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An assessment of the genetic diversity and structure of a population is essential for designing recovery plans for threatened species. Italy hosts two brown bear populations

In light of the current biodiversity crisis, investigating the human impact on non-human primate gut biology is important to understanding the ecological significance of gut community dynamics across changing habitats and its role in conservation. Using traditional coproscopic parasitological techniques, we compared the gastrointestinal protozoan and metazoan symbiont richness of two primates: the Udzungwa red colobus (Procolobus gordonorum) and the yellow baboon (Papio cynocephalus). These species live sympatrically in both protected and unprotected forests within the Udzungwa Mountains of Tanzania with distinct ecological adaptations and diets. Our results showed that terrestrial and omnivorous yellow baboons had 2 (95% CI 1.47–2.73) and 3.78 (2.62–5.46) times higher gut symbiont richness (both including and excluding rare protozoans) compared to the arboreal and leaf-eating Udzungwa red colobus in unprotected and protected forest, respectively. We also found a consistent depletion of symbiont richness in red colobus living in the unprotected forest fragment compared to the continuous protected forests [the latter having 1.97 times (95% CI 1.33–2.92) higher richness], but not in yellow baboons. Richness reduction was particularly evident in the Udzungwa red colobus monkeys, confirming the pattern we reported previously for gut bacterial communities. This study demonstrates the impact of human activities even on the microbiodiversity of the intestinal tract of this species. Against the background of rapid global change and habitat degradation, and given the health benefits of intact gut communities, the decrease in natural gut symbionts reported here is worrying. Further study of these communities should form an essential part of the conservation framework.

Almost 40% of terrestrial organisms depend directly or indirectly on soil during their life cycle. In particular, the soils of Alpine pastures have been managed for centuries and therefore, harbor specific soil fauna and microbial communities. In fact, the below-ground biomass in pastures is estimated to be much greater than the above-ground biomass, even including livestock. Excluding roots and algae, the below-ground biomass is mainly composed of microorganisms, which play a central role in fertility and carbon cycles. Moreover, soil bacteria and fungi interact with components of soil microfauna and mesofauna such as nematodes and collembolans, as well as soil macrofauna (i.e., earthworms, insects, spiders), and plants through the rhizosphere soil. To add to the complexity, each invertebrate taxa hosts its own microbiota, crucial for development, survival and reproduction,. Although many aspects of this biodiversity have already been described, the complex interactions between the microbiota of soil, rhizosphere soil, and soil fauna are almost unknown.Given the importance of soil biodiversity for the sustainability of Alpine agro-ecosystems, and the possible impact of climate change scenarios on the complex network of interactions, there is an urgent need to fill the fundamental knowledge gap concerning microbial and soil fauna diversity, their composition, function and interaction in Alpine soils. Recent advances in next generation DNA sequencing technologies now make it possible to characterize the composition of microorganisms present in a soil, fecal or gut sample through the amplification and sequencing of the 16S rRNA bacterial and ITS fungal genes (‘metataxonomics’). However, the comparison of microbiota composition of various matrices has been limited.In MICROVALU: Evaluating microbiodiversity in alpine pastures (a EUREGIO - Interregional Project Network project), we optimized laboratory protocols that, for the first time, will allow the comparison of microbiota from different sample types. In three replicate sites, we sampled soil microfauna (nematodes), mesofauna (collembolans) and macrofauna (earthworms, ground beetles and rove beetles), as well as rhizosphere soil and fecal pellets deposited by wild mammals and domestic livestock. Sampling was repeated at four different altitudes (1000, 1500, 2000, 2500 m asl) to investigate how microclimate could effect microbiota interactions. After metataxonomic and bioinformatics analysis, our results indicate that each soil type and faunal taxa has a unique microbiota, overlapping to different degrees depending on life cycle, as well as phylogenetic and tropic relationships. In combination with climatic and soil chemistry data, our results will an important step towards a more complete understanding of the relationships between soil organisms and their effect on soil processes.

Surveillance of Echinococcus multilocularis at the edge of its range is hindered by fragmented distributional patterns and low prevalence in definitive hosts. Thus, tests with adequate levels of sensitivity are especially important for discriminating between infected and non-infected areas. In this study we reassessed the prevalence of E. multilocularis at the southern border of its distribution in Province of Bolzano (Alto Adige, northeastern Alps, Italy), to improve surveillance in wildlife and provide more accurate estimates of exposure risk. We compared the diagnostic test currently implemented for surveillance based on coproscopy and multiplex PCR (CMPCR) to a real-time quantitative PCR (qPCR) in 235 fox faeces collected in 2019 and 2020. The performances of the two tests were estimated using a scraping technique (SFCT) applied to the small intestines of a subsample (n = 123) of the same foxes as the reference standard. True prevalence was calculated and the sample size required by each faecal test for the detection of the parasite was then estimated. True prevalence of E. multilocularis in foxes (14.3%) was markedly higher than reported in the last decade, which was never more than 5% from 2012 to 2018 in the same area. In addition, qPCR showed a much higher sensitivity (83%) compared to CMPCR (21%) and agreement with the reference standard was far higher for qPCR (0.816) than CMPCR (0.298) meaning that for the latter protocol, a smaller sample size would be required to detect the disease. Alto Adige should be considered a highly endemic area. Routine surveillance on definitive hosts at the edges of the E. multilocularis distribution should be applied to smaller geographic areas, and rapid, sensitive diagnostic tools using directly host faeces, such as qPCR, should be adopted.

