was found in 5.2% of these women and HPV 18 in 3.9%. In anothergroup of women, attending the gynecological department in Umeå, HPV 16 DNA was detected in 21 % by type-specific PCR. However, if consideration was taken to the medical status of the women, only 10% of women without any medical history were HPV 16 DNA positive, versus 54% of women with diseases and women with a relative progesterone dominance. Finally, by use of a two-step PCR using general primers, 20% of young women from Umeå taking part in a population-based study were demonstrated to carry HPV DNA. The most prevalent types were HPV 6 (2.0%) and HPV 16(2.7%). Among the women in this study with normal cytology, 19%were HPV positive.

  • 15.
    Evander, Magnus
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Milder winters in northern Scandinavia may contribute to larger outbreaks of haemorrhagic fever virus2009In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 2Article in journal (Refereed)
    Abstract [en]

    The spread of zoonotic infectious diseases may increase due to climate factors such as temperature, humidity and precipitation. This is also true for hantaviruses, which are globally spread haemorrhagic fever viruses carried by rodents. Hantaviruses are frequently transmitted to humans all over the world and regarded as emerging viral diseases. Climate variations affect the rodent reservoir populations and rodent population peaks coincide with increased number of human cases of hantavirus infections. In northern Sweden, a form of haemorrhagic fever called nephropathia epidemica (NE), caused by the Puumala hantavirus (PUUV) is endemic and during 2006-2007 an unexpected, sudden and large outbreak of NE occurred in this region. The incidence was 313 cases/100,000 inhabitants in the most endemic areas, and from January through March 2007 the outbreak had a dramatic and sudden start with 474 cases in the endemic region alone. The PUUV rodent reservoir is bank voles and immediately before and during the peak of disease outbreak the affected regions experienced extreme climate conditions with a record-breaking warm winter, registering temperatures 6-9 degrees C above normal. No protective snow cover was present before the outbreak and more bank voles than normal came in contact with humans inside or in close to human dwellings. These extreme climate conditions most probably affected the rodent reservoir and are important factors for the severity of the outbreak.

  • 16.
    Evander, Magnus
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Eriksson, Irene
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Pettersson, Lisa
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Juto, Per
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Olsson, Gert E
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Bucht, Göran
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Allard, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Puumala hantavirus viremia diagnosed by real-time reverse transcriptase PCR using samples from patients with hemorrhagic fever and renal syndrome.2007In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 45, no 8, p. 2491-7Article in journal (Refereed)
    Abstract [en]

    Puumala virus (PUUV) is the endemic hantavirus in northern Sweden and causes nephropathia epidemica (NE), a milder form of hemorrhagic fever with renal syndrome. There is a need for fast and reliable diagnostics to differentiate the disease from other infections. By aligning virus RNA sequences isolated from 11 different bank voles and one human patient, we designed a real-time reverse transcriptase (RT) PCR method for detection of PUUV RNA. The real-time RT-PCR assay showed linearity from 20 to 2 x 10(6) virus copies with a correlation coefficient above 0.98 to 0.99 for all experiments. The detection threshold for PUUV cDNA was two copies per reaction. A two-step qualitative RT-PCR to detect PUUV RNA showed 100% concordance with the real-time RT-PCR assay. PUUV RNA viremia was detected in 33 of 34 PUUV immunoglobulin M (IgM)-positive patients with typical clinical NE disease from the region of endemicity. One PUUV IgM-negative sample had PUUV RNA, and 4 days later, the patient was IgM positive. Of samples with indeterminate IgM, 43% were PUUV RNA positive. The kinetics of antibody titers and PUUV viremia were studied, and five of six NE patients displayed a decrease in PUUV viremia a few days after disease outbreak coupled with an increase in PUUV IgM and IgG. In one patient with continuously high PUUV RNA levels but low IgM and no IgG response, the infection was lethal. These findings demonstrated that real-time RT-PCR is a useful method for diagnosis of PUUV viremia and for detecting PUUV RNA at early time points, before the appearance of IgM antibodies.

  • 17.
    Evander, Magnus
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Putkuri, Niina
    Eliasson, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lwande, Olivia Wesula
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Vapalahti, Olli
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Seroprevalence and Risk Factors of Inkoo Virus in Northern Sweden2016In: American Journal of Tropical Medicine and Hygiene, ISSN 0002-9637, E-ISSN 1476-1645, Vol. 94, no 5, p. 1103-1106Article in journal (Refereed)
    Abstract [en]

    The mosquito-borne Inkoo virus (INKV) is a member of the California serogroup in the family Bunyaviridae, genus Orthobunyavirus These viruses are associated with fever and encephalitis, although INKV infections are not usually reported and the incidence is largely unknown. The aim of the study was to determine the prevalence of anti-INKV antibodies and associated risk factors in humans living in northern Sweden. Seroprevalence was investigated using the World Health Organization Monitoring of Trends and Determinants in Cardiovascular Disease study, where a randomly selected population aged between 25 and 74 years (N = 1,607) was invited to participate. The presence of anti-INKV IgG antibodies was determined by immunofluorescence assay. Seropositivity for anti-INKV was significantly higher in men (46.9%) than in women (34.8%; P < 0.001). In women, but not in men, the prevalence increased somewhat with age (P = 0.06). The peak in seropositivity was 45-54 years for men and 55-64 years for women. Living in rural areas was associated with a higher seroprevalence. In conclusion, the prevalence of anti-INKV antibodies was high in northern Sweden and was associated with male sex, older age, and rural living. The age distribution indicates exposure to INKV at a relatively early age. These findings will be important for future epidemiological and clinical investigations of this relatively unknown mosquito-borne virus.

  • 18. Hardestam, Jonas
    et al.
    Petterson, Lisa
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lundkvist, Ake
    Klingström, Jonas
    Antiviral effect of human saliva against hantavirus.2008In: Journal of medical virology, ISSN 1096-9071, Vol. 80, no 12, p. 2122-6Article in journal (Refereed)
    Abstract [en]

    Hemorrhagic fever with renal syndrome (HFRS) and Hantavirus pulmonary syndrome are zoonotic diseases caused by rodent borne hantaviruses. Transmission to humans occurs usually by inhalation of aerozolized virus-contaminated rodent excreta. Although human-to-human transmission of Andes hantavirus has been observed, the mode of transmission is currently not known. Saliva from Puumala hantavirus (PUUV)-infected patients was shown recently to contain viral RNA. To test if human saliva interferes with hantavirus replication, the effect of saliva and salivary proteins on hantavirus replication was studied. It was observed that saliva from healthy individuals reduced Hantaan hantavirus (HTNV) infectivity, although not completely. Furthermore, HTNV was resistant against the antiviral capacity of histatin 5, lysozyme, lactoferrin, and SLPI, but was inhibited by mucin. Inoculation of bank voles (Myodes glareolus) with HFRS-patient saliva, positive for PUUV-RNA, did not induce sero-conversion. In conclusion, no evidence of infectious virus in patient saliva was found. However, the in vitro experiments showed that HTNV, the prototype hantavirus, is insensitive to several antiviral salivary proteins, and is partly resistant to the antiviral effect of saliva. It therefore remains to be shown if human saliva might contain infectious virions early during infection, that is, before seroconversion.

