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  • 1. Alemu, Yihun Mulugeta
    et al.
    Awoke, Worku
    Wilder-Smith, Annalies
    Institute of Public Health, Heidelberg University, Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    Determinants for tuberculosis in HIV-infected adults in Northwest Ethiopia: a multicentre case-control study2016In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 6, no 4, e009058Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The objective of this study was to identify determinants for tuberculosis (TB) among HIV-infected adults in Northwest Ethiopia.

    DESIGN: Case-control study.

    SETTING: Three hospitals and 10 health centres in Northwest Ethiopia.

    PARTICIPANTS: A total of 446 individuals consented to participate in the study (150 cases and 296 controls). Cases were HIV-infected adults diagnosed with active TB, and controls were HIV-infected adults without active TB.

    MAIN OUTCOME MEASURE: The link between TB and determinants was assessed using logistic regression. Determinants were categorised as sociodemographic, host-related, clinical and environmental.

    RESULTS: Smoking (adjusted OR (AOR) 5.47; 95% CI 2.26 to 13.22), presence of a TB patient in the family (AOR 2.66; 95% CI 1.25 to 5.66), alcohol consumption (AOR 2.49; 95% CI 1.29 to 4.80) and chewing khat (AOR 2.22; 95% CI 1.11 to 4.41) were independent determinants for increased occurrence of TB. Highly active antiretroviral therapy (HAART) (AOR 0.25; 95% CI 0.13 to 0.51), isoniazid preventive therapy (IPT) (AOR 0.22; 95% CI 0.11 to 0.41) and cotrimoxazole preventive therapy (AOR 0.32; 95% CI 0.19 to 0.55) had a protective effect against TB.

    CONCLUSIONS: HIV-infected adults with substance abuse (tobacco smoking, khat chewing and alcohol) should be prioritised for TB screening. This study reaffirmed that HAART and IPT are some of the best strategies for reducing TB occurrence in HIV-infected adults. These findings provide impetus to intensify tracing of TB household contacts.

  • 2. Amaku, M
    et al.
    Azevedo, F
    Burattini, M N
    Coelho, G E
    Coutinho, F A B
    Greenhalgh, D
    Lopez, L F
    Motitsuki, R S
    Wilder-Smith, Annelies
    Massad, E
    Magnitude and frequency variations of vector-borne infection outbreaks using the Ross-Macdonald model: explaining and predicting outbreaks of dengue fever2016In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 144, no 16, 3435-3450 p.Article in journal (Refereed)
    Abstract [en]

    The classical Ross-Macdonald model is often utilized to model vector-borne infections; however, this model fails on several fronts. First, using measured (or estimated) parameters, which values are accepted from the literature, the model predicts a much greater number of cases than what is usually observed. Second, the model predicts a single large outbreak that is followed by decades of much smaller outbreaks, which is not consistent with what is observed. Usually towns or cities report a number of recurrences for many years, even when environmental changes cannot explain the disappearance of the infection between the peaks. In this paper, we continue to examine the pitfalls in modelling this class of infections, and explain that, if properly used, the Ross-Macdonald model works and can be used to understand the patterns of epidemics and even, to some extent, be used to make predictions. We model several outbreaks of dengue fever and show that the variable pattern of yearly recurrence (or its absence) can be understood and explained by a simple Ross-Macdonald model modified to take into account human movement across a range of neighbourhoods within a city. In addition, we analyse the effect of seasonal variations in the parameters that determine the number, longevity and biting behaviour of mosquitoes. Based on the size of the first outbreak, we show that it is possible to estimate the proportion of the remaining susceptible individuals and to predict the likelihood and magnitude of the eventual subsequent outbreaks. This approach is described based on actual dengue outbreaks with different recurrence patterns from some Brazilian regions.

  • 3. Balasingam, Shobana
    et al.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technology University, Singapore 308232, Singapore.
    Randomized controlled trials for influenza drugs and vaccines: a review of controlled human infection studies2016In: International Journal of Infectious Diseases, ISSN 1201-9712, E-ISSN 1878-3511, Vol. 49, 18-29 p.Article, review/survey (Refereed)
    Abstract [en]

    OBJECTIVES: Controlled human infection, the intentional infection of healthy volunteers, allows disease pathogenesis to be studied and vaccines and therapeutic interventions to be evaluated in a controlled setting. A systematic review of randomized controlled trials of countermeasures for influenza that used the experimental human infection platform was performed. The primary objective was to document the scope of trials performed to date and the main efficacy outcome in the trials. The secondary objective was to assess safety and identify serious adverse events.

    METHODS: The PubMed database was searched for randomized controlled influenza human challenge studies with predetermined search terms. Review papers, papers without outcomes, community-acquired infections, duplicated data, pathogenesis studies, and observational studies were excluded.

    RESULTS: Twenty-six randomized controlled trials published between 1947 and 2014 fit the study inclusion criteria. Two-thirds of these trials investigated antivirals and one-third investigated influenza vaccines. Among 2462 subjects inoculated with influenza virus, the incidence of serious adverse events was low (0.04%). These challenge studies helped to down-select three antivirals and one vaccine that were subsequently approved by the US Food and Drug Administration (FDA).

    CONCLUSIONS: Controlled human infection studies are an important research tool in assessing promising influenza vaccines and antivirals. These studies are performed quickly and are cost-effective and safe, with a low incidence of serious adverse events.

  • 4. Banks, S. D.
    et al.
    Murray, N.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Logan, J. G.
    Insecticide-treated clothes for the control of vector-borne diseases: a review on effectiveness and safety2014In: Medical and Veterinary Entomology, ISSN 0269-283X, E-ISSN 1365-2915, Vol. 28, no S1, 14-25 p.Article, review/survey (Refereed)
    Abstract [en]

    Insecticide-treated clothing has been used for many years by the military and in recreational activities as personal protection against bites from a variety of arthropods including ticks, chigger mites, sandflies and mosquitoes. Permethrin is the most commonly used active ingredient, but others, including bifenthrin, deltamethrin, cyfluthrin, DEET (N,N-diethyl-3-methylbenz-amide) and KBR3023, have also been trialled. Treatment is usually carried out by home or factory dipping. However, new microencapsulation technologies which may prolong the activity of insecticides on clothing are now available and may help to overcome the inevitable reduction in efficacy over time that occurs as a result of washing, ultraviolet light exposure, and the normal wear and tear of the fabric. The aim of this article is to review the evidence base for the use of insecticide-treated clothing for protection against bites from arthropods and its effect on arthropod-borne pathogen transmission. Although some studies do demonstrate protection against pathogen transmission, there are surprisingly few, and the level of protection provided varies according to the disease and the type of study conducted. For example, insecticide-treated clothing has been reported to give between 0% and 75% protection against malaria and between 0% and 79% protection against leishmaniasis. Studies vary in the type of treatment used, the age group of participants, the geographical location of the study, and the pathogen transmission potential. This makes it difficult to compare and assess intervention trials. Overall, there is substantial evidence that insecticide-treated clothing can provide protection against arthropod bites. Bite protection evidence suggests that insecticide-treated clothing may be useful in the prevention of pathogen transmission, but further investigations are required to accurately demonstrate transmission reduction.

  • 5. Banks, S De Raedt
    et al.
    Orsborne, J
    Gezan, S A
    Kaur, H
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore City, Singapore.
    Lindsey, S W
    Logan, J G
    Permethrin-treated clothing as protection against the dengue vector, Aedes aegypti: extent and duration of protection2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 399-400 p.Article in journal (Other academic)
    Abstract [en]

    Background: 3900 million people globally are at risk of dengue fever infection, with its distribution increasing rapidly over the past 50 years. Since the primary vector, Aedes aegypti, is exophilic and most active during the day, personal protection technologies, such as insecticide treated clothing, could provide significant protection from mosquito bites.

    Methods: World Health Organisation Pesticide Evaluation Scheme (WHOPES) cone and arm-in-cage assays were used to assess protection, knockdown and mortality against factory, home-dipped and microencapsulated permethrin-treated fabrics using Ae. aegypti mosquitoes. Factory-treated clothing was then analysed further to investigate the effects of insecticide resistance, clothing coverage, washing, Ultra-violet light and ironing.

    Results: Factory-treated clothing showed the greatest protective effect (1 h KD 96.5% and 24 h mortality 97.1%), landing protection (59% (95% CI = 49.2–66.9) and bite protection (100%). Landing and biting protection reduced significantly from 58.9% to 18.5% and 28.6% to 11.1% after 10 washes for simulated hand washing. Resistance to permethrin had no effect on the efficacy of the clothing, with coverage playing an important role. Full coverage provided the highest protection (79.4% landing protection, 100% biting protection). Free flight room assays showed no difference in landing protection between the two coverage types but bite protection was significantly greater (>90%) with full coverage. HPLC confirmed ironing reduced permethrin content after 1 week simulated use, with a 96.7% decrease after 3 months. UV exposure was shown to have no effect.

    Conclusion: Insecticide treated clothing can provide significant biting and landing protection, even in a resistant strain. However, our findings also suggest that clothing may provide only short-term protection due to the effect of washing and ironing, highlighting the need for improved clothing treatment techniques.

    Disclosure: Nothing to disclose.

  • 6. Boggild, Andrea K
    et al.
    Castelli, Francesco
    Gautret, Philippe
    Torresi, Joseph
    von Sonnenburg, Frank
    Barnett, Elizabeth D
    Greenaway, Christina A
    Lim, Poh-Lian
    Schwartz, Eli
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Wilson, Mary E
    Latitudinal patterns of travel among returned travelers with influenza: results from the GeoSentinel Surveillance Network, 1997-2007.2012In: Journal of Travel Medicine, ISSN 1195-1982, E-ISSN 1708-8305, Vol. 19, no 1, 4-8 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Influenza is a common vaccine-preventable disease among international travelers, but few data exist to guide use of reciprocal hemisphere or out-of-season vaccines.

