Microtus Agrestis Research Articles

Fluctuations in field vole abundance indirectly influence red grouse productivity via a shared predator guild

Changes in the abundance of one prey species may indirectly affect other prey species by triggering responses in generalist predators. Here we examine relationships between two prey species that do not compete directly, the field vole Microtus agrestis, a common rodent with fluctuating populations, and the red grouse Lagopus lagopus scotica, a gamebird inhabiting open moorland, during a 27-year study on a moor in south-west Scotland. First, we test whether vole abundance was related to grouse density and demographic rates. Second, we test whether vole abundance was related to abundance indices of four common predators of both voles and grouse (red fox Vulpes vulpes, weasel Mustela nivalis, hen harrier Circus cyaneus and common buzzard Buteo buteo). Third, we test whether these vole–grouse and vole–predator relationships differ in relation to grouse management, which includes the culling of foxes and weasels. We found no association between vole abundance and grouse densities, adult summer survival or nesting success. However, the ratio of young grouse per adult and the proportion of female grouse with broods in July were negatively associated with field vole abundance, suggesting increased predation of grouse chicks in years with high vole abundance. Fox indices showed a weak positive association with vole abundance when their numbers were not controlled, whilst weasel indices showed no relationship with voles. The numbers of breeding hen harriers and buzzards were also not associated with vole abundance, but the number of buzzard sightings was higher when voles were more plentiful. Our results are consistent with a negative interaction between field voles and red grouse chick survival in a pattern expected for apparent competition. Although the underlying mechanisms could not be disentangled, this interaction may be at least partly mediated by rodent-hunting raptors such as buzzards and, in periods without grouse management, foxes.

Transcriptome-wide analysis reveals different categories of response to a standardised immune challenge in a wild rodent

Individuals vary in their immune response and, as a result, some are more susceptible to infectious disease than others. Little is known about the nature of this individual variation in natural populations, or which components of immune pathways are most responsible, but defining this underlying landscape of variation is an essential first step to understanding the drivers of this variation and, ultimately, predicting the outcome of infection. We describe transcriptome-wide variation in response to a standardised immune challenge in wild field voles. We find that genes (hereafter 'markers') can be categorised into a limited number of types. For the majority of markers, the response of an individual is dependent on its baseline expression level, with significant enrichment in this category for conventional immune pathways. Another, moderately sized, category contains markers for which the responses of different individuals are also variable but independent of their baseline expression levels. This category lacks any enrichment for conventional immune pathways. We further identify markers which display particularly high individual variability in response, and could be used as markers of immune response in larger studies. Our work shows how a standardised challenge performed on a natural population can reveal the patterns of natural variation in immune response.

Associations between different Laelapidae (Mesostigmata: Dermanyssoidea) mites and small rodents from Lithuania

Associations between species of Laelapidae (Mesostigmata: Dermanyssoidea) mites and small rodents have been studied insufficiently. The aim of this study was to investigate infestation patterns of small rodent species by laelapid mites at six locations in Lithuania. A total of 728 rodents were snap- and live-trapped in various locations during 2013-2016. Eight rodent species were identified, namely Apodemus flavicollis, Apodemus agrarius, Myodes glareolus, Micromys minutus, Mus musculus, Microtus oeconomus, Microtus arvalis and Microtus agrestis. A total of 343 (47.1%) rodents were found to be infested with up to eight species of parasitic mites from the Laelapidae family (n = 1363): Laelaps agilis, Laelaps hilaris, Hyperlaelaps microti, Haemogamasus nidi, Haemogamasus hirsutus, Eulaelaps stabularis, Hirstionyssus sunci and Myonyssus gigas. The dominant species of mite found on rodents was L. agilis (89.1%), found on 43.4% of all hosts. Abundance and mean intensity of infestation with mites varied among species of hosts and were highest for A. flavicollis. We document new geographical and host records for gamasid mites of eight rodent species in Lithuania.

Retrieval of the Complete Coding Sequence of the UK-Endemic Tatenale Orthohantavirus Reveals Extensive Strain Variation and Supports Its Classification as a Novel Species.