  • 19.
    Hassan, Osama Ahmed
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Public Health Institute, Khartoum, Sudan.
    Affognon, Hippolyte
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Mburu, Peter
    Sang, Rosemary
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    The One Health approach to identify knowledge, attitudes and practices that affect community involvement in the control of Rift Valley fever outbreaks2017In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 11, no 2, article id e0005383Article in journal (Refereed)
    Abstract [en]

    Rift Valley fever (RVF) is a viral mosquito-borne disease with the potential for global expansion, causes hemorrhagic fever, and has a high case fatality rate in young animals and in humans. Using a cross-sectional community-based study design, we investigated the knowledge, attitudes and practices of people living in small village in Sudan with respect to RVF outbreaks. A special One Health questionnaire was developed to compile data from 235 heads of household concerning their knowledge, attitudes, and practices with regard to controlling RVF. Although the 2007 RVF outbreak in Sudan had negatively affected the participants' food availability and livestock income, the participants did not fully understand how to identify RVF symptoms and risk factors for both humans and livestock. For example, the participants mistakenly believed that avoiding livestock that had suffered spontaneous abortions was the least important risk factor for RVF. Although the majority noticed an increase in mosquito population during the 2007 RVF outbreak, few used impregnated bed nets as preventive measures. The community was reluctant to notify the authorities about RVF suspicion in livestock, a sentinel for human RVF infection. Almost all the respondents stressed that they would not receive any compensation for their dead livestock if they notified the authorities. In addition, the participants believed that controlling RVF outbreaks was mainly the responsibility of human health authorities rather than veterinary authorities. The majority of the participants were aware that RVF could spread from one region to another within the country. Participants received most their information about RVF from social networks and the mass media, rather than the health system or veterinarians. Because the perceived role of the community in controlling RVF was fragmented, the probability of RVF spread increased.

  • 20.
    Hassan, Osama Ahmed
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Department of Epidemiology and Diseases Control, Public Health Institute, Federal Ministry of Health, Khartoum, Sudan.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    A need for One Health approach: lessons learned from outbreaks of Rift Valley fever in Saudi Arabia and Sudan2014In: Infection Ecology & Epidemiology, ISSN 2000-8686, E-ISSN 2000-8686, Vol. 4, article id 20710Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Rift Valley fever (RVF) is an emerging viral zoonosis that impacts human and animal health. It is transmitted from animals to humans directly through exposure to blood, body fluids, or tissues of infected animals or via mosquito bites. The disease is endemic to Africa but has recently spread to Saudi Arabia and Yemen. Our aim was to compare two major outbreaks of RVF in Saudi Arabia (2000) and Sudan (2007) from a One Health perspective.

    METHODS: Using the terms 'Saudi Arabia', 'Sudan', and 'RVF', articles were identified by searching PubMed, Google Scholar, and web pages of international organizations as well as local sources in Saudi Arabia and Sudan.

    RESULTS: The outbreak in Saudi Arabia caused 883 human cases, with a case fatality rate of 14% and more than 40,000 dead sheep and goats. In Sudan, 698 human cases of RVF were recognized (case fatality, 31.5%), but no records of affected animals were available. The ecology and environment of the affected areas were similar with irrigation canals and excessive rains providing an attractive habitat for mosquito vectors to multiply. The outbreaks resulted in livestock trade bans leading to a vast economic impact on the animal market in the two countries. The surveillance system in Sudan showed a lack of data management and communication between the regional and federal health authorities, while in Saudi Arabia which is the stronger economy, better capacity and contingency plans resulted in efficient countermeasures. Studies of the epidemiology and vectors were also performed in Saudi Arabia, while in Sudan these issues were only partly studied.

    CONCLUSION: We conclude that a One Health approach is the best option to mitigate outbreaks of RVF. Collaboration between veterinary, health, and environmental authorities both on national and regional levels is needed.

  • 21.
    Hassan, Osama Ahmed
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Federal Ministry of Health, Khartoum, Sudan.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Sang, Rosemary
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    The 2007 rift valley Fever outbreak in Sudan2011In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 5, no 9, article id e1229Article, review/survey (Refereed)
    Abstract [en]

    Rift Valley fever (RVF) is a neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health and economy. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of animals. The virus is transmitted through bites from mosquitoes and exposure to viremic blood, body fluids, or tissues of infected animals. During 2007 a large RVF outbreak occurred in Sudan with a total of 747 confirmed human cases including 230 deaths (case fatality 30.8%); although it has been estimated 75,000 were infected. It was most severe in White Nile, El Gezira, and Sennar states near to the White Nile and the Blue Nile Rivers. Notably, RVF was not demonstrated in livestock until after the human cases appeared and unfortunately, there are no records or reports of the number of affected animals or deaths. Ideally, animals should serve as sentinels to prevent loss of human life, but the situation here was reversed. Animal contact seemed to be the most dominant risk factor followed by animal products and mosquito bites. The Sudan outbreak followed an unusually heavy rainfall in the country with severe flooding and previous studies on RVF in Sudan suggest that RVFV is endemic in parts of Sudan. An RVF outbreak results in human disease, but also large economic loss with an impact beyond the immediate influence on the directly affected agricultural producers. The outbreak emphasizes the need for collaboration between veterinary and health authorities, entomologists, environmental specialists, and biologists, as the best strategy towards the prevention and control of RVF.

  • 22. Hoffman, Tove
    et al.
    Lindeborg, Mats
    Barboutis, Christos
    Erciyas-Yavuz, Kiraz
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Fransson, Thord
    Figuerola, Jordi
    Jaenson, Thomas G. T.
    Kiat, Yosef
    Lindgren, Per-Eric
    Lundkvist, Åke
    Mohamed, Nahla
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Moutailler, Sara
    Nyström, Fredrik
    Olsen, Björn
    Salaneck, Erik
    Alkhurma Hemorrhagic Fever Virus RNA in Hyalomma rufipes Ticks Infesting Migratory Birds, Europe and Asia Minor2018In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 24, no 5, p. 879-882Article in journal (Refereed)
    Abstract [en]

    Alkhurma hemorrhagic fever virus RNA was detected in immature Hyalomma rufipes ticks infesting northward migratory birds caught in the North Mediterranean Basin. This finding suggests a role for birds in the ecology of the Alkhurma hemorrhagic fever virus and a potential mechanism for dissemination to novel regions. Increased surveillance is warranted.

  • 23. Ianevski, Aleksandr
    et al.
    Zusinaite, Eva
    Kuivanen, Suvi
    Strand, Mårten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lysvand, Hilde
    Teppor, Mona
    Kakkola, Laura
    Paavilainen, Henrik
    Laajala, Mira
    Kallio-Kokko, Hannimari
    Valkonen, Miia
    Kantele, Anu
    Telling, Kaidi
    Lutsar, Irja
    Letjuka, Pille
    Metelitsa, Natalja
    Oksenych, Valentyn
    Bjoras, Magnar
    Nordbo, Svein Arne
    Dumpis, Uga
    Vitkauskiene, Astra
    Ohrmalm, Christina
    Bondeson, Kare
    Bergqvist, Anders
    Aittokallio, Tero
    Cox, Rebecca J.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Hukkanen, Veijo
    Marjomaki, Varpu
    Julkunen, Ilkka
    Vapalahti, Olli
    Tenson, Tanel
    Merits, Andres
    Kainov, Denis
    Novel activities of safe-in-human broad-spectrum antiviral agents2018In: Antiviral Research, ISSN 0166-3542, E-ISSN 1872-9096, Vol. 154, p. 174-182Article in journal (Refereed)
    Abstract [en]

    According to the WHO, there is an urgent need for better control of viral diseases. Re-positioning existing safe-inhuman antiviral agents from one viral disease to another could play a pivotal role in this process. Here, we reviewed all approved, investigational and experimental antiviral agents, which are safe in man, and identified 59 compounds that target at least three viral diseases. We tested 55 of these compounds against eight different RNA and DNA viruses. We found novel activities for dalbavancin against echovirus 1, ezetimibe against human immunodeficiency virus 1 and Zika virus, as well as azacitidine, cyclosporine, minocycline, oritavancin and ritonavir against Rift valley fever virus. Thus, the spectrum of antiviral activities of existing antiviral agents could be expanded towards other viral diseases.

