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David W Macdonald - One of the best experts on this subject based on the ideXlab platform.
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woodland recovery after suppression of deer cascade effects for small mammals wood mice apodemus sylvaticus and bank voles Myodes glareolus
PLOS ONE, 2012Co-Authors: Emma R Bush, Christina D Buesching, Eleanor M Slade, David W MacdonaldAbstract:Over the past century, increases in both density and distribution of deer species in the Northern Hemisphere have resulted in major changes in ground flora and undergrowth vegetation of woodland habitats, and consequentially the animal communities that inhabit them. In this study, we tested whether recovery in the vegetative habitat of a woodland due to effective deer management (from a peak of 0.4–1.5 to <0.17 deer per ha) had translated to the small mammal community as an example of a higher order cascade effect. We compared deer-free exclosures with neighboring open woodland using capture-mark-recapture (CMR) methods to see if the significant difference in bank vole (Myodes glareolus) and wood mouse (Apodemus sylvaticus) numbers between these environments from 2001–2003 persisted in 2010. Using the multi-state Robust Design method in program MARK we found survival and abundance of both voles and mice to be equivalent between the open woodland and the experimental exclosures with no differences in various metrics of population structure (age structure, sex composition, reproductive activity) and individual fitness (weight), although the vole population showed variation both locally and temporally. This suggests that the vegetative habitat - having passed some threshold of complexity due to lowered deer density - has allowed recovery of the small mammal community, although patch dynamics associated with vegetation complexity still remain. We conclude that the response of small mammal communities to environmental disturbance such as intense browsing pressure can be rapidly reversed once the disturbing agent has been removed and the vegetative habitat is allowed to increase in density and complexity, although we encourage caution, as a source/sink dynamic may emerge between old growth patches and the recently disturbed habitat under harsh conditions.
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reasons for arboreality in wood mice apodemus sylvaticus and bank voles Myodes glareolus
Mammalian Biology, 2008Co-Authors: Christina D Buesching, Chris Newman, Rachael Twell, David W MacdonaldAbstract:Although it is broadly accepted that small mammals often climb trees, only few studies explore arboreality in woodland rodents systematically. Here, we investigate the three-dimensional habitat use of wood mice Apodemus sylvaticus and bank voles Myodes glareolus at three different sites in Wytham Woods, Oxfordshire, under varying environmental conditions. A total of 12 trapping sessions was carried out between March and September 2003 and 2004. During each session, 100 Longworth live-traps with shrew escape holes were set in a 25-point-grid for 3 succeeding nights. Each time, 50 traps were placed on the ground, and 50 in surrounding trees at heights of 30–250 cm. Wood mice were significantly more arboreal than bank voles, and male wood mice spent significantly more time in trees than did females. Arboreality in bank voles occurred only under high population densities and food shortage, and both species were significantly more arboreal in woodland with dense understorey. Thus we conclude that while arboreality is predominantly a result of inter- and intra-specific competition, of the two species we studied, only wood mice, being more agile, can afford to utilize trees without getting caught by predators, and that sex differences are due to male territoriality. Estimates of population sizes and distribution, as well as studies of inter-specific interactions and socio-spatial behaviour are presumed to be affected by these results, and are currently likely to underestimate rodent numbers considerably.
Heikki Henttonen - One of the best experts on this subject based on the ideXlab platform.
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Tick-borne Encephalitis Virus in Wild Rodents in Winter, Finland, 2008–2009
Emerging Infectious Diseases, 2020Co-Authors: Elina Tonteri, Liina Voutilainen, Heikki Henttonen, Jukka Niemimaa, Antti Vaheri, Anu Jääskeläinen, T. Tikkakoski, Olli VapalahtiAbstract:Rodents might maintain tick-borne encephalitis virus (TBEV) in nature through latent persistent infections. During 2 subsequent winters, 2008 and 2009, in Finland, we detected RNA of European and Siberian subtypes of TBEV in Microtus agrestis and Myodes glareolus voles, respectively. Persistence in rodent reservoirs may contribute to virus overwintering.
