Rabies, Canine Distemper, and Canine Parvovirus Exposure in Large Carnivore Communities from Two Zambian Ecosystems

Abstract

Disease transmission within and among wild and domestic carnivores can have significant impacts on populations, particularly for threatened and endangered species. We used serology to evaluate potential exposure to rabies virus, canine distemper virus (CDV), and canine parvovirus (CPV) for populations of African lions (Panthera leo), African wild dogs (Lycaon pictus), and spotted hyenas (Crocuta crocuta) in Zambia's South Luangwa National Park (SLNP) and Liuwa Plain National Park (LPNP) as well as community lands bordering these areas. In addition, domestic dogs in the study region were evaluated for exposure to CDV and rabies. We provide the first comprehensive disease exposure data for these species in these ecosystems. Twenty-one lions, 20 hyenas, 13 wild dogs, and 38 domestic dogs were sampled across both regions from 2009 to 2011. Laboratory results show 10.5% of domestic dogs, 5.0% of hyenas, and 7.7% of wild dogs sampled were positive for CDV exposure. All lions were negative. Exposure to CPV was 10.0% and 4.8% for hyenas and lions, respectively. All wild dogs were negative, and domestic dogs were not tested due to insufficient serum samples. All species sampled were negative for rabies virus neutralizing antibodies except lions. Forty percent of lions tested positive for rabies virus neutralizing antibodies. Because these lions appeared clinically healthy, this finding is consistent with seroconversion following exposure to rabies antigen. To our knowledge, this finding represents the first ever documentation of rabies virus neutralizing antibodies consistent with rabies exposure that did not lead to clinical disease in free-ranging African lions from this region. With ever-increasing human pressure on these ecosystems, understanding disease transmission dynamics is essential for proper management and conservation of these carnivore species.

Cross-species transmission of canine distemper virus—an update

“…Seropositivity of living animals indicates that Serengeti hyenas may also become subclinically infected without overt disease or can recover from disease, respectively [118]. Similarly, CDV exposure has been reported from Zambian hyenas [41].

Fig. 6Canine distemper virus infection in a spotted hyena from the Serengeti National Park; demonstration of viral antigen in nuclei (arrows) and cytoplasm (arrowheads) of neuronal and glial cells of the brain by immunohistochemistry.

…”

“…Endangered African wild dogs ( Lycaon pictus ) have been reported to be exposed to CDV and are highly susceptible to develop distemper [41], [42]. Molecular analyses of isolates from African wild dogs suggest that CDV is endemic in wildlife carnivore populations in Tanzania (Serengeti ecosystem) [43], [44].…”

Detecting declines of apex carnivores and evaluating their causes: An example with Zambian lions

“…Zambia is one of eight remaining African countries containing a lion stronghold (Riggio et al, 2012); however its lion populations are geographically and numerically limited by human encroachment, direct mortality due to wire-snare poaching by-catch, prey depletion due to poaching, trophy hunting, disease, and humanlion conflict (Yamazaki, 1996;ZAWA, 2009;Becker et al, 2013aBecker et al, , 2013bBerentsen et al, 2013;Watson et al, 2013Watson et al, , 2014Midlane et al, 2014;Lindsey et al, 2014). The relative importance of these factors, their trends through time, and the associated demographic impacts on lions are poorly understood.…”

Advances in canine distemper virus pathogenesis research: a wildlife perspective

“…To sustain an epidemic of CD, dense populations of susceptible individuals and the continued presence of a biological reservoir are required [54,58]. Owing to their wide distribution, domestic dogs (C. familiaris) are key reservoirs for a variety of diseases and are considered the primary reservoir for CDV infection [58][59][60][61][62]. Domestic dogs, from communities surrounding protected wildlife areas, are often unvaccinated and occur in high densities with a rapid population turnover.…”

“…A systematic literature review of all possible non-dog hosts of CDV showed that ELISA was used 13.8 % of the time as serological test, followed by IFAT (7.7 %) [29]. The highly specific and sensitive serum-neutralization test is more commonly used (75.4 %) for the detection of CDV from serum samples and can be seen as the gold standard for detecting antibodies [29,59,115,116]. Serology as a diagnostic test is, however, not reliable in distinguishing between naturally acquired CDV infection (wild-type CDV strain), infection with attenuated virus vaccine strain [as used in the modified live vaccine (MLV)] or immune response to recombinant, virus-vectored vaccine and should thus if possible be combined with other techniques, such as RT-PCR and viral antigen ELISA [104,[117][118][119].…”