    METHODS: We analyzed records of ill-returned travelers in the GeoSentinel Surveillance Network to determine latitudinal travel patterns in those who acquired influenza abroad.

    RESULTS: Among 37,542 ill-returned travelers analyzed, 59 were diagnosed with influenza A and 11 with influenza B. Half of travelers from temperate regions to the tropics departed outside influenza season. Twelve travelers crossed hemispheres from one temperate region to another, five during influenza season. Ten of 12 travelers (83%) with influenza who crossed hemispheres were managed as inpatients. Proportionate morbidity estimates for influenza A acquisition were highest for travel to the East-Southeast Asian influenza circulation network with 6.13 (95% CI 4.5-8.2) cases per 1000 ill-returned travelers, a sevenfold increased proportionate morbidity compared to travel outside the network.

    CONCLUSIONS: Alternate hemisphere and out-of-season influenza vaccine availability may benefit a small proportion of travelers. Proportionate morbidity estimates by region of travel can inform pre-travel consultation and emphasize the ease of acquisition of infections such as influenza during travel.

  • 7. Burattini, M N
    et al.
    Coutinho, F A B
    Lopez, L F
    Ximenes, R
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Massad, E
    Potential exposure to Zika virus for foreign tourists during the 2016 Carnival and Olympic Games in Rio de Janeiro, Brazil2016In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 144, no 9, 1904-1906 p.Article in journal (Refereed)
  • 8.
    Byass, Peter
    et al.
    Umeå University.
    Wilder-Smith, Annelies
    Umeå University. Nanyang Technol Univ, Lee Kong Chian Sch Med, Singapore .
    Utilising additional sources of information on microcephaly2016In: The Lancet, ISSN 0140-6736, E-ISSN 1474-547X, Vol. 387, no 10022, 940-941 p.Article in journal (Refereed)
  • 9. Chen, Lin H
    et al.
    Hill, David R
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Vaccination of travelers: how far have we come and where are we going?2011In: Expert review of vaccines, ISSN 1744-8395, Vol. 10, no 11, 1609-20 p.Article in journal (Refereed)
    Abstract [en]

    Vaccine recommendations are a prominent part of health preparations before international travel. We review progress made in the past decade regarding vaccines used primarily by persons traveling from high-income countries to low- and middle-income countries. The combined hepatitis A-B vaccine, the recently licensed Vero cell-derived Japanese encephalitis vaccine and conjugated quadrivalent meningococcal vaccines are discussed. This article provides updates on yellow fever vaccine-associated visceral and neurologic adverse events, indications for influenza vaccine in travelers, the rapid immunization schedule for tick-borne encephalitis vaccine, schedules for postexposure rabies prophylaxis, and new insights about oral cholera vaccines following the outbreak in Haiti. The future should bring vaccines for serogroup B Neiserria meningitidis, dengue and malaria, as well as an inactivated yellow fever vaccine.

  • 10. DeRaedt Banks, Sarah
    et al.
    Orsborne, James
    Gezan, Salvador A
    Kaur, Harparkash
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Lindsey, Steve W
    Logan, James G
    Permethrin-Treated Clothing as Protection against the Dengue Vector, Aedes aegypti: Extent and Duration of Protection2015In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 9, no 10, e0004109Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Dengue transmission by the mosquito vector, Aedes aegypti, occurs indoors and outdoors during the day. Personal protection of individuals, particularly when outside, is challenging. Here we assess the efficacy and durability of different types of insecticide-treated clothing on laboratory-reared Ae. aegypti.

    METHODS: Standardised World Health Organisation Pesticide Evaluation Scheme (WHOPES) cone tests and arm-in-cage assays were used to assess knockdown (KD) and mortality of Ae. aegypti tested against factory-treated fabric, home-dipped fabric and microencapsulated fabric. Based on the testing of these three different treatment types, the most protective was selected for further analysis using arm-in cage assays with the effect of washing, ultra-violet light, and ironing investigated using high pressure liquid chromatography.

    RESULTS: Efficacy varied between the microencapsulated and factory dipped fabrics in cone testing. Factory-dipped clothing showed the greatest effect on KD (3 min 38.1%; 1 hour 96.5%) and mortality (97.1%) with no significant difference between this and the factory dipped school uniforms. Factory-dipped clothing was therefore selected for further testing. Factory dipped clothing provided 59% (95% CI = 49.2%- 66.9%) reduction in landing and a 100% reduction in biting in arm-in-cage tests. Washing duration and technique had a significant effect, with insecticidal longevity shown to be greater with machine washing (LW50 = 33.4) compared to simulated hand washing (LW50 = 17.6). Ironing significantly reduced permethrin content after 1 week of simulated use, with a 96.7% decrease after 3 months although UV exposure did not reduce permethrin content within clothing significantly after 3 months simulated use.

    CONCLUSION: Permethrin-treated clothing may be a promising intervention in reducing dengue transmission. However, our findings also suggest that clothing may provide only short-term protection due to the effect of washing and ironing, highlighting the need for improved fabric treatment techniques.

  • 11. Durbin, Anna
    et al.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine. Nanyang Technol Univ, Singapore ; London Sch Hyg & Trop Med, London, England.
    An update on Zika vaccine developments2017In: Expert Review of Vaccines, ISSN 1476-0584, E-ISSN 1744-8395, Vol. 16, no 8, 781-787 p.Article in journal (Refereed)
    Abstract [en]

    Introduction: The devastating consequences of congenital Zika virus (ZIKV) infection led to a global response directed toward a better understanding of the epidemiology and pathogenesis of ZIKV and to efforts at vaccine development. As a result, there are currently 45 ZIKV vaccine candidates in development. Areas covered: Both traditional (purified inactivated, live attenuated, viral-vectored, recombinant sub-unit) and novel (DNA, self-replicating RNA, mRNA) vaccine platforms are being utilized. For emergency use, vaccines that are appropriate for women of child-bearing age (including pregnant women) are being developed. Live vaccines that may be contraindicated in pregnancy are also in development for potential inclusion in national immunization programmes in childhood or pre-teenage age groups. WHO developed a target product profile for Zika vaccines for use in an emergency. Expert commentary: Although ZIKV vaccine development had a quick head start, further development may be hampered because of the inability to conduct large efficacy trials with the decline in cases globally and unpredictability of new outbreaks. Furthermore, there are complex ethical issues involved in conducting efficacy trials in pregnant women.

  • 12. Earnest, A
    et al.
    Tan, S B
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Meteorological factors and El Niño Southern Oscillation are independently associated with dengue infections2012In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 140, no 07, 1244-1251 p.Article in journal (Refereed)
    Abstract [en]

    Our objective was to determine the association between temperature, humidity, rainfall and dengue activity in Singapore, after taking into account lag periods as well as long-term climate variability such as the El Niño Southern Oscillation Index (SOI). We used a Poisson model which allowed for autocorrelation and overdispersion in the data. We found weekly mean temperature and mean relative humidity as well as SOI to be significantly and independently associated with dengue notifications. There was an interaction effect by periods of dengue outbreaks, but periods where El Niño was present did not moderate the relationship between humidity and temperature with dengue notifications. Our results help to understand the temporal trends of dengue in Singapore, and further reinforce the findings that meteorological factors are important in the epidemiology of dengue.

  • 13. Flores-Figueroa, Jose
    et al.
    Okhuysen, Pablo C
    von Sonnenburg, Frank
    DuPont, Herbert L
    Libman, Michael D
    Keystone, Jay S
    Hale, Devon C
    Burchard, Gerd
    Han, Pauline V
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Freedman, David O
    Patterns of illness in travelers visiting Mexico and Central America: the GeoSentinel experience.2011In: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, ISSN 1537-6591, Vol. 53, no 6, 523-531 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Mexico and Central America are important travel destinations for North American and European travelers. There is limited information on regional differences in travel related morbidity.

    METHODS: We describe the morbidity among 4779 ill travelers returned from Mexico and Central America who were evaluated at GeoSentinel network clinics during December 1996 to February 2010.

    RESULTS: The most frequent presenting syndromes included acute and chronic diarrhea, dermatologic diseases, febrile systemic illness, and respiratory disease. A higher proportion of ill travelers from the United States had acute diarrhea, compared with their Canadian and European counterparts (odds ratio, 1.9; P < .0001). During the 2009 H1N1 influenza outbreak from March 2009 through February 2010, the proportionate morbidity (PM) associated with respiratory illnesses in ill travelers increased among those returned from Mexico, compared with prior years (196.0 cases per 1000 ill returned travelers vs 53.7 cases per 1000 ill returned travelers; P < .0001); the PM remained constant in the rest of Central America (57.3 cases per 1000 ill returned travelers). We identified 50 travelers returned from Mexico and Central America who developed influenza, including infection due to 2009 H1N1 strains and influenza-like illness. The overall risk of malaria was low; only 4 cases of malaria were acquired in Mexico (PM, 2.2 cases per 1000 ill returned travelers) in 13 years, compared with 18 from Honduras (PM, 79.6 cases per 1000 ill returned travelers) and 14 from Guatemala (PM, 34.4 cases per 1000 ill returned travelers) during the same period. Plasmodium vivax malaria was the most frequent malaria diagnosis.

    CONCLUSIONS: Travel medicine practitioners advising and treating travelers visiting these regions should dedicate special attention to vaccine-preventable illnesses and should consider the uncommon occurrence of acute hepatitis A, leptospirosis, neurocysticercosis, acute Chagas disease, onchocerciasis, mucocutaneous leishmaniasis, neurocysticercosis, HIV, malaria, and brucellosis.

