Canine Distemper Virus: an Emerging Disease in Wild Endangered Amur Tigers ( <i>Panthera tigris altaica</i> )

Recognition of disease emergence in wildlife is a rare occurrence. Here, for the first time, we identify and characterize a canine distemper virus (CDV), the second most common cause of infectious disease death in domestic dogs and a viral disease of global importance in common and endangered carnivores, as the etiology of neurologic disease and fatal encephalitis in wild, endangered Amur tigers. We establish that in 2010 CDV directly or indirectly killed -1% of Amur tigers. Location of positive cases over an expansive geographic area suggests that CDV is widely distributed across the tiger range. Interspecies interactions are increasing as human populations grow and expand into wildlife habitats. Identifying animal reservoirs for CDV and identifying the CDV strains that are transmissible to and among wildlife species, including Amur tigers and sympatric critically endangered Amur leopards (Panthera pardus orientalis), is essential for guiding conservation and mitigation efforts.