The Western European house mouse is chromosomally diverse, with diploid karyotypes ranging from the standard 40 telocentric chromosomes down to 22 chromosomes. Karyotypes are modified through Robertsonian (Rb) fusion of 2 telocentrics into a single metacentric, occurring repeatedly with fixation, and whole-arm reciprocal translocations (WARTs) generating additional novel karyotypes. Over 100 metacentric populations (chromosomal races) have been identified, geographically clustered into “systems.” Chromosomal races within systems often hybridise, and new races may emerge through this hybridisation (“zonal raciation”). We wished to determine the degree to which chromosomal races in a system have evolved independently or share common ancestry. Recombination between chromosomes from hybridising chromosomal races can erase the signals associated with a particular metacentric of interest, making inferences challenging. However, reduced recombination near the centromeres of chromosomal race-specific metacentrics makes centromere-adjacent markers ideal for solving this problem. For the Northern Italy System (NIS), we used microsatellite markers near the centromere to test previous hypotheses about evolutionary relationships of 5 chromosomal races. We chose markers from chromosomes 1, 3, 4, and 6, all of which comprise one arm of a metacentric in at least 2 of these NIS metacentric populations. We used estimates of FST and RST, as well as principal components analyses and neighbour-joining phylogenetic analyses, to infer evolutionary relationships between these 5 chromosomal races and neighbouring mice with the standard karyotype. We showed that the metacentric populations form a single grouping distinct from the standard populations, consistent with their common origin and consistent with a parsimonious sequence of chromosomal rearrangements to explain the relationship of the chromosomal races. That origin and evolution of the chromosomal races in the system would have involved Rb fusions, explaining the occurrence of chromosomal races with diploid numbers as low as 22. However, WARTs and zonal raciation have also been inferred, and the rare occurrence of chromosome 1 in different metacentrics in closely related chromosomal races is almost certainly explained by a WART. Our results with centromeric microsatellites are consistent with the above scenarios, illustrating, once again, the value of markers in the centromeric region to test evolutionary hypotheses in house mouse chromosomal systems.

BackgroundSurveillance of E. multilocularis at the edge of its range is hindered by fragmented distributional patterns and low prevalence and burden in definitive hosts. Thus, tests with adequate levels of sensitivity are especially important for discriminating between infected and non-infected areas.AimWe reassessed the prevalence of E. multilocularis at the southern border of its distribution in Alto Adige (Italy), to improve surveillance in wildlife and provide more accurate estimates of exposure risk.MethodsWe compared results from the diagnostic test currently implemented for surveillance (based on Coproscopy+Multiplex PCR - CMPCR), against a real-time quantitative PCR (qPCR) for 235 fox faeces collected in 2019-2020. The performances of the two tests were estimated using a scraping technique (SFCT) as the gold standard applied to the small intestines of a subsample (n=123) of the same hosts. True prevalence was calculated and sample size required by each faecal test for the detection of the parasite was then estimated.ResultsTrue prevalence of E. multilocularis in foxes (14.3%) was definitely higher than reported in the last decade (never >5% from 2012 to 2018). The qPCR also had a higher sensitivity (83%) compared to CMPCR (21%). Agreement with the gold standard was far higher for qPCR (0.816) than CMPCR (0.298) as well, determining a smaller sample size required to detect the disease.ConclusionsAlto Adige should be considered a highly endemic area. Surveillance at the edges of E. multilocularis distribution should adopt qPCR diagnostics on definitive hosts on a small geographic scale.AUTHOR SUMMARYEchinococcus multilocularis is an intestinal flatworm, whose adult stage in Europe is harboured mainly by the red fox (Vulpes vulpes), which spreads parasite’s eggs by faeces. This parasite is the agent of a severe and potentially lethal zoonosis, the alveolar echinococcosis, affecting humans after accidental ingestion of parasite’s eggs. In the Italian Alpine area, which represents the southernmost border of E. multilocularis European range, surveillance is hindered by a fragmented distributional pattern, where presence in foxes has been consistently reported only in few isolated foci in Alto Adige (Bolzano province – Italy) of low prevalence. In order to improve the efficiency of monitoring efforts, we tested the performances of two diagnostic protocols on fox faeces (sedimentation, filtration, counting technique followed by standard PCR, and whole stool real-time PCR) against a benchmark technique on fox intestines (scraping, filtration, counting technique - considered as the gold standard). This allowed not only to determine qPCR as a far more sensitive and sample-efficient diagnostic tool for E. multilocularis detection in marginally affected areas, but also to re-assess its prevalence in Alto Adige, which should be considered a highly endemic area. Consequent actions in the field and modifications in the surveillance strategy should be therefore considered.

The development of new diagnostic methods resulted in the discovery of novel hepaciviruses in wild populations of the bank vole (Myodes glareolus, syn. Clethrionomys glareolus). The naturally infected voles demonstrate signs of hepatitis similar to those induced by hepatitis C virus (HCV) in humans. The aim of the present research was to investigate the geographical distribution of bank vole-associated hepaciviruses (BvHVs) and their genetic diversity in Europe. Real-time reverse transcription polymerase chain reaction (RT-qPCR) screening revealed BvHV RNA in 442 out of 1838 (24.0%) bank voles from nine European countries and in one of seven northern red-backed voles (Myodes rutilus, syn. Clethrionomys rutilus). BvHV RNA was not found in any other small mammal species (n = 23) tested here. Phylogenetic and isolation-by-distance analyses confirmed the occurrence of both BvHV species (Hepacivirus F and Hepacivirus J) and their sympatric occurrence at several trapping sites in two countries. The broad geographical distribution of BvHVs across Europe was associated with their presence in bank voles of different evolutionary lineages. The extensive geographical distribution and high levels of genetic diversity of BvHVs, as well as the high population fluctuations of bank voles and occasional commensalism in some parts of Europe warrant future studies on the zoonotic potential of BvHVs.

The picornavirus named ‘Ljungan virus’ (LV, species Parechovirus B) has been detected in a dozen small mammal species from across Europe, but detailed information on its genetic diversity and host specificity is lacking. Here, we analyze the evolutionary relationships of LV variants circulating in free-living mammal populations by comparing the phylogenetics of the VP1 region (encoding the capsid protein and associated with LV serotype) and the 3Dpol region (encoding the RNA polymerase) from 24 LV RNA-positive animals and a fragment of the 5′ untranslated region (UTR) sequence (used for defining strains) in sympatric small mammals. We define three new VP1 genotypes: two in bank voles (Myodes glareolus) (genotype 8 from Finland, Sweden, France, and Italy, and genotype 9 from France and Italy) and one in field voles (Microtus arvalis) (genotype 7 from Finland). There are several other indications that LV variants are host-specific, at least in parts of their range. Our results suggest that LV evolution is rapid, ongoing and affected by genetic drift, purifying selection, spillover and host evolutionary history. Although recent studies suggest that LV does not have zoonotic potential, its widespread geographical and host distribution in natural populations of well-characterized small mammals could make it useful as a model for studying RNA virus evolution and transmission.

