Risk of disease spillover at wild-domestic carnivore interface

Many mammalian carnivore species have been reduced to small, isolated populations by habitat destruction, fragmentation, poaching, and human conflict. Their limited genetic variability and increased exposure to domestic animals such as dogs place them at risk of further losses from infectious diseases. In India, domestic and feral dogs are associated with villages in and around protected areas, and may serve as reservoirs and vectors of pathogens to the carnivores within. India’s Kanha Tiger Reserve is home to a number of threatened and endangered mammalian carnivores including tigers (Panthera tigris), leopards (Panthera pardus), wolves (Canis lupus), and dhole (Cuon alpinus). It also has more than 150 villages with associated dog populations. We found that dog populations ranged from 14 to 45/village (3.7 to 23.7/km2), and did not vary with village area, human population size, or distance from the reserve core area, though they all increased between summer 2014 and winter 2015, primarily through reproduction. No dog tested positive for rabies but seroprevalence levels to three other generalist viral pathogens were high in summer (N=67) and decreased somewhat by winter (N=168): canine parvovirus (83.6% to 68.4%), canine distemper virus (50.7% to 30.4%) and canine adenovirus (41.8% to 30.9%). The declines in seroprevalence were due primarily to births in the population, of animals not exposed to the viruses. Wild carnivores frequently entered the villages, as shown by tracks, scats, kills and other indicators, and the dogs are known to leave the villages so that encounters between dogs and wild carnivores may be common. We concluded that there is a large population of unvaccinated dogs in and around Kanha Tiger Reserve, with high levels of seroprevalence to pathogens with broad host ranges and which interact with wild carnivores, therefore posing a high risk of disease spillover to the wild carnivores.