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Short Communication Associations between MHC genes and Puumala virus infection in Myodes glareolus are detected in wild populations, but not from experimental infection data
2020Co-Authors: Emmanuel Guivier, Katrien Tersago, Liina Voutilainen, Heikki Henttonen, Maxime Galan, Gert E Olsson, Eva R Kallio, Pierrejean G Male, Denis Augot, Nathalie CharbonnelAbstract:Usc Vecpar, AFSSA LERPAZ, JE2533, Universite´ de Reims Champagne-Ardenne,UFR Pharmacie, 51 rue Cognacq-Jay, 51100 Reims, FranceWe analysed the influence of MHC class II Dqa and Drb genes on Puumala virus (PUUV) infectionin bank voles (Myodes glareolus). We considered voles sampled in five European localities orderived from a previous experiment that showed variable infection success of PUUV. The geneticvariation observed in the Dqa and Drb genes was assessed by using single-strand conformationpolymorphism and pyrosequencing methods, respectively. Patterns were compared with thoseobtained from 13 microsatellites. We revealed significant genetic differentiation between PUUV-seronegative and -seropositive bank voles sampled in wild populations, at the Drb gene only. Theabsence of genetic differentiation observed at neutral microsatellites confirmed the important roleof selective pressures in shaping these Drb patterns. Also, we found no significant associationsbetween infection success and MHC alleles among laboratory-colonized bank voles, which isexplained by a loss of genetic variability that occurred during the captivity of these voles.
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The hidden faces of a biological invasion: parasite dynamics of invaders and natives.
International Journal for Parasitology, 2020Co-Authors: Peter Stuart, Heikki Henttonen, Colin Lawton, Linda Paredis, Claudia A. Ochoa Torres, Celia V. HollandAbstract:Abstract One of the primary drivers of emerging infectious diseases (EIDs) is human intervention via host or parasite translocations. A unique opportunity to study host and parasite dispersal during a bio-invasion currently exists in Ireland due to the introduction of the bank vole (Myodes glareolus) in the 1920s. The continuing range expansion of M. glareolus within Ireland presents a natural large-scale perturbation experiment. This study used the Irish M. glareolus model to conduct a spatiotemporal study analysing the parasite dynamics of native and invasive species throughout their range. Myodes glareolus and native Apodemus sylvaticus were trapped in woodlands across Ireland and surveyed for their helminth parasites. Myodes glareolus in Ireland were found to have lower parasite diversity in comparison to records of M. glareolus from across Europe and A. sylvaticus in Ireland. Increased density of M. glareolus resulted in a dilution effect, with significantly lower levels of parasitism overall in native hosts, where M. glareolus has been established longest. However, three helminth parasite species of A. sylvaticus increased in abundance in the presence of M. glareolus. Furthermore, M. glareolus at the expansion front were less parasitised (lower abundance and prevalence of certain parasites and lower parasite diversity) than M. glareolus from the core population. This “enemy release” is believed to be mediating the continued successful spread of the invader across Ireland. Our results identify two important variables, seasonality and the stage of the invasion, which should not be overlooked when investigating or managing the changing distribution of hosts and their parasites. Studies of bio-invasions and parasite transmission have primarily focused on the invasive host species or the native host species in cases where virulent pathogen spillover is observed. Our results demonstrate how the concurrent study of invasive and native hosts, and the careful identification of their parasite communities, allows the dynamic processes influencing the parasite component and intracommunity to be identified.
