Diseases of feral dogs: Threat to wild tigers?

Background/Question/Methods: In many parts of the world, domestic dogs pose a significant though often overlooked threat to protected wildlife.  In countries such as India, dogs thrive on human leftovers and can form large populations that move freely among towns, agricultural fields and protected areas. These free-ranging or semi-owned dogs are generally unvaccinated and can serve as reservoirs for rabies, canine distemper virus (CDV), canine parvovirus (CPV),canine adenovirus(CAV), and tuberculosis, which threaten humans, livestock and wildlife. For example, domestic dogs are believed to have been the source of a CDV epidemic that ravaged lions in the Serengeti National Park in the 1990s.  More generally, CDV is the most common cause of death from infectious diseases in domestic dogs, and is emerging as a global health concern for endangered wild carnivores.  We are studying the role of semi-owned dogs around the Kanha Tiger Reserve in central India as reservoirs of CDV and other diseases that threaten protected carnivores including tigers (Panthera tigris).  

 Results/Conclusions: Our surveys found that most of these dogs are communally owned, largely unvaccinated, and in poor health.  Still, they reach high densities and frequently enter the Reserve where they come in contact with wild carnivores. Our preliminary studies found that 85% of the dogs were sero-positive for CPV, 43% were positive for CDV and 52% were positive for, CAV representing past infections and not necessarily current infectivity.  None were sero-positive for rabies, though infected individuals would be expected to die quickly and not be detected.  We opportunistically examined samples from various wild carnivores, and are comparing the genetic composition of pathogens that jump species and calculating the odds ratio of infection at the carnivore metacommunity level.  Our work to date suggests that tigers and other wild carnivores are at a risk from diseases carried by these feral dogs.