Retrospective analysis of necropsy findings on the European brown hare (Lepus europeus) in AGES Mödling between 2018 and 2023, with a focus on tularaemia

The European brown hare (EBH) can carry various diseases, including zoonoses such as brucellosis, tularaemia, pasteurellosis, pseudotuberculosis and staphylococcosis. The hare is small game and a food source and it shares its habitat with humans and farm animals, so it is important to survey the population for diseases. We report a retrospective investigation of the pathomorphological and microbiological findings of 218 EBH carcasses that were sent to AGES Mödling between 2018 and 2023. A large proportion of the specimens were submitted from the federal state of Salzburg (116/218). The data were categorized and sorted, then visualized and interpreted, with a focus on individuals that had tested positive for tularaemia. During postmortem analysis the animals most frequently showed alterations in the lower digestive tract (44.1 %) and the respiratory system (23.9 %). Signs of trauma (33.9 %) and septicaemia (14.7 %) were common. The prevalence of tularaemia was 33.9 % (74/218) but there was no consistent, significant increase in the number of cases from 2018 to 2023. Splenomegaly (56.8 %) and necrotic lesions in the lungs (35.1 %), lymph nodes (17.6 %), testicles (14.9 %) and liver (12.2 %) were frequent in hares positive for Francisella tularensis. Sixty-five isolates were subtyped as either biovar I or biovar II, with an unexpectedly high number of cases of biovar I (32/65). This biovar is usually endemic to western Austria but appears to have spread eastward. Further research is needed to evaluate the extent to which biovar I is established in eastern Austria.

Österreichische Agentur für Gesundheit und Ernährungssicherheit GmbH