In the light of unprecedented change in global biodiversity, real-time and accurate ecosystem and biodiversity assessments are becoming increasingly essential. Nevertheless, estimation of biodiversity using ecological field data can be difficult for several reasons. For instance, for very large areas, it is challenging to collect data that provide reliable information. Some of these restrictions in Earth observation can be avoided through the use ofremote sensingapproaches. Various studies have estimated biodiversity on the basis of the Spectral Variation Hypothesis (SVH). According to this hypothesis, spectral heterogeneity over the different pixel units of a spatial grid reflects a higher niche heterogeneity, allowing more organisms to coexist. Recently, the spectral species concept has been derived, following the consideration that spectral heterogeneity at a landscape scale corresponds to a combination of subspaces sharing a similarspectral signature. With the use of high resolution remote sensing data, on a local scale, these subspaces can be identified as separate spectral entities, the so called “spectral species”. Our approach extends this concept over wide spatial extents and to a higher level of biological organization. We applied this method toMODISimagery data across Europe. Obviously, in this case, a spectral species identified by MODIS is not associated to a singleplant speciesin the field but rather to a species assemblage, habitat, or ecosystem. Based on such spectral information, we propose a straightforward method to deriveα- (local relative abundance and richness of spectral species) andβ-diversity (turnover of spectral species) maps over wide geographical areas.

The gut microbiota may modulate the disposition and toxicity of environmental contaminants within a host but, conversely, contaminants may also impact gut bacteria. Such contaminant-gut microbial connections, which could lead to alteration of host health, remain poorly known and are rarely studied in free-ranging wildlife. The polar bear (Ursus maritimus) is a long-lived, wide-ranging apex predator that feeds on a variety of high trophic position seal and cetacean species and, as such, is exposed to among the highest levels of biomagnifying contaminants of all Arctic species. Here, we investigate associations between mercury (THg; a key Arctic contaminant), diet, and the diversity and composition of the gut microbiota of polar bears inhabiting the southern Beaufort Sea, while accounting for host sex, age class and body condition. Bacterial diversity was negatively associated with seal consumption and mercury, a pattern seen for both Shannon and Inverse Simpson alpha diversity indices (adjusted R2 = 0.35, F1,18 = 8.00, P = 0.013 and adjusted R2 = 0.26, F1,18 = 6.04, P = 0.027, respectively). No association was found with sex, age class or body condition of polar bears. Bacteria known to either be involved in THg methylation or considered to be highly contaminant resistant, including Lactobacillales, Bacillales and Aeromonadales, were significantly more abundant in individuals that had higher THg concentrations. Conversely, individuals with higher THg concentrations showed a significantly lower abundance of Bacteroidales, a bacterial order that typically plays an important role in supporting host immune function by stimulating intraepithelial lymphocytes within the epithelial barrier. These associations between diet-acquired mercury and microbiota illustrate a potentially overlooked outcome of mercury accumulation in polar bears.

The illegal trade has been threatening tortoise populations worldwide for decades. Nowadays, however, DNA typing and forensic genetic approaches allow us to investigate the geographic origin of confiscated animals and to relocate them into the wild, providing that suitable molecular tools and reference data are available. Here we assess the suitability of a small panel of microsatellite markers to investigate patterns of illegal translocations and to assist forensic genetic applications in the endangered Mediterranean land tortoise Testudo hermanni hermanni. Specific allelic ladders were created for each locus and tested on several reference samples. We used the microsatellite panel to (i) increase our understanding of the population genetic structure in wild populations with new data from previously unsampled geographic areas (overall 461 wild individuals from 28 sampling sites); (ii) detect the presence of non-native individuals in wild populations; and (iii) identify the most likely geographic area of origin of 458 confiscated individuals hosted in Italian seizure and recovery centers. Our analysis initially identified six major genetic clusters corresponding to different geographic macro-areas along the Mediterranean range. Long-distance migrants among wild populations, due to translocations, were found and removed from the reference database. Assignment tests allowed us to allocate approximately 70 % of confiscated individuals of unknown origin to one of the six Mediterranean macro-areas. Most of the assigned tortoises belonged to the genetic cluster corresponding to the area where the respective captivity center was located. However, we also found evidence of long-distance origins of confiscated individuals, especially in centers along the Adriatic coast and facing the Balkan regions, a well-known source of illegally traded individuals. Our results clearly show that the microsatellite panel and the reference dataset can play a beneficial role in reintroduction and repatriation projects when confiscated individuals need to be re-assigned to their respective macro-area of origin before release, and can assist future forensic genetic applications in detecting the illegal trade and possession of Testudo hermanni individuals.

In the light of unprecedented change in global biodiversity, real-time and accurate ecosystem and biodiversity assessments are becoming increasingly essential. Nevertheless, estimation of biodiversity using ecological field data can be difficult for several reasons. For instance, for very large areas, it is challenging to collect data that provide reliable information. Some of these restrictions in Earth observation can be avoided through the use of remote sensing approaches. Various studies have estimated biodiversity on the basis of the Spectral Variation Hypothesis (SVH). According to this hypothesis, spectral heterogeneity over the different pixel units of a spatial grid reflects a higher niche heterogeneity, allowing more organisms to coexist. Recently, the spectral species concept has been derived, following the consideration that spectral heterogeneity at a landscape scale corresponds to a combination of subspaces sharing a similar spectral signature. With the use of high resolution remote sensing data, on a local scale, these subspaces can be identified as separate spectral entities, the so called “spectral species”. Our approach extends this concept over wide spatial extents and to a higher level of biological organization. We applied this method to MODIS imagery data across Europe. Obviously, in this case, a spectral species identified by MODIS is not associated to a single plant species in the field but rather to a species assemblage, habitat, or ecosystem. Based on such spectral information, we propose a straightforward method to derive α- (local relative abundance and richness of spectral species) and β-diversity (turnover of spectral species) maps over wide geographical areas.

International audience; Ljungan virus (LV), which belongs to the Parechovirus genus in the Picornaviridae family, was first isolated from bank voles (Myodes glareolus) in Sweden in 1998 and proposed as a zoonotic agent. To improve knowledge of the host association and geographical distribution of LV, tissues from 1685 animals belonging to multiple rodent and insectivore species from 12 European countries were screened for LV-RNA using reverse transcriptase (RT)-PCR. In addition, we investigated how the prevalence of LV-RNA in bank voles is associated with various intrinsic and extrinsic factors. We show that LV is widespread geographically, having been detected in at least one host species in nine European countries. Twelve out of 21 species screened were LV-RNA PCR positive, including, for the first time, the red vole (Myodes rutilus) and the root or tundra vole (Alexandromys formerly Microtus oeconomus), as well as in insectivores, including the bicolored white-toothed shrew (Crocidura leucodon) and the Valais shrew (Sorex antinorii). Results indicated that bank voles are the main rodent host for this virus (overall RT-PCR prevalence: 15.2%). Linear modeling of intrinsic and extrinsic factors that could impact LV prevalence showed a concave-down relationship between body mass and LV occurrence, so that subadults had the highest LV positivity, but LV in older animals was less prevalent. Also, LV prevalence was higher in autumn and lower in spring, and the amount of precipitation recorded during the 6 months preceding the trapping date was negatively correlated with the presence of the virus. Phylogenetic analysis on the 185 base pair species-specific sequence of the 5 ' untranslated region identified high genetic diversity (46.5%) between 80 haplotypes, although no geographical or host-specific patterns of diversity were detected.

