Analysis of a European general wildlife health surveillance program: Chances, challenges and recommendations.

In a One Health perspective general wildlife health surveillance (GWHS) gains importance worldwide, as pathogen transmission among wildlife, domestic animals and humans raises health, conservation and economic concerns. However, GWHS programs operate in the face of legal, geographical, financial, or administrative challenges. The present study uses a multi-tiered approach to understand the current characteristics, strengths and gaps of a European GWHS that operates in a fragmented legislative and multi-stakeholder environment. The aim is to support the implementation or improvement of other GWHS systems by managers, surveillance experts, and administrations. To assess the current state of wildlife health investigations and trends within the GWHS, we retrospectively analyzed 20 years of wildlife diagnostic data to explore alterations in annual case numbers, diagnosed diseases, and submitter types, conducted an online survey and phone interviews with official field partners (hunting administrators, game wardens and hunters) to assess their case submission criteria as well as their needs for post-mortem investigations, and performed in-house time estimations of post-mortem investigations to conduct a time-per-task analysis. Firstly, we found that infectious disease dynamics, the level of public awareness for specific diseases, research activities and increasing population sizes of in depth-monitored protected species, together with biogeographical and political boundaries all impacted case numbers and can present unexpected challenges to a GWHS. Secondly, we found that even a seemingly comprehensive GWHS can feature pronounced information gaps, with underrepresentation of common or easily recognizable diseases, blind spots in non-hunted species and only a fraction of discovered carcasses being submitted. Thirdly, we found that substantial amounts of wildlife health data may be available at local hunting administrations or disease specialist centers, but outside the reach of the GWHS and its processes. In conclusion, we recommend that fragmented and federalist GWHS programs like the one addressed require a central, consistent and accessible collection of wildlife health data. Also, considering the growing role of citizen observers in environmental research, we recommend using online reporting systems to harness decentrally available information and fill wildlife health information gaps.

Detection of novel RNA viruses in wild noble crayfish (Astacus astacus): A virome analysis in Swiss water bodies.

European native crayfish populations are undergoing a strong decline due to environmental factors and the introduction of highly competitive non-native species. Pathogens are an additional threat to native crayfish. However, aside from the crayfish plague, other infectious diseases are still widely unknown. This study aimed to investigate viruses present in seven populations of wild noble crayfish (Astacus astacus) in Switzerland, through high-throughput sequencing. Sequence analysis revealed the presence of 11 novel RNA viruses (one bunya-like, four hepe-like, two dicistro-like, three picorna-like, and one permutotetra-like) in the samples. The discovery of a novel bunya-like virus in noble crayfish without associated mortality or macroscopical alterations is of particular interest since it is closely related to the bunya-like brown spot virus, a virus described in 2019 from diseased native white-clawed crayfish (Austropotamobius pallipes) during a mass mortality event in France. It seems that these two closely related viruses have very different impacts on their respective hosts, raising the need for further investigations on virulence factors and host susceptibility towards these viruses. This study provides a basis for future investigations, permitting to gradually fill the knowledge gap in crayfish viral diseases.

Sarcoptic mange in Felidae: does Sarcoptes scabiei var. felis exist? A first molecular study.

Domestic and wild felids are considered suitable hosts for the parasitic mite Sarcoptes scabiei, and sarcoptic mange is reported in several felid species in the scientific literature. However, the historic classification of Sarcoptes mites into host-specific varieties does not include S. scabiei var. felis. It is unclear whether sarcoptic mange transmission in felids involves canids, other sympatric species, or exclusively felids. This study aimed to characterize the genetic structure of S. scabiei mites from domestic cats (Felis catus) and Eurasian lynx (Lynx lynx carpathicus), comparing them with Sarcoptes mites from sympatric domestic and wild carnivores. Ten Sarcoptes microsatellite markers were used to genotype 81 mites obtained from skin scrapings of 36 carnivores: 4 domestic cats, one dog (Canis lupus familiaris), 4 Eurasian lynx, 23 red foxes (Vulpes vulpes), and 4 grey wolves (Canis lupus lupus) from either Italy, Switzerland or France. Two genetic clusters of S. scabiei with a geographical distribution pattern were detected: mites from cats originating from Central Italy clustered with those from sympatric wolves. In contrast, all the other mites from Switzerland, France and Northern Italy clustered together. These results strengthen the previously advanced hypothesis that genetic variants of S. scabiei have a predominant geographic-related distribution with cryptic transmission patterns. These patterns may rely on the interactions between different hosts living in the same ecological niche rather than a simple infection among hosts belonging to the same taxon, reinforcing the idea that the S. scabiei historic classification into "var" might have little ongoing relevance.

