| 1. |
- Obanda, Vincent, et al.
(författare)
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Livestock Presence Influences the Seroprevalence of Crimean Congo Hemorrhagic Fever Virus on Sympatric Wildlife in Kenya
- 2021
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert. - 1530-3667 .- 1557-7759. ; 21:10, s. 809-816
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Tidskriftsartikel (refereegranskat)abstract
- Crimean Congo Hemorrhagic Fever (CCHF) is an emerging tick-borne zoonotic viral disease with the potential of causing public health emergencies. However, less is known about the role of wildlife and livestock in spreading the virus. Therefore, we aimed to assess how the interactions between African buffalo (Syncerus caffer) and cattle may influence the seroprevalence of CCHF across livestock-wildlife management systems in Kenya. The study included archived sera samples from buffalo and cattle from wildlife only habitats (Lake Nakuru National Park and Solio conservancy), open wildlife-livestock integrated habitats (Maasai Mara ecosystem and Meru National Park), and closed wildlife-livestock habitats (Ol Pejeta Conservancy) in Kenya. We analyzed 191 buffalo and 139 cattle sera using IDvet multispecies, double-antigen IgG enzyme-linked immunosorbent assay (ELISA). The seroprevalence toward Crimean Congo hemorrhagic fever virus (CCHFV) was significantly higher for buffalo compared to cattle (75.3% and 28.1%, respectively, p < 0.001). We obtained the highest seroprevalence among buffalo of 92.1% in closed wildlife only systems compared to 28.8% and 46.1% prevalence in closed-integrated and open-integrated systems, respectively. The regression coefficients were all negative for cattle compared to buffalo in both closed-integrated and open-integrated compared to wildlife only system. Our results show that CCHFV circulates among the diverse animal community in Kenya in spatially disconnected foci. The habitat overlap between cattle and buffalo makes cattle a "bridge species" or superspreader host for CCHFV and increases transmission risks to humans. The effect of animal management system on prevalence is depended on tick control on the cattle and not the animal per se. We conclude that buffalo, a host with a longer life span than livestock, is a reservoir and may serve as a sentinel population for longitudinal surveillance of CCHFV.
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| 2. |
- Engdahl, Cecilia, et al.
(författare)
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Identification of Swedish mosquitoes based on molecular barcoding of the COI gene and SNP analysis
- 2014
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 14:3, s. 478-488
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Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne infectious diseases are emerging in many regions of the world. Consequently, surveillance of mosquitoes and concomitant infectious agents is of great importance for prediction and prevention of mosquito-borne infectious diseases. Currently, morphological identification of mosquitoes is the traditional procedure. However, sequencing of specified genes or standard genomic regions, DNA barcoding, has recently been suggested as a global standard for identification and classification of many different species. Our aim was to develop a genetic method to identify mosquitoes and to study their relationship. Mosquitoes were captured at collection sites in northern Sweden and identified morphologically before the cytochrome c oxidase subunit I (COI) gene sequences of 14 of the most common mosquito species were determined. The sequences obtained were then used for phylogenetic placement, for validation and benchmarking of phenetic classifications and finally to develop a hierarchical PCR-based typing scheme based on single nucleotide polymorphism sites (SNPs) to enable rapid genetic identification, circumventing the need for morphological characterization. The results showed that exact phylogenetic relationships between mosquito taxa were preserved at shorter evolutionary distances, but at deeper levels, they could not be inferred with confidence using COI gene sequence data alone. Fourteen of the most common mosquito species in Sweden were identified by the SNP/PCR-based typing scheme, demonstrating that genetic typing using SNPs of the COI gene is a useful method for identification of mosquitoes with potential for worldwide application.
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| 3. |
- Pettersson, Lisa, et al.