The factors that influence the diversity and composition of raw milk and fecal microbiota in healthy commercial dairy herds are not fully understood, partially because the majority of metataxonomic studies involve experimental farms and/or single factors. We analyzed the raw milk and fecal microbiota of 100 healthy cows from 10 commercial alpine farms from the Province of Trento, Italy, using metataxonomics and applied statistical modelling to investigate which extrinsic and intrinsic parameters (e.g. herd, diet and milk characteristics) correlated with microbiota richness and composition in these relatively small traditional farms. We confirmed that Firmicutes, Ruminococcaceae and Lachnospiraceae families dominated the fecal and milk samples of these dairy cows, but in addition, we found an association between the number of observed OTUs and Shannon entropy on each farm that indicates higher microbiota richness is associated with increased microbiota stability. Modelling showed that herd was the most significant factor affecting the variation in both milk and fecal microbiota composition. Furthermore, the most important predictors explaining the variation of microbiota richness were milk characteristics (i.e. percentage fat) and diet for milk and fecal samples, respectively. We discuss how high intra-herd variation could affect the development of treatments based on microbiota manipulation.

Gut microbiota diversity has become the subject of extensive research in human and nonhuman animals, linking diversity and composition to gut function and host health. Because wild primates are good indicators of tropical ecosystem health, we developed the idea that they are a suitable model to observe the consequences of advancing global change (e.g., habitat degradation) on gut microbiota. So far, most of the studies focus mainly on gut bacteria; however, they are not the only component of the gut: fungi also serve essential functions in gut homeostasis. Here, for the first time, we explore and measure diversity and composition of both bacterial and fungal microbiota components of two tropical primate species living in highly different habitat types (intact versus degraded forests). Results on their microbiota diversity and composition are discussed in light of conservation issues and potential applications., Human exploitation and destruction of tropical resources are currently threatening innumerable wild animal species, altering natural ecosystems and thus, food resources, with profound effects on gut microbiota. Given their conservation status and the importance to tropical ecosystems, wild nonhuman primates make excellent models to investigate the effect of human disturbance on the diversity of host-associated microbiota. Previous investigations have revealed a loss of fecal bacterial diversity in primates living in degraded compared to intact forests. However, these data are available for a limited number of species, and very limited information is available on the fungal taxa hosted by the gut. Here, we estimated the diversity and composition of gut bacterial and fungal communities in two primates living sympatrically in both human-modified and pristine forests in the Udzungwa Mountains of Tanzania. Noninvasively collected fecal samples of 12 groups of the Udzungwa red colobus (Procolobus gordonorum) (n = 89), a native and endangered primate (arboreal and predominantly leaf-eating), and five groups of the yellow baboon (Papio cynocephalus) (n = 69), a common species of least concern (ground-feeding and omnivorous), were analyzed by the V1-V3 region of the 16S rRNA gene (bacterial) and ITS1-ITS2 (fungal) sequencing. Gut bacterial diversities were associated with habitat in both species, most likely depending on their ecological niches and associated digestive physiology, dietary strategies, and locomotor behavior. In addition, fungal communities also show distinctive traits across hosts and habitat type, highlighting the importance of investigating this relatively unexplored gut component. IMPORTANCE Gut microbiota diversity has become the subject of extensive research in human and nonhuman animals, linking diversity and composition to gut function and host health. Because wild primates are good indicators of tropical ecosystem health, we developed the idea that they are a suitable model to observe the consequences of advancing global change (e.g., habitat degradation) on gut microbiota. So far, most of the studies focus mainly on gut bacteria; however, they are not the only component of the gut: fungi also serve essential functions in gut homeostasis. Here, for the first time, we explore and measure diversity and composition of both bacterial and fungal microbiota components of two tropical primate species living in highly different habitat types (intact versus degraded forests). Results on their microbiota diversity and composition are discussed in light of conservation issues and potential applications.

Rodent-borne hanta- and arenaviruses are an emerging public health threat in Europe; however, their circulation in human populations is usually underestimated since most infections are asymptomatic. Compared to other European countries, Italy is considered 'low risk' for these viruses, yet in the Province of Trento, two pathogenic hantaviruses (Puumala and Dobrava-Belgrade virus) and one arenavirus (Lymphocytic Choriomeningitis Virus) are known to circulate in rodent reservoirs. In this paper, we performed a follow-up serological screening in humans to detect variation in the prevalence of these three viruses compared to previous analyses carried out in 2002. We also used a statistical model to link seropositivity to risk factors such as occupational exposure, cutting firewood, hunting, collecting mushrooms, having a garden and owning a woodshed, a dog or a companion rodent. We demonstrate a significant increase in the seroprevalence of all three target viruses between 2002 and 2015, but no risk factors that we considered were significantly correlated with this increase. We conclude that the general exposure of residents in the Alps to these viruses has probably increased during the last decade. These results provide an early warning to public health authorities, and we suggest more detailed diagnostic and clinical investigations on suspected cases.

Tick-borne encephalitis is an important zoonosis in many parts of north-western, central and eastern Europe, Russia and the Far East, with considerable altitudinal and latitudinal shifts described during recent decades. The reported routes of transmission for TBE virus include the saliva-activated non-viraemic transmission between co-feeding ticks taking place on rodent hosts. During the period 2001-2014, a population of the yellow-necked mouse (Apodemus flavicollis), which is considered among the most efficient TBE competent host, especially in central and western Europe, was intensively live-trapped in a known TBE focus in the Province of Trento, Italy. Individual live-trapped mice were checked for the number and position of feeding ticks and serologically screened for TBEv antibodies. A combined effect of climatic conditions and density of both roe deer and mice on the number of co-feeding tick groups was observed. Specifically, the occurrence of co-feeding ticks on mice during the questing season was affected by autumnal cooling in the previous season. On the other hand, co-feeding occurrence was also positively associated with roe deer abundance, while mouse density showed a hump-shaped pattern. Individual features of A. flavicollis such as weight and sex also affected co-feeding occurrence with the heaviest (breeding adult) males carrying more co-feeding ticks. We also found that the overall number of co-feeding ticks on mice positively affected TBEv antibody detection in this species the following year. In conclusion, a specific combination of climatic conditions in conjunction with certain rodent and roe deer densities are the principal determinants of the number of co-feeding ticks on A. flavicollis and, consequently, TBEv circulation. These variables can be used to provide an early warning signal for a TBE hazard, thus representing a useful tool for Public Health authorities to prepare action for prevention and control within TBEv circulation areas.