Orthohantaviruses are globally distributed viruses, associated with rodents and other small mammals. However, data on the circulation of orthohantaviruses within the UK, particularly the UK-endemic Tatenale virus, is sparse. In this study, 531 animals from five rodent species were collected from two locations in northern and central England and screened using a degenerate, pan- orthohantavirus RT-PCR assay. Tatenale virus was detected in a single field vole (Microtus agrestis) from central England and twelve field voles from northern England. Unbiased high-throughput sequencing of the central English strain resulted in the recovery of the complete coding sequence of a novel strain of Tatenale virus, whilst PCR-primer walking of the northern English strain recovered almost complete coding sequence of a previously identified strain. These findings represented the detection of a third lineage of Tatenale virus in the United Kingdom and extended the known geographic distribution of these viruses from northern to central England. Furthermore, the recovery of the complete coding sequence revealed that Tatenale virus was sufficiently related to the recently identified Traemersee virus, to meet the accepted criteria for classification as a single species of orthohantavirus.

Fishing for mammals: Landscape‐level monitoring of terrestrial and semi‐aquatic communities using eDNA from riverine systems

Abstract Environmental DNA (eDNA) metabarcoding has revolutionized biomonitoring in both marine and freshwater ecosystems. However, for semi‐aquatic and terrestrial animals, the application of this technique remains relatively untested. We first assess the efficiency of eDNA metabarcoding in detecting semi‐aquatic and terrestrial mammals in natural lotic ecosystems in the UK by comparing sequence data recovered from water and sediment samples to the mammalian communities expected from historical data. Secondly, using occupancy modelling we compared the detection efficiency of eDNA metabarcoding to multiple conventional non‐invasive survey methods (latrine surveys and camera trapping). eDNA metabarcoding detected a large proportion of the expected mammalian community within each area. Common species in the areas were detected at the majority of sites. Several key species of conservation concern in the UK were detected by eDNA sampling in areas where authenticated records do not currently exist, but potential false positives were also identified. Water‐based eDNA metabarcoding provided comparable results to conventional survey methods in per unit of survey effort for three species (water vole, field vole and red deer) using occupancy models. The comparison between survey ‘effort’ to reach a detection probability of ≥.95 revealed that 3–6 water replicates would be equivalent to 3–5 latrine surveys and 5–30 weeks of single camera deployment, depending on the species. Synthesis and applications. eDNA metabarcoding can be used to generate an initial ‘distribution map’ of mammalian diversity at the landscape level. If conducted during times of peak abundance, carefully chosen sampling points along multiple river courses provide a reliable snapshot of the species that are present in a catchment area. In order to fully capture solitary, rare and invasive species, we would currently recommend the use of eDNA metabarcoding alongside other non‐invasive surveying methods (i.e. camera traps) to maximize monitoring efforts.

Blood parasites (Babesia, Hepatozoon and Trypanosoma) of rodents, Lithuania: part I. Molecular and traditional microscopy approach.

Wild rodents, as natural reservoir hosts carrying various species of pathogens, play an important role in the evolution and emergence of zoonotic diseases. In this study, protist parasites, namely Babesia sp., Trypanosoma sp. and Hepatozoon sp. were studied in rodent populations in Lithuania. Two hundred forty rodent specimens of seven species were analysed by a combined approach using polymerase chain reaction (PCR)-based techniques and traditional microscopic examination. The total prevalence of blood parasites reached 35% in rodent communities. The prevalence of Hepatozoon sp. reached the highest value (32%), followed by Trypanosoma sp. (5%) and Babesia sp. (3%). Myodes glareolus and Microtus agrestis were the most heavily infected rodent species. Comparison of microscopy and PCR-based methods showed that the two approaches might give different results and thus can lead to an underestimation of the actual prevalence and abundance of parasites. In our study, PCR-based assays were more sensitive and robust than traditional microscopy. However, precise molecular results for the estimation of the prevalence of Babesia sp. and Hepatozoon sp. were achieved only by using several sets of primers. To avoid inaccurate results, the improvement and detailed description of molecular and microscopy protocols are required.