  • 14. Franco, L
    et al.
    Cnops, L
    Navascues, A
    Boillat, N
    Neumayr, A
    Norman, F
    Vanio, K
    Dudman, S
    Van Esbroeck, M
    Molero, F
    Hernandez, L
    Potente, A
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Hatz, C
    Sanchez-Seco, M P
    Dengue in Africa: sustained and silent circulation of multiple serotypes and genotypes, detected in travelers from 2010 to 20142015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 107-108 p.Article in journal (Other academic)
    Abstract [en]

    Introduction: Dengue is caused by 4 different related viruses, DENV 1 to 4, transmitted to humans via Aedes mosquitoes. The disease is endemic in more than 100 countries. In Africa, the estimated dengue burden is 15 million of clinical cases and about 48 millions of inapparent infections. However, dengue remains largely unrecognized in Africa. Due to the lack of laboratory confirmation, a febrile syndrome is frequently misdiagnosed as malarial infection. The circulation of different dengue serotypes is also poorly documented. However, some information is provided by reports of dengue infections in travellers returning from Africa. In the present study we attempt the identification of dengue serotypes and genotypes circulating in Africa from 2010 to 2014 detected in travellers returning to Europe.

    Methods: We collected samples from viraemic travellers returning from Africa who attended TropNet clinics in Europé from 2010 to 2014. Sequences of the Envelope gene were used to identify the serotype and genotype.

    Results: During the study period we identified 3 DENV serotypes circulating in Africa. DENV 1 strains were detected in East Africa in 2010 (Eritrea) and in 2012 (Kenia), whereas in Central Africa in 2013(Angola and DRC). Strains from East Africa were grouped within Asian genotype, close to virus isolated in previous years in Djibouti and Kenia; we found American /African genotype in Central Africa. Both genotypes have circulated in West Africa for many years. DENV 2 strains were detected in West Africa (Senegal) and in East Africa (Tanzania) in 2014. Dengue 2 from Tanzania belongs to cosmopolitan genotype, but form a distinct clade different from the old African group. However, DENV 2 from Senegal surprisingly fell into genotype America /Asia. To our knowledge this is the first time identified in Africa. Finally, DENV 3 was detected in 2010 in Mali and Burkina Faso and again in Burkina Faso in 2013. All DENV 3 belong to genotype III and form a cluster with the African strains identified since 2008.

    Conclusion: DENV 1 of both genotypes was identified previously in Africa indicating endemic transmission as well as with DENV 3. Meanwhile, a new DENV 2 appeared in Tanzania, introduced from South East Asia, and in Senegal from the Americas. These results confirm silent and sustained circulation of dengue in Africa and show the usefulness of travelers for sentinel surveillance to unmask the dengue problem in Africa.

    Disclosure: Nothing to disclose.

  • 15. Franco, L
    et al.
    Fernandez, M D
    Serre, N
    Martinez, M
    Sulleiro, E
    Neumayr, A
    Molero, F
    Schunk, M
    Guido, C
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Hatz, C
    Sanchez-Seco, M P
    Dengue serotypes and genotypes circulating in recent years in the Caribbean and imported to Europe2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 104-105 p.Article in journal (Other academic)
    Abstract [en]

    Introduction: Dengue viruses (DENV) are the most widespread arthropod-borne viruses endemic in the tropics and transmitted to humans through the bites of Aedes mosquitoes. Travelers can act as vectors to introduce DENV to uninfected areas or regions. Travelers can also serve as sentinels for ongoing outbreaks and dominating serotypes and genotypes in the source countries. We set out to describe the importation of dengue virus from the Caribbean via travelers to Europe.

    Methods: From 2011 to 2014, we collected samples from viraemic travelers returning from the Caribbean with confirmed dengue to 11 TropNet clinics in Europe that are participating in the DengueTools project. Sequences of the Envelope gene were used to identify serotype and genotype.

    Results: The main countries of importation were Barbados, Cuba, Dominican Republic, Guadeloupe, Haiti, Martinique, Netherlands Antilles and Puerto Rico. All 4 DENV serotypes were identified. DENV 1 strains were grouped within genotype V creating a new clade. All DENV 2 sequences clustered within a clade in the American/Asian genotype which was recently also identified in other Caribbean and Brazilian strains. DENV 3 strains were grouped within genotype III. All DENV 4 strains were phylogenetically grouped within a modern Caribbean basin clade in genotype II.

    Conclusions: Travelers provides unique insights into the global picture of circulating DENV strains. This study from the Caribbean region led to the identification of novel clades. Moreover, we were be able to detect dengue strains circulating in Cuba from 2011 to 2013, although officially no dengue was reported during that time period. Travelers serve as sentinels to provide timely information about current distribution of dengue serotypes and genotypes associated or not with outbreaks and track the spread of DENV strains in areas with scarce epidemiological information.

    Disclosure: Nothing to disclose.

  • 16. Franco, L.
    et al.
    Serre, N.
    Poluda, D.
    Kurolt, I.
    Molero, F.
    Zarzuela, F.
    Neumayr, A.
    Hatz, C.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Tenorio, A.
    Deciphering the origin of dengue virus introduced in Madeira, Portugal2013Conference paper (Other academic)
  • 17. Gessner, Bradford D
    et al.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Institute of Public Health, University of Heidelberg, Germany.
    Estimating the public health importance of the CYD-tetravalent dengue vaccine: vaccine preventable disease incidence and numbers needed to vaccinate2016In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 34, no 20, 2397-2401 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: To evaluate the potential public health impact of the live attenuated tetravalent Sanofi Pasteur dengue vaccine (CYD-TDV) we analyzed data from the reported clinical trials to calculate vaccine preventable disease incidence (VPDI) and number needed to vaccinate (NNV) based on the licensure indication for persons age 9 years and above.

    METHODS: VPDI is defined as incidence in an unvaccinated population X vaccine efficacy (VE), and thus incorporates both VE and the underlying burden of disease. NNV was calculated as 100,000 divided by VPDI divided by 2-year length of study. We compared these values to data for three newer vaccines that are currently integrated into some national immunization programs in Asia and Latin America, namely pneumococcal conjugate, Haemophilus influenzae type b, and rotavirus vaccines.

    RESULTS: In the Asian-Pacific trial, in the first 25 months after the first dose of the dengue vaccine, CYD-TDV prevented annually 2639 cases of virologically confirmed dengue for every 100,000 persons vaccinated, for an NNV of 18. In the Latin American trial, given the overall lower annual dengue incidence compared to Asia, VPDI was 1707, and NNV 28. For the Asian-Pacific and Latin American studies, the VPDIs for hospitalized virologically confirmed disease at the trials' end were 638 and 239 per 100,000 population per year, respectively, with NNVs of 75 and 201. VPDI for confirmed dengue hospitalization was higher than that for Hib vaccine against Hib meningitis or all cause severe pneumonia while lower than that for rotavirus vaccine against severe rotavirus gastroenteritis.

    CONCLUSIONS: Our analysis found that the CYD-TDV dengue vaccine had favorable VPDI and NNV, also when compared to existing vaccines used in Latin America and Asia. VPDI and NNV varied by serotype distribution, extent of prior dengue exposure (baseline seroprevalence) and country. These findings will help policy-makers decide where and how to introduce this vaccine post-licensure.

  • 18. Harrison, Lee H
    et al.
    Pelton, Stephen I
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Holst, Johan
    Safadi, Marco A P
    Vazquez, Julio A
    Taha, Muhamed-Kheir
    LaForce, F Marc
    von Gottberg, Anne
    Borrow, Ray
    Plotkin, Stanley A
    The global Meningococcal initiative: recommendations for reducing the global burden of meningococcal disease2011In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 29, no 18, 3363-3371 p.Article in journal (Refereed)
    Abstract [en]

    The Global Meningococcal Initiative (GMI) is composed of an international group of scientists, clinicians and public health officials with expertise in meningococcal immunology, epidemiology and prevention. The primary goal of the GMI is the promotion of the global prevention of invasive meningococcal disease through education and research. The GMI members reviewed global meningococcal disease epidemiology, immunization strategies, and research needs. Over the past decade, substantial advances in meningococcal vaccine development have occurred and much has been learned about prevention from countries that have incorporated meningococcal vaccines into their immunization programs. The burden of meningococcal disease is unknown for many parts of the world because of inadequate surveillance, which severely hampers evidence-based immunization policy. As the field of meningococcal vaccine development advances, global surveillance for meningococcal disease needs to be strengthened in many regions of the world. For countries with meningococcal vaccination policies, research on vaccine effectiveness and impact, including indirect effects, is crucial for informing policy decisions. Each country needs to tailor meningococcal vaccination policy according to individual country needs and knowledge of disease burden. Innovative approaches are needed to introduce and sustain meningococcal vaccination programs in resource-poor settings with a high incidence of meningococcal disease.

