Inconspicuous post-mortem findings in rabbits from Switzerland naturally -infected with Rabbit Haemorrhagic -Disease Virus 2.

INTRODUCTION: Rabbit Haemorrhagic Disease Virus 2 (RHDV-2) emerged in France in 2010. In Switzerland, RHDV-2 was first identified in 2015 and apparently has almost replaced the classical Rabbit Haemorrhagic Disease Virus (RHDV) by now. Like RHDV, RHDV-2 causes a viral hepatitis with a peracute course and an increased mortality rate within the rabbitry. RHDV infection causes consistent gross pathological findings, especially in the liver and respiratory tract. Reports about gross pathology for animals naturally infected with RHDV-2 is scarce. The present study analysed the anamnesis and necropsy reports of 35 rabbits examined during routine diagnostics between March 2015 and May 2017. A reverse transcriptase real-time polymerase chain reaction (RT-qPCR) specific for RHDV-2 and RHDV proved a total of 25 animals to be positive for RHDV-2, while none was positive for RHDV. Additionally, histological examinations were performed on liver, lung, and kidney of 18 rabbits that had tested positive by RHDV-2 RT-qPCR. The anamnestic report more often stated an increased mortality rate in RHDV-2 positive (16/18, 89 %) compared to RHDV-2 negative rabbits (3/9, 33 %). Gross pathology did not reveal any pathognomonic changes in RHDV-2 positive animals. Histologically, the liver showed the most severe lesions followed by lung and kidney. Animals positive for RHDV-2 frequently showed signs of gastro-intestinal disease (n = 5) and/or septicaemia (n = 6) masking possible indicators of an RHDV-2 infection, such as the rather unspecific findings of an enlarged spleen or an enlarged, friable, tan-coloured liver. The authors want to raise awareness among clinicians and pathologists that in case of sudden death in commercial or pet rabbits, RHDV-2 needs to be considered as differential diagnosis and should be confirmed by laboratory diagnosis.

INTRODUCTION: Le virus 2 de la maladie hémorragique du lapin (RHDV-2) est apparu en France en 2010. En Suisse, le RHDV-2 a été identifié pour la première fois en 2015 et semble avoir presque remplacé le virus classique de la maladie hémorragique du lapin (RHDV). Comme le RHDV, le RHDV-2 provoque une hépatite virale avec une évolution suraiguë et un taux de mortalité élevé chez les lapins. L'infection par le RHDV entraîne des constatations pathologiques bruts cohérents, notamment au niveau du foie et des voies respiratoires. Les rapports sur la pathologie macroscopique des animaux naturellement infectés par le RHDV-2 sont rares. La présente étude a analysé les rapports d'anamnèse et de nécropsie de 35 lapins examinés lors de diagnostics de routine entre mars 2015 et mai 2017. Une réaction en chaîne par polymérase en temps réel à la transcriptase inverse (RT-qPCR) spécifique pour le RHDV-2 et le RHDV a prouvé qu'un total de 25 animaux étaient positifs pour le RHDV-2, tandis qu'aucun n'était positif pour le RHDV. De plus, des examens histologiques ont été réalisés sur le foie, les poumons et les reins de 18 lapins qui avaient été testés positifs par RT-qPCR pour le RHDV-2. Le rapport anamnestique faisait plus souvent état d'un taux de mortalité accru chez les lapins RHDV-2 positifs (16/18, 89 %) que chez les lapins RHDV-2 négatifs (3/9, 33 %). La pathologie macroscopique n'a révélé aucun changement pathognomonique chez les animaux RHDV-2 positifs. Sur le plan histologique, le foie présentait les lésions les plus graves, suivi des poumons et des reins. Les animaux positifs pour le RHDV-2 présentaient fréquemment des signes de maladie gastro-intestinale (n = 5) et/ou de septicémie (n = 6) masquant les indicateurs possibles d'une infection par le RHDV-2, tels que les découvertes plutôt peu spécifiques d'une rate hypertrophiée ou d'un foie hypertrophié, friable et de couleur beige. Les auteurs souhaitent sensibiliser les cliniciens et les pathologistes au fait qu'en cas de mort subite chez des lapins d'élevage ou de compagnie, le RHDV-2 doit être considéré comme un diagnostic différentiel et doit être confirmé par un diagnostic de laboratoire.

Primary leiomyosarcoma in the heart of a guinea pig.

Leiomyosarcoma was diagnosed in the heart of a 3-year-old female guinea pig. Neoplastic tissue was located in the ventricular septum extending into the right ventricular lumen, but was not obvious grossly. Microscopically, the mass was nodular and infiltrative and was composed of streams and bundles of spindle cells. Immunohistochemically, the neoplastic cells expressed vimentin and α-smooth muscle actin. There was no cross striation of the muscle cells. This is the first report of cardiac leiomyosarcoma in a guinea pig.

Gonadal activity in male and female captive fossas (Cryptoprocta ferox) during the mating season.

The fossa is an endangered, mongoose-like carnivore species endemic to Madagascar with a breeding season (BS) in the southern hemisphere spring. For the present study, faecal samples of captive fossas were collected for over 1 year for five males and four non-pregnant females, and for two pregnant animals during the reproductive period. The goal was to assess gonadal activity using non-invasive hormone measurements of faecal testosterone (T) and gestagen metabolites using assays previously established in our laboratory and further validated in this study. All study animals were housed in northern hemisphere zoos. In males, the seasonal T metabolite profile revealed a peak in spring (March). High performance liquid chromatography (HPLC) analysis was used to characterize the faecal hormone metabolite composition. The highest immunoreactivity was detected in the position of dihydrotestosterone, whereas native T was not detected. In the two pregnant females, gestagen metabolite concentrations increased 4-9 days after the initial matings and remained elevated throughout gestation with concentrations dramatically higher than those of the non-pregnant females during the BS. In these females, gestagen metabolite analyses did not reveal a seasonal pattern similar to the males. The HPLC-analysis revealed that the major proportion of immunoreactivity was associated with an unknown metabolite, whereas native progesterone was undetectable. The seasonal hormone pattern of male fossas gives proof of the reproductive seasonality of this species. The elevated 5alpha-pregnan-3beta-ol-20-one levels in pregnant animals allows for the characterization of pregnancy in the fossa based on analysis of faecal steroid metabolite concentrations.