Discovery and Prevalence of Divergent RNA Viruses in European Field Voles and Rabbits.

The advent of unbiased metagenomic virus discovery has revolutionized studies of virus biodiversity and evolution. Despite this, our knowledge of the virosphere, including in mammalian species, remains limited. We used unbiased metagenomic sequencing to identify RNA viruses in European field voles and rabbits. Accordingly, we identified a number of novel RNA viruses including astrovirus, rotavirus A, picorna-like virus and a narmovirus (paramyxovirus). In addition, we identified a sobemovirus and a novel luteovirus that likely originated from the rabbit diet. These newly discovered viruses were often divergent from those previously described. The novel astrovirus was most closely related to a virus sampled from the rodent-eating European roller bird (Coracias garrulous). PCR screening revealed that the novel narmovirus in the UK field vole had a prevalence of approximately 4%, and shared common ancestry with other rodent narmoviruses sampled globally. Two novel rotavirus A sequences were detected in a UK field vole and a French rabbit, the latter with a prevalence of 5%. Finally, a highly divergent picorna-like virus found in the gut of the French rabbit virus was only ~35% similar to an arilivirus at the amino acid level, suggesting the presence of a novel viral genus within the Picornaviridae.

NEW FINDINGS OF CHIGGER MITES (ACARIFORMES: TROMBICULIDAE) IN THE REPUBLIC OF KARELIA AND THE ARKHANGELSK REGION

The article provides information on the occurrence of chigger mites (Acariformes, Trombiculidae), obtained as a result of long-term studies of the ectoparasite fauna of small mammals from 1992 to 2018 in Karelia, Murmansk Region (2015), Arkhangelsk Region (2007) and Finland (1999, 2007). A total of 6154 specimens of small mammals of the orders Rodentia (Myodes glareolus, M. rutilus, M. rufocanus, Microtus agrestis, M. oeconomus, Arvicola terrestris, Sicista betulina, Micromys minutus, Apodemus agrarius, A. flavicollis) and Eulipotyphla (Sorex araneus, S. caecutiens, S. isodon, S. minutus, Neomys fodiens) were examined and 878 chiggers were collected. Hirsutiella zachvatkini (Schluger 1948) and Neotrombicula (Digenualea) uliginosa Kudryashova 1998 were found. Their prevalences were 0.84 % and 0.16 %, respectively. H. zachvatkini (parasite associated with the bank vole) was found only in southern Karelia and south-western Arkhangelsk Region. The northernmost record of this species in Karelia comes from the Kizhi Archipelago (Medvezhjegorsky District), where after long-term monitoring and with a large number of host individuals examined, chiggers were found only on Malyi Lelikovsky Island (N61.989°; E35.15°). A high relative abundance of H. zachvatkini was observed in the south-west of Karelia, in the Lahdenpohsky District. The second species, N. uliginosa, was noted only in the north-west of Karelia (Voknavolok, N65.046857°; E30.603793°) on Microtus agrestis, Myodes glareolus and Neomys fodiens. Its prevalence and abundance were 12.3 % and 0.86 spm., respectively. This paper is the first report on the fauna of chiggers on small mammals in Karelia. Further focused studies of this group of arthropods may expand the list of species.

Small mammal responses to long-term large-scale woodland creation: the influence of local and landscape-level attributes.

