Epidemiology of Viral Pathogens of Free-Ranging Dogs and Indian Foxes in a Human-Dominated Landscape in Central India

Abstract

There is an increasing concern that free-ranging domestic dog (Canis familiaris) populations may serve as reservoirs of pathogens which may be transmitted to wildlife. We documented the prevalence of antibodies to three viral pathogens, canine parvovirus (CPV), canine distemper virus (CDV) and canine adenovirus (CAV), in free-ranging dog and sympatric Indian fox (Vulpes bengalensis) populations in and around the Great Indian Bustard Wildlife Sanctuary, in Maharashtra, central India. A total of 219 dogs and 33 foxes were sampled during the study period. Ninety-three percentage of dogs and 87% of foxes were exposed to one or more of the three pathogens. Exposure rates in dogs were high: >88% for CPV, >72% for CDV and 71% for CAV. A large proportion of adult dogs had antibodies against these pathogens due to seroconversion following earlier natural infection. The high prevalence of exposure to these pathogens across the sampling sessions, significantly higher exposure rates of adults compared with juveniles, and seroconversion in some unvaccinated dogs documented during the study period suggests that these pathogens are enzootic. The prevalence of exposure to CPV, CDV and CAV in foxes was 48%, 18% and 52%, respectively. Further, a high rate of mortality was documented in foxes with serologic evidence of ongoing CDV infection. Dogs could be playing a role in the maintenance and transmission of these pathogens in the fox population, but our findings show that most dogs in the population are immune to these pathogens by virtue of earlier natural infection, and therefore, these individuals make little current or future contribution to viral maintenance. Vaccination of this cohort will neither greatly improve their collective immune status nor contribute to herd immunity. Our findings have potentially important implications for dog disease control programmes that propose using canine vaccination as a tool for conservation management of wild carnivore populations.

Landscape Structures Affect Risk of Canine Distemper in Urban Wildlife

“…Spontaneous interspecific transmission between foxes and raccoons during the second infection period would explain the areal distribution of seropositive foxes compared to the patchy pattern during the first CDV spreading period in Berlin's foxes in 2008. Agonistic interactions among dogs (Canis familiaris) and indian foxes (Vulpes bengalensis) are assumed to be a major driver of transmission of virulent diseases such as CDV, as both species can host the same viruses and viral strains (Belsare et al, 2014). Moreover, CDV can persist for several days without a host in cold environments (Deem et al, 2000).…”

Cross-species transmission of canine distemper virus—an update

“…CDV infections have been reported in red foxes ( Vulpes vulpes ) from various European countries including Germany [46], [47], Italy [48], [49], Spain [50], and Portugal [51]. Disease has been reported also in swift foxes ( Vulpes velox ) [52], kit foxes ( Vulpes macrotis ) [52], Indian foxes ( Vulpes bengalensis ) [53], and fennec foxes ( Vulpes zerda ) [54]. Infected foxes show abnormal behavior including loss of fear for humans, disorientation, and/or respiratory distress.…”

Long‐lived immunity to canine core vaccine antigens in UK dogs as assessed by an in‐practice test kit

“…These kits are developed to give a positive reading that correlates with a minimum protective titre as determined by the gold standard tests, and some have been validated independently, with supportive evidence published in the scientific literature ( Waner et al . 2006, Belsare et al . 2014.…”