Predicting the geographical distribution of a species is a central topic in ecology, conservation and management of natural resources especially for invasive organisms. Invasive species can modify the structure and function of invaded ecosystems, altering their biodiversity, and causing significant economic losses locally and globally. Therefore, measuring and visualizing the uncertainty inherent in species’ potential distributions is fundamental for effective biodiversity monitoring and planning conservation interventions. This paper discusses a new Bayesian approach to mapping this uncertainty using cartograms, previously published knowledge, and presence/absence data.

The gut microbiota plays a critical role in host health, yet remains poorly studied in wild species. Polar bears (Ursus maritimus), key indicators of Arctic ecosystem health and environmental change, are currently affected by rapid shifts in habitat that may alter gut homeostasis. Declining sea ice has led to a divide in the southern Beaufort Sea polar bear subpopulation such that an increasing proportion of individuals now inhabit onshore coastal regions during the open-water period (‘onshore bears’) while others continue to exhibit their typical behaviour of remaining on the ice (‘offshore bears’). We propose that bears that have altered their habitat selection in response to climate change will exhibit a distinct gut microbiota diversity and composition, which may ultimately have important consequences for their health. Here, we perform the first assessment of abundance and diversity in the faecal microbiota of wild polar bears using 16S rRNA Illumina technology. We find that bacterial diversity is significantly higher in onshore bears compared to offshore bears. The most enriched OTU abundance in onshore bears belonged to the phylum Proteobacteria, while the most depleted OTU abundance within onshore bears was seen in the phylum Firmicutes. We conclude that climate-driven changes in polar bear land use are associated with distinct microbial communities. In doing so, we present the first case of global change mediated alterations in the gut microbiota of a free-roaming wild animal.

The first natural chromosomal variation in the house mouse was described nearly 50 years ago in Val Poschiavo on the Swiss side of the Swiss–Italian border in the Central Eastern Alps. Studies have extended into neighboring Valtellina, and the house mice of the Poschiavo-Valtellina area have been subject to detailed analysis, reviewed here. The maximum extent of this area is 70 km, yet it has 4 metacentric races and the standard 40-chromosome telocentric race distributed in a patchwork fashion. The metacentric races are characterized by highly reduced diploid numbers (2n = 22–26) resulting from Robertsonian fusions, perhaps modified by whole-arm reciprocal translocations. The races hybridize and the whole Poschiavo-Valtellina area can be considered a “hybrid zone.” The studies of this area have provided insights into origin of races within hybrid zones, gene flow within hybrid zones and the possibility of speciation in hybrid zones. This provides a case study of how chromosomal rearrangements may impact the genetic structure of populations and their diversification. Fil: Giménez, Mabel Dionisia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina. University of York; Reino Unido Fil: Förster, Daniel W.. Leibniz-institute For Zoo And Wildlife Research; Alemania. University of York; Reino Unido Fil: Jones, Eleanor P.. University of York; Reino Unido. Fera Science; Reino Unido Fil: Jóhannesdóttir, Fríđa. University of York; Reino Unido. Cornell University; Estados Unidos Fil: Gabriel, Sofia I.. Universidade de Lisboa; Portugal. University of York; Reino Unido Fil: Panithanarak, Thadsin. Burapha University; Tailandia. University of York; Reino Unido Fil: Scascitelli, Moira. University of York; Reino Unido Fil: Merico, Valeria. Universita Di Pavia; Italia Fil: Garagna, Silvia. Universita Di Pavia; Italia Fil: Searle, Jeremy B.. University of York; Reino Unido. Cornell University; Estados Unidos Fil: Hauffe, Heidi C.. Instituto Agrario San Michele All'adige Fondazione Edmund Mach. Centro Ricerca E Innovazione; Italia. University of York; Reino Unido

Western house mice (Mus musculus domesticus) and common shrews (Sorex araneus) are important models for study of chromosomal speciation. Both had ancestral karyotypes consisting of telocentric chromosomes, and each is subdivided into numerous chromosomal races many of which have resulted from fixation of new mutations (Robertsonian fusions and whole-arm reciprocal translocations). However, some chromosomal races in both species may alternatively have originated through hybridization, with particular homozygous recombinant products reaching fixation. Here, we demonstrate the process of generation of hybrid chromosomal races for the first time in either species using molecular markers. Analysis of centromeric microsatellite markers show that the Mid Valtellina (IMVA) and Upper Valtellina (IUVA) chromosomal races of the house mouse are recombinant products of hybridization of the Lower Valtellina (ILVA) and Poschiavo (CHPO) chromosomal races, supporting earlier theoretical analysis. IMVA and IUVA occupy a small area of the Italian Alps where ILVA makes contact with CHPO. IUVA and CHPO have previously been shown to be reproductively isolated in one village, emphasizing that hybrid chromosomal races in small mammals, as in plants, have the potential to be part of the speciation process.

