Estimating canine distemper virus exposure in captive carnivores in Thai zoos using a pseudotype-based serum neutralization test

Abstract

Despite its name, Canine distemper virus (CDV) infection is not restricted to canids but extends to several species of the order Carnivora. The extent of CDV exposure in captive carnivores in Thailand has never been estimated before. Therefore, the objective of this study is to estimate CDV exposure in captive carnivores in Thai zoos using a pseudotype-based neutralization assay (SNT). A total of 264 archived serum samples collected between 2005 and 2020 from captive carnivore species from 6 zoos of the Zoological Park Organization of Thailand (ZPOT) (211 samples) and Tiger Kingdom (TK) (53 samples) were tested in this study. CDV neutralizing antibodies were detected in almost all families of the order Carnivora included in this study, namely Felidae (11%, 17/155), Viverridae (7%, 2/29), Mustelidae (50%, 1/2), Canidae (100%, 1/1), Hyaenidae (29%, 2/7), and Ursidae (38%, 6/16), except for the family Herpestidae (0%, 0/1). Notably, CDV neutralizing antibodies were detected in four carnivore species that have never been reported before, including Asiatic black bear (80%, 4/5), Malayan sun bear (18%, 2/11), Clouded leopard (13%, 6/45) and Asiatic golden cat (100%, 1/1). These findings confirm the occurrence of CDV in captive carnivores in Thai zoos. Overall, this study highlights the need for continued monitoring and management of CDV in captive carnivore population in Thailand to mitigate the potential threats to endangered species and contribute to the conservation efforts of wildlife.