A retroviral survey of endangered Eurasian lynx (Lynx lynx) from Croatia

Abstract

The feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) may cause persistent, lifelong and lethal infections in domestic and wild felids worldwide. FIV has been confirmed in most Felidae species, while FeLV infection is rare among non-domestic cats. The view that retroviruses are pathogenic in domestic cats but not in other free-ranging felid species was disproved by recent findings of retroviral pathology in several wild felids. The epidemiology of retroviral infections in felids in Croatia was only investigated in urban domestic cats, while there are no data for wild cat species. As the reintroduced Dinaric lynx (Lynx lynx) population suffers from low genetic diversity, which reduces their ability to adapt to new viral outbreaks, the health status of this lynx population is of particular concern. Two different commercial immunochromatographic assays were used for qualitative detection of FIV antibodies and FeLV antigens, while PCR was used for amplification of proviral gag and env genes in Eurasian lynx blood samples. All the 17 Eurasian lynx samples collected between 2001 and 2019 tested negative in both immunochromatographic and molecular tests. Even though our sample size was rather small, considering the fact that the population size of lynx in Croatia is estimated at 40 - 60 animals, our results can be considered representative for the population’s health status. Also, data about retroviral prevalence in Eurasian lynxes are scarce, so any new findings are very valuable.