Fil: Förster, Daniel W. Universidad de York. Departamento de Biología; Reino Unido. Fil: Förster, Daniel W. Leibniz-Institute for Zoo and Wildlife Research. Department of Evolutionary Genetics; Alemania. Fil: Jones, Eleanor P. Universidad de York. Departamento de Biología; Reino Unido. Fil: Jones, Eleanor P. Fera Science; Reino Unido. Fil: Jóhannesdóttir, Fríða. Universidad de York. Departamento de Biología; Reino Unido. Fil: Jóhannesdóttir, Fríða. Universidad de Uppsala. Departamento de Ecología y Genética; Suecia. Fil: Jóhannesdóttir, Fríða. Universidad de Cornell. Departamento de Ecología y Evolución; Estados Unidos. Fil: Gabriel, Sofia I. Universidad de Aveiro. Centro de Estudio del Ambiente y del Mar; Portugal. Fil: Gabriel, Sofia I. Universidad de Lisboa. Facultad de Ciencias. Departamento de Biología Animal; Portugal. Fil: Giménez, Mabel Dionisia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico (Nordeste). Instituto de Biología Subtropical. Instituto de Biología Subtropical Nodo Posadas; Argentina. Fil: Giménez, Mabel Dionisia. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales. Instituto de Biología Subtropical. Instituto de Biología Subtropical Nodo Posadas; Argentina. Fil: Giménez, Mabel Dionisia. Universidad de York. Departamento de Biología; Reino Unido. Fil: Panithanarak, Thadsin. Universidad de Burapha. Instituto de Ciencias Marinas; Tailandia. Fil: Hauffe, Heidi Christine. Universidad de York. Departamento de Biología; Reino Unido. Fil: Hauffe, Heidi Christine. Instituto Agrario San Michele All'adige. Fondazione Edmund Mach. Centro Ricerca e Innovazione. Departamento de Biodiversidad y Ecología Molecular; Italia. Fil: Searle, Jeremy B. Universidad de York. Departamento de Biología; Reino Unido. Fil: Searle, Jeremy B. Universidad de Cornell. Departamento de Ecología y Evolución; Estados Unidos. The importance of chromosomal rearrangements for speciation can be inferred from studies of genetic exchange between hybridising chromosomal races within species. Reduced fertility or recombination suppression in karyotypic hybrids has the potential to maintain or promote genetic differentiation in genomic regions near rearrangement breakpoints. We studied genetic exchange between two hybridising groups of chromosomal races of house mouse in Upper Valtellina (Lombardy, Italy), using microsatellites. These groups differ by Robertsonian fusions and/or whole-arm reciprocal translocations such that F1 hybrids have a chain-of-five meiotic configuration. Previous studies showed genetic differentiation in two chromosomes in the chain-of-five (10 and 12) close to their centromeres (i.e. the rearrangement breakpoints); we have shown here that the centromeric regions of the other two chromosomes in the chain (2 and 8) are similarly differentiated. The internal chromosomes of the chain (8 and 12) show the greatest differentiation, which may reflect pairing and recombination properties of internal and external elements in a meiotic chain. Importantly, we found that centromeric regions of some non-rearranged chromosomes also showed genetic differentiation between the hybridising groups, indicating a complex interplay between chromosomal rearrangements and other parts of the genome in maintaining or promoting differentiation and potentially driving speciation between chromosomal races.

An indirect method for estimating biodiversity from Earth observations is the Spectral Variation Hypothesis (SVH). SVH states that the higher the spatial variability of the spectral response of an optical remotely sensed image, the higher the number of available ecological niches and hence, the higher the diversity of tree species in the considered area. Here for the first time we apply the concept of the SVH to Light Detection and Ranging (LiDAR) data to understand the relationship between the height heterogeneity (HH) of a forest and its tree species diversity, a concept we have named the ‘Height Variation Hypothesis’ (HVH). We tested HVH in two different European forest types: a coniferous mountain forest in the eastern Italian Alps and a mixed temperate forest in southern Germany. We used the heterogeneity index Rao’s Q to estimate HH using a Canopy Height Model (CHM) at different resolutions derived from LiDAR data, and linear regression models and relation analysis to assess the relationships between HH and three species diversity indices derived from in situ collected data: Shannon’s H, Simpson’s S and species richness. The relationships were calculated for all plots in both study areas, and separately for plots with a defined Canopy Closure (CC > 70%, CC > 80%, CC > 90%) to understand the effect of forest density on the relationship between HH and tree species diversity. Our results showed that HH is related to the tree species diversity of the forest ecosystems reaching (in the case of Shannon’s H) values of R 2 = 0.63 for the coniferous mountain forest and R 2 = 0.56 for the mixed temperate forest, particularly when calculated with a CHM resolution of 2.5 m. The associations also increased with increasing canopy closure suggesting that HVH is scale and forest density dependent. Our results also underlined that the abundance-based diversity measures are more highly correlated with HH than with species richness. Finally, our findings suggest that the HVH is a valuable tool for assessing tree species diversity in forest ecosystems, and could also be useful for overall biodiversity estimates.

The incidence of tick-borne diseases caused by Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum and Rickettsia spp. has been rising in Europe in recent decades. Early pre-assessment of acarological hazard still represents a complex challenge. The aim of this study was to model Ixodes ricinus questing nymph density and its infection rate with B. burgdorferi s.l., A. phagocytophilum and Rickettsia spp. in five European countries (Italy, Germany, Czech Republic, Slovakia, Hungary) in various land cover types differing in use and anthropisation (agricultural, urban and natural) with climatic and environmental factors (Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Land Surface Temperature (LST) and precipitation). We show that the relative abundance of questing nymphs was significantly associated with climatic conditions, such as higher values of NDVI recorded in the sampling period, while no differences were observed among land use categories. However, the density of infected nymphs (DIN) also depended on the pathogen considered and land use. These results contribute to a better understanding of the variation in acarological hazard for Ixodes ricinus transmitted pathogens in Central Europe and provide the basis for more focused ecological studies aimed at assessing the effect of land use in different sites on tick–host pathogens interaction.

Directly-transmitted rodent-borne zoonotic viruses, such as lymphocytic choriomeningitis virus (LCMV) can cause nervous system infections. Rodent-borne Ljungan virus (LV) is considered potentially zoonotic possibly causing neurological symptoms. Our objective was to understand the role of these two viruses compared to other pathogens in causing neurological infections in Finnish patients. Routine screening data were available for 400 patients aged 5-50 years, collected from December 2013 to December 2014 with suspected neurological infection. Depending on symptoms, patients were variously tested for herpesviruses, enteroviruses, varicella zoster virus, and Mycoplasma pneumoniae, while those suspected of tick bite were further tested for Borrelia spp. and tick-borne encephalitis virus using antibody and/or nucleic acid tests. For 380 patients, we also screened the RNA and antibody prevalence of LCMV and LV in order to test if either of these viruses were the causative agent. Data collected indicated that the causative microbial agent was confirmed in only 15.5% of all Finnish patients with neurological symptoms, with M. pneumoniae (26 cases) being the most common causative agent found in sera, whereas Borrelia spp. (15), herpes simplex viruses (7), and enteroviruses (5) were the most common agents confirmed in the CSF. The seroprevalences for LV and LCMV were 33.8% and 5.0%, respectively, but no samples were PCR-positive. In this study, M. pneumoniae and Borrelia spp. were the most common causative agents of neurological infections in Finland. No LCMV or LV infections were detected. We conclude there was no association of LV with neurological diseases in this patient cohort.