  • 24.
    Islam, Md. Koushikul
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Baudin, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Eriksson, Jonas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Öberg, Christopher
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Habjan, Matthias
    Weber, Friedemann
    Överby, Anna K.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    High-Throughput Screening Using a Whole-Cell Virus Replication Reporter Gene Assay to Identify Inhibitory Compounds against Rift Valley Fever Virus Infection2016In: Journal of Biomolecular Screening, ISSN 1087-0571, E-ISSN 1552-454X, Vol. 21, no 4, p. 354-362Article in journal (Refereed)
    Abstract [en]

    Rift Valley fever virus (RVFV) is an emerging virus that causes serious illness in humans and livestock. There are no approved vaccines or treatments for humans. The purpose of the study was to identify inhibitory compounds of RVFV infection without any preconceived idea of the mechanism of action. A whole-cell-based high-throughput drug screening assay was developed to screen 28,437 small chemical compounds targeting RVFV infection. To accomplish both speed and robustness, a replication-competent NSs-deleted RVFV expressing a fluorescent reporter gene was developed. Inhibition of fluorescence intensity was quantified by spectrophotometry and related to virus infection in human lung epithelial cells (A549). Cell toxicity was assessed by the Resazurin cell viability assay. After primary screening, 641 compounds were identified that inhibited RVFV infection by 80%, with 50% cell viability at 50 mu M concentration. These compounds were subjected to a second screening regarding dose-response profiles, and 63 compounds with 60% inhibition of RVFV infection at 3.12 mu M compound concentration and 50% cell viability at 25 mu M were considered hits. Of these, six compounds with high inhibitory activity were identified. In conclusion, the high-throughput assay could efficiently and safely identify several promising compounds that inhibited RVFV infection.

  • 25.
    Islam, Md. Koushikul
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Strand, Mårten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Saleeb, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Svensson, Richard
    Baranczewski, Pawel
    Artursson, Per
    Wadell, Göran
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Elofsson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Anti-Rift Valley fever virus activity in vitro, pre-clinical pharmacokinetics and oral bioavailability of benzavir-2, a broad-acting antiviral compound2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 1925Article in journal (Refereed)
    Abstract [en]

    Rift Valley fever virus (RVFV) is a mosquito-borne hemorrhagic fever virus affecting both humans and animals with severe morbidity and mortality and is classified as a potential bioterror agent due to the possible aerosol transmission. At present there is no human vaccine or antiviral therapy available. Thus, there is a great need to develop new antivirals for treatment of RVFV infections. Benzavir-2 was previously identified as potent inhibitor of human adenovirus, herpes simplex virus type 1, and type 2. Here we assess the anti-RVFV activity of benzavir-2 together with four structural analogs and determine pre-clinical pharmacokinetic parameters of benzavir-2. In vitro, benzavir-2 efficiently inhibited RVFV infection, viral RNA production and production of progeny viruses. In vitro, benzavir-2 displayed satisfactory solubility, good permeability and metabolic stability. In mice, benzavir-2 displayed oral bioavailability with adequate maximum serum concentration. Oral administration of benzavir-2 formulated in peanut butter pellets gave high systemic exposure without any observed toxicity in mice. To summarize, our data demonstrated potent anti-RVFV activity of benzavir-2 in vitro together with a promising pre-clinical pharmacokinetic profile. This data support further exploration of the antiviral activity of benzavir-2 in in vivo efficacy models that may lead to further drug development for human use.

  • 26. Khalil, Hussein
    et al.
    Ecke, Frauke
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Hornfeldt, Birger
    Selective predation on hantavirus-infected voles by owls and confounding effects from landscape properties2016In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 181, no 2, p. 597-606Article in journal (Refereed)
    Abstract [en]

    It has been suggested that predators may protect human health through reducing disease-host densities or selectively preying on infected individuals from the population. However, this has not been tested empirically. We hypothesized that Tengmalm's owl (Aegolius funereus) selectively preys on hantavirus-infected individuals of its staple prey, the bank vole (Myodes glareolus). Bank voles are hosts of Puumala hantavirus, which causes a form of hemorrhagic fever in humans. Selective predation by owls on infected voles may reduce human disease risk. We compared the prevalence of anti-Puumala hantavirus antibodies (seroprevalence), in bank voles cached by owls in nest boxes to seroprevalence in voles trapped in closed-canopy forest around each nest box. We found no general difference in seroprevalence. Forest landscape structure could partly account for the observed patterns in seroprevalence. Only in more connected forest patches was seroprevalence in bank voles cached in nest boxes higher than seroprevalence in trapped voles. This effect disappeared with increasing forest patch isolation, as seroprevalence in trapped voles increased with forest patch isolation, but did not in cached voles. Our results suggest a complex relationship between zoonotic disease prevalence in hosts, their predators, and landscape structure. Some mechanisms that may have caused the seroprevalence patterns in our results include higher bank vole density in isolated forest patches. This study offers future research potential to shed further light on the contribution of predators and landscape properties to human health.

  • 27. Khalil, Hussein
    et al.
    Ecke, Frauke
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Magnusson, Magnus
    Hornfeldt, Birger
    Declining ecosystem health and the dilution effect2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 31314Article in journal (Refereed)
    Abstract [en]

    The "dilution effect" implies that where species vary in susceptibility to infection by a pathogen, higher diversity often leads to lower infection prevalence in hosts. For directly transmitted pathogens, non-host species may "dilute" infection directly (1) and indirectly (2). Competitors and predators may (1) alter host behavior to reduce pathogen transmission or (2) reduce host density. In a well-studied system, we tested the dilution of the zoonotic Puumala hantavirus (PUUV) in bank voles (Myodes glareolus) by two competitors and a predator. Our study was based on long-term PUUV infection data (2003-2013) in northern Sweden. The field vole (Microtus agrestis) and the common shrew (Sorex araneus) are bank vole competitors and Tengmalm's owl (Aegolius funereus) is a main predator of bank voles. Infection probability in bank voles decreased when common shrew density increased, suggesting that common shrews reduced PUUV transmission. Field voles suppressed bank vole density in meadows and clear-cuts and indirectly diluted PUUV infection. Further, Tengmalm's owl decline in 1980-2013 may have contributed to higher PUUV infection rates in bank voles in 2003-2013 compared to 1979-1986. Our study provides further evidence for dilution effect and suggests that owls may have an important role in reducing disease risk.

