Disease ecology of free-ranging dogs in Central India : implications for wildlife conservation

I obtained baseline demographic and epidemiologic data for village dog populations around a protected area in central India, with the objective of evaluating the risks dog populations present to sympatric wild carnivores. Demographic surveys indicated that dogs occurred at high densities in the study villages (> 526 dogs per km2 ). Epidemiological surveys documented a high prevalence of exposure to three pathogens of conservation concern, canine parvovirus (CPV), canine distemper virus (CDV), and canine adenovirus (CAV). An in-depth analysis of the epidemiological data indicated that these pathogens actively circulate in the dog populations, and therefore pose a significant threat to susceptible wild carnivore species in the region. The finding that foxes with ongoing or recent CDV infection had a high mortality rate further supported this conclusion. Study findings also suggest that most adult dogs in the population are immune to these pathogens, and play no current or future role in the maintenance or transmission of these pathogens. Unsurprisingly, the village-level vaccination experiment indicated that vaccine-based management of enzootic pathogens in large, free-ranging dog populations would be ineffective and unnecessary, as much of the effort is put into vaccinating dogs that are already antibody positive (thus protected). I used a modeling approach to explore and contrast potential disease control strategies. This work highlights the use of an approach combining data from ecological and epidemiological studies of free-ranging populations with model explorations to better understand disease threats, and identify potential disease management interventions.Includes bibliographical references (pages 130-140)

The street is no place for dogs: swinging wildly between wanton killing of dogs and extreme ‘pro-life’ interventions, India has never framed a rational, scientifically valid dog ownership or population control strategy

Everyday, India wakes up to horrific stories of attacks on people by street dogs and equally horrific acts of cruelty towards dogs. There is extreme polarisation on this issue between the advocates of human rights versus animal rights. The lack of a critical and scientific analysis is glaring

Use of Xylazine Hydrochloride-Ketamine Hydrochloride for Immobilization of India Fox (Vulpes Bengalensis) In Field Situations

Reports on doses of anesthetic agents for safe and effective immobilization of most wild species occurring in India are very limited. Further, the anesthetic agents available in India for field immobilizations are limited to xylazine hydrochloride and ketamine hydrochloride. A safe and effective dosage of xylazine–ketamine for Indian fox (Vulpes bengalensis) is reported, based on 37 wild Indian fox immobilizations between April 2006 and May 2007. Foxes captured for a radiotelemetry and health monitoring study were immobilized with a mixture of xylazine (2.27 ± 0.44 mg/kg) and ketamine (13.39 ± 2.26 mg/kg). Induction and recovery was smooth and uneventful in all foxes. The duration of anesthesia was sufficient for the fitting of radiotransmitters, morphometric measurements, and blood sampling. No life-threatening adverse effects of immobilization were documented for at least 1 mo postimmobilization. The results suggest that field immobilization of Indian foxes with 2 mg/kg xylazine and 13 mg/kg ketamine is effective and safe

Epidemiology of Viral Pathogens of Free-Ranging Dogs and Indian Foxes in a Human-Dominated Landscape in Central India

There is an increasing concern that free-ranging domestic dog (Canis familiaris) populations may serve as reservoirs of pathogens which may be transmitted to wildlife. We documented the prevalence of antibodies to three viral pathogens, canine parvovirus (CPV), canine distemper virus (CDV) and canine adenovirus (CAV), in free-ranging dog and sympatric Indian fox (Vulpes bengalensis) populations in and around the Great Indian Bustard Wildlife Sanctuary, in Maharashtra, central India. A total of 219 dogs and 33 foxes were sampled during the study period. Ninety-three percentage of dogs and 87% of foxes were exposed to one or more of the three pathogens. Exposure rates in dogs were high: >88% for CPV, >72% for CDV and 71% for CAV. A large proportion of adult dogs had antibodies against these pathogens due to seroconversion following earlier natural infection. The high prevalence of exposure to these pathogens across the sampling sessions, significantly higher exposure rates of adults compared with juveniles, and seroconversion in some unvaccinated dogs documented during the study period suggests that these pathogens are enzootic. The prevalence of exposure to CPV, CDV and CAV in foxes was 48%, 18% and 52%, respectively. Further, a high rate of mortality was documented in foxes with serologic evidence of ongoing CDV infection. Dogs could be playing a role in the maintenance and transmission of these pathogens in the fox population, but our findings show that most dogs in the population are immune to these pathogens by virtue of earlier natural infection, and therefore, these individuals make little current or future contribution to viral maintenance. Vaccination of this cohort will neither greatly improve their collective immune status nor contribute to herd immunity. Our findings have potentially important implications for dog disease control programmes that propose using canine vaccination as a tool for conservation management of wild carnivore populations