  • 19.
    Horstick, Olaf
    et al.
    Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
    Tozan, Yesim
    Institute of Public Health, University of Heidelberg, Heidelberg, Germany ; Steinhardt School of Culture, Education and Human Development and Global Institute of Public Health, New York University, New York, New York, United States of America.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Heidelberg, Germany ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Reviewing dengue: still a neglected tropical disease?2015In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 9, no 4, e0003632Article, review/survey (Refereed)
    Abstract [en]

    Dengue is currently listed as a "neglected tropical disease" (NTD). But is dengue still an NTD or not? Classifying dengue as an NTD may carry advantages, but is it justified? This review considers the criteria for the definition of an NTD, the current diverse lists of NTDs by different stakeholders, and the commonalities and differences of dengue with other NTDs. We also review the current research gaps and research activities and the adequacy of funding for dengue research and development (R&D) (2003-2013). NTD definitions have been developed to a higher precision since the early 2000s, with the following main features: NTDs are characterised as a) poverty related, b) endemic to the tropics and subtropics, c) lacking public health attention, d) having poor research funding and shortcomings in R&D, e) usually associated with high morbidity but low mortality, and f) often having no specific treatment available. Dengue meets most of these criteria, but not all. Although dengue predominantly affects resource-limited countries, it does not necessarily only target the poor and marginalised in those countries. Dengue increasingly attracts public health attention, and in some affected countries it is now a high profile disease. Research funding for dengue has increased exponentially in the past two decades, in particular in the area of dengue vaccine development. However, despite advances in dengue research, dengue epidemics are increasing in frequency and magnitude, and dengue is expanding to new areas. Specific treatment and a highly effective vaccine remain elusive. Major research gaps exist in the area of integrated surveillance and vector control. Hence, although dengue differs from many of the NTDs, it still meets important criteria commonly used for NTDs. The current need for increased R& D spending, shared by dengue and other NTDs, is perhaps the key reason why dengue should continue to be considered an NTD.

  • 20. Jaenisch, Thomas
    et al.
    Sakuntabhai, Anavaj
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dengue research funded by the European commission: scientific strategies of three European dengue research consortia2013In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 7, no 12, e2320- p.Article in journal (Refereed)
  • 21. Jentes, Emily S
    et al.
    Poumerol, Gilles
    Gershman, Mark D
    Hill, David R
    Lemarchand, Johan
    Lewis, Rosamund F
    Staples, J Erin
    Tomori, Oyewale
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    Monath, Thomas P
    The revised global yellow fever risk map and recommendations for vaccination, 2010: consensus of the Informal WHO Working Group on geographic risk for Yellow Fever.2011In: Lancet. Infectious diseases (Print), ISSN 1473-3099, E-ISSN 1474-4457, Vol. 11, no 8, 622-632 p.Article in journal (Refereed)
    Abstract [en]

    The changing epidemiology of yellow fever and continued reports of rare but serious adverse events associated with yellow fever vaccine have drawn attention to the need to revisit criteria for the designation of areas with risk for yellow fever virus activity, and to revise the vaccine recommendations for international travel. WHO convened a working group of international experts to review factors important for the transmission of yellow fever virus and country-specific yellow fever information, to establish criteria for additions to or removal from the list of countries with risk for yellow fever virus transmission, to update yellow fever risk maps, and to revise the recommendations for vaccination for international travel. This report details the recommendations made by the working group about criteria for the designation of risk and specific changes to the classification of areas with risk for transmission of yellow fever virus.

  • 22. Kittayapong, P.
    et al.
    Olanratmanee, P.
    Maskhao, P.
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Louis, V.
    Gubler, D.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Innovative dengue prevention and control using permethrin-impregnated school uniforms: experiences from a 1-year field trial in Thailand2013Conference paper (Other academic)
  • 23. Kittayapong, P
    et al.
    Olarantmanee, P
    Maskao, P
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Lohr, Wolfgang
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Gubler, D
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    A school-based intervention trial using insecticide-treated school uniforms to reduce dengue infections in school-aged children2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 114-114 p.Article in journal (Other academic)
    Abstract [en]

    Background: There is an urgent need to enhance our armamentarium to prevent dengue infections in children. Since dengue vectors (Aedes mosquitoes) are active mainly during the day, a potential target for control should be schools where children spend a considerable amount of their day. School uniforms are the cultural norm in most developing countries, worn throughout the day. We hypothesized that insecticide-treated school uniforms will  reduce the incidence of dengue infection in school-aged children. Our objective was to determine the impact of impregnated school uniforms on dengue incidence.

    Methods: A randomised controlled trial was conducted in 10 schools in eastern Thailand in 2012. Pre-fabricated school uniforms were commercially treated to ensure consistent high quality of insecticide impregnation with permethrin. The 1-h-knock-down effect and 24 h mortality of Aedes mosquitoes by the impregnated cloth was tested at baseline and then once per month using WHOPES cone test. Blood samples were taken at baseline and at the end of the school-term for the hemagglutination-inhibition assay to identify serologically confirmed dengue infections during the study period. Students were randomized into intervention schools (all students wearing impregnated uniforms) versus control schools (uniforms had the same appearance and odor, but were not impregnated).

    Results: A total of 1808 students in 10 schools were enrolled, mean age 10.07 years. Of these, 1651 had paired blood samples taken, which showed an incidence of new dengue infection of 3.3 % over the school term (5  months). There was no difference in the incidence of dengue infections in intervention versus control schools. Both the knock-down and mortality at baseline were close to 100%, but rapidly waned after only 8 washes to 20% e.g. after only 1 month of wearing the uniform.

    Conclusion: Although the results of mosquitoes’ knock-down and mortality of impregnated schools looked very promising, we did not see a protective effect of impregnated uniforms on reducing dengue infections in this school-based trial. The most likely reason for the apparent failure was the rapid waning efficacy of impregnation after washing. New technologies need to be developed to overcome rapid waning efficacy of impregnated clothing.

    Disclosure: This research was funded by the European Commission 7th Framework and was conducted by ‘DengueTools’ partners.

  • 24. Kittayapong, P
    et al.
    Ruangsri, B.
    Intasanta, V
    Phanomkate, N
    Subjalerndee, N
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Efficacy of permethrin-impregnated clothing on knock-down and mortality of dengue mosquito vectors2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 110-110 p.Article in journal (Other academic)
    Abstract [en]

    Introduction: As vector control for dengue has proven to be elusive, additional methods to protect against dengue are urgently needed. We have previously shown that pre-fabricated clothing impregnated with permethrin in a proprietary manner had a close to 100% 1 h knock-down and 24 h-mortality effect on Aedes mosquito vectors. However, this effect rapidly declined with repeated washing. Here we investigated different impregnation techniques to assess the best method with the lowest waning efficacy after washing. Materials and methods School clothes were impregnated with permethrin by two different technologies: pad-dry-cure versus exhaustion. Impregnated products were tested for their efficacy using laboratory-reared Aedes mosquito vectors using WHOPES cone test, before and after 10 washes.

    Results: The 1 h knock down effect and 24 h mortality rate of school clothes treated by both technologies were both found to be 100%. However, the clothes treated by pad-dry-cure technology could stand frequent washing better than those treated by exhaustion technology. The decrease in efficacy of up to about 60% of the clothes treated by pad-dry-cure technology was observed after washing 8 times while those treated by exhaustion technology showed decrease in knock-down effect (67.27%) and mortality rate (74.29%) after washing only 4 times.

    Conclusion: The knock-down and 24 h mortality results look very promising to support impregnated clothing as a potential strategy to protect against day-biting Aedes mosquito vectors to prevent dengue infections. However, rapid waning efficacy of impregnated clothing after <10 washes suggests that impregnation techniques for sustainable effect are sub-optimal and hence such an approach is not recommended at this point in time. Either new impregnation technologies will need to be developed to overcome the waning efficacy after washing, or clothing such as aprons or vests will need to be employed. Since school aprons are hanged in classrooms after daily use without washing through out the school term, they could potentially have a prolonged impact of permethrin on mosquito vectors (in terms of knock-down and mortality) and eventually dengue transmission in school.

    This research was funded by the European Union 7th Frame- work Programme through ‘DengueTools’ and Mahidol University.

    Disclosure: Nothing to disclose

  • 25. Kittayapong, Pattamaporn
    et al.
    Olanratmanee, Phanthip
    Maskhao, Pongsri
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Logan, James
    Tozan, Yesim
    Louis, Valérie
    Gubler, Duane J
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. London School of Hygiene and Tropical Medicine, London, United Kingdom; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
    Mitigating Diseases Transmitted by Aedes Mosquitoes: A Cluster-Randomised Trial of Permethrin-Impregnated School Uniforms2017In: PLoS Neglected Tropical Diseases, ISSN 1935-2727, E-ISSN 1935-2735, Vol. 11, no 1, e0005197Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Viral diseases transmitted via Aedes mosquitoes are on the rise, such as Zika, dengue, and chikungunya. Novel tools to mitigate Aedes mosquitoes-transmitted diseases are urgently needed. We tested whether commercially insecticide-impregnated school uniforms can reduce dengue incidence in school children.

    METHODS: We designed a cluster-randomised controlled trial in Thailand. The primary endpoint was laboratory-confirmed dengue infections. Secondary endpoints were school absenteeism; and impregnated uniforms' 1-hour knock-down and 24 hour mosquito mortality as measured by standardised WHOPES bioassay cone tests at baseline and after repeated washing. Furthermore, entomological assessments inside classrooms and in outside areas of schools were conducted.

    RESULTS: We enrolled 1,811 pupils aged 6-17 from 5 intervention and 5 control schools. Paired serum samples were obtained from 1,655 pupils. In the control schools, 24/641 (3.7%) and in the intervention schools 33/1,014 (3.3%) students had evidence of new dengue infections during one school term (5 months). There was no significant difference in proportions of students having incident dengue infections between the intervention and control schools, with adjustment for clustering by school. WHOPES cone tests showed a 100% knock down and mortality of Aedes aegypti mosquitoes exposed to impregnated clothing at baseline and up to 4 washes, but this efficacy rapidly declined to below 20% after 20 washes, corresponding to a weekly reduction in knock-down and mosquito mortality by 4.7% and 4.4% respectively. Results of the entomological assessments showed that the mean number of Aedes aegypti mosquitoes caught inside the classrooms of the intervention schools was significantly reduced in the month following the introduction of the impregnated uniforms, compared to those collected in classrooms of the control schools (p = 0.04).