Habitat loss and fragmentation greatly affect biological diversity. Actions to counteract their negative effects include increasing the quality, amount and connectivity of seminatural habitats at the landscape scale. However, much of the scientific evidence underpinning landscape restoration comes from studies of habitat loss and fragmentation, and it is unclear whether the ecological principles derived from habitat removal investigations are applicable to habitat creation. In addition, the relative importance of local‐ (e.g., improving habitat quality) vs. landscape‐level (e.g., increasing habitat connectivity) actions to restore species is largely unknown, partly because studying species responses over sufficiently large spatial and temporal scales is challenging. We studied small mammal responses to large‐scale woodland creation spanning 150 yr, and assessed the influence of local‐ and landscape‐level characteristics on three small mammal species of varying woodland affinity. Woodland specialists, generalists, and grassland specialists were present in woodlands across a range of ages from 10 to 160 yr, demonstrating that these species can quickly colonize newly created woodlands. However, we found evidence that woodlands become gradually better over time for some species. The responses of individual species corresponded to their habitat specificity. A grassland specialist (Microtus agrestis) was influenced only by landscape attributes; a woodland generalist (Apodemus sylvaticus) and specialist (Myodes glareolus) were primarily influenced by local habitat attributes, and partially by landscape characteristics. At the local scale, high structural heterogeneity, large amounts of deadwood, and a relatively open understory positively influenced woodland species (both generalists and specialists); livestock grazing had strong negative effects on woodland species abundance. Actions to enhance habitat quality at the patch scale focusing on these attributes would benefit these species. Woodland creation in agricultural landscapes is also likely to benefit larger mammals and birds of prey feeding on small mammals and increase ecosystem processes such as seed dispersal.

Glacial cycles drive rapid divergence of cryptic field vole species.

Understanding the factors that contribute to the generation of reproductively isolated forms is a fundamental goal of evolutionary biology. Cryptic species are an especially interesting challenge to study in this context since they lack obvious morphological differentiation that provides clues to adaptive divergence that may drive reproductive isolation. Geographical isolation in refugial areas during glacial cycling is known to be important for generating genetically divergent populations, but its role in the origination of new species is still not fully understood and likely to be situation dependent. We combine analysis of 35,434 single‐nucleotide polymorphisms (SNPs) with environmental niche modeling (ENM) to investigate genomic and ecological divergence in three cryptic species formerly classified as the field vole (Microtus agrestis). The SNPs demonstrate high genomic divergence (pairwise F ST values of 0.45–0.72) and little evidence of gene flow among the three field vole cryptic species, and we argue that genetic drift may have been a particularly important mechanism for divergence in the group. The ENM reveals three areas as potential glacial refugia for the cryptic species and differing climatic niches, although with spatial overlap between species pairs. This evidence underscores the role that glacial cycling has in promoting genetic differentiation and reproductive isolation by subdivision into disjunct distributions at glacial maxima in areas relatively close to ice sheets. Future investigation of the intrinsic barriers to gene flow between the field vole cryptic species is required to fully assess the mechanisms that contribute to reproductive isolation. In addition, the Portuguese field vole (M. rozianus) shows a high inbreeding coefficient and a restricted climatic niche, and warrants investigation into its conservation status.

Makhnevskaya Ledyanaya Cave (Middle Urals, Russia): Biostratigraphical reconstruction

Pollen and fossil mammals of the terrigenous deposits in the Makhnevskaya Ledyanaya Cave (59°26′ N 57°41’ E), located in the northern part of the Middle Urals and on the border with the Northern Urals, were studied. The spore-and-pollen spectra are divided into four pollen zones. In all the spectra, pollen concentrations of tree species amount to 50–70%. The presence of pollen in thermophilic (Quercus robur-type, Tilia cordata-type, Ulmus sp., Carpinus betulus, Corylus avellana-type) and moderate boreal (Abies, Picea, Pinus, Betula, Alnus) species and a lack of any tundra flora elements indicate their interglacial nature. The following have been identified as small mammal fauna: 8 taxa of insectivorous mammals, 4 taxa of bats, 2 taxa of lagomorphs, 4 species of carnivores, 16 species of rodents, 1 species of odd-toed ungulates and 4 species of even-toed ungulates. The remains of cryoxerophilous (Dicrostonyx sp., Lasiopodomys gregalis) and steppe (Ochotona sp.) species are scarce in the studied fauna. Species typical of forests (genus Sorex, genus Craseomys, genus Myodes, Myopus schisticolor, Microtus agrestis) are dominant. Remains of Erinaceus sp., Talpa sp., Crocidura leucodon, Sciurus vulgaris, Hystrix brachyura, Dryomys nitedula, Apodemus flavicollis, Stephanorhinus kirchbergensis have been found. The morphology and dimensions of the teeth of Panthera spelaea fossilis, Hystrix brachyura, Dryomys nitedula, Arvicola amphibius, mice of genus Apodemus are described. The compositions of the palynocomplexes and mammal fauna as well as the SDQ values for m1 of Arvicola amphibius allow us to date the deposits from the Makhnevskaya Ledyanaya Cave to the Eemian interglacial period (MIS 5e).