Harvest strategies for the elimination of low prevalence wildlife diseases

The intensive harvesting of hosts is often the only practicable strategy for controlling emerging wildlife diseases. Several harvesting approaches have been explored theoretically with the objective of lowering transmission rates, decreasing the transmission period or specifically targeting spatial disease clusters or high-risk demographic groups. Here, we present a novel model-based approach to evaluate alternative harvest regimes, in terms of demographic composition and rates, intended to increase the probability to remove all infected individuals in the population during the early phase of an outbreak. We tested the utility of the method for the elimination of chronic wasting disease based on empirical data for reindeer (Rangifer tarandus) in Norway, in populations with (Nordfjella) and without (Hardangervidda) knowledge about exact disease prevalence and population abundance. Low and medium harvest intensities were unsuccessful in eliminating the disease, even at low prevalence. High-intensity harvesting had a high likelihood of eliminating the disease, but probability was strongly influenced by the disease prevalence. We suggest that the uncertainty about disease prevalence can be mitigated by using an adaptive management approach: forecast from models after each harvest season with updated data, derive prevalence estimates and forecast further harvesting. We identified the problems arising from disease surveillance with large fluctuations in harvesting pressure and hence sample sizes. The elimination method may be suitable for pathogens that cause long-lasting infections and with slow epidemic growth, but the method should only be attempted if there is a low risk ofreinfection, either by a new disease introduction event (e.g. dispersing hosts) or due to environmental reservoirs. Our simulations highlighted the short time window when such a strategy is likely to be successful before approaching near complete eradication of the population

Leopards in Human dominated Areas: a Spillover from Sustained Translocations Into Nearby Forests?

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Getting in front of chronic wasting disease: Model-informed proactive approach for managing an emerging wildlife disease

Continuing geographic spread of chronic wasting disease (CWD) poses a serious threat to the sustainable future of cervids and hunting in North America. Moreover, CWD has been detected in captive cervids in South Korea and, in recent years, in free-ranging reindeer in Europe (Norway). Management of this disease is limited by logistical, financial, and sociopolitical considerations, and current strategies primarily focus on reducing host densities through hunter harvest and targeted culling. The success of such strategies in mitigating the spread and prevalence of CWD only upon detection is questionable. Here, we propose a proactive approach that emphasizes pre-emptive management through purposeful integration of virtual experiments (simulating alternate interventions as model scenarios) with the aim of evaluating their effectiveness. Here, we have used a published agent-based model that links white-tailed deer demography and behavior with CWD transmission dynamics to first derive a CWD outbreak trajectory and then use the trajectory to highlight issues associated with different phases of the CWD outbreak (pre-establishment/transition/endemic). Specifically, we highlight the practical constraints on surveillance in the pre-establishment phase and recommend that agencies use a realistic detection threshold for their CWD surveillance programs. We further demonstrate that many disease introductions are “dead ends” not leading to a full epidemic due to high stochasticity and harvesting in the pre-establishment phase of CWD. Model evaluated pre-emptive (pre-detection) harvest strategies could increase the resilience of the deer population to CWD spread and establishment. We conclude it is important to adaptively position CWD management ahead of, rather than behind, the CWD front