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microevolution of bank voles Myodes glareolus at neutral and immune related genes during multiannual dynamic cycles consequences for puumala hantavirus epidemiology
Infection Genetics and Evolution, 2017Co-Authors: Heikki Henttonen, Jeanfrancois Cosson, Maxime Galan, Jukka Niemimaa, Maria Razzauti, Adelaide Dubois, Bertrand Gauffre, Liina VoutilainenAbstract:Understanding how host dynamics, including variations of population size and dispersal, may affect the epidemiology of infectious diseases through ecological and evolutionary processes is an active research area. Here we focus on a bank vole (Myodes glareolus) metapopulation surveyed in Finland between 2005 and 2009. Bank vole is the reservoir of Puumala hantavirus (PUUV), the agent of nephropathia epidemica (NE, a mild form of hemorrhagic fever with renal symptom) in humans. M. glareolus populations experience multiannual density fluctuations that may influence the level of genetic diversity maintained in bank voles, PUUV prevalence and NE occurrence. We examine bank vole metapopulation genetics at presumably neutral markers and immune-related genes involved in susceptibility to PUUV (Tnf-promoter, Tlr4, Tlr7 and Mx2 gene) to investigate the links between population dynamics, microevolutionary processes and PUUV epidemiology. We show that genetic drift slightly and transiently affects neutral and adaptive genetic variability within the metapopulation. Gene flow seems to counterbalance its effects during the multiannual density fluctuations. The low abundance phase may therefore be too short to impact genetic variation in the host, and consequently viral genetic diversity. Environmental heterogeneity does not seem to affect vole gene flow, which might explain the absence of spatial structure previously detected in PUUV in this area. Besides, our results suggest the role of vole dispersal on PUUV circulation through sex-specific and density-dependent movements. We find little evidence of selection acting on immune-related genes within this metapopulation. Footprint of positive selection is detected at Tlr-4 gene in 2008 only. We observe marginally significant associations between Mx2 genotype and PUUV genogroups. These results show that neutral processes seem to be the main factors affecting the evolution of these immune-related genes at a contemporary scale, although the relative effects of neutral and adaptive forces could vary temporally with density fluctuations. Immune related gene polymorphism may in turn partly influence PUUV epidemiology in this metapopulation.
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physiological condition of bank voles Myodes glareolus during the increase and decline phases of the population cycle
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2015Co-Authors: Petteri Nieminen, Liina Voutilainen, Heikki Henttonen, Otso Huitu, Mikko Finnila, Juhani Itamies, Vesa Karja, S Saarela, Toivo Halonen, Annemari MustonenAbstract:The dynamics of animal populations are greatly influenced by interactions with their natural enemies and food resources. However, quantifying the relative effects of these factors on demographic rates remains a perpetual challenge for animal population ecology. Food scarcity is assumed to limit the growth and to initiate the decline of cyclic herbivore populations, but this has not been verified with physiological health indices. We hypothesized that individuals in declining populations would exhibit signs of malnutrition-induced deterioration of physiological condition. We evaluated the association of body condition with population cycle phase in bank voles (Myodes glareolus) during the increase and decline phases of a population cycle. The bank voles had lower body masses, condition indices and absolute masses of particular organs during the decline. Simultaneously, they had lower femoral masses, mineral contents and densities. Hemoglobin and hematocrit values and several parameters known to respond to food deprivation were unaffected by the population phase. There were no signs of lymphopenia, eosinophilia, granulocytosis or monocytosis. Erythrocyte counts were higher and plasma total protein levels and tissue proportions of essential polyunsaturated fatty acids lower in the population decline. Ectoparasite load was lower and adrenal gland masses or catecholamine concentrations did not suggest higher stress levels. Food availability seems to limit the size of voles during the decline but they can adapt to the prevailing conditions without clear deleterious health effects. This highlights the importance of quantifying individual health state when evaluating the effects of complex trophic interactions on the dynamics of wild animal populations.
Liina Voutilainen - One of the best experts on this subject based on the ideXlab platform.
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Short Communication Associations between MHC genes and Puumala virus infection in Myodes glareolus are detected in wild populations, but not from experimental infection data
2020Co-Authors: Emmanuel Guivier, Katrien Tersago, Liina Voutilainen, Heikki Henttonen, Maxime Galan, Gert E Olsson, Eva R Kallio, Pierrejean G Male, Denis Augot, Nathalie CharbonnelAbstract:Usc Vecpar, AFSSA LERPAZ, JE2533, Universite´ de Reims Champagne-Ardenne,UFR Pharmacie, 51 rue Cognacq-Jay, 51100 Reims, FranceWe analysed the influence of MHC class II Dqa and Drb genes on Puumala virus (PUUV) infectionin bank voles (Myodes glareolus). We considered voles sampled in five European localities orderived from a previous experiment that showed variable infection success of PUUV. The geneticvariation observed in the Dqa and Drb genes was assessed by using single-strand conformationpolymorphism and pyrosequencing methods, respectively. Patterns were compared with thoseobtained from 13 microsatellites. We revealed significant genetic differentiation between PUUV-seronegative and -seropositive bank voles sampled in wild populations, at the Drb gene only. Theabsence of genetic differentiation observed at neutral microsatellites confirmed the important roleof selective pressures in shaping these Drb patterns. Also, we found no significant associationsbetween infection success and MHC alleles among laboratory-colonized bank voles, which isexplained by a loss of genetic variability that occurred during the captivity of these voles.
