Contact with domestic dogs increases pathogen exposure in endangered African wild dogs (Lycaon pictus).

Rosie Woodroffe,Patricia A Conrad,Edward J Dubovi,Linda Munson,Katherine C Prager,Jonna A K Mazet,Wayne M. Getz

doi:10.1371/journal.pone.0030099

Abstract

BackgroundInfectious diseases have contributed to the decline and local extinction of several wildlife species, including African wild dogs (Lycaon pictus). Mitigating such disease threats is challenging, partly because uncertainty about disease dynamics makes it difficult to identify the best management approaches. Serious impacts on susceptible populations most frequently occur when generalist pathogens are maintained within populations of abundant (often domestic) “reservoir” hosts, and spill over into less abundant host species. If this is the case, disease control directed at the reservoir host might be most appropriate. However, pathogen transmission within threatened host populations may also be important, and may not be controllable by managing another host species.Methodology/Principal FindingsWe investigated interspecific and intraspecific transmission routes, by comparing African wild dogs' exposure to six canine pathogens with behavioural measures of their opportunities for contact with domestic dogs and with other wild dogs. Domestic dog contact was associated with exposure to canine parvovirus, Ehrlichia canis, Neospora caninum and perhaps rabies virus, but not with exposure to canine distemper virus or canine coronavirus. Contact with other wild dogs appeared not to increase the risk of exposure to any of the pathogens.Conclusions/SignificanceThese findings, combined with other data, suggest that management directed at domestic dogs might help to protect wild dog populations from rabies virus, but not from canine distemper virus. However, further analyses are needed to determine the management approaches – including no intervention – which are most appropriate for each pathogen.

Highlights

Infectious diseases have contributed to the decline and local extinction of several wildlife species [1,2,3], and may threaten many more
We describe patterns of exposure to six canine pathogens with diverse transmission mechanisms: rabies virus and canine distemper virus, which are transmitted by direct contact [27,28]; parvovirus and coronavirus, which are transmitted through faeces [29,30]; Ehrlichia canis, which is transmitted by a tick vector [31]; and Neospora caninum, which may be transmitted by consumption of infected prey or by contact with infected faeces, as well as across the placenta from mother to foetus [32]
The domestic dog density experienced in the 12 months prior to sampling was higher for 20 wild dogs living mainly on community lands, than for 37 living mainly on commercial ranches (Figure 1; GLMM of log-transformed domestic dog contact risk, effect of land use type, p = 0.008)

Summary

Introduction

Infectious diseases have contributed to the decline and local extinction of several wildlife species [1,2,3], and may threaten many more. Serious impacts on host populations most frequently occur when generalist pathogens are maintained within populations of abundant ‘‘reservoir’’ hosts and ‘‘spill-over’’ into less abundant, and potentially more susceptible, host species [4,5] Such situations represent a form of parasite-mediated apparent competition [6] which can threaten the persistence of spill-over host species [1]. Infectious diseases have contributed to the decline and local extinction of several wildlife species, including African wild dogs (Lycaon pictus) Mitigating such disease threats is challenging, partly because uncertainty about disease dynamics makes it difficult to identify the best management approaches. Serious impacts on susceptible populations most frequently occur when generalist pathogens are maintained within populations of abundant (often domestic) ‘‘reservoir’’ hosts, and spill over into less abundant host species If this is the case, disease control directed at the reservoir host might be most appropriate. Pathogen transmission within threatened host populations may be important, and may not be controllable by managing another host species

Methods

Results

Conclusion