Umeå University's logo

Objectives: Vaccine responses in haematopoietic stem cell transplant (alloHCT) recipients vary, with different degrees of B-cell reconstitution likely playing a key role. However, mechanistic understanding of the B-cell receptor (BCR) repertoire and its functional impact post-alloHCT remain limited.

Methods: Within the scope of a mRNA SARS-CoV-2 vaccine phase IV clinical trial in alloHCT recipients (n = 77), we have measured antibody titers and avidity, and performed B-cell immunophenotyping and B-cell receptor repertoire sequencing in sub-populations.

Results: AlloHCT patients receiving prime-boost mRNA vaccination within 12 months post-transplant exhibited lower vaccine-specific antibody levels and memory B-cell frequencies than vaccinated healthy controls. Responses were comparable to healthy controls in patients vaccinated later than 12 months post transplant. BCR repertoire sequencing showed reduced somatic hypermutation (SHM) levels in bulk IgG+ B cells from alloHCT patients. Although some alloHCT patients showed exceptional expansion of a few IgG clones of unknown specificity, their overall B-cell repertoires remained polyclonal. Vaccine-specific B-cell clonotypes detected in patients responding to vaccination showed similar proportional expansion and SHM as in controls. The level of immature CD24hiCD38hi transitional B cells pre-vaccination was negatively correlated to the vaccine response, and can be used as a predictor of antibody titres.

Conclusion: Our data indicate that mRNA vaccination can stimulate expansion of vaccine-specific B cells to affinity mature in many alloHCT recipients, though restricted by the presence of immature B-cell populations.

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants with bioaccumulative, biomagnifying and toxic potential, and largely unknown fate and health effects in terrestrial wildlife. In a contaminated area, we studied PFAS in a terrestrial food web including soil, mushrooms, berries, and wild-living herbivores (bank vole and two ungulate species) and a specialized predator (Tengmalm’s owl). In addition, in voles, we studied potential PFAS-induced liver damage and infection with a zoonotic pathogen. Concentrations of PFAS in vole livers were among the highest reported in terrestrial wildlife. Results suggest biomagnification of PFAS from soil, mushrooms, and berries to bank voles, from mushrooms to ungulates and from voles to the owl. Most vole livers showed diffuse cytoplasmic granulation, ranging from mild to severe, as well as mild and variable hepatocellular hypertrophy. We found high prevalence of Orthohantavirus puumalaense infection in bank voles, highlighting the possibility of PFAS-induced infection susceptibility. Our study supports that terrestrial wildlife magnifies PFAS from the environment and highlights largely unexplored yet worrying effects on wildlife health.

Objectives: Dengue virus (DENV) is a global public health concern owing to its widespread distribution, significant morbidity, and potentially severe outcomes. Although not yet reported in Rwanda, this study aimed to explore the DENV seroprevalence in selected health facilities. Methods: Serum samples from 2286 patients who visited 11 health facilities nationwide were investigated for DENV and Zika virus immunoglobulin G. Bivariate and multivariate logistic regression analyses were performed to determine the predictors. Results: The DENV seroprevalence was 30.4 %, but Zika virus immunoglobulin G was not detected. Participants’ mean age was 40.5 ± 16.3 years; 62.2 % were females and 37.8 % were males. In total, 85.8 % were farmers, 4.7 % were office workers, and 3 % were vocational professionals. Farmers had a higher risk of past DENV infections than other professionals. No significant differences in past infections were observed between sexes or age groups. Conclusions: These findings indicate past DENV infections in Rwanda, highlighting the need for DENV surveillance and enhanced diagnostic capacity. Strengthening these efforts will help prevent infectious diseases, reduce unnecessary treatments, and mitigate the risk of antimicrobial resistance.

Mosquitoes are known to vector arthropod-borne viruses (arboviruses) that pose a global public health issue in the form of mosquito-borne viral diseases such as chikungunya fever, dengue fever, Japanese encephalitis, yellow fever, and Zika. Besides, mosquitoes may also carry insect-specific viruses (ISVs), which are evolutionarily alike arboviruses yet do not infect vertebrates. These ISVs have been shown to affect the ability of mosquitoes to transmit arboviruses, as well as potentially inhibit arbovirus infections in vertebrate hosts. Yet, ISVs still constitute a relatively new and little-researched area where further studies may yield new knowledge regarding their distribution, their future importance in the control of mosquito-borne viral disease and potential role in biological control of mosquitoes. This review provides insights into ISV classification, transmission, and biology, as well as historical and future aspects. It mainly focuses on the characterization of the transmission dynamics of ISVs to highlight the various potential arboviral pathogen transmission blocking mechanisms along with evolution and host tropism. The review also provides additional information on the potential use of ISVs as a method of biological control in comparison to other proposed methods as well as delving into current research into arbovirus-based vaccines and antiviral drug development.