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Tick-borne Encephalitis Virus in Wild Rodents in Winter, Finland, 2008–2009
Emerging Infectious Diseases, 2020Co-Authors: Elina Tonteri, Liina Voutilainen, Heikki Henttonen, Jukka Niemimaa, Antti Vaheri, Anu Jääskeläinen, T. Tikkakoski, Olli VapalahtiAbstract:Rodents might maintain tick-borne encephalitis virus (TBEV) in nature through latent persistent infections. During 2 subsequent winters, 2008 and 2009, in Finland, we detected RNA of European and Siberian subtypes of TBEV in Microtus agrestis and Myodes glareolus voles, respectively. Persistence in rodent reservoirs may contribute to virus overwintering.
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microevolution of bank voles Myodes glareolus at neutral and immune related genes during multiannual dynamic cycles consequences for puumala hantavirus epidemiology
Infection Genetics and Evolution, 2017Co-Authors: Heikki Henttonen, Jeanfrancois Cosson, Maxime Galan, Jukka Niemimaa, Maria Razzauti, Adelaide Dubois, Bertrand Gauffre, Liina VoutilainenAbstract:Understanding how host dynamics, including variations of population size and dispersal, may affect the epidemiology of infectious diseases through ecological and evolutionary processes is an active research area. Here we focus on a bank vole (Myodes glareolus) metapopulation surveyed in Finland between 2005 and 2009. Bank vole is the reservoir of Puumala hantavirus (PUUV), the agent of nephropathia epidemica (NE, a mild form of hemorrhagic fever with renal symptom) in humans. M. glareolus populations experience multiannual density fluctuations that may influence the level of genetic diversity maintained in bank voles, PUUV prevalence and NE occurrence. We examine bank vole metapopulation genetics at presumably neutral markers and immune-related genes involved in susceptibility to PUUV (Tnf-promoter, Tlr4, Tlr7 and Mx2 gene) to investigate the links between population dynamics, microevolutionary processes and PUUV epidemiology. We show that genetic drift slightly and transiently affects neutral and adaptive genetic variability within the metapopulation. Gene flow seems to counterbalance its effects during the multiannual density fluctuations. The low abundance phase may therefore be too short to impact genetic variation in the host, and consequently viral genetic diversity. Environmental heterogeneity does not seem to affect vole gene flow, which might explain the absence of spatial structure previously detected in PUUV in this area. Besides, our results suggest the role of vole dispersal on PUUV circulation through sex-specific and density-dependent movements. We find little evidence of selection acting on immune-related genes within this metapopulation. Footprint of positive selection is detected at Tlr-4 gene in 2008 only. We observe marginally significant associations between Mx2 genotype and PUUV genogroups. These results show that neutral processes seem to be the main factors affecting the evolution of these immune-related genes at a contemporary scale, although the relative effects of neutral and adaptive forces could vary temporally with density fluctuations. Immune related gene polymorphism may in turn partly influence PUUV epidemiology in this metapopulation.
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physiological condition of bank voles Myodes glareolus during the increase and decline phases of the population cycle
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2015Co-Authors: Petteri Nieminen, Liina Voutilainen, Heikki Henttonen, Otso Huitu, Mikko Finnila, Juhani Itamies, Vesa Karja, S Saarela, Toivo Halonen, Annemari MustonenAbstract:The dynamics of animal populations are greatly influenced by interactions with their natural enemies and food resources. However, quantifying the relative effects of these factors on demographic rates remains a perpetual challenge for animal population ecology. Food scarcity is assumed to limit the growth and to initiate the decline of cyclic herbivore populations, but this has not been verified with physiological health indices. We hypothesized that individuals in declining populations would exhibit signs of malnutrition-induced deterioration of physiological condition. We evaluated the association of body condition with population cycle phase in bank voles (Myodes glareolus) during the increase and decline phases of a population cycle. The bank voles had lower body masses, condition indices and absolute masses of particular organs during the decline. Simultaneously, they had lower femoral masses, mineral contents and densities. Hemoglobin and hematocrit values and several parameters known to respond to food deprivation were unaffected by the population phase. There were no signs of lymphopenia, eosinophilia, granulocytosis or monocytosis. Erythrocyte counts were higher and plasma total protein levels and tissue proportions of essential polyunsaturated fatty acids lower in the population decline. Ectoparasite load was lower and adrenal gland masses or catecholamine concentrations did not suggest higher stress levels. Food availability seems to limit the size of voles during the decline but they can adapt to the prevailing conditions without clear deleterious health effects. This highlights the importance of quantifying individual health state when evaluating the effects of complex trophic interactions on the dynamics of wild animal populations.
