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Rodents are important reservoirs for zoonotic pathogens that cause diseases in humans. Biodiversity is hypothesized to be closely related to pathogen prevalence through multiple direct and indirect pathways. For example, the presence of non‐host species can reduce contact rates of the main reservoir host and thus reduce the risk of transmission ("dilution effect"). In addition, an overlap in ecological niches between two species could lead to increased interspecific competition, potentially limiting host densities and reducing density‐dependent pathogen transmission processes. In this study, we investigated the relative impact of population‐level regulation of direct and indirect drivers of the prevalence of Puumala orthohantavirus (PUUV) in bank voles (Clethrionomys glareolus) during years with high abundance. We compiled data on small mammal community composition from four regions in Germany between 2010 and 2013. Structural equation modeling revealed a strong seasonality in PUUV control mechanisms in bank voles. The abundance of shrews tended to have a negative relationship with host abundance, and host abundance positively influenced PUUV seroprevalence, while at the same time increasing the abundance of competing non‐hosts like the wood mouse (Apodemus sylvaticus) and the yellow‐necked field mouse (Apodemus flavicollis) were associated with reduced PUUV seroprevalence in the host. These results indicate that for PUUV in bank voles, dilution is associated with increased interspecific competition. Anthropogenic pressures leading to the decline of Apodemus spp. in a specific habitat could lead to the amplification of mechanisms promoting PUUV transmission within the host populations. [ABSTRACT FROM AUTHOR]

Cowpox virus (CPXV), genus Orthopoxvirus, family Poxviridae, is a zoonotic pathogen in Eurasian wild rodents. High seroprevalences have been reported previously for vole and murine species in Europe. In contrast, viral DNA was only rarely detected, and very few reservoir-derived CPXV isolates exist. In this study, CPXV DNA and CPXV-reactive antibodies were monitored in wild small mammals for 5 years in four German federal states. Screening of liver tissues of 3966 animals by CPXV real-time PCR (qPCR) revealed five voles of two species positive for CPXV DNA. Two positive bank voles (Myodes glareolus) and two positive common voles (Microtus arvalis) originated from two plots in Baden-Wuerttemberg. One positive bank vole originated from Mecklenburg-Western Pomerania. None of the small mammals from Thuringia and North Rhine-Westphalia was positive in the qPCR. CPXV antigen-based indirect immunofluorescence assays of 654 highly diluted chest cavity fluid samples detected two bank voles and two common voles from the same sites in Baden-Wuerttemberg to be highly seroreactive. Five animals were CPXV DNA positive, and four other animals were orthopoxvirus seropositive. Our study indicates both a very low prevalence and a patchy occurrence of CPXV in common and bank voles and absence in other rodent and shrew species in Germany. The multiple detection of infected voles at one site in Baden-Wuerttemberg and continued detection in a region of Mecklenburg-Western Pomerania classify these regions as potential endemic foci. [ABSTRACT FROM AUTHOR]

Puumala orthohantavirus (PUUV) causes most human hantavirus disease cases in Europe. PUUV disease outbreaks are usually synchronized Germany‐wide driven by beech mast‐induced irruptions of its host (bank vole, Myodes glareolus). Recent data indicate high vole abundance, high PUUV prevalence and high human incidence in summer 2019 for some regions, but elsewhere values were low to moderate. This significant lack of synchrony among regions in Germany is in contrast to previous studies. Health institutions need to be informed about the heterogeneous distribution of human PUUV infection risk to initiate appropriate actions. [ABSTRACT FROM AUTHOR]

Francisella tularensis is a zoonotic, gram‐negative bacterium that causes tularemia in humans. Depending on its subspecies and the route of transmission, mild to lethal courses have been reported. F. tularensis subsp. holarctica is the only subspecies found in Europe and affects a plenitude of vertebrates including lagomorphs and rodents. Population outbreaks of certain rodent species are likely to be involved in the transmission of this pathogen. This molecular survey aims to evaluate the presence of F. tularensis in small mammals from three Central European countries. Using a real‐time polymerase chain reaction, F. tularensis DNA was detected in common voles (Microtus arvalis) from Switzerland and in field voles (Microtus agrestis) and a bank vole (Myodes glareolus) from Germany, but not in any other small mammal species. All common voles from the Czech Republic were negative for F. tularensis DNA. The prevalence in the three vole species varied between 1.3% and 3.0%. In conclusion, Francisella tularensis DNA was detected in three vole species in two of three countries investigated. The observed low prevalence raises questions on the role of voles for the transmission of Francisella tularensis in Central Europe. [ABSTRACT FROM AUTHOR]

Cowpox virus (CPXV) is a zoonotic orthopoxvirus (OPV) that infects a wide range of mammals. CPXV-specific DNA and antibodies were detected in different vole species, such as common voles (Microtus arvalis) and bank voles (Myodes glareolus). Therefore, voles are the putative main reservoir host of CPXV. However, CPXV was up to now only isolated from common voles. Here we report the detection and isolation of a bank vole-derived CPXV strain (GerMygEK 938/17) resulting from a large-scale screening of bank voles collected in Thuringia, Germany, during 2017 and 2018. Phylogenetic analysis using the complete viral genome sequence indicated a high similarity of the novel strain to CPXV clade 3 and to OPV "Abatino" but also to Ectromeliavirus (ECTV) strains. Phenotypic characterization of CPXV GerMygEK 938/17 using inoculation of embryonated chicken eggs displayed hemorrhagic pock lesions on the chorioallantoic membrane that are typical for CPXV but not for ECTV. CPXV GerMygEK 938/17 replicated in vole-derived kidney cell lines but at lower level than on Vero76 cell line. In conclusion, the first bank vole-derived CPXV isolate provides new insights into the genetic variability of CPXV in the putative reservoir host and is a valuable tool for further studies about CPXV-host interaction and molecular evolution of OPV. [ABSTRACT FROM AUTHOR]