THYROID STATUS IN MOUSE-LIKE RODENTS UNDER THE INFLUENCE OF SYNTHETIC PYRETHROID CYPERMETHRIN

The aim of this work was to evaluate the thyroid status in mouse-like rodents under the influence of synthetic pyrethroid cypermethrin. The studies were performed on 168 male rats (Rattus norvegicus) and 112 male red voles (Myodes rutilus). When simulating acute intoxication, cypermethrin was injected once into the stomach at a dose of lA LD50 followed by observation of rats for 30 days and voles for 7 days. When studying chronic intoxication, cypermethrin was administered to rats at a dose of 1/100 LD50, the duration of the experiment was 120 days. Acaricidal treatment of the forest was carried out on a one-hectare site, and the results of the capture of voles and their thyroid status were compared with voles caught on the background site. Synthetic pyrethroid cypermethrin in acute and chronic experiments causes a change in thyroid status in laboratory rats, which is reflected in a decrease in the level of thyroid hormones in the blood serum. Moreover, there is an increase in the level of thyroid-stimulating hormone in rats. The introduction of a high dose of cypermethrin (A LD50) into male voles under field vivarium conditions also revealed the sensitivity of representatives of this species to the action of synthetic pyrethroids, which was manifested in a decrease in the synthesis of T4 and T3 in their thyroid glands. Acaricidal forest treatment contributes to a temporary change in thyroid status in male red field vole (Myodes rutilus) caught in the treated area, which, apparently, is a consequence of adaptive changes and migration processes in the population of this species.

Field vole-associated Traemmersee hantavirus from Germany represents a novel hantavirus species.

Vole-associated hantaviruses occur in the Old and New World. Tula orthohantavirus (TULV) is widely distributed throughout the European continent in its reservoir, the common vole (Microtus arvalis), but the virus was also frequently detected in field voles (Microtus agrestis) and other vole species. TULV and common voles are absent from Great Britain. However, field voles there harbor Tatenale and Kielder hantaviruses. Here we screened 126 field voles and 13 common voles from Brandenburg, Germany, for hantavirus infections. One common vole and four field voles were anti-TULV antibody and/or TULV RNA positive. In one additional, seropositive field vole a novel hantavirus sequence was detected. The partial S and L segment nucleotide sequences were only 61.1% and 75.6% identical to sympatrically occurring TULV sequences, but showed highest similarity of approximately 80% to British Tatenale and Kielder hantaviruses. Subsequent determination of the entire nucleocapsid (N), glycoprotein (GPC), and RNA-dependent RNA polymerase encoding sequences and determination of the pairwise evolutionary distance (PED) value for the concatenated N and GPC amino acid sequences confirmed a novel orthohantavirus species, tentatively named Traemmersee orthohantavirus. The identification of this novel hantavirus in a field vole from eastern Germany underlines the necessity of a large-scale, broad geographical hantavirus screening of voles to understand evolutionary processes of virus-host associations and host switches.

Relative size variations in two vole species: A climatic proxy for the identification of humid-arid pulses during Late Pleistocene in Southwestern Europe?

In this study, we analysed the relative size variations of the first lower molar of the common vole Microtus arvalis and the field vole Microtus agrestis from three Late Pleistocene sites with long sequences: Fumane Cave (north-eastern Italy), Portalón and Arbreda Cave (northern and north-eastern Iberian Peninsula). The relative size variations of the two species have been quantified applying the Lagr/Larv index. We tried to relate the changes in the index values to the climatic fluctuations that characterize Marine Isotope Stage (MIS) 3 and 2. The obtained results are compared with previous studies of palaeoclimatic and palaeoenvironmental reconstructions to investigate the efficacy of the Lagr/Larv index as proxy for climatic oscillations through MIS 3-2. The data have also been compared with other available data from Late Pleistocene sites of Spain, Italy, and Hungary, to analyse the responses of the two species to the climatic oscillations in different geographic and climatic areas. Our study showed that the Lagr/Larv index is a potential tool to identify climatic oscillations and changes between humid/dry conditions in Southwestern Europe.

