A Serological Survey of Infectious Disease in Yellowstone National Park’s Canid Community

Abstract

BackgroundGray wolves (Canis lupus) were reintroduced into Yellowstone National Park (YNP) after a >70 year absence, and as part of recovery efforts, the population has been closely monitored. In 1999 and 2005, pup survival was significantly reduced, suggestive of disease outbreaks.Methodology/Principal FindingsWe analyzed sympatric wolf, coyote (Canis latrans), and red fox (Vulpes vulpes) serologic data from YNP, spanning 1991–2007, to identify long-term patterns of pathogen exposure, identify associated risk factors, and examine evidence for disease-induced mortality among wolves for which there were survival data. We found high, constant exposure to canine parvovirus (wolf seroprevalence: 100%; coyote: 94%), canine adenovirus-1 (wolf pups [0.5–0.9 yr]: 91%, adults [≥1 yr]: 96%; coyote juveniles [0.5–1.5 yrs]: 18%, adults [≥1.6 yrs]: 83%), and canine herpesvirus (wolf: 87%; coyote juveniles: 23%, young adults [1.6–4.9 yrs]: 51%, old adults [≥5 yrs]: 87%) suggesting that these pathogens were enzootic within YNP wolves and coyotes. An average of 50% of wolves exhibited exposure to the protozoan parasite, Neospora caninum, although individuals’ odds of exposure tended to increase with age and was temporally variable. Wolf, coyote, and fox exposure to canine distemper virus (CDV) was temporally variable, with evidence for distinct multi-host outbreaks in 1999 and 2005, and perhaps a smaller, isolated outbreak among wolves in the interior of YNP in 2002. The years of high wolf-pup mortality in 1999 and 2005 in the northern region of the park were correlated with peaks in CDV seroprevalence, suggesting that CDV contributed to the observed mortality.Conclusions/SignificanceOf the pathogens we examined, none appear to jeopardize the long-term population of canids in YNP. However, CDV appears capable of causing short-term population declines. Additional information on how and where CDV is maintained and the frequency with which future epizootics might be expected might be useful for future management of the Northern Rocky Mountain wolf population.

Dynamics of a morbillivirus at the domestic–wildlife interface: Canine distemper virus in domestic dogs and lions

“…CDV serology was carried out using neutralization assays at Intervet (United Kingdom), Animal Health Diagnostic Center (Cornell University, Ithaca, NY), and University of Glasgow (United Kingdom). We used a cutoff titer value equivalent to a 1:16 dilution to define prior exposure, as in other studies of CDV exposure in wild carnivore species (23,24). Fig.…”

“…In northern Kenya, for example, domestic dog populations adjacent to wildlife protected areas show patterns of exposure consistent with reoccurring outbreaks rather than persistent infection (23), suggesting that the dog population is insufficiently large to maintain CDV and that infection needs to be reintroduced from outside sources (e.g., other domestic dog or wildlife communities). In other large, protected areas such as the Yellowstone National Park, the periodic nature of CDV occurrence in wild carnivore communities and the small size of the dog population around the park suggest disease persistence in the wild populations themselves (24).…”

Parasite invasion following host reintroduction: a case study of Yellowstone's wolves

“…CHV is transmitted both vertically and through direct contact with oral, nasal or genital secretions, and induces lifelong infection with periodic recrudescence activated by stress or by other forms of immunosuppression [35]. All three of these viruses invaded the Yellowstone wolf population so rapidly and completely, possibly via multiple spillover events, that we were unable to discern any spatial patterning to their invasion [30].…”

“…Within the first year following their release, wildborn (unvaccinated) wolves acquired several viral infections that had been present in Yellowstone coyotes prior to wolf reintroduction [30,31]. By 1997, after only a year of ranging on the Yellowstone landscape, 100 per cent (18/18) CPV is transmitted via faecaloral contact and the exchange of oral -nasal exudates, shedding can last 30 days post-infection, and because the virus is both extremely stable in the environment (six months at 208C) and can induce carrier states, the effective infectious period can be remarkably long and permit persistence in the host population [32].…”

Use of Real-time PCR to Detect Canine Parvovirus in Feces of Free-ranging Wolves

“…We collected fecal samples from two populations of wolves exhibiting 100% CPV antibody prevalence: Superior National Forest (SNF) and Yellowstone National Park (YNP; Mech and Goyal, 2011;Almberg et al, 2009). In SNF, we collected 15 wolf feces ,1 mo old (based on dark color and moisture) in June and July 2008.…”