(författare)
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Viral load and humoral immune response in association with disease severity in Puumala hantavirus-infected patients-implications for treatment
- 2014
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Ingår i: Clinical Microbiology and Infection. - : Wiley-Blackwell. - 1198-743X .- 1469-0691. ; 20:3, s. 235-241
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Tidskriftsartikel (refereegranskat)abstract
- Hantaviruses are the causative agents of haemorrhagic fever with renal syndrome (HFRS) in Eurasia and of hantavirus cardiopulmonary syndrome (HCPS) in the Americas. The case fatality rate varies between different hantaviruses and can be up to 40%. At present, there is no specific treatment available. The hantavirus pathogenesis is not well understood, but most likely, both virus-mediated and host-mediated mechanisms are involved. The aim of the present study was to investigate the association among Puumala hantavirus (PUUV) viral RNA load, humoral immune response and disease severity in patients with HFRS. We performed a study of 105 PUUV-infected patients that were followed during the acute phase of disease and for up to 1-3 months later. Fifteen of the 105 patients (14%) were classified as having moderate/severe disease. A low PUUV-specific IgG response (p <0.05) and also a higher white blood cell count (p <0.001) were significantly associated with more severe disease. The PUUV RNA was detected in a majority of patient plasma samples up to 9 days after disease onset; however, PUUV RNA load or longevity of viraemia were not significantly associated with disease severity. We conclude that a low specific IgG response was associated with disease severity in patients with HFRS, whereas PUUV RNA load did not seem to affect the severity of HFRS. Our results raise the possibility of passive immunotherapy as a useful treatment for hantavirus-infected patients.
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| 4. |
- Khalil, Hussein, et al.
(författare)
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The importance of bank vole density and rainy winters in predicting nephropathia epidemica incidence in Northern Sweden.
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic hantaviruses (family Bunyaviridae, genus Hantavirus) are rodent-borne viruses causing hemorrhagic fever with renal syndrome (HFRS) in Eurasia. In Europe, there are more than 10,000 yearly cases of nephropathia epidemica (NE), a mild form of HFRS caused by Puumala virus (PUUV). The common and widely distributed bank vole (Myodes glareolus) is the host of PUUV. In this study, we aim to explain and predict NE incidence in boreal Sweden using bank vole densities. We tested whether the number of rainy days in winter contributed to variation in NE incidence. We forecast NE incidence in July 2013-June 2014 using projected autumn vole density, and then considering two climatic scenarios: 1) rain-free winter and 2) winter with many rainy days. Autumn vole density was a strong explanatory variable of NE incidence in boreal Sweden in 1990-2012 (R2 = 79%, p<0.001). Adding the number of rainy winter days improved the model (R2 = 84%, p<0.05). We report for the first time that risk of NE is higher in winters with many rainy days. Rain on snow and ground icing may block vole access to subnivean space. Seeking refuge from adverse conditions and shelter from predators, voles may infest buildings, increasing infection risk. In a rainy winter scenario, we predicted 812 NE cases in boreal Sweden, triple the number of cases predicted in a rain-free winter in 2013/2014. Our model enables identification of high risk years when preparedness in the public health sector is crucial, as a rainy winter would accentuate risk.
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| 5. |
- Meheretu, Yonas, et al.
(författare)
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Prevalence of orthohantavirus-reactive antibodies in humans and peri-domestic rodents in northern Ethiopia
- 2021
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Ingår i: Viruses. - : MDPI. - 1999-4915. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from low-and high-density stone bund fields adjacent to houses and community-protected semi-natural habitats in Atsbi and Hagere Selam, where Tigray orthohantavirus was first discovered. We collected blood samples from both small mammals and residents using filter paper. The presence of orthohantavirus-reactive antibodies in blood was then analyzed using immunofluorescence assay (human samples) and enzyme linked immunosorbent assays (small mammal samples) with Puumala orthohantavirus as antigen. Viral RNA was detected by RT-PCR using small mammal blood samples. Total orthohantavirus prevalence (antibodies or virus RNA) in the small mammals was 3.37%. The positive animals were three Stenocephalemys albipes rats (prevalence in this species = 13.04%). The low prevalence made it impossible to determine whether season and stone bunds were associated with orthohantavirus prevalence in the small mammals. In humans, we report the first detection of orthohantavirus-reactive IgG antibodies in Ethiopia (seroprevalence = 5.26%). S. albipes lives in close proximity to humans, likely increasing the risk of zoonotic transmission.