The aim of this study was to determine the occurrence of Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., and Candidatus Neoehrlichia mikurensis in Ixodes spp. ticks removed from wildlife, domestic animals and humans in the Province of Trento (northern Italy) in order to better understand their ecology and provide public health professionals with an updated list of pathogens which should be considered during their diagnostic procedures after a tick bite. During 2011-2012, 848 feeding ticks at all life stages (adults, nymphs and larvae) from various hosts (wild ungulates, birds and rodents; domestic sheep, dogs and humans) were collected. The highest prevalences of A. phagocytophilum and Rickettsia spp. were detected in adult and nymphal tick stages feeding on wild ungulates (11.4% prevalence for both pathogens), while the Babesia spp. prevailed in nymphal and larval ticks feeding on wild birds (7.7%). A wide spectrum of tick-borne agents was present in larval ticks: those detached from wild ungulates were positive for A. phagocytophilum, B. venatorum, R. helvetica, R. monacensis and R. raoultii, while those removed from wild rodents were positive for B. venatorum, R. helvetica, R. monacensis and Ca. N. mikurensis, and ticks from wild birds carried A. phagocytophilum, B. venatorum, B. capreoli and R. helvetica. This study provides evidence of circulation of five tick-borne pathogens not reported in this region before, specifically R. raoultii, R. monacensis, B. venatorum, B. capreoli and B. microti. Furthermore, it discusses the epidemiological role of the animal species from which the ticks were collected highlighting the needs for more experimental studies especially for those pathogens where transovarial transmission in ticks has been demonstrated.

The identification and evaluation of the ecological and environmental factors shaping patterns of natural genetic variation are fundamental goals of population and conservation genetics. Many studies focus on factors affecting single species, but it is also important to test whether some influential biotic and abiotic factors are common drivers of genetic diversity across species, or if species or species groups are each affected by different forces; a multi-species analysis is necessary for this. Here we analysed the molecular variation from five mammal species (roe deer, red deer, chamois, mountain hare and European brown hare) at mtDNA and microsatellite loci from the eastern Italian Alps. We use phylogeographical and landscape-level analyses to test the relative influence of large-scale geographical history and contemporary environmental characteristics of the landscape on genetic diversity and differentiation. We found: (1) all study species except brown hare are strongly differentiated into two main groups, located west and east of a major river valley; (2) significant correlations between levels of within-population diversity at both mtDNA and microsatellite loci, and several landscape features such as alpine grassland, water courses and anthropized areas. We conclude that heterogeneous landscape has some influence on within-population diversity, but biogeographical history has probably had the stronger influence on current genetic patterns, despite an apparently large dispersal potential of certain species. However, our results for brown hare show that management actions such as stocking may alter these large-scale patterns.

Contact zones between two evolutionary lineages are often useful for understanding the process of speciation because the observed genetic pattern reflects the history of differentiation. The Eurasian lacertid lizard Zootoca vivipara is a potentially interesting model for studying the role of reproductive mode in the speciation of squamate reptiles because it has both oviparous (Zootoca vivipara carniolica) and viviparous (Zootoca vivipara vivipara) populations that have recently been shown to be genetically distinct. We studied a newly-discovered syntopic area of these two Zootoca subspecies in the central Italian Alps using genetic markers to investigate the level of introgression between them. Patterns of genetic differentiation in a fragment of the mitochondrial DNA cytb gene and a set of nuclear microsatellites show that the speciation process is complete in this area, with no evidence of recent introgression. Phylogenetic and genotypic divergence suggests that the two subspecies have experienced long independent evolutionary histories, during which genetic and phenotypic differences evolved. The possible roles of biogeography, reproductive mode, and cytogenetic differentiation in this speciation process are dis- cussed. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 566-573.

A wealth of human studies have demonstrated the importance of gut microbiota to health. Research on non-human animal gut microbiota is now increasing, but what insight does it provide? We reviewed 650 publications from this burgeoning field (2009-2016) and determined that animals driving this research were predominantly 'domestic' (48.2%), followed by 'model' (37.5%), with least studies on 'wild' (14.3%) animals. Domestic studies largely experimentally perturbed microbiota (81.8%) and studied mammals (47.9%), often to improve animal productivity. Perturbation was also frequently applied to model animals (87.7%), mainly mammals (88.1%), for forward translation of outcomes to human health. In contrast, wild animals largely characterised natural, unperturbed microbiota (79.6%), particularly in pest or pathogen vectoring insects (42.5%). We used network analyses to compare the research foci of each animal group: 'diet' was the main focus in all three, but to different ends: to enhance animal production (domestic), to study non-infectious diseases (model), or to understand microbiota composition (wild). Network metrics quantified model animal studies as the most interdisciplinary, while wild animals incorporated the fewest disciplines. Overall, animal studies, especially model and domestic, cover a broad array of research. Wild animals, however, are the least investigated, but offer under-exploited opportunities to study 'real-life' microbiota.The ISME Journal advance online publication, 11 August 2017; doi:10.1038/ismej.2017.133.

Background: Human granulocytic anaplasmosis is a zoonotic bacterial disease with increasing relevance for public health in Europe. The understanding of its sylvatic cycle and identification of competent reservoir hosts are essential for improving disease risk models and planning preventative measures.Results: In 2012 we collected single ear biopsy punches from 964 live-trapped rodents in the Province of Trento, Italy. Genetic screening for Anaplasma phagocytophilum (AP) was carried out by PCR amplification of a fragment of the 16S rRNA gene. Fifty-two (5.4%) samples tested positive: 49/245 (20%) from the bank vole (Myodes glareolus) and 3/685 (0.4%) samples collected from the yellow-necked mouse (Apodemus flavicollis). From these 52 positive samples, we generated 38 groEL and 39 msp4 sequences. Phylogenetic analysis confirmed the existence of a distinct rodent strain of AP.Conclusions: Our results confirm the circulation of a specific strain of AP in rodents in our study area; moreover, they provide further evidence of the marginal role of A. flavicollis compared to M. glareolus as a reservoir host for this pathogen.