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Life-long shedding of Puumala hantavirus in wild bank voles (Myodes glareolus).
The Journal of general virology, 2015Co-Authors: Liina Voutilainen, Malin Karlsson, Tarja Sironen, Heikki Henttonen, Jukka Niemimaa, Elina Tonteri, Anne Tuiskunen Bäck, Maria Razzauti, Maria Wahlström, Ake LundkvistAbstract:The knowledge of viral shedding patterns and viraemia in the reservoir host species is a key factor in assessing the human risk of zoonotic viruses. The shedding of hantaviruses (family Bunyaviridae) by their host rodents has widely been studied experimentally, but rarely in natural settings. Here we present the dynamics of Puumala hantavirus (PUUV) shedding and viraemia in naturally infected wild bank voles (Myodes glareolus). In a monthly capture-mark-recapture study, we analysed 18 bank voles for the presence and relative quantity of PUUV RNA in the excreta and blood from 2 months before up to 8 months after seroconversion. The proportion of animals shedding PUUV RNA in saliva, urine and faeces peaked during the first month after seroconversion, but continued throughout the study period with only a slight decline. The quantity of shed PUUV in reverse transcription quantitative PCR (RT-qPCR) positive excreta was constant over time. In blood, PUUV RNA was present for up to 7 months but both the probability of viraemia and the virus load declined with time. Our findings contradict the current view of a decline in virus shedding after the acute phase and a short viraemic period in hantavirus infection - an assumption widely adopted in current epidemiological models. We suggest the life-long shedding as a means of hantaviruses to survive over host population bottlenecks, and to disperse in fragmented habitats where local host and/or virus populations face temporary extinctions. Our results indicate that the kinetics of pathogens in wild hosts may differ considerably from those observed in laboratory settings.
Ake Lundkvist - One of the best experts on this subject based on the ideXlab platform.
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Predicting High Risk for Human Hantavirus Infections, Sweden
Emerging Infectious Diseases, 2020Co-Authors: Gert E Olsson, Ake Lundkvist, Marika Hjertqvist, Birger HörnfeldtAbstract:An increased risk for hemorrhagic fever with renal syndrome caused by Puumala hantavirus was forecast for Sweden in 2007. The forecast was based on a predicted increase in the number of Myodes glareolus rodents (reservoir hosts). Despite raised awareness and preparedness, the number of human cases during July 2007–June 2008 was 1,483, a new high.
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Life-long shedding of Puumala hantavirus in wild bank voles (Myodes glareolus).
The Journal of general virology, 2015Co-Authors: Liina Voutilainen, Malin Karlsson, Tarja Sironen, Heikki Henttonen, Jukka Niemimaa, Elina Tonteri, Anne Tuiskunen Bäck, Maria Razzauti, Maria Wahlström, Ake LundkvistAbstract:The knowledge of viral shedding patterns and viraemia in the reservoir host species is a key factor in assessing the human risk of zoonotic viruses. The shedding of hantaviruses (family Bunyaviridae) by their host rodents has widely been studied experimentally, but rarely in natural settings. Here we present the dynamics of Puumala hantavirus (PUUV) shedding and viraemia in naturally infected wild bank voles (Myodes glareolus). In a monthly capture-mark-recapture study, we analysed 18 bank voles for the presence and relative quantity of PUUV RNA in the excreta and blood from 2 months before up to 8 months after seroconversion. The proportion of animals shedding PUUV RNA in saliva, urine and faeces peaked during the first month after seroconversion, but continued throughout the study period with only a slight decline. The quantity of shed PUUV in reverse transcription quantitative PCR (RT-qPCR) positive excreta was constant over time. In blood, PUUV RNA was present for up to 7 months but both the probability of viraemia and the virus load declined with time. Our findings contradict the current view of a decline in virus shedding after the acute phase and a short viraemic period in hantavirus infection - an assumption widely adopted in current epidemiological models. We suggest the life-long shedding as a means of hantaviruses to survive over host population bottlenecks, and to disperse in fragmented habitats where local host and/or virus populations face temporary extinctions. Our results indicate that the kinetics of pathogens in wild hosts may differ considerably from those observed in laboratory settings.