The pandemic threat from newly emerging viral diseases constitutes a major unsolved issue for global health. Antiviral therapy can play an important role in treating and preventing the spread of unprecedented viral infections. A repository of compounds exhibiting broad-spectrum antiviral activity against a series of different viral families would be an invaluable asset to be prepared for future pandemic threats. Utilizing an open innovation crowd-sourcing paradigm, we were able to identify a compound class of diphenylureas that exhibits in vitro antiviral activity against multiple viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), adenovirus, dengue virus, herpes, and influenza viruses. Compound 4 among the series exhibits strong activity against dengue virus, a growing global health problem with high medical need and no approved antiviral drug. The compounds are active against SARS-CoV-2 in a primary human stem cell-based mucociliary airway epithelium model and also active in vivo, as shown in a murine SARS-CoV-2 infection model. These results demonstrate the potential of the chemical class as antivirals on the one hand and the power of open innovation, crowd-sourcing, and repurposing on the other hand.

Arthropod-borne (arbo) viruses cause emerging diseases that affect the livelihoods of people around the world. They are linked to disease outbreaks resulting in high morbidity, mortality, and economic loss. In sub-Saharan Africa, numerous arbovirus outbreaks have been documented, but the circulation and magnitude of illness caused by these viruses during inter-epidemic periods remains unknown in many regions. In Rwanda, there is limited knowledge on the presence and distribution of arboviruses. This study aimed at determining the occurrence and distribution of selected arboviruses, i.e., chikungunya virus (CHIKV), o’nyong-nyong virus (ONNV), dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKV), Rift Valley fever virus (RVFV) and Crimean-Congo haemorrhagic fever virus (CCHFV), among febrile patients visiting health centres in Rwanda. A total of 2294 dry blood spots (DBS) were collected on filter papers during August 2019 – December 2020. Reverse-transcription polymerase chain reaction (RT-PCR) was performed on samples in pools of ten, using both quantitative (DENV, ZIKV, RVFV) and conventional PCR (CHIKV, ONNV, WNV, CCHFV) with virus specific primers, followed by sequencing. Demographic data and clinical manifestations of illness were analysed. ONNV infection was detected in 12 of 230 pools (5.2%) and ZIKV in three pools (1.3%). The other arboviruses were not detected. All ONNV cases were found in the Rwaniro health centre, while ZIKV infection was found among patients visiting the Kirinda and Zaza health centres. There was temporal variability in ONNV infections with most cases being recorded during the long dry season, while ZIKV infection occurred during both dry and wet seasons. Patients with ONNV were older and more were females. In conclusion, ONNV and ZIKV infection were detected in acute patients and can explain some of the feverish diseases in Rwanda.

mRNA vaccines are likely to become widely used for the prevention of infectious diseases in the future. Nevertheless, a notable gap exists in mechanistic data, particularly concerning the potential effects of sequential mRNA immunization or preexisting immunity on the early innate immune response triggered by vaccination. In this study, healthy adults, with or without documented prior SARS-CoV-2 infection, were vaccinated with the BNT162b2/Comirnaty mRNA vaccine. Prior infection conferred significantly stronger induction of proinflammatory and type I IFN-related gene signatures, serum cytokines, and monocyte expansion after the prime vaccination. The response to the second vaccination further increased the magnitude of the early innate response in both study groups. The third vaccination did not further increase vaccine-induced inflammation. In vitro stimulation of PBMCs with TLR ligands showed no difference in cytokine responses between groups, or before or after prime vaccination, indicating absence of a trained immunity effect. We observed that levels of preexisting antigen-specific CD4 T cells, antibody, and memory B cells correlated with elements of the early innate response to the first vaccination. Our data thereby indicate that preexisting memory formed by infection may augment the innate immune activation induced by mRNA vaccines.