  • 28. Khalil, Hussein
    et al.
    Hörnfeldt, Birger
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Magnusson, Magnus
    Olsson, Gert
    Ecke, Frauke
    Dynamics and Drivers of Hantavirus Prevalence in Rodent Populations2014In: Vector Borne and Zoonotic Diseases, ISSN 1530-3667, E-ISSN 1557-7759, Vol. 14, no 8, p. 537-551Article, review/survey (Refereed)
    Abstract [en]

    Human encroachment on wildlife habitats has contributed to the emergence of several zoonoses. Pathogenic hantaviruses are hosted by rodents and cause severe diseases in the Americas and Eurasia. We reviewed several factors that potentially drive prevalence (the proportion of infected rodents) in host populations. These include demography, behavior, host density, small mammal diversity, predation, and habitat and landscape characteristics. This review is the first to include a quantitative summary of the literature investigating hantavirus prevalence in rodents. Demographic structure and density were investigated the most and predation the least. Reported effects of demographic structure and small mammal diversity were consistent, whereby reproductive males were most likely to be infected and prevalence decreased with small mammal diversity. The influences of habitat and landscape properties are often complex and indirect. The relationship between density and prevalence merits more investigation. Most hantavirus hosts are habitat generalists and their control is challenging. Incorporating all potential factors and their interactions is essential to understanding and controlling infection in host populations.

  • 29. Khalil, Hussein
    et al.
    Olsson, Gert
    Ecke, Frauke
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Hjertqvist, Marika
    Magnusson, Magnus
    Löfvenius, Mikaell Ottosson
    Hörnfeldt, Birger
    The importance of bank vole density and rainy winters in predicting nephropathia epidemica incidence in Northern Sweden.2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 11, article id e111663Article in journal (Refereed)
    Abstract [en]

    Pathogenic hantaviruses (family Bunyaviridae, genus Hantavirus) are rodent-borne viruses causing hemorrhagic fever with renal syndrome (HFRS) in Eurasia. In Europe, there are more than 10,000 yearly cases of nephropathia epidemica (NE), a mild form of HFRS caused by Puumala virus (PUUV). The common and widely distributed bank vole (Myodes glareolus) is the host of PUUV. In this study, we aim to explain and predict NE incidence in boreal Sweden using bank vole densities. We tested whether the number of rainy days in winter contributed to variation in NE incidence. We forecast NE incidence in July 2013-June 2014 using projected autumn vole density, and then considering two climatic scenarios: 1) rain-free winter and 2) winter with many rainy days. Autumn vole density was a strong explanatory variable of NE incidence in boreal Sweden in 1990-2012 (R2 = 79%, p<0.001). Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05). We report for the first time that risk of NE is higher in winters with many rainy days. Rain on snow and ground icing may block vole access to subnivean space. Seeking refuge from adverse conditions and shelter from predators, voles may infest buildings, increasing infection risk. In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014. Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.

  • 30. Khalil, Hussein
    et al.
    Olsson, Gert
    Magnusson, Magnus
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Hornfeldt, Birger
    Ecke, Frauke
    Spatial prediction and validation of zoonotic hazard through micro-habitat properties: where does Puumala hantavirus hole - up?2017In: BMC Infectious Diseases, ISSN 1471-2334, E-ISSN 1471-2334, Vol. 17, article id 523Article in journal (Refereed)
    Abstract [en]

    Background: To predict the risk of infectious diseases originating in wildlife, it is important to identify habitats that allow the co-occurrence of pathogens and their hosts. Puumala hantavirus (PUUV) is a directly-transmitted RNA virus that causes hemorrhagic fever in humans, and is carried and transmitted by the bank vole (Myodes glareolus). In northern Sweden, bank voles undergo 3-4 year population cycles, during which their spatial distribution varies greatly.

    Methods: We used boosted regression trees; a technique inspired by machine learning, on a 10 - year time-series (fall 2003-2013) to develop a spatial predictive model assessing seasonal PUUV hazard using micro-habitat variables in a landscape heavily modified by forestry. We validated the models in an independent study area approx. 200 km away by predicting seasonal presence of infected bank voles in a five-year-period (2007-2010 and 2015).

    Results: The distribution of PUUV-infected voles varied seasonally and inter-annually. In spring, micro-habitat variables related to cover and food availability in forests predicted both bank vole and infected bank vole presence. In fall, the presence of PUUV-infected voles was generally restricted to spruce forests where cover was abundant, despite the broad landscape distribution of bank voles in general. We hypothesize that the discrepancy in distribution between infected and uninfected hosts in fall, was related to higher survival of PUUV and/ or PUUV-infected voles in the environment, especially where cover is plentiful.

    Conclusions: Moist and mesic old spruce forests, with abundant cover such as large holes and bilberry shrubs, also providing food, were most likely to harbor infected bank voles. The models developed using long-term and spatially extensive data can be extrapolated to other areas in northern Fennoscandia. To predict the hazard of directly transmitted zoonoses in areas with unknown risk status, models based on micro-habitat variables and developed through machine learning techniques in well-studied systems, could be used.

  • 31. Lindgren, Therese
    et al.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Mohamed, Nahla
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ljunggren, Hans-Gustaf
    Björkström, Niklas K
    Longitudinal analysis of the human T cell response during acute hantavirus infection2011In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 85, no 19, p. 10252-10260Article in journal (Refereed)
    Abstract [en]

    Longitudinal studies of T cell immune responses during viral infections in humans are essential for our understanding of how effector T cell responses develop, clear infection, and provide long-lasting immunity. Here, following an outbreak of a Puumala hantavirus infection in the human population, we longitudinally analyzed the primary CD8 T cell response in infected individuals from the first onset of clinical symptoms until viral clearance. A vigorous CD8 T cell response was observed early following the onset of clinical symptoms, determined by the presence of high numbers of Ki67(+)CD38(+)HLA-DR(+) effector CD8 T cells. This response encompassed up to 50% of total blood CD8 T cells, and it subsequently contracted in parallel with a decrease in viral load. Expression levels of perforin and granzyme B were high throughout the initial T cell response and likewise normalized following viral clearance. When monitoring regulatory components, no induction of regulatory CD4 or CD8 T cells was observed in the patients during the infection. However, CD8 as well as CD4 T cells exhibited a distinct expression profile of inhibitory PD-1 and CTLA-4 molecules. The present results provide insight into the development of the T cell response in humans, from the very onset of clinical symptoms following a viral infection to resolution of the disease.

  • 32. Lundström, Jan O
    et al.
    Schäfer, Martina L
    Hesson, Jenny C
    Blomgren, Eric
    Lindström, Anders
    Wahlqvist, Pernilla
    Halling, Arne
    Hagelin, Anna
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Broman, Tina
    CBNR Defense and Security, Swedish Defense Research Agency, SE-90185 Umeå, Sweden.
    Forsman, Mats
    CBNR Defense and Security, Swedish Defense Research Agency, SE-90185 Umeå, Sweden.
    Persson Vinnersten, Thomas Z
    The geographic distribution of mosquito species in Sweden2013In: Journal of the European Mosquito Control Association, Vol. 31, p. 21-35Article in journal (Refereed)
    Abstract [en]

    Surveillance of the actual distribution of mosquito species in Northern Europe is fundamental for evaluating risk for emerging pathogens, and for research on potential vectors. The Swedish mosquito fauna composition and geographic distribution, originally described by Professor Christine Dahl in the 1970´s, included 43 species. We have compiled the information published from 1978 to 2012, and our own surveillance data from 2001 to 2013, and compared this with the species list and geographic distribution provided in "Taxonomy and geographic distribution of Swedish Culicidae" by Dahl (1977). New species detected during these 36 years were Culiseta (Culicella) ochroptera (Peus, 1935) published 1984, Aedes (Aedes) rossicus Dolbeskin, Goritzkaja & Mitrofanova, 1930 published 1986, Anopheles (Anopheles) beklemishevi published 1986, Aedes (Ochlerotatus) euedes (Howard, Dyar & Knab, 1912) published 2001, Aedes (Ochlerotatus) nigrinus (Eckstein, 1918) first recorded in 2012, and Anopheles (Anopheles) algeriensis Theobald, 1903, first recorded in 2013. We provide maps with the distribution by province for each species, including historic information up until 1977, and new records from 1978 to 2013, showing the similarities and differences between the old and the new records. Important findings in recent years include the wide distribution of the Sindbis virus enzootic vector Culex (Culex) torrentium Martinii, 1925, and the more limited distribution of the potential West Nile virus vector Culex (Culex) pipiens Linnaeus, 1758. The updated list of mosquito species in Sweden now includes 49 species.

