The effect of protected areas on pathogen exposure in endangered African wild dog (Lycaon pictus) populations

Abstract

a b s t r a c tInfectious diseases impact African wild dogs (Lycaon pictus), but the nature and magnitude of this threat likely varies among populations according to different factors, such as the presence and prevalence of pathogens and land-use characteristics. We systematically evaluated these factors to assist development of locally appropriate strategies to mitigate disease risk. Wild dogs from 16 sites representing five unconnected populations were examined for rabies virus, canine distemper virus (CDV), canine parvovirus, canine coronavirus, and Babesia spp. exposure. Analyses revealed widespread exposure to viral pathogens, but Babesia was never detected. Exposure to CDV was associated with unprotected and protected-unfenced areas where wild dogs likely have a high probability of domestic dog contact and, in the case of protected-unfenced areas, likely reside amongst high wildlife densities. Our findings also suggest that domestic dog contact may increase rabies and coronavirus exposure risk. Therefore, domestic dogs may be a source of CDV, rabies and coronavirus, while wildlife may also play an important role in CDV transmission dynamics. Relatively high parvovirus seroprevalence across land-use types suggests that it might persist in the absence of spillover from domestic dogs. Should intervention be needed to control pathogens in wild dogs, efforts to prevent rabies and coronavirus exposure might be directed at reducing infection in the presumed domestic dog reservoir through vaccination. If prevention of CDV and parvovirus infections were deemed a management necessity, control of disease in domestic dogs may be insufficient to reduce transmission risks, and vaccination of wild dogs themselves may be the optimal strategy.

An Infectious Disease and Mortality Survey in a Population of Free-Ranging African Wild Dogs and Sympatric Domestic Dogs

“…Consistent with Prager et al [5], which included samples shared from our study, we found a low to zero prevalence of antibodies to CDV and CPV in the animals sampled. We caution that these findings are concerning given the presence of these pathogens in sympatric domestic dogs and the severe consequences of these infectious diseases for small, immunologically naïve populations.…”

“…Another concern for CPV is the highly persistent nature of this pathogen in the environment, with viral particles remaining infectious for months to years depending on environmental conditions [23]. Prager et al [5] demonstrated high prevalence of CPV antibodies in wild dogs with limited to not known domestic dog contact, an indication that due to prolonged pathogen persistence in the environment CPV may become self-perpetuating in small wildlife populations even in the absence of a domestic dog reservoir.…”

“…The impacts of infectious disease on wildlife populations and the importance of disease surveillance for endangered species conservation and management programmes have been repeatedly demonstrated [1][2][3][4][5]. The KwaZulu-Natal (KZN) African Wild Dog Reintroduction and Conservation Programme, in the South African province of KwaZuluNatal, has incorporated infectious pathogen and disease surveillance as one of many components within their longterm population monitoring strategy.…”

“…Due to land-use practices in KZN province, such dispersal requires movement between and among many small, separate protected areas and subpopulations. Disease risks are heightened during such dispersal events as contact with domestic dogs (Canis familiaris) may enable transmission of key threatening diseases to dispersing wild dogs [5,14] and subsequently between their subpopulations. Unfortunately, long-term consequences of infectious pathogens for persistence of free-ranging African wild dog populations remain poorly understood and difficult to evaluate, due in part to a variety of interacting factors affecting disease dynamics [15].…”

“…Although CPV has not been considered as important a disease threat as CDV to endangered wild carnivores [24], it poses a major risk to small populations due to the potential for significant early pup mortality [25] and can negatively affect all age classes in immunologically naïve populations [26]. Seroprevalence to CPV among African wild dogs has been demonstrated across southern Africa [5], indicating that pathogen exposure does occur, albeit with unknown population-level impacts.…”