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Hepatitis A virus (HAV) is a common human pathogen found exclusively in primates. In a molecular and serologic study of 64 alpacas in Bolivia, we detected RNA of distinct HAV in ≈9% of animals and HAV antibodies in ≈64%. Complete-genome analysis suggests a long association of HAV with alpacas.

Spillover of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) to North American white-tailed deer (Odocoileus virginianus) has been documented. However, it is unclear if this is a phenomenon specific to North American deer or is a broader problem. We evaluated pre and pandemic exposure of German and Austrian deer species using a SARS-CoV-2 pseudoneutralization assay. In stark contrast to North American white-tailed deer, we found no evidence of SARS-CoV-2 exposure.

The population of Rattus norvegicus was assessed using live traps and hair sampling tubes in 71 discrete patches distributed in the urban area of the city of Salzburg, Austria. R. norvegicus occurred in 35% of the examined habitats and reached a maximum density of 113.12 individuals/km along water banks. The occurrence of rats was strongly influenced by vegetation, habitat modification and man-made impact in the area. The results of this study could be used to support the development of a new, more scientifically based rat management plan in cooperation with the city of Salzburg.

Camera traps are very useful tools in determining the presence/absence of rare and cryptic species while shedding light on behavioral traits. Passive infrared triggered cameras are routinely used in homeothermic animals, but in ectothermic reptiles, this surveillance method has proven highly unreliable. As part of the conservation goal to provide better understanding and protection for the critically endangered freshwater turtle Batagur baska, we investigated their largely unknown nesting behavior and tested video-based motion detection by comparing 2 different camera-trapping systems and their settings under controlled conditions at the Vienna Zoo. A pixel-based video surveillance camera was superior to a camera trap with motion sensor. The surveillance camera allowed reliable motion detection at sensitive settings, and video capture precision could be enhanced by marking the terrapin with reflective tape. This video surveillance camera was then deployed over 2 breeding seasons (2019 and 2020) in the conservation breeding project of the northern river terrapin (B. baska, Gray 1830) in Bhawal National Park in Bangladesh. Analysis of video recording demonstrated for the first time that female northern river terrapins nested on average for a period of 1.5 hrs and produced a single clutch per year. Results indicate that females inspect sandbanks and visit suitable nesting sites several times before egg deposition, suggesting that nest-site selection is not random in B. baska. In addition, water temperature measurements of the breeding ponds in 2 captive breeding sites of the B. baska project showed an annual average temperature decrease to 168C–188C during the mating season and an average increase to 288C–318C before the nesting season. Temperatures on nesting nights vary between the 2 breeding sites and differ between nesting events within each site, suggesting that overall seasonal temperature shifts initiate the nesting periods, while other physiological and environmental factors might trigger the actual nesting event. With the help of consistent motion-triggered video recording, our study provides a first underpinning of the nesting ecology of B. baska.

Background A sudden decline of the European brown hare ( Lepus europaeus ) population in one of the best hunting districts for small game species in northern Germany, the German North-Sea island Pellworm, in the years 2007/08 following marked habitat changes led to the implementation of a thorough health assessment program of the population. 110 animals were collected during the normal hunting season in the years 2010 and 2011. A post-mortem examination and histopathological investigation was performed on all animals. Additionally, routine bacteriology of the small intestine and parasitology were carried out. Sera of hares were tested for European Brown Hare Syndrome (EBHS) by enzyme linked immunosorbent assay, and for Treponema sp. by indirect immunofluorescent test. Additional testing was performed when deemed necessary. Results The most striking result was a shift in the intestinal bacterial flora towards Gram-negative Enterobacteriaceae with a predominance of either Escherichia coli , or Aeromonas sp., or a high-grade double-infection with these two pathogens with subsequent catarrhal enteritis. Additionally, a marked coccidiosis, and varying infestations with the nematode Trichostrongylus retortaeformis were found. The sero-prevalence for EBHS was 78.1%, and for Treponema 43.9%. Conclusions The shift and decrease in diversity of the intestinal flora was the main and most consistent result found. In the authors’ opinion the change of the habitat combined with other stressors increased the animals’ sensitivity to ubiquitous bacterial species and parasites which usually would not have such fatal effects.

We used non-invasive ultrasonography to investigate seasonal changes in liver size of an obligate hibernator; the edible dormouse ( Glis glis ). We repeatedly measured liver size in dormice at two study sites, (1) an enclosure-housed colony and (2) a free-ranging population. We observed a significant increase in transverse liver size throughout the active season; however, this effect was most pronounced in animals with low body mass early in the active season. Ultrasonography imaging revealed that the content of fat in the liver (distributed in an unexpected pattern of discrete focal areas) visibly increased at the end of the active season both in the field and enclosure. Thus, the observed increase in liver size of dormice seems mainly related to fat accumulation. We found no principal differences in the time courses of transversal liver size between the two study sites. Our results support the view that non-invasive ultrasonography is an accurate method to study internal organ sizes, such as liver, in the laboratory and in the field.

The Przewalski's horse (Equus caballus przewalskii) became extinct in the wild in the 1960s. Since 1997, captive-bred horses have been released into the Gobi-B Strictly Protected Area (SPA) in southwestern Mongolia, and successful reproduction in the wild started in 1999. In 2002, the population formed 3 harem groups and 1 bachelor group (total 38) in the wild, and 3 harem groups (24) awaited release in summer 2003 within acclimatization enclosures, totaling 62 individuals. We used the stochastic population simulation model VORTEX to (1) identify key variables and their threshold values in population dynamics, (2) predict extinction risk, and (3) optimize project management and release regime by comparing model parameters with our population data. Maximum age of reproduction, foal mortality, and fecundity rates were key factors in population dynamics, while number of released animals, release interval, and duration of supplementation played lesser roles. The severity level of natural catastrophes had the greatest influence on extinction risk and population size according to VORTEX. Assuming a maximum reproductive age of 16 years, an initial population of >140 horses is necessary to achieve a 95% probability of survival over 100 years under the low-severity level of catastrophes scenario. The corresponding extinction risk for high-severity level of catastrophes is 37%, even for initial population sizes >500. The low natural growth rate of the Przewalski's horse may have been the essential prerequisite for extinction in this remote area of Mongolia. However, uncertainty of results was high and limits the predictive value of the model. Comparisons between model parameters with observed population characteristics over the past 10 years reveal some discrepancies that may require readjustment of the model if present trends continue. While our model currently underestimates reproductive rate and foal survival, adult mortality tends to be higher than estimated in the model. We believe that adult survival can be improved in the wild and that the reintroduction program has a realistic chance of success. We stress the importance of an intensive monitoring program of the Przewalski's horse population and consecutive modeling exercises to reevaluate success of this reintroduction program.