    CONCLUSIONS: Entomological assessments showed that the intervention had some impact on the number of Aedes mosquitoes inside treatment schools immediately after impregnation and before insecticidal activity declined. However, there was no serological evidence of protection against dengue infections over the five months school term, best explained by the rapid washing-out of permethrin after 4 washes. If rapid washing-out of permethrin could be overcome by novel technological approaches, insecticide-treated clothes might become a potentially cost-effective and scalable intervention to protect against diseases transmitted by Aedes mosquitoes such as dengue, Zika, and chikungunya.

    TRIAL REGISTRATION: ClinicalTrials.gov NCT01563640.

  • 26. Lim, Jacqueline Kyungah
    et al.
    Lee, Yong-Seok
    Wilder-Smith, Annelies
    Thiry, Georges
    Mahoney, Richard
    Yoon, In-Kyu
    Points for Consideration for dengue vaccine introduction: recommendations by the Dengue Vaccine Initiative2016In: Expert Review of Vaccines, ISSN 1476-0584, E-ISSN 1744-8395, Vol. 15, no 4, 529-538 p.Article, review/survey (Refereed)
    Abstract [en]

    Dengue is a public health problem in the tropics and subtropics. There are several vaccine candidates in clinical development. However, there may be gaps in the new vaccine introduction after vaccine licensure before it becomes available in developing countries. In anticipation of the first dengue vaccine candidate to be licensed, Dengue Vaccine Initiative (DVI) and, its predecessor, Pediatric Dengue Vaccine Initiative (PDVI) have been working on points for consideration to accelerate evidence-based dengue vaccine introduction, once a vaccine becomes available. In this paper, we review the history of PDVI and its successor, the DVI, and elaborate on the points of consideration for dengue vaccine introduction.

  • 27.
    Liu-Helmersson, Jing
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Stenlund, Hans
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    Ebi, K
    Massad, E
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Seasonality of dengue epidemic potential in Europe - based on vectorial capacity for Aedes mosquitoes2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 113-113 p.Article in journal (Other academic)
    Abstract [en]

    Introduction: Dengue is a mosquito-borne viral infection that has become a major public health concern. About 390 million people are infected yearly. Increased global connectivity and population movement as well as climate change affect the global distribution of both dengue vectors and the virus, facilitating the spread of dengue to new geographic areas. Weather is an important factor determining mosquito behaviour and effectiveness of dengue virus transmission. Dengue epidemic potential depends on vectorial capacity of Aedes mosquitoes, which depend on climate, such as, temperature and diurnal temperature range. This study aims at identifying high-risk areas and high-risk time windows in Europe based on temperature, in order for timely vector surveillance and control.

    Methods: Relative vectorial capacity (rVc) was used to estimate dengue epidemic potential. Using historical and projected temperature data over two centuries (1901–2099) and temperature dependent vector parameters for Aedes vectors, rVc was calculated for 10 selected European cities from Stockholm in the North to Malaga in the South.

    Results: Compared to dengue endemic areas, rVc in Europe was lower and showed more prominent seasonality. The peak and width of the seasonal windows in rVc were generally higher in the South than the North. Currently, only South and Central-East Europe and the summer season corresponds to rVc that is over the threshold for possible dengue transmission. By the end of this century, in the best case scenario, all the Central and Southern European cities would be at risk for dengue transmission during the warmer months; in the worst case scenario, this risk would extend to Northern European to include Stockholm if dengue vectors were established and virus introduced.

    Conclusion: As travel and globalization become more frequent channels for dengue vector and virus introduction, Europe may face the reality of more frequent dengue outbreaks in their warmer months. Madeira's outbreak in 2012 underlines this concern. The future's high risk area and time window depend sensitively on climate scenarios. Therefore, it is important to emphasize climate change mitigation and enhance vector surveillance and control in Europe.

    Acknowledgement: This research was funded by the European Union 7th Framework Programme through 'DengueTools' (www.denguetools.net).

    Disclosure: Nothing to disclose.

  • 28.
    Liu-Helmersson, Jing
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Stenlund, Hans
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Ebi, Kristie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. University of Washington, Seattle, Washington, USA.
    Massad, Eduardo
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Climate Change and Aedes Vectors: 21st Century Projections for Dengue Transmission in Europe.2016In: EBioMedicine, ISSN 0360-0637, E-ISSN 2352-3964, Vol. 7, 267-277 p.Article in journal (Refereed)
    Abstract [en]

    Warming temperatures may increase the geographic spread of vector-borne diseases into temperate areas. Although a tropical mosquito-borne viral disease, a dengue outbreak occurred in Madeira, Portugal, in 2012; the first in Europe since 1920s. This outbreak emphasizes the potential for dengue re-emergence in Europe given changing climates. We present estimates of dengue epidemic potential using vectorial capacity (VC) based on historic and projected temperature (1901-2099). VC indicates the vectors' ability to spread disease among humans. We calculated temperature-dependent VC for Europe, highlighting 10 European cities and three non-European reference cities. Compared with the tropics, Europe shows pronounced seasonality and geographical heterogeneity. Although low, VC during summer is currently sufficient for dengue outbreaks in Southern Europe to commence-if sufficient vector populations (either Ae. aegypti and Ae. albopictus) were active and virus were introduced. Under various climate change scenarios, the seasonal peak and time window for dengue epidemic potential increases during the 21st century. Our study maps dengue epidemic potential in Europe and identifies seasonal time windows when major cities are most conducive for dengue transmission from 1901 to 2099. Our findings illustrate, that besides vector control, mitigating greenhouse gas emissions crucially reduces the future epidemic potential of dengue in Europe.

  • 29.
    Liu-Helmersson, Jing
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Stenlund, Hans
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Ebi, Kristie
    University of Washington, Seattle, Washington, USA.
    Massad, Eduardo
    School of Medicine, University of Sao Paulo, Brazil.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Climate Change and Aedes Vectors: 21st Century Projections for Dengue Transmission in EuropeArticle in journal (Refereed)
    Abstract [en]

    Warming temperatures may increase the geographic spread of vector-borne diseases into temperate areas. Although a tropical mosquito-borne viral disease, a dengue outbreak occurred in Madeira, Portugal, in 2012; the first in Europe since 1920s. This outbreak emphasizes the potential for dengue re-emergence in Europe given changing climates. We present estimates of dengue epidemic potential using vectorial capacity (VC) based on historic and projected temperature (1901 - 2099). VC indicates the vectors’ ability to spread disease among humans. We calculated temperature-dependent VC for Europe, highlighting 10 European cities and three non-European reference cities. Compared with the tropics, Europe shows pronounced seasonality and geographical heterogeneity. Although low, VC during summer is currently sufficient for dengue outbreaks in Southern Europe to commence–if sufficient vector populations (either Ae. aegypti and Ae. albopictus) were active and virus were introduced. Under various climate change scenarios, the seasonal peak and time window for dengue epidemic potential increases during the 21st century. Our study maps dengue epidemic potential in Europe and identifies seasonal time windows when major cities are most conducive for dengue transmission from 1901-2099. Our findings illustrate, that besides vector control, mitigating greenhouse gas emissions crucially reduces the future epidemic potential of dengue in Europe.

  • 30.
    Liu-Helmersson, Jing
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Stenlund, Hans
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Vectorial Capacity of Aedes aegypti: Effects of Temperature and Implications for Global Dengue Epidemic Potential2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, e89783- p.Article in journal (Refereed)
    Abstract [en]

    Dengue is a mosquito-borne viral disease that occurs mainly in the tropics and subtropics but has a high potential to spread to new areas. Dengue infections are climate sensitive, so it is important to better understand how changing climate factors affect the potential for geographic spread and future dengue epidemics. Vectorial capacity (VC) describes a vector's propensity to transmit dengue taking into account human, virus, and vector interactions. VC is highly temperature dependent, but most dengue models only take mean temperature values into account. Recent evidence shows that diurnal temperature range (DTR) plays an important role in influencing the behavior of the primary dengue vector Aedes aegypti. In this study, we used relative VC to estimate dengue epidemic potential (DEP) based on the temperature and DTR dependence of the parameters of A. aegypti. We found a strong temperature dependence of DEP; it peaked at a mean temperature of 29.3 degrees C when DTR was 0 degrees C and at 20 degrees C when DTR was 20 degrees C. Increasing average temperatures up to 29 degrees C led to an increased DEP, but temperatures above 29 degrees C reduced DEP. In tropical areas where the mean temperatures are close to 29 degrees C, a small DTR increased DEP while a large DTR reduced it. In cold to temperate or extremely hot climates where the mean temperatures are far from 29 degrees C, increasing DTR was associated with increasing DEP. Incorporating these findings using historical and predicted temperature and DTR over a two hundred year period (1901-2099), we found an increasing trend of global DEP in temperate regions. Small increases in DEP were observed over the last 100 years and large increases are expected by the end of this century in temperate Northern Hemisphere regions using climate change projections. These findings illustrate the importance of including DTR when mapping DEP based on VC.