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| 6. |
- Baudin, Maria, 1982-, et al.
(författare)
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Importance of charge interactions in Rift Valley fever virus attachment to host cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The mosquito-borne Rift Valley fever virus (RVFV) cause disease in both humans and animals and can infect a large range of animals as well as humans. Many different cell types are infected both in vivo and in vitro. To enter a cell the virus needs to attach and enter, and this initial binding to the host cell surface could depend on both general mechanisms, and different specific receptors. Our aim was to characterize determinants for RVFV entry into its host cells.To examine RVFV attachment to host cells we based our experimental assay on RVF virus-like particles containing a reporter gene. The enveloped RVFV uses protruding glycoproteins (Gn and Gc) for attachment and entry and to investigate potential virus-cell surface interactions, the net surface charge of the glycoproteins was first calculated. The RVFV glycoprotein Gn had a predicted isoelectric point (pI) of 7.6 and a net positive charge of +6.9 at pH 7.0, suggesting a charge interaction between the Gn ectodomain and the negatively charged cell surface. RVFV Gc on the other hand, was highly negatively charged, -12.8 at neutral pH, most probably reflecting that Gc is not exposed until after receptor binding. To characterize the general conditions needed for RVFV attachment, cells or virus were treated with various compounds. Both sodium chloride and the negatively charged heparin inhibited RVF virus-like particle infection, strongly indicating that viral binding was charge-dependent. Treatment with sodium periodate pointed to a carbohydrate structure as a cellular interaction partner. Removal of sialic acid or heparan sulfate receptors on the cell surface by enzymatic treatment and blocking of the heparan sulfate receptor did not inhibit virus attachment.In conclusion, RVFV binding to host cells was charge dependent and the results point to a carbohydrate structure with negative charge as a potential attachment factor.
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| 7. |
- Rusanganwa, Vincent, et al.
(författare)
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Arbovirus surveillance in febrile patients attending selected health facilities in Rwanda
- 2024
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Ingår i: Infection Ecology & Epidemiology. - : Taylor & Francis. - 2000-8686. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Näslund, Jonas, et al.
(författare)
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Emerging Mosquito-Borne Viruses Linked to Aedes aegypti and Aedes albopictus : Global Status and Preventive Strategies
- 2021
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert. - 1530-3667 .- 1557-7759. ; 21:10, s. 731-746
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Forskningsöversikt (refereegranskat)abstract
- Emerging mosquito-borne viruses continue to cause serious health problems and economic burden among billions of people living in and near the tropical belt of the world. The highly invasive mosquito species Aedes aegypti and Aedes albopictus have successively invaded and expanded their presence as key vectors of Chikungunya virus, dengue virus, yellow fever virus, and Zika virus, and that has consecutively led to frequent outbreaks of the corresponding viral diseases. Of note, these two mosquito species have gradually adapted to the changing weather and environmental conditions leading to a shift in the epidemiology of the viral diseases, and facilitated their establishment in new ecozones inhabited by immunologically naive human populations. Many abilities of Ae. aegypti and Ae. albopictus, as vectors of significant arbovirus pathogens, may affect the infection and transmission rates after a bloodmeal, and may influence the vector competence for either virus. We highlight that many collaborating risk factors, for example, the global transportation systems may result in sporadic and more local outbreaks caused by mosquito-borne viruses related to Ae. aegypti and/or Ae. albopictus. Those local outbreaks could in synergy grow and produce larger epidemics with pandemic characters. There is an urgent need for improved surveillance of vector populations, human cases, and reliable prediction models. In summary, we recommend new and innovative strategies for the prevention of these types of infections.
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| 9. |
- Lwande, Olivia Wesula, et al.