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the three subtypes of tick borne encephalitis virus induce encephalitis in a natural host the bank vole Myodes glareolus
PLOS ONE, 2013Co-Authors: Elina Tonteri, Anja Kipar, Liina Voutilainen, Sirkka Vene, Antti Vaheri, Olli Vapalahti, Ake LundkvistAbstract:Tick-borne encephalitis virus (TBEV) infects bank voles (Myodes glareolus) in nature, but the relevance of rodents for TBEV transmission and maintenance is unclear. We infected colonized bank voles subcutaneously to study and compare the infection kinetics, acute infection, and potential viral persistence of the three known TBEV subtypes: European (TBEV-Eur), Siberian (TBEV-Sib) and Far Eastern (TBEV-FE). All strains representing the three subtypes were infective and highly neurotropic. They induced (meningo)encephalitis in some of the animals, however most of the cases did not present with apparent clinical symptoms. TBEV-RNA was cleared significantly slower from the brain as compared to other organs studied. Supporting our earlier findings in natural rodent populations, TBEV-RNA could be detected in the brain for up to 168 days post infection, but we could not demonstrate infectivity by cell culture isolation. Throughout all time points post infection, RNA of the TBEV-FE was detected significantly more often than RNA of the other two strains in all organs studied. TBEV-FE also induced prolonged viremia, indicating distinctive kinetics in rodents in comparison to the other two subtypes. This study shows that bank voles can develop a neuroinvasive TBEV infection with persistence of viral RNA in brain, and mount an anti-TBEV IgG response. The findings also provide further evidence that bank voles can serve as sentinels for TBEV endemicity.
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A model system for in vitro studies of bank vole borne viruses.
PLOS ONE, 2011Co-Authors: Malin Stoltz, Ake Lundkvist, Sirkka Vene, Karin Sundström, Asa Hidmark, Conny Tolf, Clas Ahlm, A. Michael Lindberg, Jonas KlingstromAbstract:The bank vole (Myodes glareolus) is a common small mammal in Europe and a natural host for several important emerging zoonotic viruses, e.g. Puumala hantavirus (PUUV) that causes hemorrhagic fever ...
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associations between mhc genes and puumala virus infection in Myodes glareolus are detected in wild populations but not from experimental infection data
Journal of General Virology, 2010Co-Authors: Emmanuel Guivier, Katrien Tersago, Ake Lundkvist, Liina Voutilainen, Heikki Henttonen, Maxime Galan, Gert E Olsson, Eva R Kallio, Pierrejean G Male, Denis AugotAbstract:We analysed the influence of MHC class II Dqa and Drb genes on Puumala virus (PUUV) infection in bank voles (Myodes glareolus). We considered voles sampled in five European localities or derived from a previous experiment that showed variable infection success of PUUV. The genetic variation observed in the Dqa and Drb genes was assessed by using single-strand conformation polymorphism and pyrosequencing methods, respectively. Patterns were compared with those obtained from 13 microsatellites. We revealed significant genetic differentiation between PUUV-seronegative and -seropositive bank voles sampled in wild populations, at the Drb gene only. The absence of genetic differentiation observed at neutral microsatellites confirmed the important role of selective pressures in shaping these Drb patterns. Also, we found no significant associations between infection success and MHC alleles among laboratory-colonized bank voles, which is explained by a loss of genetic variability that occurred during the captivity of these voles.
Maxime Galan - One of the best experts on this subject based on the ideXlab platform.