  • 31.
    Liyanage, Prasad
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Ministry of Health, Colombo 01000, Sri Lanka.
    Tissera, Hasitha
    Sewe, Maquins
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. KEMRI Centre for Global Health Research, Kisumu, Kenya, Box 1578, Kisumu 40100, Kenya.
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Amarasinghe, Ananda
    Palihawadana, Paba
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.
    Louis, Valerie R.
    Tozan, Yesim
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    A Spatial Hierarchical Analysis of the Temporal Influences of the El Niño-Southern Oscillation and Weather on Dengue in Kalutara District, Sri Lanka2016In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 13, no 11, 1087Article in journal (Refereed)
    Abstract [en]

    Dengue is the major public health burden in Sri Lanka. Kalutara is one of the highly affected districts. Understanding the drivers of dengue is vital in controlling and preventing the disease spread. This study focuses on quantifying the influence of weather variability on dengue incidence over 10 Medical Officer of Health (MOH) divisions of Kalutara district. Weekly weather variables and data on dengue notifications, measured at 10 MOH divisions in Kalutara from 2009 to 2013, were retrieved and analysed. Distributed lag non-linear model and hierarchical-analysis was used to estimate division specific and overall relationships between weather and dengue. We incorporated lag times up to 12 weeks and evaluated models based on the Akaike Information Criterion. Consistent exposure-response patterns between different geographical locations were observed for rainfall, showing increasing relative risk of dengue with increasing rainfall from 50 mm per week. The strongest association with dengue risk centred around 6 to 10 weeks following rainfalls of more than 300 mm per week. With increasing temperature, the overall relative risk of dengue increased steadily starting from a lag of 4 weeks. We found similarly a strong link between the Oceanic Niño Index to weather patterns in the district in Sri Lanka and to dengue at a longer latency time confirming these relationships. Part of the influences of rainfall and temperature can be seen as mediator in the causal pathway of the Ocean Niño Index, which may allow a longer lead time for early warning signals. Our findings describe a strong association between weather, El Niño-Southern Oscillation and dengue in Sri Lanka.

  • 32. Lopez, Luis Fernandez
    et al.
    Amaku, Marcos
    Coutinho, Francisco Antonio Bezerra
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Burattini, Marcelo Nascimento
    Struchiner, Claudio José
    Wilder-Smith, Annelies
    Massad, Eduardo
    Modeling Importations and Exportations of Infectious Diseases via Travelers2016In: Bulletin of Mathematical Biology, ISSN 0092-8240, E-ISSN 1522-9602, Vol. 78, no 2, 185-209 p.Article in journal (Refereed)
    Abstract [en]

    This paper is an attempt to estimate the risk of infection importation and exportation by travelers. Two countries are considered: one disease-free country and one visited or source country with a running endemic or epidemic infectious disease. Two models are considered. In the first model (disease importation), susceptible individuals travel from their disease-free home country to the endemic country and come back after some weeks. The risk of infection spreading in their home country is then estimated supposing the visitors are submitted to the same force of infection as the local population but do not contribute to it. In the second model (disease exportation), it is calculated the probability that an individual from the endemic (or epidemic) country travels to a disease-free country in the condition of latent infected and eventually introduces the infection there. The input of both models is the force of infection at the visited/source country, assumed known. The models are deterministic, but a preliminary stochastic formulation is presented as an appendix. The models are exemplified with two distinct real situations: the risk of dengue importation from Thailand to Europe and the risk of Ebola exportation from Liberia to the USA.

  • 33. Louis, Valérie R
    et al.
    Montenegro Quiñonez, Carlos Alberto
    Kusumawathie, Pad
    Palihawadana, Paba
    Janaki, Sakoo
    Tozan, Yesim
    Wijemuni, Ruwan
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. nstitute of Public Health, Heidelberg University, Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Tissera, Hasitha A
    Characteristics of and factors associated with dengue vector breeding sites in the City of Colombo, Sri Lanka.2016In: Pathogens and Global Health, ISSN 2047-7724, E-ISSN 2047-7732, Vol. 110, no 2, 79-86 p.Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Dengue has emerged as a major public health problem in Sri Lanka. Vector control at community level is a frequent and widespread strategy for dengue control. The aim of the study was to assess Aedes mosquito breeding sites and the prevention practices of community members in a heavily urbanized part of Colombo.

    METHODS: A cross-sectional entomological survey was conducted from April to June 2013 in 1469 premises located in a subdistrict of the City of Colombo. Types of breeding sites and, where found, their infestation with larvae or pupae were recorded. Furthermore, a questionnaire was administered to the occupants of these premises to record current practices of dengue vector control.

    RESULTS: The surveyed premises consisted of 1341 residential premises and 110 non-residential premises (11 schools, 99 work or public sites), 5 open lands, and 13 non-specified. In these 1469 premises, 15447 potential breeding sites suitable to host larvae of pupae were found; of these sites18.0% contained water. Among the 2775 potential breeding sites that contained water, 452 (16.3%) were positive for larvae and/or pupae. Schools were associated with the proportionally highest number of breeding sites; 85 out of 133 (63.9%) breeding sites were positive for larvae and/or pupae in schools compared with 338 out of 2288 (14.8%) in residential premises. The odds ratio (OR) for schools and work or public sites for being infested with larvae and/or pupae was 2.77 (95% CI 1.58, 4.86), when compared to residential premises. Occupants of 80.8% of the residential premises, 54.5% of the schools and 67.7% of the work or public sites reported using preventive measures. The main prevention practices were coverage of containers and elimination of mosquito breeding places. Occupants of residential premises were much more likely to practice preventive measures than were those of non-residential premises (OR 2.23; 1.49, 3.36).

    CONCLUSION: Schools and working sites were associated with the highest numbers of breeding sites and lacked preventive measures for vector control. In addition to pursuing vector control measures at residential level, public health strategies should be expanded in schools and work places.

  • 34. Louis, Valérie R
    et al.
    Phalkey, Revati
    Horstick, Olaf
    Ratanawong, Pitcha
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, Heidelberg University Medical School, Heidelberg, Germany.
    Tozan, Yesim
    Dambach, Peter
    Modeling tools for dengue risk mapping - a systematic review2014In: International Journal of Health Geographics, ISSN 1476-072X, Vol. 13, 50Article, review/survey (Refereed)
    Abstract [en]

    INTRODUCTION: The global spread and the increased frequency and magnitude of epidemic dengue in the last 50 years underscore the urgent need for effective tools for surveillance, prevention, and control. This review aims at providing a systematic overview of what predictors are critical and which spatial and spatio-temporal modeling approaches are useful in generating risk maps for dengue.

    METHODS: A systematic search was undertaken, using the PubMed, Web of Science, WHOLIS, Center for Disease Control (CDC) and OvidSP databases for published citations, without language or time restrictions. A manual search of the titles and abstracts was carried out using predefined criteria, notably the inclusion of dengue cases. Data were extracted for pre-identified variables, including the type of predictors and the type of modeling approach used for risk mapping.

    RESULTS: A wide variety of both predictors and modeling approaches was used to create dengue risk maps. No specific patterns could be identified in the combination of predictors or models across studies. The most important and commonly used predictors for the category of demographic and socio-economic variables were age, gender, education, housing conditions and level of income. Among environmental variables, precipitation and air temperature were often significant predictors. Remote sensing provided a source of varied land cover data that could act as a proxy for other predictor categories. Descriptive maps showing dengue case hotspots were useful for identifying high-risk areas. Predictive maps based on more complex methodology facilitated advanced data analysis and visualization, but their applicability in public health contexts remains to be established.

    CONCLUSIONS: The majority of available dengue risk maps was descriptive and based on retrospective data. Availability of resources, feasibility of acquisition, quality of data, alongside available technical expertise, determines the accuracy of dengue risk maps and their applicability to the field of public health. A large number of unknowns, including effective entomological predictors, genetic diversity of circulating viruses, population serological profile, and human mobility, continue to pose challenges and to limit the ability to produce accurate and effective risk maps, and fail to support the development of early warning systems.

  • 35. Lover, Andrew A
    et al.
    Sutton, Brett A
    Asy, Angelina J
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Germany.
    An exploratory study of treated-bed nets in Timor-Leste: patterns of intended and alternative usage.2011In: Malaria Journal, ISSN 1475-2875, Vol. 10, 199- p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The Timor-Leste Ministry of Health has recently finalized the National Malaria Control Strategy for 2010-2020. A key component of this roadmap is to provide universal national coverage with long-lasting insecticide-treated nets (LLINs) in support of achieving the primary goal of reducing both morbidity and mortality from malaria by 30% in the first three years, followed by a further reduction of 20% by end of the programme cycle in 2020 1. The strategic plan calls for this target to be supported by a comprehensive information, education and communication (IEC) programme; however, there is limited prior research into household and personal usage patterns to assist in the creation of targeted, effective, and socio-culturally specific behaviour change materials.

    METHODS: Nine separate focus group discussions (FGDs) were carried out in Dili, Manatuto, and Covalima districts, Democratic Republic of Timor-Leste, in July 2010.These focus groups primarily explored themes of perceived malaria risk, causes of malaria, net usage patterns within families, barriers to correct and consistent usage, and the daily experience of users (both male and female) in households with at least one net. Comprehensive qualitative analysis utilized open source analysis software.

    RESULTS: The primary determinants of net usage were a widespread perception that nets could or should only be used by pregnant women and young children, and the availability of sufficient sleeping space under a limited number of nets within households. Both nuisance biting and disease prevention were commonly cited as primary motivations for usage, while seasonality was not a significant factor. Long-term net durability and ease of hanging were seen as key attributes in net design preference. Very frequent washing cycles were common, potentially degrading net effectiveness. Finally, extensive re-purposing of nets (fishing, protecting crops) was both reported and observed, and may significantly decrease availability of nighttime sleeping space for all family members if distributed nets do not remain within the household.

    CONCLUSIONS: Emphasizing that net usage is acceptable and important for all family members regardless of age or gender, and addressing the complex behavioural economics of alternative net usages could have significant impacts on malaria control efforts in Timor-Leste, as the country's programmes make progress towards universal net coverage.