Title: La gale sarcoptique chez les félidés : Sarcoptes scabiei var. felis existe-t-il ? Première étude moléculaire. Abstract: Les félidés domestiques et sauvages sont considérés comme des hôtes appropriés pour l'acarien parasite Sarcoptes scabiei, et la gale sarcoptique est signalée chez plusieurs espèces de félidés dans la littérature scientifique. Cependant, la classification traditionnelle des acariens du genre Sarcoptes en variétés spécifiques à l'hôte n'inclut pas S. scabiei var. felis. On ne sait pas si la transmission de la gale sarcoptique chez les félidés implique des canidés, d'autres espèces sympatriques ou exclusivement des félidés. Cette étude visait à caractériser la structure génétique des acariens S. scabiei des chats domestiques (Felis catus) et du lynx eurasien (Lynx lynx carpathicus), en les comparant aux Sarcoptes des carnivores domestiques et sauvages sympatriques. Dix marqueurs microsatellites de Sarcoptes ont été utilisés pour génotyper 81 acariens issus de grattages cutanés de 36 carnivores : 4 chats domestiques, un chien (Canis lupus familiaris), 4 lynx eurasiens, 23 renards roux (Vulpes vulpes) et 4 loups gris (Canis lupus lupus) d'Italie, de Suisse ou de France. Deux groupes génétiques de S. scabiei, qui suivent un modèle de distribution géographique, ont été détectés. Les acariens des chats originaires du centre de l'Italie se regroupent avec ceux des loups sympatriques. En revanche, tous les autres acariens de Suisse, de France et d'Italie du Nord sont groupés ensemble. Ces résultats renforcent l'hypothèse précédemment avancée selon laquelle les variants génétiques de S. scabiei ont une distribution géographique prédominante avec des schémas de transmission cryptiques. Ces modèles peuvent reposer sur les interactions entre différents hôtes vivant dans la même niche écologique plutôt que sur une simple transmission parmi des hôtes appartenant au même taxon, renforçant l'idée que la classification historique de S. scabiei en "var" a peu de pertinence.

Description of a Sarcoptic Mange Outbreak in Alpine Chamois Using an Enhanced Surveillance Approach.

Since 1995, the Alpine chamois (Rupicapra r. rupicapra) population of the Dolomites has been affected by sarcoptic mange with considerable management concerns. In this study, 15 years (2006-2020) of passive surveillance and demographic data were analyzed in order to describe a mange outbreak. Furthermore, an enhanced passive surveillance protocol was implemented in order to evaluate the efficiency of ordinary vs. enhanced surveillance protocol in identifying dead chamois in the field and in reaching a correct diagnosis. Our results confirm the role of mange as a determining factor for chamois mortality, while stressing the importance of a wider view on the factors affecting population dynamics. The enhanced passive surveillance protocol increased the probability of carcass retrieval and identification of the cause of death; however, its adoption may be too costly if applied for long periods on a wide scale. Passive surveillance, in both ordinary and enhanced surveillance protocol, should encompass the use of other strategies in the future to study the eco-epidemiology of the disease in wild Caprinae.

Phylogeography and population genetic structure of the European roe deer in Switzerland following recent recolonization.