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Short Communication Associations between MHC genes and Puumala virus infection in Myodes glareolus are detected in wild populations, but not from experimental infection data
2020Co-Authors: Emmanuel Guivier, Katrien Tersago, Liina Voutilainen, Heikki Henttonen, Maxime Galan, Gert E Olsson, Eva R Kallio, Pierrejean G Male, Denis Augot, Nathalie CharbonnelAbstract:Usc Vecpar, AFSSA LERPAZ, JE2533, Universite´ de Reims Champagne-Ardenne,UFR Pharmacie, 51 rue Cognacq-Jay, 51100 Reims, FranceWe analysed the influence of MHC class II Dqa and Drb genes on Puumala virus (PUUV) infectionin bank voles (Myodes glareolus). We considered voles sampled in five European localities orderived from a previous experiment that showed variable infection success of PUUV. The geneticvariation observed in the Dqa and Drb genes was assessed by using single-strand conformationpolymorphism and pyrosequencing methods, respectively. Patterns were compared with thoseobtained from 13 microsatellites. We revealed significant genetic differentiation between PUUV-seronegative and -seropositive bank voles sampled in wild populations, at the Drb gene only. Theabsence of genetic differentiation observed at neutral microsatellites confirmed the important roleof selective pressures in shaping these Drb patterns. Also, we found no significant associationsbetween infection success and MHC alleles among laboratory-colonized bank voles, which isexplained by a loss of genetic variability that occurred during the captivity of these voles.
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experimental infections of wild bank voles Myodes glareolus from nephropatia epidemica endemic and non endemic regions revealed slight differences in puumala virological course and immunological responses
Virus Research, 2017Co-Authors: Adelaide Dubois, Guillaume Castel, Severine Murri, Coralie Pulido, Jeanbaptiste Pons, Laure Benoit, Anne Loiseau, Latifa Lakhdar, Maxime GalanAbstract:Abstract In Europe, the occurrence of nephropathia epidemica (NE), a human disease caused by Puumala virus (PUUV), exhibits considerable geographical heterogeneity despite the continuous distribution of its reservoir, the bank vole Myodes glareolus . To better understand the causes of this heterogeneity, wild voles sampled in two adjacent NE endemic and non-endemic regions of France were infected experimentally with PUUV. The responses of bank voles to PUUV infection, based on the levels of anti-PUUV IgG and viral RNA, were compared. Slight regional differences were highlighted despite the high inter-individual variability. Voles from the NE non-endemic region showed greater immune responsiveness to PUUV infection, but lower levels of RNA in their organs than voles from the endemic region. These results suggest the existence of regional variations in the sensitivity of bank voles that could contribute to the apparent absence of PUUV circulation among voles and the absence of NE in the non-endemic region.
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microevolution of bank voles Myodes glareolus at neutral and immune related genes during multiannual dynamic cycles consequences for puumala hantavirus epidemiology
Infection Genetics and Evolution, 2017Co-Authors: Heikki Henttonen, Jeanfrancois Cosson, Maxime Galan, Jukka Niemimaa, Maria Razzauti, Adelaide Dubois, Bertrand Gauffre, Liina VoutilainenAbstract:Understanding how host dynamics, including variations of population size and dispersal, may affect the epidemiology of infectious diseases through ecological and evolutionary processes is an active research area. Here we focus on a bank vole (Myodes glareolus) metapopulation surveyed in Finland between 2005 and 2009. Bank vole is the reservoir of Puumala hantavirus (PUUV), the agent of nephropathia epidemica (NE, a mild form of hemorrhagic fever with renal symptom) in humans. M. glareolus populations experience multiannual density fluctuations that may influence the level of genetic diversity maintained in bank voles, PUUV prevalence and NE occurrence. We examine bank vole metapopulation genetics at presumably neutral markers and immune-related genes involved in susceptibility to PUUV (Tnf-promoter, Tlr4, Tlr7 and Mx2 gene) to investigate the links between population dynamics, microevolutionary processes and PUUV epidemiology. We show that genetic drift slightly and transiently affects neutral and adaptive genetic variability within the metapopulation. Gene flow seems to counterbalance its effects during the multiannual density fluctuations. The low abundance phase may therefore be too short to impact genetic variation in the host, and consequently viral genetic diversity. Environmental heterogeneity does not seem to affect vole gene flow, which might explain the absence of spatial structure previously detected in PUUV in this area. Besides, our results suggest the role of vole dispersal on PUUV circulation through sex-specific and density-dependent movements. We find little evidence of selection acting on immune-related genes within this metapopulation. Footprint of positive selection is detected at Tlr-4 gene in 2008 only. We observe marginally significant associations between Mx2 genotype and PUUV genogroups. These results show that neutral processes seem to be the main factors affecting the evolution of these immune-related genes at a contemporary scale, although the relative effects of neutral and adaptive forces could vary temporally with density fluctuations. Immune related gene polymorphism may in turn partly influence PUUV epidemiology in this metapopulation.
