Veterinary session

Zoos play an important role in educating the general public about venomous snakes and in the conservation of endangered species. In order to successfully treat these species, it is essential to understand the pathomechanism of morbidity and mortality, which can be attempted through post-mortem analysis.

In my thesis, I performed a retrospective analysis of pathological examinations in venomous snakes at the Budapest Zoo and Botanical Garden, between 2009 and 2023. In this study, 71 specimens from 19 species of venomous snake were included. Information about the circumstances of mortality was not available for 12.7% of the 71 snakes, and for another 32.4%, no histopathological reports were available, therefore the lesions found during their necropsy were documented. Among the 71 snakes, the age of 23 individuals was known, with the highest number of deaths occurring between ages 6 to 10 years (13 individuals), followed by the age group between 11 and 15 years (4 individuals). Of the snakes in the study, the sex of 25 was known, with 15 being females and 10 being males. The most common causes of mortality consisted of infectious diseases, accounting for 24.2% of total number of patients, with Mycobacterium spp. and Aspergillus spp. infections among the causative agents. Systemic multi-organ infections also proved a frequent finding (22.6%). A total of 7 animals were euthanized, typically due to anorexia and prolonged chronic diseases.

In terms of organ systems, the most common post-mortem lesions were found in the digestive system, followed by the urinary system. Hepatitis (19.4%) and enteritis (16.1%) were the most frequently found lesions of the digestive tract. Nephrosis (41.9%) was the primary cause of the lesions found in the urinary system, followed by nephritis (12.9%) and neoplastic lesions (3.2%). Uricosis was also a frequent ailment, occurring in 35.5% of all the snakes.

From our results we can see that there are numerous factors that affect venomous snakes housed in captivity in zoological institutions. Even though the dataset may not be complete in all cases, the ailments found to cause morbidity and mortality in these species may help us improve the housing circumstances where relevant, as well as ensuring that these species are kept under the highest level of care at all times.