  • 33.
    Lwande, Olivia Wesula
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Bucht, Goran
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ahlm, Kristoffer
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Naslund, Jonas
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Mosquito-borne Inkoo virus in northern Sweden - isolation and whole genome sequencing2017In: Virology Journal, ISSN 1743-422X, E-ISSN 1743-422X, Vol. 14, article id 61Article in journal (Refereed)
    Abstract [en]

    Background: Inkoo virus (INKV) is a less known mosquito-borne virus belonging to Bunyaviridae, genus Orthobunyavirus, California serogroup. Studies indicate that INKV infection is mainly asymptomatic, but can cause mild encephalitis in humans. In northern Europe, the sero-prevalence against INKV is high, 41% in Sweden and 51% in Finland. Previously, INKV RNA has been detected in adult Aedes (Ae.) communis, Ae. hexodontus and Ae. punctor mosquitoes and Ae. communis larvae, but there are still gaps of knowledge regarding mosquito vectors and genetic diversity. Therefore, we aimed to determine the occurrence of INKV in its mosquito vector and characterize the isolates.

    Methods: About 125,000 mosquitoes were collected during a mosquito-borne virus surveillance in northern Sweden during the summer period of 2015. Of these, 10,000 mosquitoes were processed for virus isolation and detection using cell culture and RT-PCR. Virus isolates were further characterized by whole genome sequencing. Genetic typing of mosquito species was conducted by cytochrome oxidase subunit I (COI) gene amplification and sequencing (genetic barcoding).

    Results: Several Ae. communis mosquitoes were found positive for INKV RNA and two isolates were obtained. The first complete sequences of the small (S), medium (M), and large (L) segments of INKV in Sweden were obtained. Phylogenetic analysis showed that the INKV genome was most closely related to other INKV isolates from Sweden and Finland. Of the three INKV genome segments, the INKV M segment had the highest frequency of non-synonymous mutations. The overall G/C-content of INKV genes was low for the N/NSs genes (43.8–45.5%), polyprotein (Gn/Gc/NSm) gene (35.6%) and the RNA polymerase gene (33.8%) This may be due to the fact that INKV in most instances utilized A or T in the third codon position.

    Conclusions: INKV is frequently circulating in northern Sweden and Ae. communis is the key vector. The high mutation rate of the INKV M segment may have consequences on virulence

  • 34.
    Lwande, Olivia Wesula
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Section of Virology. Umeå University, Arctic Research Centre at Umeå University.
    Näslund, Jonas
    Lundmark, Eva
    Ahlm, Kristoffer
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ahlm, Clas
    Umeå University, Arctic Research Centre at Umeå University. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Bucht, Göran
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Section of Virology. Umeå University, Arctic Research Centre at Umeå University.
    Experimental Infection and Transmission Competence of Sindbis Virus in Culex torrentium and Culex pipiens Mosquitoes from Northern Sweden2019In: Vector Borne and Zoonotic Diseases, ISSN 1530-3667, E-ISSN 1557-7759, Vol. 19, no 2, p. 128-133Article in journal (Refereed)
    Abstract [en]

    Introduction: Sindbis virus (SINV) is a mosquito-borne Alphavirus known to infect birds and cause intermittent outbreaks among humans in Fenno-Scandia. In Sweden, the endemic area has mainly been in central Sweden. Recently, SINV infections have emerged to northern Sweden, but the vectorial efficiency for SINV of mosquito species in this northern region has not yet been ascertained.

    Objective: Mosquito larvae were sampled from the Umea region in northern Sweden and propagated in a laboratory to adult stage to investigate the infection, dissemination, and transmission efficiency of SINV in mosquitoes.

    Materials and Methods: The mosquito species were identified by DNA barcoding of the cytochrome oxidase I gene. Culex torrentium was the most abundant (82.2%) followed by Culex pipiens (14.4%), Aedes annulipes (1.1%), Anopheles claviger (1.1%), Culiseta bergrothi (1.1%), or other unidentified species (1.1%). Mosquitoes were fed with SINV-infected blood and monitored for 29 days to determine the viral extrinsic incubation period. Infection and dissemination were determined by RT-qPCR screening of dissected body parts of individual mosquitoes. Viral transmission was determined from saliva collected from individual mosquitoes at 7, 14, and 29 days. SINV was detected by cell culture using BHK-21 cells, RT-qPCR, and sequencing.

    Results: Cx. torrentium was the only mosquito species in our study that was able to transmit SINV. The overall transmission efficiency of SINV in Cx. torrentium was 6.8%. The rates of SINV infection, dissemination, and transmission in Cx. torrentium were 11%, 75%, and 83%, respectively.

    Conclusions: Cx. torrentium may be the key vector involved in SINV transmission in northern Sweden.

  • 35.
    Lwande, Olivia Wesula
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Obanda, Vincent
    Bucht, Göran
    Mosomtai, Gladys
    Otieno, Viola
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Global emergence of Alphaviruses that cause arthritis in humans2015In: Infection Ecology & Epidemiology, ISSN 2000-8686, E-ISSN 2000-8686, Vol. 5, article id 29853Article in journal (Refereed)
    Abstract [en]

    Arthropod-borne viruses (arboviruses) may cause severe emerging and re-emerging infectious diseases, which pose a significant threat to human and animal health in the world today. These infectious diseases range from mild febrile illnesses, arthritis, and encephalitis to haemorrhagic fevers. It is postulated that certain environmental factors, vector competence, and host susceptibility have a major impact on the ecology of arboviral diseases. Presently, there is a great interest in the emergence of Alphaviruses because these viruses, including Chikungunya virus, O'nyong'nyong virus, Sindbis virus, Ross River virus, and Mayaro virus, have caused outbreaks in Africa, Asia, Australia, Europe, and America. Some of these viruses are more common in the tropics, whereas others are also found in temperate regions, but the actual factors driving Alphavirus emergence and re-emergence remain unresolved. Furthermore, little is known about the transmission dynamics, pathophysiology, genetic diversity, and evolution of circulating viral strains. In addition, the clinical presentation of Alphaviruses may be similar to other diseases such as dengue, malaria, and typhoid, hence leading to misdiagnosis. However, the typical presence of arthritis may distinguish between Alphaviruses and other differential diagnoses. The absence of validated diagnostic kits for Alphaviruses makes even routine surveillance less feasible. For that purpose, this review describes the occurrence, genetic diversity, clinical characteristics, and the mechanisms involving Alphaviruses causing arthritis in humans. This information may serve as a basis for better awareness and detection of Alphavirus-caused diseases during outbreaks and in establishing appropriate prevention and control measures.