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apport de l immunogenetique a la comprehension des interactions entre le campagnol roussâtre Myodes glareolus et l hantavirus puumala insights into Myodes glareolus puumala hantavirus interactions from rodent immunogenetics
2013Co-Authors: Par Audrey Rohfritsch, Emmanuel Guivier, Yannick Chaval, Jeanfrancois Cosson, Maxime Galan, Nathalie CharbonnelAbstract:Le campagnol roussâtre Myodes glareolus est le reservoir de l’hantavirus Puumala (PUUV), responsable chez l’Homme d’une forme attenuee de Fievre Hemorragique a Syndrome Renal (FHSR), la Nephropathie Epidemique (NE). En Europe, l’incidence de la NE presente, malgre la distribution continue du reservoir, une forte variabilite geographique dont les causes ne sont a ce jour pas identifiees. Aux hypotheses climatiques et paysageres, nous proposons que des facteurs intrinseques aux campagnols puissent egalement etre impliques. Une plus forte tolerance a l’infection par le virus PUUV, chez certains campagnols roussâtres, favoriserait la persistance et la transmission de ce virus, ce qui devrait accroitre le risque de NE chez l’Homme. Nous avons teste cette hypothese en etudiant les polymorphismes et/ou les niveaux d'expression de six genes candidats impliques dans la reponse immunitaire a PUUV (DRB-CMH, promoteur du TNF, TLR4, TLR7, Mx2, integrine 3) chez dix populations de campagnols echantillonnees le long d’un axe nord/sud dans les Ardennes francaises, couvrant des zones endemiques et non endemiques a PUUV.
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apport de l immunogenetique a la comprehension des interactions entre le campagnol roussâtre Myodes glareolus et l hantavirus puumala
Bulletin De L Academie Veterinaire De France, 2013Co-Authors: Audrey Rohfritsch, Emmanuel Guivier, Yannick Chaval, Jeanfrancois Cosson, Maxime Galan, Nathalie CharbonnelAbstract:Nephropathia epidemica (NE) is a mild form of hemorrhagic fever with renal syndrome (HFRS) caused by the hantavirus Puumala (PUUV). In Europe, its distribution is fragmented, whereas the bank vole Myodes glareolus, which is the reservoir of PUUV, is common all over the continent. Determining the causes underlying this heterogeneity is of main importance to better understand and prevent the risks of NE emergence. Besides climatic and ecological hypotheses, we have proposed that the geographic variability of bank vole immune responses to PUUV infection could shape differences in PUUV prevalence, and consequently NE incidence. We have tested this hypothesis by studying polymorphisms and / or expression levels of six candidate genes involved in the immune response to PUUV (DRB-MHC, TNF-alpha promoter, TLR4, TLR7, Mx2, Integrin beta3) on ten populations of bank voles sampled in the French Ardennes, along a North-South transect including PUUV endemic and non-endemic areas. Signatures of selection have been evidenced for TNF-alpha and Mx2 genes using population genetics (FST scan) and genotype - phenotype association approaches. These genes have antiviral properties but also induce immunological damages, what make them central for driving a balance of resistance / tolerance to PUUV. Bank voles vary in their basal ability to tolerate/resist to PUUV. In high PUUV prevalence areas, TNF-alpha and Mx2 expression seemed down-regulated what suggest selection or phenotypic plasticity for higher tolerance to PUUV, at the benefit of lower immunopathological costs. Some of these results have been confirmed at the European scale.
