MHC class II DRB diversity in raccoons (Procyon lotor) reveals associations with raccoon rabies virus (Lyssavirus).

In North America, the raccoon rabies virus (RRV) is an endemic wildlife disease which causes acute encephalopathies and is a strong selective force on raccoons (Procyon lotor), with estimates of ∼85% of the population succumbing to the disease when epizootic. RRV is regarded as a lethal disease if untreated; therefore, no evolutionary response would be expected of raccoon populations. However, variable immune responses to RRV have been observed in raccoons indicating a potential for evolutionary adaptation. Studies of variation within the immunologically important major histocompatibility complex (MHC) have revealed relationships between MHC alleles and diseases in humans and other wildlife species. This enhances our understanding of how hosts and pathogens adapt and co-evolve. In this study, we used RRV as a model system to study host-pathogen interaction in raccoons from a challenge study and from four wild populations that differ in exposure times and viral lineages. We investigated the potential role of Prlo-DRB polymorphism in relation to susceptibility/resistance to RRV in 113 RRV positive and 143 RRV negative raccoons. Six alleles were found to be associated with RRV negative status and five alleles with RRV positive animals. We found variable patterns of MHC associations given the relative number of selective RRV sweeps in the studied regions and correlations between MHC diversity and RRV lineages. The allelic associations established provide insight into how the genetic variation of raccoons may affect the disease outcome and this can be used to examine similar associations between other rabies variants and their hosts.

Multiple movement modes by large herbivores at multiple spatiotemporal scales.

Recent theory suggests that animals should switch facultatively among canonical movement modes as a complex function of internal state, landscape characteristics, motion capacity, and navigational capacity. We tested the generality of this paradigm for free-ranging elk (Cervus elaphus) over 5 orders of magnitude in time (minutes to years) and space (meters to 100 km). At the coarsest spatiotemporal scale, elk shifted from a dispersive to a home-ranging phase over the course of 1-3 years after introduction into a novel environment. At intermediate spatiotemporal scales, elk continued to alternate between movement modes. During the dispersive phase, elk alternated between encamped and exploratory modes, possibly linked to changes in motivational goals from foraging to social bonding. During the home-ranging phase, elk movements were characterized by a complex interplay between attraction to preferred habitat types and memory of previous movements across the home-range. At the finest temporal and spatial scale, elk used area-restricted search while browsing, interspersed with less sinuous paths when not browsing. Encountering a patch of high-quality food plants triggered the switch from one mode to the next, creating biphasic movement dynamics that were reinforced by local resource heterogeneity. These patterns suggest that multiphasic structure is fundamental to the movement patterns of elk at all temporal and spatial scales tested.

ONRAB® oral rabies vaccine is shed from, but does not persist in, captive mammals.

ONRAB® is a human adenovirus rabies glycoprotein recombinant vaccine developed to control rabies in wildlife. To support licensing and widespread use of the vaccine, safety studies are needed to assess its potential residual impact on wildlife populations. We examined the persistence of the ONRAB® vaccine virus in captive rabies vector and non-target mammals. This research complements work on important rabies vector species (raccoon, striped skunk, and red fox) but also adds to previous findings with the addition of some non-target species (Virginia opossum, Norway rats, and cotton rats) and a prolonged period of post vaccination monitoring (41 days). Animals were directly inoculated orally with the vaccine and vaccine shedding was monitored using quantitative real-time PCR applied to oral and rectal swabs. ONRAB® DNA was detected in both oral and rectal swabs from 6 h to 3 days post-inoculation in most animals, followed by a resurgence of shedding between days 17 and 34 in some species. Overall, the duration over which ONRAB® DNA was detectable was shorter for non-target mammals, and by day 41, no animal had detectable DNA in either oral or rectal swabs. All target species, as well as cotton rats and laboratory-bred Norway rats, developed robust humoral immune responses as measured by competitive ELISA, with all individuals being seropositive at day 31. Similarly, opossums showed good response (89% seropositive; 8/9), whereas only one of nine wild caught Norway rats was seropositive at day 31. These results support findings of other safety studies suggesting that ONRAB® does not persist in vector and non-target mammals exposed to the vaccine. As such, we interpret these data to reflect a low risk of adverse effects to wild populations following distribution of ONRAB® to control sylvatic rabies.