  • 36.
    Lwande, Olivia Wesula
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Consortium for Epidemiology and Ecology (CEER-Africa), Minnesota, USA.
    Paul, George Omondi
    Chiyo, Patrick I.
    Ng'ang'a, Eliud
    Otieno, Viola
    Obanda, Vincent
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Spatio-temporal variation in prevalence of Rift Valley fever: a post-epidemic serum survey in cattle and wildlife in Kenya2015In: Infection Ecology & Epidemiology, ISSN 2000-8686, E-ISSN 2000-8686, Vol. 5, article id 30106Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Rift Valley fever (RVF) is a fatal arthropod-borne zoonotic disease of livestock and humans. Since the identification of RVF in Kenya in the 1930s, repeated epizootics and epidemics coinciding with El Niño events have occurred in several locations in Africa and Saudi Arabia, causing mass deaths of livestock and humans. RVF is of great interest worldwide because of its negative effect on international livestock trade and its potential to spread globally. The latter is due to the increasing incidence of extreme climatic phenomena caused by global warming, as well as to the increase in global trade and international travel. How RVF is maintained and sustained between epidemics and epizootics is not clearly understood, but it has been speculated that wildlife reservoirs and trans-ovarian transmission in the vector may be important. Several studies have examined the role of wildlife and livestock in isolation or in a limited geographical location within the one country over a short time (usually less than a year). In this study, we examined the seroprevalence of anti-RVF antibodies in cattle and several wildlife species from several locations in Kenya over an inter-epidemic period spanning up to 7 years.

    METHODS: A serological survey of immunoglobulin G (IgG) antibodies to RVF using competitive ELISA was undertaken on 297 serum samples from different wildlife species at various locations in Kenya. The samples were collected between 2008 and 2015. Serum was also collected in 2014 from 177 cattle from Ol Pejeta Conservancy; 113 of the cattle were in close contact with wildlife and the other 64 were kept separate from buffalo and large game by an electric fence.

    RESULTS: The seroprevalence of RVF virus (RVFV) antibody was 11.6% in wildlife species during the study period. Cattle that could come in contact with wildlife and large game were all negative for RVFV. The seroprevalence was relatively high in elephants, rhinoceros, and buffalo, but there were no antibodies in zebras, baboons, vervet monkeys, or wildebeest.

    CONCLUSIONS: Diverse species in conservation areas are exposed to RVFV. RVFV exposure in buffalo may indicate distribution of the virus over wide geographical areas beyond known RVFV foci in Kenya. This finding calls for thorough studies on the epizootology of RVFV in specific wildlife species and locations.

  • 37. Magnusson, M.
    et al.
    Ecke, F.
    Khalil, H.
    Olsson, G.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Niklasson, B.
    Hornfeldt, B.
    Spatial and temporal variation of hantavirus bank vole infection in managed forest landscapes2015In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 6, no 9, article id 163Article in journal (Refereed)
    Abstract [en]

    Zoonoses are major contributors to emerging infectious diseases globally. Hemorrhagic fever with renal syndrome (HFRS) is a zoonosis caused by rodent-borne hantaviruses. In Europe, Puumala hantavirus (PUUV) carried and shed by the bank vole (Myodes glareolus), is the most common cause of HFRS. We explore the relationship of PUUV infection in bank voles, as measured by PUUV antibody detection, with habitat and landscape scale properties during two successive vole cycles in boreal Sweden. Our analysis revealed that PUUV infection in the population was not uniform between cycles and across different landscapes. The mean density index of PUUV antibody positive and negative bank voles were highest in old forest, second highest in cut-over forest (approx. 0-30 years old) and lowest on mires. Most importantly, old forest was the core habitat, where PUUV antibody positive bank voles were found through the low density phase and the transition between successive vole cycles. In spring, occurrence of antibody positive voles was negatively related to the proportion of cut-over forest in the surrounding landscape, suggesting that large scale human induced land-use change altered the occurrence of PUUV infection in voles which has not been shown before. Dependence of PUUV infection on habitat and landscape structure, and the variation in infection load within and between cycles are of importance for human risk assessment.

  • 38. Matiko, Mirende Kichuki
    et al.
    Salekwa, Linda Peniel
    Kasanga, Christopher Jacob
    Kimera, Sharadhuli Idd
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Nyangi, Wambura Philemon
    Serological evidence of inter-epizootic/interepidemic circulation of Rift Valley fever virus in domestic cattle in Kyela and Morogoro, Tanzania2018In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 12, no 11, article id e0006931Article in journal (Refereed)
    Abstract [en]

    Background: Tanzania is among the Rift Valley fever (RVF) epizootic/endemic countries in sub Saharan Africa, where RVF disease outbreaks occur within a range of 3 to 17-year intervals. Detection of Rift Valley fever virus (RVFV) antibodies in animals in regions with no previous history of outbreaks raises the question of whether the disease is overlooked due to lack-of effective surveillance systems, or if there are strains of RVFV with low pathogenicity. Furthermore, which vertebrate hosts are involved in the inter-epidemic and inter-epizootic maintenance of RVFV? In our study region, the Kyela and Morogoro districts in Tanzania, no previous RVF outbreaks have been reported.

    Methodology: The study was conducted from June 2014 to October 2015 in the Kyela and Morogoro districts, Tanzania. Samples (n = 356) were retrieved from both the local breed of zebu cattle (Bos indicus) and Bos indicus/Bos Taurus cross breed. RVFV antibodies were analyzed by two enzyme-linked immunosorbent assay (ELISA) approaches. Initially, samples were analyzed by a RVFV multi-species competition ELISA (cELISA), which detected both RVFV IgG and IgM antibodies. All serum samples that were positive with the cELISA method were specifically analysed for the presence of RVFV IgM antibodies to trace recent infection. A plaque reduction neutralization assay (PRNT80) was performed to determine presence of RVFV neutralizing antibodies in all cELISA positive samples.

    Findings: Overall RVFV seroprevalence rate in cattle by cELISA in both districts was 29.2% (104 of 356) with seroprevalence rates of 33% (47/147) in the Kyela district and 27% (57/209) in the Morogoro district. In total, 8.4% (30/356) of all cattle sampled had RVFV IgM antibodies, indicating current disease transmission. When segregated by districts, the IgM antibody seroprevalence was 2.0% (3/147) and 12.9% (27/209) in Kyela and Morogoro districts respectively. When the 104 cELISA positive samples were analyzed by PRNT80 to confirm that RVFV-specific antibodies were present, the majority (89%, 93/104) had RVFV neutralising antibodies.

    Conclusion: The results provided evidence of widespread prevalence of RVFV antibody among cattle during an inter-epizootic/inter-epidemic period in Tanzania in regions with no previous history of outbreaks. There is a need for further investigations of RVFV maintenance and transmission in vertebrates and vectors during the long inter-epizootic/inter-epidemic periods.

  • 39. Milhano, Natacha
    et al.
    Korslund, Lars
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Vainio, Kirsti
    Dudman, Susanne G.
    Andreassen, Ashild
    Circulation and diagnostics of Puumala virus in Norway: nephropatia epidemica incidence and rodent population dynamics2017In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 125, no 8, p. 732-742Article in journal (Refereed)
    Abstract [en]

    Hantaviruses pose a public health concern worldwide causing haemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Puumala virus (PUUV) is the most prevalent hantavirus in Central and Northern Europe, and causes a mild form of HFRS, also known as nephropathia epidemica (NE). In nature, the main host of PUUV is the bank vole (Myodes glareolus), and transmission to humans occurs through inhalation of aerosols from rodent excreta. Nephropathia epidemica is particularly prevalent in Nordic countries, however, few studies of PUUV have been performed in Norway. The aim of this study was to analyse the dynamics of PUUV in Norway and compare with bank vole population dynamics, and also to complement the current diagnostic methodology of NE in Norway. Our results showed a significant seasonal and geographical variation of NE, and a general parallel peak trend between bank vole population densities and human NE incidence. A real-time and a nested PCR were successfully established as an invaluable diagnostic tool, with detection and sequencing of PUUV in a human serum sample for the first time in Norway. Phylogenetic analysis showed clustering of the obtained human sample with previous Norwegian bank vole isolates.