In the early 1800s, the European roe deer (Capreolus capreolus) was probably extirpated from Switzerland, due to overhunting and deforestation. After a federal law was enacted in 1875 to protect lactating females and young, and limiting the hunting season, the roe deer successfully recovered and recolonized Switzerland. In this study, we use mitochondrial DNA and nuclear DNA markers to investigate the recolonization and assess contemporary genetic structure in relation to broad topographic features, in order to understand underlying ecological processes, inform future roe deer management strategies, and explore the opportunity for development of forensic traceability tools. The results concerning the recolonization origin support natural, multidirectional immigration from neighboring countries. We further demonstrate that there is evidence of weak genetic differentiation within Switzerland among topographic regions. Finally, we conclude that the genetic data support the recognition of a single roe deer management unit within Switzerland, within which there is a potential for broad-scale geographic origin assignment using nuclear markers to support law enforcement.

First description of peritoneal and pleural metacestodosis caused by Mesocestoides vogae in a European wild cat (Felis silvestris silvestris).

Tapeworms of the genus Mesocestoides (Cestoda: Cyclophyllidea: Mesocestoididae) are still enigmatic to scientists, due to their high morphological variability, low host specificity, and unknown details of their life cycle. They are found worldwide, with carnivorous mammals as the main definitive hosts, and the disease is potentially zoonotic. After ingestion by a definitive host, the tetrathyridium can occasionally migrate through the intestinal wall and reach the peritoneal cavity or abdominal organs causing peritoneal metacestodosis. Here, we report on a case of metacestodosis of a European wild cat (Felis silvestris silvestris) found dead in Croatia. At necropsy, a large number of white, rice-like structures were found free in the abdominal and thoracic cavities, as well as along the serous surfaces and in the lungs. DNA isolated from the nodules was genotyped and based on a 320-base pair long 12S fragment classified as Mesocestoides vogae. Although post-mortem changes were advanced, severe emaciation due to the severe parasitic infection and gastrointestinal bleeding was diagnosed as the likely cause of death. Intestinal cestodosis was previously reported in wild cats, but according to our knowledge, this is the first description of peritoneal and pleural metacestodosis caused by M. vogae tetrathyridia (metacestodes) in any wild carnivore species.

Spatiotemporal spread of sarcoptic mange in the red fox (Vulpes vulpes) in Switzerland over more than 60 years: lessons learnt from comparative analysis of multiple surveillance tools.

BACKGROUND: Sarcoptic mange is a contagious skin disease of wild and domestic mammals caused by the mite Sarcoptes scabiei. Reports of sarcoptic mange in wildlife increased worldwide in the second half of the 20th century, especially since the 1990s. The aim of this study was to provide new insights into the epidemiology of mange by (i) documenting the emergence of sarcoptic mange in the red fox (Vulpes vulpes) in the last decades in Switzerland; and (ii) describing its spatiotemporal spread combining data obtained through different surveillance methods. METHODS: Retrospective analysis of archived material together with prospective data collection delivered a large dataset from the 19th century to 2018. Methods included: (i) a review of historical literature; (ii) screening of necropsy reports from general health surveillance (1958-2018); (iii) screening of data on mange (1968-1992) collected during the sylvatic rabies eradication campaign; (iv) a questionnaire survey (<1980-2017) and (v) evaluation of camera-trap bycatch data (2005-2018). RESULTS: Sarcoptic mange in red foxes was reported as early as 1835 in Switzerland. The first case diagnosed in the framework of the general health surveillance was in 1959. Prior to 1980, sarcoptic mange occurred in non-adjacent surveillance districts scattered all over the country. During the period of the rabies epidemic (1970s-early 1990s), the percentage of foxes tested for rabies with sarcoptic mange significantly decreased in subregions with rabies, whereas it remained high in the few rabies-free subregions. Sarcoptic mange re-emerged in the mid-1990s and continuously spread during the 2000-2010s, to finally extend to the whole country in 2017. The yearly prevalence of mange in foxes estimated by camera-trapping ranged from 0.1-12%. CONCLUSIONS: Sarcoptic mange has likely been endemic in Switzerland as well as in other European countries at least since the mid-19th century. The rabies epidemics seem to have influenced the pattern of spread of mange in several locations, revealing an interesting example of disease interaction in free-ranging wildlife populations. The combination of multiple surveillance tools to study the long-term dynamics of sarcoptic mange in red foxes in Switzerland proved to be a successful strategy, which underlined the usefulness of questionnaire surveys.