(författare)
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Seewis hantavirus in common shrew (Sorex araneus) in Sweden
- 2020
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Ingår i: Virology Journal. - : BioMed Central (BMC). - 1743-422X. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Rodent borne hantaviruses are emerging viruses infecting humans through inhalation. They cause hemorrhagic fever with renal syndrome and hemorrhagic cardiopulmonary syndrome. Recently, hantaviruses have been detected in other small mammals such as Soricomorpha (shrews, moles) and Chiroptera (bats), suggested as reservoirs for potential pandemic viruses and to play a role in the evolution of hantaviruses. It is important to study the global virome in different reservoirs, therefore our aim was to investigate whether shrews in Sweden carried any hantaviruses. Moreover, to accurately determine the host species, we developed a molecular method for identification of shrews.Method: Shrews (n = 198), caught during 1998 in Sweden, were screened with a pan-hantavirus PCR using primers from a conserved region of the large genome segment. In addition to morphological typing of shrews, we developed a molecular based typing method using sequencing of the mitochondrial cytochrome C oxidase I (COI) and cytochrome B (CytB) genes. PCR amplified hantavirus and shrew fragments were sequenced and phylogenetically analysed.Results: Hantavirus RNA was detected in three shrews. Sequencing identified the virus as Seewis hantavirus (SWSV), most closely related to previous isolates from Finland and Russia. All three SWSV sequences were retrieved from common shrews (Sorex araneus) sampled in Västerbotten County, Sweden. The genetic assay for shrew identification was able to identify native Swedish shrew species, and the genetic typing of the Swedish common shrews revealed that they were most similar to common shrews from Russia.Conclusion: We detected SWSV RNA in Swedish common shrew samples and developed a genetic assay for shrew identification based on the COI and CytB genes. This was the first report of presence of hantavirus in Swedish shrews.
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| 10. |
- Baudin, Maria, 1982-
(författare)
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Rift Valley fever : consequences of virus-host interactions
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rift Valley fever virus (RVFV) is a mosquito-borne virus which has the ability to infect a large variety of animals including humans in Africa and Arabian Peninsula. The abortion rate among these animals are close to 100%, and young animals develop severe disease which often are lethal.In humans, Rift Valley fever (RVF) presents in most cases as a mild illness with influenza-like symptoms. However, in about 8% of the cases it progresses into a more severe disease with a high case fatality rate. Since there is such a high abortion rate among infected animals, a link between human miscarriage and RVFV has been suggested, but never proven.We could in paper I for the first time show an association between acute RVFV infection and miscarriage in humans. We observed an increase in pregnant women arriving at the Port Sudan Hospital with fever of unknown origin, and several of the patients experienced miscarriage. When we analysed their blood samples for several viral diseases we found that many had an acute RVFV infection and of these, 54% experienced a miscarriage. The odds of having a miscarriage was 7 times higher for RVFV patients compared to the RVFV negative women of which only 12% miscarried. These results indicated that RVFV infection could be a contributing factor to miscarriage.RVFV is an enveloped virus containing the viral glycoproteins n and c (Gn and Gc respectively), where Gn most likely is responsible for the initial cellular contact. The protein DC-SIGN on dendritic cells and the glycosaminoglycan heparan sulfate has been suggested as cellular receptors for RVFV, however other mechanisms are probably also involved in binding and entry. Charge is a driving force for molecular interaction and has been shown to be important for cellular attachment of several viruses, and in paper II we could show that when the charge around the cells was altered, the infection was affected. We also showed that Gn most likely has a positive charge at a physiological pH.When we added negatively charged molecules to the viral particles before infection, we observed a decreased infection efficiency, which we also observed after removal of carbohydrate structures from the cell surface.Our results suggested that the cellular interaction partner for initial attachment is a negatively charged carbohydrate. Further investigations into the mechanisms of RVFV cellular interactions has to be undertaken in order to understand, and ultimately prevent, infection and disease.There is currently no vaccine approved for human use and no specific treatments for RVF, so there is a great need for developing safe effective drugs targeting this virus. We designed a whole-cell based high-throughput screen (HTS) assay which we used to screen libraries of small molecular compounds for anti-RVFV properties. After dose-response and toxicity analysis of the initial hits, we identified six safe and effective inhibitors of RVFV infection that with further testing could become drug candidates for treatment of RVF. This study demonstrated the application of HTS using a whole-cell virus replication reporter gene assay as an effective method to identify novel compounds with potential antiviral activity against RVFV.
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