  • 40.
    Mistry, Nitesh
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Drobni, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Näslund, Jonas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Sunkari, Vivekananda Gupta
    Jenssen, Håvard
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    The anti-papillomavirus activity of human and bovine lactoferricin.2007In: Antiviral Research, ISSN 0166-3542, E-ISSN 1872-9096, Vol. 75, no 3, p. 258-265Article in journal (Refereed)
    Abstract [en]

    Human papillomavirus (HPV) cause common warts, laryngeal papilloma and genital condylomata and is necessary for the development of cervical cancer. We have previously found that lactoferrin has antiviral activity against HPV-16 and others have demonstrated that lactoferricin, an N-terminal fragment of lactoferrin, has inhibitory activities against several viruses. Two cell lines and two virus types, HPV-5 and HPV-16, were used to study if lactoferrin and lactoferricin could inhibit HPV pseudovirus (PsV) infection. We demonstrated that bovine lactoferrin (bLf) and human lactoferrin (hLf) were both potent inhibitors of HPV-5 and -16 PsV infections. Among the four lactoferricin derivatives we analyzed, a 15 amino acid peptide from bovine lactoferricin (bLfcin) 17-31 was the most potent inhibitor of both HPV-5 and HPV-16 PsV infection. Among the other derivatives, the human lactoferricin (hLfcin) 1-49 showed some antiviral activity against HPV PsV infection while bLfcin 17-42 inhibited only HPV-5 PsV infection in one of the cell lines. When we studied initial attachment of HPV-16, only bLfcin 17-42 and hLfcin 1-49 had an antiviral effect. This is the first time that lactoferricin was demonstrated to have an inhibitory effect on HPV infection and the antiviral activity differed depending on size, charge and structures of the lactoferricin.

  • 41.
    Mistry, Nitesh
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Drobni, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Wibom, Carl
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Entry of human Papillomavirus type 5 is only partly dependent of a heparan sulfate receptorManuscript (Other academic)
  • 42.
    Mistry, Nitesh
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Nord, Stefan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Drobni, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Wibom, Carl
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Mucosal and cutaneous papillomaviruses interact differently with the attachment receptor heparan sulfate on the cell surface.Manuscript (Other academic)
  • 43.
    Mistry, Nitesh
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Simonsson, Monika
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Transcriptional activation of the human papillomavirus type 5 and 16 long control region in cells from cutaneous and mucosal origin2007In: Virology journal, ISSN 1743-422X, Vol. 4, p. 4:27-Article in journal (Refereed)
  • 44.
    Mistry, Nitesh
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Wibom, Carl
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Cutaneous and mucosal human papillomaviruses differ in net surface charge, potential impact on tropism.2008In: Virology journal, ISSN 1743-422X, Vol. 5, p. 118-Article in journal (Refereed)
    Abstract [en]

    Papillomaviruses can roughly be divided into two tropism groups, those infecting the skin, including the genus beta PVs, and those infecting the mucosa, predominantly genus alpha PVs. The L1 capsid protein determines the phylogenetic separation between beta types and alpha types and the L1 protein is most probably responsible for the first interaction with the cell surface. Virus entry is a known determinant for tissue tropism and to study if interactions of the viral capsid with the cell surface could affect HPV tropism, the net surface charge of the HPV L1 capsid proteins was analyzed and HPV-16 (alpha) and HPV-5 (beta) with a mucosal and cutaneous tropism respectively were used to study heparin inhibition of uptake. The negatively charged L1 proteins were all found among HPVs with cutaneous tropism from the beta- and gamma-PV genus, while all alpha HPVs were positively charged at pH 7.4. The linear sequence of the HPV-5 L1 capsid protein had a predicted isoelectric point (pI) of 6.59 and a charge of -2.74 at pH 7.4, while HPV-16 had a pI of 7.95 with a charge of +2.98, suggesting no interaction between HPV-5 and the highly negative charged heparin. Furthermore, 3D-modelling indicated that HPV-5 L1 exposed more negatively charged amino acids than HPV-16. Uptake of HPV-5 (beta) and HPV-16 (alpha) was studied in vitro by using a pseudovirus (PsV) assay. Uptake of HPV-5 PsV was not inhibited by heparin in C33A cells and only minor inhibition was detected in HaCaT cells. HPV-16 PsV uptake was significantly more inhibited by heparin in both cells and completely blocked in C33A cells.

  • 45.
    Mohamed, Nahla
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Nilsson, Elin
    Johansson, Patrik
    Klingström, Jonas
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Bucht, Göran
    Development and evaluation of a broad reacting SYBR-green based quantitative real-time PCR for the detection of different hantaviruses2013In: Journal of Clinical Virology, ISSN 1386-6532, E-ISSN 1873-5967, Vol. 56, no 4, p. 280-285Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Hantaviruses are endemic in most parts of the world and cause hundreds of thousand human cases of hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS) annually throughout Eurasia and the Americas. They are zoonotic viruses, most commonly transmitted to humans by aerosolized rodent excreta. New hantaviruses are frequently discovered in previously unknown reservoir species and geographic areas. Consequently, there is a need to improve hantavirus diagnostics. OBJECTIVES: This paper describes the design and evaluation of a rapid and robust quantitative real-time PCR (QRT-PCR) assay able to detect a wide range of hantaviruses. STUDY DESIGN: Primers with the potential to detect different hantaviruses were designed from conserved regions of different hantavirus L segments, as identified from multiple sequence alignments. RESULTS: By using SYBR-green-based QRT-PCR 100-1000 target molecules of in vitro produced RNA and less than 100 copies of hantavirus RNA from different hantavirus clades and regions of the world were detected. When using the assay on clinical samples from patients with acute HFRS, Puumala hantavirus (PUUV) RNA was confirmed in all previously positive samples. Notably, the broad reacting L-segment QRT-PCR also detected viral RNA in HFRS patient samples, previously negative by a QRT-PCR targeting the S segment of PUUV. CONCLUSIONS: This novel assay provides a powerful tool for diagnosis of hantaviruses from different clades and regions and may also be useful in surveys with the purpose of finding new hantaviruses in rodent or insectivore species.