  • 36. Massad, E
    et al.
    Lopez, L F
    Amaku, M
    Coutinho, F A B
    Quam, Mikkel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Burattini, M N
    Struchiner, C J
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
    The risk of infectious diseases introduction into non-infected countries by travelers visiting endemic countries2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 340-340 p.Article in journal (Other academic)
    Abstract [en]

    This work is an attempt to estimate the risk of infections importation and exportation by travelers. In it we propose a model that takes into account the force of infection of the disease in the endemic country, which can either be a visited country (source of infection importation) or a country from where local residents export the infection when travel in the latent condition for disease-free countries. The model is deterministic but a preliminary stochastic formulation is presented in the appendix. It considers two countries: one is the host home-country and the other is the source country (with an endemic infectious disease). Susceptible individuals travel from their home-country to the endemic country and eventually return infected. The input of the model is the force of infection at the visited/source country which is assumed to be known and we assume that, in the case of disease importation, travelers are subject to the same risk of infection as local residents but do not contribute to it. In the case of disease exportation, the model calculates the probability that a latent individual travels from an endemic (or epidemic) country to a disease-free country. We exemplify the model with two distinct situation, namely, the risk of dengue importation from Thailand to Europe and the risk of Ebola exportation from Liberia to the USA.

    Disclosure: Nothing to disclose.

  • 37. Massad, E.
    et al.
    Nascimento Burattini, M.
    Khan, K.
    Struchiner, C. J.
    Coutinho, F. A. B.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    On the origin and timing of Zika virus introduction in Brazil2017In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 145, no 11, 2303-2312 p.Article in journal (Refereed)
    Abstract [en]

    The timing and origin of Zika virus (ZIKV) introduction in Brazil has been the subject of controversy. Initially, it was assumed that the virus was introduced during the FIFA World Cup in June-July 2014. Then, it was speculated that ZIKV may have been introduced by athletes from French Polynesia (FP) who competed in a canoe race in Rio de Janeiro in August 2014. We attempted to apply mathematical models to determine the most likely time window of ZIKV introduction in Brazil. Given that the timing and origin of ZIKV introduction in Brazil may be a politically sensitive issue, its determination (or the provision of a plausible hypothesis) may help to prevent undeserved blame. We used a simple mathematical model to estimate the force of infection and the corresponding individual probability of being infected with ZIKV in FP. Taking into account the air travel volume from FP to Brazil between October 2013 and March 2014, we estimated the expected number of infected travellers arriving at Brazilian airports during that period. During the period between December 2013 and February 2014, 51 individuals travelled from FP airports to 11 Brazilian cities. Basing on the calculated force of ZIKV infection (the per capita rate of new infections per time unit) and risk of infection (probability of at least one new infection), we estimated that 18 (95% CI 12-22) individuals who arrived in seven of the evaluated cities were infected. When basic ZIKV reproduction numbers greater than one were assumed in the seven evaluated cities, ZIKV could have been introduced in any one of the cities. Based on the force of infection in FP, basic reproduction ZIKV number in selected Brazilian cities, and estimated travel volume, we concluded that ZIKV was most likely introduced and established in Brazil by infected travellers arriving from FP in the period between October 2013 and March 2014, which was prior to the two aforementioned sporting events.

  • 38. Massad, E.
    et al.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Coutinho, F.
    Struchiner, C.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Determining the main driver for the increase of epidemic dengue in Singapore2013Conference paper (Other academic)
  • 39. Massad, E
    et al.
    Rocklöv, Joacim
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dengue infections in non-immune travellers to Thailand2013In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 141, no 2, 412-417 p.Article in journal (Refereed)
    Abstract [en]

    Dengue is the most frequent arboviral disease and is expanding geographically. Dengue is also increasingly being reported in travellers, in particular in travellers to Thailand. However, data to quantify the risk of travellers acquiring dengue when travelling to Thailand are lacking. Using mathematical modelling, we set out to estimate the risk of non-immune persons acquiring dengue when travelling to Thailand. The model is deterministic with stochastic parameters and assumes a Poisson distribution for the mosquitoes' biting rate and a Gamma distribution for the probability of acquiring dengue from an infected mosquito. From the force of infection we calculated the risk of dengue acquisition for travellers to Thailand arriving in a typical year (averaged over a 17-year period) in the high season of transmission. A traveller arriving in the high season of transmission and remaining for 7 days has a risk of acquiring dengue of 0.2% (95% CI 0.16-0.23), whereas the risk for travel of 15 and 30 days' duration is 0.46% (95% CI 0.41-0.50) and 0.81% (95% CI 0.76-0.87), respectively. Our data highlight that the risk of non-immune travellers acquiring dengue in Thailand is substantial. The incidence of 0.81% after a 1-month stay is similar to that reported in prospective seroconversion studies in Israeli travellers to Thailand, highlighting that our models are consistent with actual data. Risk estimates based on mathematical modelling offer more detailed information depending on various travel scenarios, and will help the travel medicine provider give better evidence-based advice for travellers to dengue-endemic countries.

  • 40. Massad, Eduardo
    et al.
    Amaku, Marcos
    Bezerra Coutinho, Francisco Antonio
    Kittayapong, Pattamaporn
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Theoretical impact of insecticide-impregnated school uniforms on dengue incidence in Thai children2013In: Global health action, ISSN 1654-9880, Vol. 6, 1-6 p.Article in journal (Refereed)
    Abstract [en]

    Background: Children carry the main burden of morbidity and mortality caused by dengue. Children spend a considerable amount of their day at school; hence strategies that reduce human-mosquito contact to protect against the day-biting habits of Aedes mosquitoes at schools, such as insecticide-impregnated uniforms, could be an effective prevention strategy.

    Methodology: We used mathematical models to calculate the risk of dengue infection based on force of infection taking into account the estimated proportion of mosquito bites that occur in school and the proportion of school time that children wear the impregnated uniforms. Principal findings: The use of insecticide-impregnated uniforms has efficacy varying from around 6% in the most pessimistic estimations, to 55% in the most optimistic scenarios simulated.

    Conclusions: Reducing contact between mosquito bites and human hosts via insecticide-treated uniforms during school time is theoretically effective in reducing dengue incidence and may be a valuable additional tool for dengue control in school-aged children. The efficacy of this strategy, however, is dependent on the compliance of the target population in terms of proper and consistent wearing of uniforms and, perhaps more importantly, the proportion of bites inflicted by the Aedes population during school time.

  • 41. Massad, Eduardo
    et al.
    Bezerra Coutinho, Francisco Antonio
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Singapore.
    The olympically mismeasured risk of Zika virus in Rio de Janeiro: authors' reply2016In: The Lancet, ISSN 0140-6736, E-ISSN 1474-547X, Vol. 388, no 10045, 658-659 p.Article in journal (Other academic)
  • 42. Massad, Eduardo
    et al.
    Burattini, Marcelo N.
    Ximenes, Raphael
    Amaku, Marcos
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Dengue outlook for the World Cup in Brazil2014In: Lancet. Infectious diseases (Print), ISSN 1473-3099, E-ISSN 1474-4457, Vol. 14, no 7, 552-553 p.Article in journal (Refereed)
  • 43. Massad, Eduardo
    et al.
    Coutinho, Francisco Antonio Bezerra
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Singapore.
    Is Zika a substantial risk for visitors to the Rio de Janeiro Olympic Games?2016In: The Lancet, ISSN 0140-6736, E-ISSN 1474-547X, Vol. 388, no 10039, 25-25 p.Article in journal (Other (popular science, discussion, etc.))
  • 44. Massad, Eduardo
    et al.
    Tan, Ser-Han
    Khan, Kamran
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Germany ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Estimated Zika virus importations to Europe by travellers from Brazil2016In: Global Health Action, ISSN 1654-9716, E-ISSN 1654-9880, Vol. 9, 1-7 p., 31669Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Given the interconnectivity of Brazil with the rest of the world, Zika virus (ZIKV) infections have the potential to spread rapidly around the world via viremic travellers. The extent of spread depends on the travel volume and the endemicity in the exporting country. In the absence of reliable surveillance data, we did mathematical modelling to estimate the number of importations of ZIKV from Brazil into Europe.

    DESIGN: We applied a previously developed mathematical model on importations of dengue to estimate the number of ZIKV importations into Europe, based on the travel volume, the probability of being infected at the time of travel, the population size of Brazil, and the estimated incidence of ZIKV infections.

    RESULTS: Our model estimated between 508 and 1,778 imported infections into Europe in 2016, of which we would expect between 116 and 355 symptomatic Zika infections; with the highest number of importations being into France, Portugal and Italy.

    CONCLUSIONS: Our model identified high-risk countries in Europe. Such data can assist policymakers and public health professionals in estimating the extent of importations in order to prepare for the scale up of laboratory diagnostic assays and estimate the occurrence of Guillain-Barré Syndrome, potential sexual transmission, and infants with congenital ZIKV syndrome.

  • 45. Massad, Eduardo
    et al.
    Wilder-Smith, Annelies
    Lee Kong Chian School of Medicine, Nanyang University, Singapore.
    Ximenes, Raphael
    Amaku, Marcos
    Lopez, Luis Fernandez
    Coutinho, Francisco Antonio Bezerra
    Coelho, Giovanini Evelim
    Silva, Jarbas Barbosa da
    Struchiner, Claudio José
    Burattini, Marcelo Nascimento
    Risk of symptomatic dengue for foreign visitors to the 2014 FIFA World Cup in Brazil2014In: Memórias do instituto Oswaldo Cruz, ISSN 1678-8060, E-ISSN 1678-8060, Vol. 109, no 3, 394-397 p.Article in journal (Refereed)
    Abstract [en]

    Brazil will host the FIFA World Cup™, the biggest single-event competition in the world, from June 12-July 13 2014 in 12 cities. This event will draw an estimated 600,000 international visitors. Brazil is endemic for dengue. Hence, attendees of the 2014 event are theoretically at risk for dengue. We calculated the risk of dengue acquisition to non-immune international travellers to Brazil, depending on the football match schedules, considering locations and dates of such matches for June and July 2014. We estimated the average per-capita risk and expected number of dengue cases for each host-city and each game schedule chosen based on reported dengue cases to the Brazilian Ministry of Health for the period between 2010-2013. On the average, the expected number of cases among the 600,000 foreigner tourists during the World Cup is 33, varying from 3-59. Such risk estimates will not only benefit individual travellers for adequate pre-travel preparations, but also provide valuable information for public health professionals and policy makers worldwide. Furthermore, estimates of dengue cases in international travellers during the World Cup can help to anticipate the theoretical risk for exportation of dengue into currently non-infected areas.

