| 1. |
- Ecke, Frauke, et al.
(författare)
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Orthohantaviruses in the Arctic : present and future
- 2022
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Ingår i: Arctic one health. - Cham : Springer. - 9783030878528 - 9783030878559 - 9783030878535 ; , s. 393-414
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Bokkapitel (refereegranskat)abstract
- Orthohantaviruses, family Hantaviridae, are globally distributed except for Antarctica where they are absent. In animals, orthohantaviruses are transmitted horizontally, either directly through aggressive interactions and grooming or by inhaling infectious particles shed from urine, feces, or saliva in the environment. Humans become infected by inhaling aerosols of the virus-contaminated excretions of small mammals. Orthohantaviral infections in humans cause severe hantavirus pulmonary syndrome (HPS) in the North American Artic and hemorrhagic fever with renal syndrome (HFRS) in the Eurasian Arctic. In the Arctic, 16 rodent species (order Rodentia) and five shrew species (order Eulipotyphla) have been identified as reservoirs of orthohantaviruses by RNA detection. The two most important reservoir rodents in the Arctic are the bank vole (Myodes glareolus) in Eurasia carrying Puumala orthohantavirus (PUUV) and North American deermouse (Peromyscus maniculatus) in the North American Arctic carrying Sin Nombre orthohantavirus (SNV); both rodents being habitat generalists occurring in natural and human-modified habitats. Global warming, either independently or in combination with onshore exploitation of natural resources, is expected to increase the distribution range of reservoirs (including bank vole and North American deermouse, rats (Rattus rattus and R. norvegicus), house mouse (Mus musculus) and field mice (Apodemus spp.)), and their associated orthohantaviruses. These changes pose the risk of introducing New World orthohantaviruses (e.g., Jemez Springs virus (JMSV) and SNV) to areas where so far only Old World orthohantaviruses (e.g., Hantaan orthohantavirus (HTNV) and PUUV) occur and vice versa. Climate change in the Arctic will likely also promote transmission and prevalence of orthohantaviruses in their reservoirs and hence increase zoonotic risk. The expected environmental changes call for increased surveillance and preparedness to mitigate potential outbreaks of orthohantavirus diseases in humans.
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| 2. |
- Ecke, Frauke, et al.
(författare)
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Puumala Orthohantavirus Infection Does Not Affect the Trapping Success of Its Reservoir Host
- 2022
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert. - 1530-3667 .- 1557-7759. ; 22:5, s. 297-299
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Tidskriftsartikel (refereegranskat)abstract
- Pathogens might affect behavior of infected reservoir hosts and hence their trappability, which could bias population estimates of pathogen prevalence. In this study, we used snap-trapping data on Puumala orthohantavirus (PUUV)-infected (n = 1619) and noninfected (n = 6940) bank voles (Myodes glareolus) from five vole cycles, normally representing increase, peak, and decline phase, to evaluate if infection status affected trapping success. If PUUV infection, as previously suggested, increases activity and/or mobility, we would expect a higher proportion of infected than noninfected specimens in the first trapping night. However, the proportion of PUUV-infected voles did not differ across the three trapping nights. We conclude that PUUV infection did not affect trapping success, confirming snap trapping as an appropriate trapping method for studies on PUUV prevalence and likely other orthohantaviruses.
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| 3. |
- Khalil, Hussein, et al.
(författare)
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Declining ecosystem health and the dilution effect
- 2016
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The "dilution effect" implies that where species vary in susceptibility to infection by a pathogen, higher diversity often leads to lower infection prevalence in hosts. For directly transmitted pathogens, non-host species may "dilute" infection directly (1) and indirectly (2). Competitors and predators may (1) alter host behavior to reduce pathogen transmission or (2) reduce host density. In a well-studied system, we tested the dilution of the zoonotic Puumala hantavirus (PUUV) in bank voles (Myodes glareolus) by two competitors and a predator. Our study was based on long-term PUUV infection data (2003-2013) in northern Sweden. The field vole (Microtus agrestis) and the common shrew (Sorex araneus) are bank vole competitors and Tengmalm's owl (Aegolius funereus) is a main predator of bank voles. Infection probability in bank voles decreased when common shrew density increased, suggesting that common shrews reduced PUUV transmission. Field voles suppressed bank vole density in meadows and clear-cuts and indirectly diluted PUUV infection. Further, Tengmalm's owl decline in 1980-2013 may have contributed to higher PUUV infection rates in bank voles in 2003-2013 compared to 1979-1986. Our study provides further evidence for dilution effect and suggests that owls may have an important role in reducing disease risk.
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| 4. |
- Khalil, Hussein, et al.