  • 46. Mosomtai, Gladys
    et al.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Mundia, Charles
    Sandström, Per
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Hassan, Osama Ahmed
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Lwande, Olivia Wesula
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Gachari, Moses K.
    Landmann, Tobias
    Sang, Rosemary
    Datasets for mapping pastoralist movement patterns and risk zones of Rift Valley fever occurrence2018In: Data in Brief, E-ISSN 2352-3409, Vol. 16, p. 762-770Article in journal (Refereed)
    Abstract [en]

    Rift Valley fever (RVF) is a zoonotic disease affecting humans and animals. It is caused by RVF virus transmitted primarily by Aedes mosquitoes. The data presented in this article propose environmental layers suitable for mapping RVF vector habitat zones and livestock migratory routes. Using species distribution modelling, we used RVF vector occurrence data sampled along livestock migratory routes to identify suitable vector habitats within the study region which is located in the central and the north-eastern part of Kenya. Eleven herds monitored with GPS collars were used to estimate cattle utilization distribution patterns. We used kernel density estimator to produce utilization contours where the 0.5 percentile represents core grazing areas and the 0.99 percentile represents the entire home range. The home ranges were overlaid on the vector suitability map to identify risks zones for possible RVF exposure. Assimilating high spatial and temporal livestock movement and vector distribution datasets generates new knowledge in understanding RVF epidemiology and generates spatially explicit risk maps. The results can be used to guide vector control and vaccination strategies for better disease control.

  • 47. Mosomtai, Gladys
    et al.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Sandström, Per
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Sang, Rosemary
    Hassan, Osama Ahmed
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Affognon, Hippolyte
    Landmann, Tobias
    Association of ecological factors with Rift Valley fever occurrence and mapping of risk zones in Kenya2016In: International Journal of Infectious Diseases, ISSN 1201-9712, E-ISSN 1878-3511, Vol. 46, p. 49-55Article in journal (Refereed)
    Abstract [en]

    Objective: Rift Valley fever (RVF) is a mosquito-borne infection with great impact on animal and human health. The objectives of this study were to identify ecological factors that explain the risk of RVF outbreaks in eastern and central Kenya and to produce a spatially explicit risk map. Methods: The sensitivity of seven selected ecological variables to RVF occurrence was assessed by generalized linear modelling (GLM). Vegetation seasonality variables (from normalized difference vegetation index (NDVI) data) and 'evapotranspiration' (ET) (metrics) were obtained from 0.25-1 km MODIS satellite data observations; 'livestock density' (N/km(2)), 'elevation' (m), and 'soil ratio' (fraction of all significant soil types within a certain county as a function of the total area of that county) were used as covariates. Results: 'Livestock density', 'small vegetation integral', and the second principal component of ET were the most significant determinants of RVF occurrence in Kenya (all p < 0.01), with high RVF risk areas identified in the counties of Tana River, Garissa, Isiolo, and Lamu. Conclusions: Wet soil fluxes measured with ET and vegetation seasonality variables could be used to map RVF risk zones on a sub-regional scale. Future outbreaks could be better managed if relevant RVF variables are integrated into early warning systems. 

  • 48. Nelson, J H
    et al.
    Hawkins, G A
    Edlund, K
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Evander, M
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Kjellberg, L
    Wadell, G
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Dillner, J
    Gerasimova, T
    Coker, A L
    Pirisi, L
    Petereit, D
    Lambert, P F
    A novel and rapid PCR-based method for genotyping human papillomaviruses in clinical samples.2000In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 38, no 2, p. 688-95Article in journal (Refereed)
    Abstract [en]

    Many human papillomavirus (HPV) genotypes are associated with cervical carcinoma. We demonstrate the utility of an innovative technique for genotyping of HPV in cervical tissue samples. This method provides an accurate means of identification of the specific HPV genotypes present in clinical specimens. By using the MY09-MY11 and the GP5(+)-GP6(+) consensus primer pairs, HPV sequences were amplified by nested PCR from DNA isolated from cervical smear samples. This led to the production of an approximately 140-bp PCR product from the L1 (major capsid) gene of any of the HPVs present in the sample. PCR was performed with a deoxynucleoside triphosphate mixture which resulted in the incorporation of deoxyuridine into the amplified DNA product at positions where deoxythymidine would normally be incorporated at a frequency of about once or twice per strand. Following the PCR, the product was treated with an enzyme mix that contains uracil N-glycosylase (UNG) and endonuclease IV. UNG removes the uracil base from the nucleotide, and endonuclease IV cleaves the phosphodiester bond at this newly formed abasic site, producing fragments of various sizes. By having end labeled one of the amplification primers, a DNA ladder which is analogous to a "T-sequencing ladder" was produced upon electrophoresis of the products. By comparing this T-sequencing ladder to the known sequences of HPVs, the genotypes of unknown HPV isolates in samples were assigned. Data showing the utility of this technique for the rapid analysis of clinical samples are presented.

  • 49.
    Näslund, Jonas
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Drobni, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Kerner, Alexander
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Bucht, Göran
    Totalförsvarets forskningsinstitut, FOI, Umeå.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    PCR detection of a hantavirus and Rift Valley fever virus using dried whole blood spotted on filter stripsManuscript (preprint) (Other academic)
    Abstract [en]

    Viral hemorrhagic fevers are serious and emerging infections among humans and animals worldwide. Presently, blood or serum samples are the main source for diagnostics. However, transportation of such samples from remote areas may be complicated and expensive. Previously, filter strips soaked with blood have been used for detection of antibodies for diagnostics and epidemiological studies of several infectious diseases.

    In this study we evaluate if a similar approach could be applied for detection of viral RNA of Rift Valley Fever virus or Hantavirus (Puumala).

    We have used whole blood spiked with known amounts of viruses. In addition, clinical samples from patients with acute hemorrhagic fever with renal syndrome have been analysed. The samples were collected on filter strips and dried before RNA was extracted at different time-points. For Puumala, the sensitivity was acceptable, although the absolute levels of viral RNA were found to be considerable lower when using filter strips. The viral RNA could be detected and analysed after 2-3 weeks storage of the dried filter strips. In contrast, for RVFV, no or very low copy numbers of viral RNA were detected. Still, RVFV filter strips contained viable virus particles up to 48 h of storage.

    In conclusion, the use of dried whole blood samples spotted on filter strips for the detection of viral RNA seems to be a reliable and simple procedure for Hantaviruses. This procedure could be useful in field studies, especially in remote areas or low-income countries where transportation and storage of biological samples might be complicated. However, the result for RVFV was unexpected and further studies are needed to improve this technique.

  • 50.
    Näslund, Jonas
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Kerner, Alexander
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Drobni, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Bucht, Göran
    Swedish Defence Research Agency, Department of CBRN Defence and Security, SE-901 82 Umeå, Sweden.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Detection of Puumala and Rift Valley Fever virus by quantitative RT-PCR and virus viability tests in samples of blood dried and stored on filter paper2011In: Journal of Virological Methods, ISSN 0166-0934, E-ISSN 1879-0984, Vol. 178, no 1-2, p. 186-90Article in journal (Refereed)
    Abstract [en]

    Haemorrhagic fever viruses cause emerging infections worldwide, and blood or serum is the main sample used for diagnosis. However, storage and transportation of such samples from remote areas to regional laboratories may be complicated and expensive. In this study, a novel approach was evaluated for the detection of Puumala hantavirus (PUUV) RNA and Rift Valley fever virus (RVFV) RNA. Whole-blood samples spiked with viable virus particles were tested in parallel with clinical samples from patients with acute haemorrhagic fever with renal syndrome (nephropathia epidemica). Individual blood samples were spotted on filter paper, dried, and used for RNA extraction at later time points. PUUV RNA was detected by RT-PCR after storage at room temperature for up to six weeks. In contrast, only low copy numbers of RVFV RNA were detected after 1-2 days even though viable RVFV was eluted from the dried filter papers after the same time. The use of filter paper to collect and store blood samples for PUUV RNA detection is therefore a simple and reliable procedure. This approach might facilitate sampling and analysis of other RNA viruses from human or animal sources and could be used for field studies in remote areas or in developing countries.

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