Stray dog population health in Jodhpur, India in the wake of an animal birth control (ABC) program.

Our objectives were to (1) estimate the prevalence of various health indices in the stray dog population in Jodhpur, India and (2) determine if there was an association between an animal birth control (ABC) program and the prevalence of these health indices in this population. A prevalence survey of 323 sexually intact stray dogs >3 months caught from the streets of Jodhpur from September to November, 2005 indicated that low body condition score (70%), skin conditions (69%) and tick infestation (68%) were the most common health problems in this population. An observational study of 888 stray dogs on the streets of Jodhpur from March to April, 2006 revealed that sterilized dogs were more likely to have a higher body condition score (BCS) than sexually intact dogs when controlling for age, based on a multinomial regression model. However, sterilized dogs were more likely to have a skin condition than sexually intact dogs, based on a logistic regression model. Our observations of the surgical/kennel facility indicated that an effective tick control program was needed. Additionally, the current parasite control protocol at the kennel/shelter facility was inadequate to treat mange, a contact-transmitted skin disease. This is the first study to evaluate the associations between an ABC program and stray dog health, apart from rabies.

Stray dog population demographics in Jodhpur, India following a population control/rabies vaccination program.

Animal Birth Control (ABC) is a program by which stray dogs are sterilized and vaccinated against rabies with the aim of controlling both dog population size and rabies. Population size and demographics of stray dogs were measured before and after implementation of an ABC program in Jodhpur, India. Dog population size declined (p<0.05) in three of five areas surveyed, showed a decreasing trend (p>0.05) in 1 area, and remained stable in 1 area between 2005 and 2007. By 2007, 61.8-86.5% of the free-roaming dog population was surgically sterilized and vaccinated for rabies in the areas surveyed. In March-May, 2007, adults comprised 80-96% of the free-roaming dog population, while subadults and puppies comprised 0-18 and 0-4%, respectively. The male:female ratio among dogs>3 months old was 1.4:1. A population demographic model predicted that at the current level of sterilization/rabies vaccination, vaccination coverage would remain above 70%, and the dog population would decrease by 69% reaching stability after 13-18 years. A surgical sterilization coverage under 40% would maintain the dog population at current levels.

Assessing reproductive patterns and disorders in free-ranging dogs in Jodhpur, India to optimize a population control program.

The objectives were to test the hypothesis that estrus and pregnancy are seasonal in free-ranging female dogs (>3 mo old) in Jodhpur, India, and to determine litter size, and the prevalence of fetal resorption in this population. The prevalence of estrus and pregnancy was determined in 5400 free-ranging bitches (trapped and released) at the time of ovariohysterectomy. In a separate study, the uteri and ovaries of 246 free-ranging bitches were examined to determine litter size and fetal resorption. The bitches exhibited seasonal estrus and pregnancy (P < 0.00001), with a higher percentage of bitches in estrus or pregnant during the late monsoon season (September to November) compared to the other three seasons. The mean litter size based on embryo/fetal counts was 4.6 (95% CI = 4.0-5.3; n = 40) and based upon placental site counts was 4.4 (95% CI = 3.9-4.8; n = 105). Prevalence of fetal resorption was 32.6% (95% CI = 20.5-47.5; n = 43) with a mean of 2.8 resorptions per litter in those with at least one resorption (95% CI = 1.8-3.8; n = 14). This was the first study to estimate previous litter size of non-pregnant, free-ranging dogs based upon placental sites. Litter size data from this study will be used in a population demographic model to predict the long-term impact of animal birth control (ABC) on the free-ranging dog population in Jodhpur. Increasing the efforts to surgically sterilize bitches prior to the time of year of peak pregnancy or whelping will help maximize the impact of an ABC program on the Jodhpur free-ranging dog population.