(författare)
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Dynamics and Drivers of Hantavirus Prevalence in Rodent Populations
- 2014
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert, Inc. publishers. - 1530-3667 .- 1557-7759. ; 14:8, s. 537-551
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Forskningsöversikt (refereegranskat)abstract
- Human encroachment on wildlife habitats has contributed to the emergence of several zoonoses. Pathogenic hantaviruses are hosted by rodents and cause severe diseases in the Americas and Eurasia. We reviewed several factors that potentially drive prevalence (the proportion of infected rodents) in host populations. These include demography, behavior, host density, small mammal diversity, predation, and habitat and landscape characteristics. This review is the first to include a quantitative summary of the literature investigating hantavirus prevalence in rodents. Demographic structure and density were investigated the most and predation the least. Reported effects of demographic structure and small mammal diversity were consistent, whereby reproductive males were most likely to be infected and prevalence decreased with small mammal diversity. The influences of habitat and landscape properties are often complex and indirect. The relationship between density and prevalence merits more investigation. Most hantavirus hosts are habitat generalists and their control is challenging. Incorporating all potential factors and their interactions is essential to understanding and controlling infection in host populations.
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| 5. |
- Khalil, Hussein, et al.
(författare)
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Spatial prediction and validation of zoonotic hazard through micro-habitat properties : where does Puumala hantavirus hole - up?
- 2017
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Ingår i: BMC Infectious Diseases. - : BioMed Central. - 1471-2334. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: To predict the risk of infectious diseases originating in wildlife, it is important to identify habitats that allow the co-occurrence of pathogens and their hosts. Puumala hantavirus (PUUV) is a directly-transmitted RNA virus that causes hemorrhagic fever in humans, and is carried and transmitted by the bank vole (Myodes glareolus). In northern Sweden, bank voles undergo 3-4 year population cycles, during which their spatial distribution varies greatly.Methods: We used boosted regression trees; a technique inspired by machine learning, on a 10 - year time-series (fall 2003-2013) to develop a spatial predictive model assessing seasonal PUUV hazard using micro-habitat variables in a landscape heavily modified by forestry. We validated the models in an independent study area approx. 200 km away by predicting seasonal presence of infected bank voles in a five-year-period (2007-2010 and 2015).Results: The distribution of PUUV-infected voles varied seasonally and inter-annually. In spring, micro-habitat variables related to cover and food availability in forests predicted both bank vole and infected bank vole presence. In fall, the presence of PUUV-infected voles was generally restricted to spruce forests where cover was abundant, despite the broad landscape distribution of bank voles in general. We hypothesize that the discrepancy in distribution between infected and uninfected hosts in fall, was related to higher survival of PUUV and/ or PUUV-infected voles in the environment, especially where cover is plentiful.Conclusions: Moist and mesic old spruce forests, with abundant cover such as large holes and bilberry shrubs, also providing food, were most likely to harbor infected bank voles. The models developed using long-term and spatially extensive data can be extrapolated to other areas in northern Fennoscandia. To predict the hazard of directly transmitted zoonoses in areas with unknown risk status, models based on micro-habitat variables and developed through machine learning techniques in well-studied systems, could be used.
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| 6. |
- 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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| 7. |
- Magnusson, Magnus, et al.
(författare)
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Spatial and temporal variation of hantavirus bank vole infection in managed forest landscapes
- 2015
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Ingår i: Ecosphere. - 2150-8925 .- 2150-8925. ; 6:9
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Tidskriftsartikel (refereegranskat)abstract
- Zoonoses are major contributors to emerging infectious diseases globally. Hemorrhagic fever with renal syndrome (HFRS) is a zoonosis caused by rodent-borne hantaviruses. In Europe, Puumala hantavirus (PUUV) carried and shed by the bank vole (Myodes glareolus), is the most common cause of HFRS. We explore the relationship of PUUV infection in bank voles, as measured by PUUV antibody detection, with habitat and landscape scale properties during two successive vole cycles in boreal Sweden. Our analysis revealed that PUUV infection in the population was not uniform between cycles and across different landscapes. The mean density index of PUUV antibody positive and negative bank voles were highest in old forest, second highest in cut-over forest (approx. 0-30 years old) and lowest on mires. Most importantly, old forest was the core habitat, where PUUV antibody positive bank voles were found through the low density phase and the transition between successive vole cycles. In spring, occurrence of antibody positive voles was negatively related to the proportion of cut-over forest in the surrounding landscape, suggesting that large scale human induced land-use change altered the occurrence of PUUV infection in voles which has not been shown before. Dependence of PUUV infection on habitat and landscape structure, and the variation in infection load within and between cycles are of importance for human risk assessment.
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| 8. |
- Sipari, Saana, et al.