  • 46. Montenegro, C A
    et al.
    Louis, V R
    Kusumawathie, P
    Palihawadana, P
    Tozan, Y
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, Heidelberg University, Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore City, Singapore.
    Tissera, H
    Entomological survey of dengue vector breeding sites in Colombo, Sri Lanka2015In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 20, no Suppl. 1, 409-410 p.Article in journal (Other academic)
    Abstract [en]

    Introduction: In Sri Lanka, the number of dengue cases has steadily increased in recent years. Prevention through disease and vector surveillance is an important strategy in dengue control. The aim of the study was to assess Aedes mosquito breeding sites and the prevention practices of community members in one heavily urbanized area of Colombo.

    Methods: A cross-sectional entomological survey was conducted from April to June 2013 in 1469 premises located in a sub-district of Colombo Municipality. Types of breeding sites and infestation with larvae or pupae were recorded and a questionnaire was administered to occupants to assess knowledge and practises concerning dengue vector control.

    Results: The surveyed premises included 1341 households (91%), 99 work or public sites and 11 schools. 126 premises were positive for Aedes larvae or pupae. 12 672 potential breeding sites susceptible to host larvae or pupae were recorded, of which 21% contained water. Among these, 6% were positive for larvae and 13% for pupae. For schools the percentage rose to 40% and 67%, respectively. The main productive breeding sites were: discarded items, water tanks, ornamental plants, ponds and flowerpots, and non-specified containers. The majority was located on outdoor ground areas. Compared to households, the odds ratio for non-household premises of being infested with larvae was 2.29 (P = 0.005, 95% CI: 1.278–4.129) and with pupae 5.76 (P < 0.001, 95% CI: 2.660–12.497). Occupants of 82% of the premises reported using preventive measures. The main practices were coverage of containers and elimination of mosquito-breeding places. 45% of schools and 19% of households took no preventive measures. There was a significant correlation between the occurrence of preventative measures taken and the type of premise involved (P = 0.002).

    Conclusion: Residential buildings had the lowest relative number of potential breeding sites, and household members reported a high use of vector control measures. Schools and working sites, however, were identified as being at highest risk for productive breeding sites combined with shortcomings in preventive measures. Hence, this study suggests that while it is important to maintain vector control and prevention practices at the household level, schools and working sites should actively be targeted to better combat dengue.

    Acknowledgements: This research was funded by 'DengueTools' of the 7th Framework Programme of the European Community.

    Disclosure: Nothing to disclose.

  • 47. Murray, N.
    et al.
    Louis, V.
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Jansarikij, S.
    Olanratmanee, P.
    Maskhao, P.
    Kittayapong, P.
    Innovative dengue prevention and control using permethrin-impregnated school uniforms: a mixed methods study on acceptability2013In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 18, no Special Issue, 52-53 p.Article in journal (Other academic)
  • 48.
    Murray, Natasha Evelyn Anne
    et al.
    Institute of Public Health, University of Heidelberg, Heidelberg, Germany; Population Health, Waikato District Health Board, Hamilton, New Zealand.
    Quam, Mikkel B.
    Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
    Wilder-Smith, Annelies
    Institute of Public Health, University of Heidelberg, Heidelberg, Germany; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Epidemiology of dengue: past, present and future prospects2013In: Clinical Epidemiology, ISSN 1179-1349, E-ISSN 1179-1349, no 5, 299-309 p.Article in journal (Refereed)
    Abstract [en]

    Dengue is currently regarded globally as the most important mosquito-borne viral disease. A history of symptoms compatible with dengue can be traced back to the Chin Dynasty of 265-420 AD. The virus and its vectors have now become widely distributed throughout tropical and subtropical regions of the world, particularly over the last half-century. Significant geographic expansion has been coupled with rapid increases in incident cases, epidemics, and hyperendemicity, leading to the more severe forms of dengue. Transmission of dengue is now present in every World Health Organization (WHO) region of the world and more than 125 countries are known to be dengue endemic. The true impact of dengue globally is difficult to ascertain due to factors such as inadequate disease surveillance, misdiagnosis, and low levels of reporting. Currently available data likely grossly underestimates the social, economic, and disease burden. Estimates of the global incidence of dengue infections per year have ranged between 50 million and 200 million; however, recent estimates using cartographic approaches suggest this number is closer to almost 400 million. The expansion of dengue is expected to increase due to factors such as the modern dynamics of climate change, globalization, travel, trade, socioeconomics, settlement and also viral evolution. No vaccine or specific antiviral therapy currently exists to address the growing threat of dengue. Prompt case detection and appropriate clinical management can reduce the mortality from severe dengue. Effective vector control is the mainstay of dengue prevention and control. Surveillance and improved reporting of dengue cases is also essential to gauge the true global situation as indicated in the objectives of the WHO Global Strategy for Dengue Prevention and Control, 2012-2020. More accurate data will inform the prioritization of research, health policy, and financial resources toward reducing this poorly controlled disease. The objective of this paper is to review historical and current epidemiology of dengue worldwide and, additionally, reflect on some potential reasons for expansion of dengue into the future.

  • 49. Murray, Natasha
    et al.
    Jansarikij, Suphachai
    Olanratmanee, Phanthip
    Maskhao, Pongsri
    Souares, Aurélia
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Heidelberg, Germany ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
    Kittayapong, Pattamaporn
    Louis, Valérie R
    Acceptability of impregnated school uniforms for dengue control in Thailand: a mixed methods approach2014In: Global health action, ISSN 1654-9880, E-ISSN 1654-9880, Vol. 7, 24887- p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: As current dengue control strategies have been shown to be largely ineffective in reducing dengue in school-aged children, novel approaches towards dengue control need to be studied. Insecticide-impregnated school uniforms represent an innovative approach with the theoretical potential to reduce dengue infections in school children.

    OBJECTIVES: This study took place in the context of a randomised control trial (RCT) to test the effectiveness of permethrin-impregnated school uniforms (ISUs) for dengue prevention in Chachoengsao Province, Thailand. The objective was to assess the acceptability of ISUs among parents, teachers, and principals of school children involved in the trial.

    METHODOLOGY: Quantitative and qualitative tools were used in a mixed methods approach. Class-clustered randomised samples of school children enrolled in the RCT were selected and their parents completed 321 self-administered questionnaires. Descriptive statistics and logistic regression were used to analyse the quantitative data. Focus group discussions and individual semi-structured interviews were conducted with parents, teachers, and principals. Qualitative data analysis involved content analysis with coding and thematic development.

    RESULTS: The knowledge and experience of dengue was substantial. The acceptability of ISUs was high. Parents (87.3%; 95% CI 82.9-90.8) would allow their child to wear an ISU and 59.9% (95% CI 53.7-65.9) of parents would incur additional costs for an ISU over a normal uniform. This was significantly associated with the total monthly income of a household and the educational level of the respondent. Parents (62.5%; 95% CI 56.6-68.1) indicated they would be willing to recommend ISUs to other parents.

    CONCLUSIONS: Acceptability of the novel tool of ISUs was high as defined by the lack of concern along with the willingness to pay and recommend. Considering issues of effectiveness and scalability, assessing acceptability of ISUs over time is recommended.

  • 50. Neumayr, Andreas
    et al.
    Muñoz, Jose
    Schunk, Mirjam
    Bottieau, Emmanuel
    Cramer, Jakob
    Calleri, Guido
    López-Vélez, Rogelio
    Angheben, Andrea
    Zoller, Thomas
    Visser, Leo
    Serre-Delcor, Núria
    Genton, Blaise
    Castelli, Francesco
    Van Esbroeck, Marjan
    Matteelli, Alberto
    Rochat, Laurence
    Sulleiro, Elena
    Kurth, Florian
    Gobbi, Federico
    Norman, Francesca
    Torta, Ilaria
    Clerinx, Jan
    Poluda, David
    Martinez, Miguel
    Calvo-Cano, Antonia
    Sanchez-Seco, Maria Paz
    Wilder-Smith, Annelies
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Institute of Public Health, University of Heidelberg, Germany.
    Hatz, Christoph
    Franco, Leticia
    Sentinel surveillance of imported dengue via travellers to Europe 2012 to 2014: TropNet data from the DengueTools Research Initiative2017In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 22, no 1, 39-47 p.Article in journal (Refereed)
    Abstract [en]

    We describe the epidemiological pattern and genetic characteristics of 242 acute dengue infections imported to Europe by returning travellers from 2012 to 2014. The overall geographical pattern of imported dengue (South-east Asia > Americas > western Pacific region > Africa) remained stable compared with 1999 to 2010. We isolated the majority of dengue virus genotypes and epidemic lineages causing outbreaks and epidemics in Asia, America and Africa during the study period. Travellers acted as sentinels for four unusual dengue outbreaks (Madeira, 2012-13; Luanda, 2013; Dar es Salaam, 2014; Tokyo, 2014). We were able to characterise dengue viruses imported from regions where currently no virological surveillance data are available. Up to 36% of travellers infected with dengue while travelling returned during the acute phase of the infection (up to 7 days after symptom onset) or became symptomatic after returning to Europe, and 58% of the patients with acute dengue infection were viraemic when seeking medical care. Epidemiological and virological data from dengue-infected international travellers can add an important layer to global surveillance efforts. A considerable number of dengue-infected travellers are viraemic after arrival back home, which poses a risk for dengue introduction and autochthonous transmission in European regions where suitable mosquito vectors are prevalent.

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