MODERN DISTRIBUTION OF NEMATODES P. SYPHACIA (NEMATODA, OXYURIDAE) IN POPULATIONS OF MOUSE-LIKE RODENTS IN THE VORONEZH RESERVE

The mouse-like rodents, inhabiting natural and anthropogenic biocenoses, are sources and distributors of various helminth infections, including syphaciosis. Currently, more than ten species of nematodes of the genus Syphacia are registered in mouse-like rodents. Syphacia exhibit narrow, guest specificity, parasitizing, as a rule, in one or three species of mouse-like rodents. The main sources of infection of rodents by these nematodes are vegetable feed, soil, forest litter. We have presented long-term (2000-2018) results of helminthological studies of mouse-like rodents, conducted in the Voronezh Reserve. At present, in the territory of mouse-like rodents, 5 species of Syphacia are registered: Syphacia agraria, S. obvelata, S. nigeriana, S. petrusewiczi, S. stroma. Taxonomic diagnosis of nematodes was carried out taking into account the guest specificity, localization in the host intestine, morphometric data, and also taking into account the structural features of the nematode head end. Nematodes of syphacia are noted in 7 host species: Mus musculus, Apodemus agrarius, Sylvemus flavicollis, Sylvemus uralensis, Myodes glareolus, Microtus agrestis, Microtus arvalis. The extensiveness of invasion ranges from 6 to 51% (on average, 30%).The study area is located in a densely populated region of the Central Black Earth region of Russia. Here, at the junction of natural and anthropogenic ecosystems, mouse-like rodents are a significant source of parasitic pollution. With a high number of rodents and high extensiveness of invasion by nematodes p. Syphacia, there is a significant accumulation of invasive beginning in the external environment, which increases the epidemiological and epizootological risks of this helminthiasis.

A new focus of the tick Haemaphysalis concinna in Western Poland

The relict tick Haemaphysalis concinna has a fragmented and focal distribution in Central Europe and Asia. Although in the majority of neighboring countries the occurrence of this tick species is well-documented (i.e., in Germany, Czech Republic, Slovakia, Ukraine), to-date its occurrence in Poland has been registered only once, in 1953 in Troszyn in North-Western Pomerania, close to the German-Polish border. In the present study we report the first documented finding of H. concinna in Western Poland, confirmed both by collection of juvenile ticks from rodent hosts and questing ticks from vegetation. Trapping of rodents took place in the summer of 2018 in three locations in Western Poland (Słonin, Nowy Młyn 1, Nowy Młyn 2). Rodents were inspected for ectoparasites, which were detached and fixed in 70% ethanol. All the collected ticks were assigned to species and developmental stages using appropriate morphological keys, and representative individuals were genotyped by molecular methods. A total of 1482 feeding ticks were collected from 106 rodents from three sites. The common tick Ixodes ricinus was found in abundance on small rodents at all three sites; Dermacentor reticulatus ticks were identified at two sites in small numbers and, finally, numerous juvenile H. concinna (n = 427) were found at one of our study sites (Nowy Młyn 2). The highest prevalence and abundance of H. concinna were recorded on voles, Microtus agrestis and M. oeconomus, from this site in August. Additionally, questing nymphs and adult H. concinna were collected locally from vegetation (n = 20). Genotyping and phylogenetic analysis confirmed the species as H. concinna. A new focus of H. concinna has been described in Western Poland. Our long-term field work monitoring the expansion of the distribution of D. reticulatus in Poland, during which all collected ticks are identified, suggests that H. concinna is still very rare in the country.