(författare)
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Climate change accelerates winter transmission of a zoonotic pathogen
- 2022
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Ingår i: Ambio. - : Springer. - 0044-7447 .- 1654-7209. ; 51:3, s. 508-517
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Tidskriftsartikel (refereegranskat)abstract
- Many zoonotic diseases are weather sensitive, raising concern how their distribution and outbreaks will be affected by climate change. At northern high latitudes, the effect of global warming on especially winter conditions is strong. By using long term monitoring data (1980–1986 and 2003–2013) from Northern Europe on temperature, precipitation, an endemic zoonotic pathogen (Puumala orthohantavirus, PUUV) and its reservoir host (the bank vole, Myodes glareolus), we show that early winters have become increasingly wet, with a knock-on effect on pathogen transmission in its reservoir host population. Further, our study is the first to show a climate change effect on an endemic northern zoonosis, that is not induced by increased host abundance or distribution, demonstrating that climate change can also alter transmission intensity within host populations. Our results suggest that rainy early winters accelerate PUUV transmission in bank voles in winter, likely increasing the human zoonotic risk in the North.
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| 9. |
- Abdelrahim, Nada A., et al.
(författare)
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Human herpes virus type-6 is associated with central nervous system infections in children in Sudan
- 2022
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Ingår i: African Journal of Laboratory Medicine. - : AOSIS. - 2225-2002 .- 2225-2010. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Human herpes virus type-6 (HHV-6) is increasingly recognised as a febrile agent in children. However, less is known in sub-Saharan African countries, including Sudan.Objective: We investigated the involvement of HHV-6 in paediatric central nervous system (CNS) infections in Khartoum, Sudan.Methods: Febrile patients aged up to 15 years with suspected CNS infections at Omdurman Hospital for Children from 01 December 2009 to 01 August 2010 were included. Viral DNA was extracted from leftover cerebrospinal fluid (CSF) specimens and quantitatively amplified by real-time polymerase chain reaction (PCR) at Umeå University in Sweden.Results: Of 503 CSF specimens, 13 (2.6%) were positive for HHV-6 (33.0% [13/40 of cases with proven infectious meningitis]). The median thermal cycle threshold for all HHV-6-positive specimens was 38 (range: 31.9-40.8). The median number of virus copies was 281.3/PCR run (1 × 105 copies/mL CSF; range: 30-44 × 103 copies/PCR run [12 × 103 - 18 × 106 copies/mL CSF]). All positive patients presented with fever and vomiting; 86.0% had seizures. The male-to-female ratio was 1:1; 50.0% were toddlers, 42.0% infants and 8.0% teenagers. Most (83.0%) were admitted in the dry season and 17.0% in the rainy season. Cerebrospinal fluid leukocytosis was seen in 33.0%, CSF glucose levels were normal in 86.0% and low in 14.0%, and CSF protein levels were low in 14.0% and high in 43.0%.Conclusion: Among children in Sudan with CNS infections, HHV-6 is common. Studies on the existence and spread of HHV-6 chromosomal integration in this population are needed.
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| 10. |
- Abdelrahim, Nada Abdelghani, et al.
(författare)
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Viral meningitis in Sudanese children : differentiation, etiology and review of literature
- 2022
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Ingår i: Medicine. - : Lippincott Williams & Wilkins. - 0025-7974 .- 1536-5964. ; 101:46
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Forskningsöversikt (refereegranskat)abstract
- Diagnosis of viral meningitis (VM) is uncommon practice in Sudan and there is no local viral etiological map. We therefore intended to differentiate VM using standardized clinical codes and determine the involvement of herpes simplex virus types-1 and 2 (HSV-1/2), varicella zoster virus, non-polio human enteroviruses (HEVs), and human parechoviruses in meningeal infections in children in Sudan. This is a cross-sectional hospital-based study. Viral meningitis was differentiated in 503 suspected febrile attendee of Omdurman Hospital for Children following the criteria listed in the Clinical Case Definition for Aseptic/Viral Meningitis. Patients were children age 0 to 15 years. Viral nucleic acids (DNA/RNA) were extracted from cerebrospinal fluid (CSF) specimens using QIAamp® UltraSens Virus Technology. Complementary DNA was prepared from viral RNA using GoScriptTM Reverse Transcription System. Viral nucleic acids were amplified and detected using quantitative TaqMan® Real-Time and conventional polymerase chain reactions (PCRs). Hospital diagnosis of VM was assigned to 0%, when clinical codes were applied; we considered 3.2% as having VM among the total study population and as 40% among those with proven infectious meningitis. Two (0.4%) out of total 503 CSF specimens were positive for HSV-1; Ct values were 37.05 and 39.10 and virus copies were 652/PCR run (261 × 103/mL CSF) and 123/PCR run (49.3 × 103/mL CSF), respectively. Other 2 (0.4%) CSF specimens were positive for non-polio HEVs; Ct values were 37.70 and 38.30, and the approximate virus copies were 5E2/PCR run (~2E5/mL CSF) and 2E2/PCR run (~8E4/mL CSF), respectively. No genetic materials were detected for HSV-2, varicella zoster virus, and human parechoviruses. The diagnosis of VM was never assigned by the hospital despite fulfilling the clinical case definition. Virus detection rate was 10% among cases with proven infectious meningitis. Detected viruses were HSV-1 and non-polio HEVs. Positive virus PCRs in CSFs with normal cellular counts were seen.
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