Surveillance of mosquito vectors is critical for early detection, prevention and control of vector borne diseases. In this study we used advanced molecular tools, such as DNA barcoding in combination with novel sequencing technologies to discover new and already known viruses in genetically identified mosquito species. Mosquitoes were captured using BG sentinel traps in Western Kenya during May and July 2019, and homogenized individually before pooled into groups of ten mosquitoes. The pools and individual samples were then used for molecular analysis and to infect cell cultures. Of a total of fifty-four (54) 10-pools, thirteen (13) showed cytopathic effect (CPE) on VeroB4 cells, eighteen (18) showed CPE on C6/36 cells. Eight (8) 10-pools out of the 31 CPE positive pools showed CPE on both VeroB4 and C6/36 cells. When using reverse transcriptase polymerase chain reaction (RT-PCR), Sanger sequencing and Twist Comprehensive Viral Research Panel (CVRP) (Twist Biosciences), all pools were found negative by RT-PCR when using genus specific primers targeting alphaviruses, orthobunyaviruses and virus specific primers towards o'nyong-nyong virus, chikungunya virus and Sindbis virus (previously reported to circulate in the region). Interestingly, five pools were RT-PCR positive for flavivirus. Two of the RT-PCR positive pools showed CPE on both VeroB4 and C6/36 cells, two pools showed CPE on C6/36 cells alone and one pool on VeroB4 cells only. Fifty individual mosquito homogenates from the five RT-PCR positive 10-pools were analyzed further for flavivirus RNA. Of these, 19 out of the 50 individual mosquito homogenates indicated the presence of flavivirus RNA. Barcoding of the flavivirus positive mosquitoes revealed the mosquito species as Aedes aegypti (1), Mansonia uniformis (6), Anopheles spp (3), Culex pipiens (5), Culex spp (1), Coquilletidia metallica (2) and Culex quinquefasciatus (1). Of the 19 flavivirus positive individual mosquitoes, five (5) virus positive homogenates were sequenced. Genome sequences of two viruses were completed. One was identified as the single-stranded RNA Culex flavivirus and the other as the double-stranded RNA Hubei chryso-like virus 1. Both viruses were found in the same Anopheles spp. homogenate extracted from a sample that showed CPE on both VeroB4 and C6/36 cells. The detection of both viruses in a single mosquito homogenate indicated coinfection. Phylogenetic analyses suggested that the Culex flavivirus sequence detected was closely related to a Culex flavivirus isolated from Uganda in 2008. All four Hubei chryso-like virus 1 segments clusters closely to Hubei chryso-like virus 1 strains isolated in Australia, China and USA. Two novel strains of insect-specific viruses in Anopheles mosquitoes were detected and characterized.

BACKGROUND: Quality healthcare is a global priority, reliant on robust health systems for evidence-based medicine. Clinical laboratories are the backbone of quality healthcare facilitating diagnostics, treatment, patient monitoring, and disease surveillance. Their effectiveness depends on sustainable delivery of accurate test results. Although the Strengthening Laboratory Management Towards Accreditation (SLMTA) programme has enhanced laboratory quality in low-income countries, the long-term sustainability of this improvement remains uncertain.

OBJECTIVE: To explore the sustainability of quality performance in clinical laboratories in Rwanda following the conclusion of SLMTA.

METHODS: A quasi-experimental design was adopted, involving 47 laboratories divided into three groups with distinct interventions. While one group received continuous mentorship and annual assessments (group two), interventions for the other groups (groups one and three) ceased following the conclusion of SLMTA. SLMTA experts collected data for 10 years through assessments using WHO's StepwiseLaboratory Quality Improvement Process Towards Accreditation (SLIPTA) checklist. Descriptive and t-test analyses were conducted for statistical evaluation.

RESULTS: Improvements in quality were noted between baseline and exit assessments across all laboratory groups (mean baseline: 35.3%, exit: 65.8%, p < 0.001). However, groups one and three experienced performance declines following SLMTA phase-out (mean group one: 64.6% in reference to 85.8%, p = 0.01; mean group three: 57.3% in reference to 64.7%, p < 0.001). In contrast, group two continued to enhance performance even years later (mean: 86.6%compared to 70.6%, p = 0.03).

CONCLUSION: A coordinated implementation of quality improvement plan that enables regular laboratory assessments to pinpoint and address the quality gaps is essential for sustaining quality services in clinical laboratories.

Background: The current SARS-CoV-2 pandemic has highlighted a need for easy and safe blood sampling in combination with accurate serological methodology. Venipuncture for testing is usually performed by trained staff at healthcare centres. Long travel distances to healthcare centres in rural regions may introduce a bias of testing towards relatively large communities with closer access. Rural regions are therefore often not represented in population-based data.

Aim: The aim of this retrospective cohort study was to develop and implement a strategy for at-home testing in a rural region of Sweden during spring 2021, and to evaluate its role to provide equal health care for its inhabitants.

Methods: We developed a sensitive method to measure antibodies to the S-protein of SARS-CoV-2 and optimised this assay for clinical use together with a strategy of at-home capillary blood sampling.

Results: We demonstrated that our ELISA gave comparable results after analysis of capillary blood or serum from SARS-CoV-2-experienced individuals. We demonstrated stability of the assay under conditions that reflected temperature and humidity during winter or summer. By assessment of capillary blood samples from 4,122 individuals, we could show both feasibility of the strategy and that implementation shifted the geographical spread of testing in favour of rural areas.

Conclusion: Implementation of at-home sampling enabled citizens living in remote rural areas access to centralised and sensitive laboratory antibody tests. The strategy for testing used here could therefore enable disease control authorities to get rapid access to information concerning immunity to infectious diseases, even across vast geographical distance.