Dirofilaria immitis heartworm infections in Hungarian zoo animals

Dirofilaria immitis is a worldwide spread, mosquito-borne nematode of zoonotic concern, with domestic and wild canids serving as the main reservoirs of the infection in Europe. In this study we describe eleven cases of cardiovascular dirofilariosis in Hungarian zoos, including three Eurasian wolves (Canis lupus lupus), two Arctic wolves (Canis lupus arctos), an African lion (Panthera leo), an African leopard (Panthera pardus pardus), a Red panda (Ailurus fulgens), an Arctic fox (Vulpes lagopus), a Harbour seal (Phoca vitulina), and an Asian small-clawed otter (Aonyx cinereus). Heartworm disease presumably contributed to the deaths of three Eurasian wolves, one Red panda, one Arctic fox and one Harbour seal, as indicated by necropsy results, whereas the remaining infections were regarded as incidental findings. These cases represent the first documented occurrence of D. immitis in captive felids in Hungary and the first report of D. immitis in Arctic wolves. The present case series provides data about host range of dirofilariosis and discusses their potential role as reservoirs of the infection in autochthonous wild animals in Europe underlining the need for implemented surveillance and preventive strategies in zoo animal populations.