Designing programs for eliminating canine rabies from islands: Bali, Indonesia as a case study.

BACKGROUND: Canine rabies is one of the most important and feared zoonotic diseases in the world. In some regions rabies elimination is being successfully coordinated, whereas in others rabies is endemic and continues to spread to uninfected areas. As epidemics emerge, both accepted and contentious control methods are used, as questions remain over the most effective strategy to eliminate rabies. The Indonesian island of Bali was rabies-free until 2008 when an epidemic in domestic dogs began, resulting in the deaths of over 100 people. Here we analyze data from the epidemic and compare the effectiveness of control methods at eliminating rabies. METHODOLOGY/PRINCIPAL FINDINGS: Using data from Bali, we estimated the basic reproductive number, R(0), of rabies in dogs, to be ~1 · 2, almost identical to that obtained in ten-fold less dense dog populations and suggesting rabies will not be effectively controlled by reducing dog density. We then developed a model to compare options for mass dog vaccination. Comprehensive high coverage was the single most important factor for achieving elimination, with omission of even small areas (<0.5% of the dog population) jeopardizing success. Parameterizing the model with data from the 2010 and 2011 vaccination campaigns, we show that a comprehensive high coverage campaign in 2012 would likely result in elimination, saving ~550 human lives and ~$15 million in prophylaxis costs over the next ten years. CONCLUSIONS/SIGNIFICANCE: The elimination of rabies from Bali will not be achieved through achievable reductions in dog density. To ensure elimination, concerted high coverage, repeated, mass dog vaccination campaigns are necessary and the cooperation of all regions of the island is critical. Momentum is building towards development of a strategy for the global elimination of canine rabies, and this study offers valuable new insights about the dynamics and control of this disease, with immediate practical relevance.

A mark-resight survey method to estimate the roaming dog population in three cities in Rajasthan, India.

BACKGROUND: Dog population management is required in many locations to minimise the risks dog populations may pose to human health and to alleviate animal welfare problems. In many cities in India, Animal Birth Control (ABC) projects have been adopted to provide population management. Measuring the impact of such projects requires assessment of dog population size among other relevant indicators. METHODS: This paper describes a simple mark-resight survey methodology that can be used with little investment of resources to monitor the number of roaming dogs in areas that are currently subject to ABC, provided the numbers, dates and locations of the dogs released following the intervention are reliably recorded. We illustrate the method by estimating roaming dog numbers in three cities in Rajasthan, India: Jaipur, Jodhpur and Jaisalmer. In each city the dog populations were either currently subject to ABC or had been very recently subject to such an intervention and hence a known number of dogs had been permanently marked with an ear-notch to identify them as having been operated. We conducted street surveys to record the current percentage of dogs in each city that are ear-notched and used an estimate for the annual survival of ear-notched dogs to calculate the current size of each marked population. RESULTS: Dividing the size of the marked population by the fraction of the dogs that are ear-notched we estimated the number of roaming dogs to be 36,580 in Jaipur, 24,853 in Jodhpur and 2,962 in Jaisalmer. CONCLUSIONS: The mark-resight survey methodology described here is a simple way of providing population estimates for cities with current or recent ABC programmes that include visible marking of dogs. Repeating such surveys on a regular basis will further allow for evaluation of ABC programme impact on population size and reproduction in the remaining unsterilised dog population.

Fecundity and longevity of roaming dogs in Jaipur, India.

BACKGROUND: Estimates of demographic parameters, such as age-specific survival and fecundity, age at first pregnancy and litter size, are required for roaming dogs (i.e. dogs that are neither confined nor restricted) to assess the likely effect of proposed methods of population control. Data resulting from individual identification of dogs spayed as part of an Animal Birth Control (ABC) programme in Jaipur, India, are used to derive such parameters for the roaming dog population of that city. RESULTS: The percentage of females becoming pregnant in any given year was estimated by inspection of over 25,000 females caught for spaying from 1995 to 2006. The point estimate is 47.5% with a 95% confidence interval from 44% to 51%. Adult annual survival of spayed females was estimated by recapture of 62 spayed females from 2002 to 2006. The point estimate is 0.70 (95% confidence interval from 0.62 to 0.78), corresponding to an expected total lifespan of 3.8 years for a spayed female at one year old. CONCLUSION: Recording the pregnancy status of dogs collected for spaying and individual marking of dogs released following spaying can provide estimates of some of the demographic parameters essential for predicting the future effectiveness of an ABC programme. Further, we suggest that recording the number and location of spayed and unspayed dogs encountered by the catching teams could be the most effective way to monitor the size and composition of the roaming dog population.

Behavioural and physiological responses of dogs entering re-homing kennels.

Behaviour and urinary cortisol/creatinine ratios (C/C) were monitored in twenty-six dogs, on days 1, 2, 3, 5, 7 and 10 following their admission to a rehoming kennel. Half had been relinquished from homes, and half were either strays or returns to the shelter. Drinking and grooming increased with time, while panting and paw-lifting decreased, but only drinking was linked with C/C; dogs observed drinking on the first day had significantly lower C/C than dogs not observed drinking. Mean molar C/C (40 x 10(-6)+/-16 x 10(-6)) tended to decrease with time in the strays and returns, and to increase in dogs relinquished from homes, although C/C on the first day was highly variable and not distinguishable between these two groups. This implies that these populations differed in their long-term, but possibly not their short-term, responses to kennelling. Dogs with rising C/C were more active on average than those with falling C/C, but the opposite trend was detected when making comparisons within-dog. The relationship between C/C and exercise is therefore complex and warrants further investigation before C/C can be considered as a reliable indicator of welfare in this species.