Presentations

The European brown hare (Lepus europaeus) is one of the most significant European game species and its population is an important reservoir of Brucella suis biovar 2 in the continent. Despite, this really important field of infectious diseases was absolutely neglected in Hungary, causing the absence of scientific data in the literature. The aim of the present study was to access preliminary data about the prevalence of B. suis biotype 2 infection in the Hungarian hare population, to describe the pathological and histological lesions caused by B. suis in European brown hares and to develop an immunohistochemical (IHC) assay for the detection of B. suis infection.

European brown hares, shot at different locations in Hungary during several hunting events over two winter hunting seasons (2008-2009 and 2009-2010), were screened by Rose-Bengal test to detect B. suis antibodies. Seropositive animals were used for pathological and histopathological examination. Hyperimmune serum for the IHC test was produced by subcutaneous infection of each of two mice with 2×109 colony forming units of live B. suis biovar 2, injected four times at one week intervals.

A total of five, female animals were found to be infected with B. suis by serology among the screened 510 European brown hares (0.98%). Numerous, yellowish-white necrotic foci of 0.1 to 0.5 cm in diameter were found in the spleen of five B. suis-infected hares and also in the lungs, uteri, kidneys, or livers of four of these cases. The foci revealed as single or coalescing granulomas with the presence of a central necrotic area on histological examination. Both bacterial isolation and IHC test gave positive results for B. suis infection in these animals. B. suis antigens were found in the form of granular or amorphous extracellular staining in the necrotic centre of several granulomas. The produced serum reacted with neither F. tularensis nor Yersinia pseudotuberculosis and only weakly with B. canis in the IHC reaction.

This is the first study describing IHC detection of B. suis in European brown hares.