Many important and rapidly emerging pathogens of humans, livestock and wildlife are ‘vector-borne’. However, the term ‘vector’ has been applied to diverse agents in a broad range of epidemiological systems. In this perspective, we briefly review some common definitions, identify the strengths and weaknesses of each and consider the functional differences between vectors and other hosts from a range of ecological, evolutionary and public health perspectives. We then consider how the use of designations can afford insights into our understanding of epidemiological and evolutionary processes that are not otherwise apparent. We conclude that from a medical and veterinary perspective, a combination of the ‘haematophagous arthropod’ and ‘mobility’ definitions is most useful because it offers important insights into contact structure and control and emphasizes the opportunities for pathogen shifts among taxonomically similar species with similar feeding modes and internal environments. From a population dynamics and evolutionary perspective, we suggest that a combination of the ‘micropredator’ and ‘sequential’ definition is most appropriate because it captures the key aspects of transmission biology and fitness consequences for the pathogen and vector itself. However, we explicitly recognize that the value of a definition always depends on the research question under study.This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.

1. Stochastic processes play an important role in the infectious disease dynamics of wildlife,especially in species subject to large population oscillations.2. Here, we study the case of a free ranging population of yellow-necked mice (Apodemusflavicollis ) in northern Italy, where circulation of Dobrava -Belgrade hantavirus (DOBV) hasbeen detected intermittently since 2001, until an outbreak emerg ed in 2010.3. We analysed the transmission dynamics of the recent outbreak using a computationalmodel that accounts for seasonal changes of the host population and territorial behaviour.Model parameters were informed by capture-mark-recapture data collected over 14 years andlongitudinal seroprevalence data from 2010 to 2013.4. The intermittent observation of DOBV before 2010 can be interpreted as repeated stochas-tic fadeouts after multiple introductions of infectious rodents migrating from neighbouringareas. We estimated that only 20% of introductions in a na€ive host population results in sus-tained transmission after 2 years, despite an effe ctive reproduction number well above the epi-demic threshold (mean 45, 95% credible intervals, CI: 065–158). Following the 2010outbreak, DOBV has become endemic in the study area, but we predict a constant probab ilityof about 47% per year that infection dies out, following large population drops in winter. Inthe absence of stochas tic fadeout, viral prevalence is predicted to continue its growth to anoscillating equilibrium around a value of 24% (95% CI: 3–57).5. We presented an example of invasion dynamics of a zoonotic virus where stochastic fade-out have played a major role and may induce future extinction of the endemic infection.

Anticipating species distributions in space and time is necessary for effective biodiversity conservation and for prioritising management interventions. This is especially true when considering invasive species. In such a case, anticipating their spread is important to effectively plan management actions. However, considering uncertainty in the output of species distribution models is critical for correctly interpreting results and avoiding inappropriate decision-making. In particular, when dealing with species inventories, the bias resulting from sampling effort may lead to an over- or under-estimation of the local density of occurrences of a species. In this paper we propose an innovative method to i) map sampling effort bias using cartogram models and ii) explicitly consider such uncertainty in the modeling procedure under a Bayesian framework, which allows the integration of multilevel input data with prior information to improve the anticipation species distributions.

Within species, populations differing by chromosomal rearrangements ("chromosomal races") may become reproductively isolated in association with reduced hybrid fertility due to meiotic aberrations. Speciation is also possible if hybridizing chromosomal races accumulate genetic differences because of reduced meiotic recombination in the heterozygous configuration in hybrids. Here, we examine recombination in pure races and hybrids within a model system for chromosomal speciation: the hybridization of the Poschiavo (CHPO) and Upper Valtellina (IUVA) chromosomal races of house mouse in Upper Valtellina, Italy. These races differ by Robertsonian fusions/whole-arm reciprocal translocations, such that hybrids produce a pentavalent meiotic configuration. We determined the number and position of the recombination points (using an antibody against the MutL homolog 1 [MLH1] protein) on synaptonemal complexes at pachytene in laboratory-reared CHPO, IUVA, and hybrid males, analyzing at least 112 spermatocytes per karyotypic group, up to a total of 534 spermatocytes. The mean ± standard deviation numbers of MLH1 foci per spermatocyte were 22.2 ± 3.2, 20.1 ± 2.9, 20.7 ± 2.3, and 21.9 ± 2.9 for CHPO, IUVA, CHPO × IUVA, and IUVA × CHPO, respectively. Altogether, 10,146 chromosome arms were examined, allowing multiple comparisons. Overall, recombination events were more frequently distal than proximal or interstitial. The average number of proximal MLH1 foci per chromosome arm decreased going from telocentric to metacentric bivalents to pentavalents (when present), which (together with other factors) influenced the average number of MLH1 foci per cell between CHPO, IUVA, and hybrid mice. The low frequency of proximal recombination in pentavalents of CHPO-IUVA hybrids may promote reproductive isolation between the CHPO and IUVA races, when coupled with reduced hybrid unfitness.

Ljungan virus (LV, genus Parechovirus, family Picornaviridae) is considered currently to be a rodent-borne virus. Despite suggested human disease associations, its zoonotic potential remains unclear. To date, LV antibody prevalence in both humans and rodents has not been studied. In this study, two different LV immunofluorescence assays (LV IFAs) were developed with LV genotypes 1 (LV strain 87-012G) and 2 (LV strain 145SLG), and cross-neutralization and -reaction studies were carried out with LV strain 145SLG. Finally, a panel of 37 Finnish sera was screened for anti-LV antibodies using two different LV IFAs (LV 145SLG and LV 87-012G) and a neutralization (NT) assay (LV 145SLG), and 50 samples from Myodes glareolus by LV IFA (LV 145SLG). The LV seroprevalence study showed 38% and 18% positivity in humans and M. glareolus, respectively. LV IFAs and NT assays were compared, and the results were in good agreement. The data are the first evidence of humans and rodents coming into contact with LV in Finland. Additional studies are required in order to acquire a better understanding of the prevalence, epidemiological patterns and possible disease association of LV infections.

This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phylogenetic studies, including changes in transmission associated with host shifts and with evolution of the unusually complex life cycles of many parasites. Understanding the forces that determine the evolution of particular transmission modes presents a fascinating medley of problems for which there is a lack of good data and often a lack of conceptual understanding or appropriate methodologies. Our best information comes from studies that have been focused on the vertical versus horizontal transmission dichotomy. With other kinds of transitions, theoretical approaches combining epidemiology and population genetics are providing guidelines for determining when and how rapidly new transmission modes may evolve, but these are still in need of empirical investigation and application to particular cases. Obtaining such knowledge is a matter of urgency in relation to extant disease threats. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.