Investigation and genome characterisation of tatenale hantavirus in wild rodent populations in the United Kingdom

Hantaviruses are a diverse group of single-stranded, negative sense RNA viruses, belonging to the Bunyaviridae family. They are primarily rodent-borne and transmitted into humans through the inhalation of aerosolised excreta of infected animals. Each hantavirus is typically associated with a single reservoir species, resulting in a persistent, yet asymptomatic infection. In humans, however, in addition to asymptomatic infection two disease syndromes are associated with hantavirus infection, hantavirus haemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Tatenale Hantavirus (TATV) was first isolated from field voles in NW England in 2013 and has since been detected at other sites in Northern England. However, only two small fragments of the L and S segments have been sequenced, precluding full phylogenetic characterisation of the virus. Field voles were sampled at two sites in Leicestershire (N=104) and Cheshire (N=12), and their lungs subjected to a degenerate pan-hantavirus RT-PCR assay, targeting a section of the polymerase gene. Eleven Cheshire and one Leicestershire sample were TATV positive, and were 94 % homologous across the amplicon. Illumina Hi-Seq sequencing revealed the complete coding regions of the Leicestershire isolate. Analysis of the sequence showed that TATV is most closely related to Khabarovsk virus, with a homology of 91%/88%/89 % (AA) across the L/M/S Segments, respectively. ICTV species demarcation requires an AA difference of >7 % across the S and M, TATV meets the requirement of a novel species. Retrieval of full coding sequence will allow further investigation into TATV, and its potential to infect humans through pseudotyping of the glycoproteins.

Genetic variation in field voles (Microtus agrestis) from the British Isles: selective sweeps or population bottlenecks?

The Eurasian field vole (Microtus agrestis) comprises three evolutionarily significant units (ESUs). The northern ESU is found at higher latitudes across the western Palaearctic region and includes six, largely allopatric, mitochondrial DNA lineages that were derived from population bottlenecks. One of these lineages is found in southern Britain and nearby areas of continental Europe. A prominent sub-lineage is nested within, and therefore derived from, the part of this lineage occupying southern Britain. The sub-lineage consists of an abundant central haplotype together with a series of closely related haplotypes, a distribution that would result from either a recent population bottleneck or a selective sweep. To distinguish between these, we sequenced a Y-chromosome marker in 167 field voles from Britain and Europe, and analysed a panel of 13 autosomal microsatellite loci in 144 field voles from eight populations in Britain. The Y-chromosome marker showed a continental-scale pattern of variation that was not aligned with that of the mitochondrial marker, while microsatellite variation did not show any evidence for a bottleneck, tentatively favouring selection instead. This implies a role for both stochastic and selective processes in generating phylogeographical patterns at different scales in the field vole.

Shared Common Ancestry of Rodent Alphacoronaviruses Sampled Globally.

The recent discovery of novel alphacoronaviruses (alpha-CoVs) in European and Asian rodents revealed that rodent coronaviruses (CoVs) sampled worldwide formed a discrete phylogenetic group within this genus. To determine the evolutionary history of rodent CoVs in more detail, particularly the relative frequencies of virus-host co-divergence and cross-species transmission, we recovered longer fragments of CoV genomes from previously discovered European rodent alpha-CoVs using a combination of PCR and high-throughput sequencing. Accordingly, the full genome sequence was retrieved from the UK rat coronavirus, along with partial genome sequences from the UK field vole and Poland-resident bank vole CoVs, and a short conserved ORF1b fragment from the French rabbit CoV. Genome and phylogenetic analysis showed that despite their diverse geographic origins, all rodent alpha-CoVs formed a single monophyletic group and shared similar features, such as the same gene constellations, a recombinant beta-CoV spike gene, and similar core transcriptional regulatory sequences (TRS). These data suggest that all rodent alpha CoVs sampled so far originate from a single common ancestor, and that there has likely been a long-term association between alpha CoVs and rodents. Despite this likely antiquity, the phylogenetic pattern of the alpha-CoVs was also suggestive of relatively frequent host-jumping among the different rodent species.

Detection of Francisella tularensis in three vole species in Central Europe

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.