BackgroundCanine 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 FindingsUsing 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/SignificanceThe 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.

BackgroundPreviously free of rabies, Bali experienced an outbreak in 2008, which has since caused a large number of human fatalities. In response, both mass dog culling and vaccination have been implemented. In order to assess potential community-driven interventions for optimizing rabies control, we conducted a study exploring the relationship between dogs, rabies, and the Balinese community. The objectives of this study were to: i) understand the human-dog relationship in Bali; ii) explore local knowledge, attitudes, and practices (KAPs) relating to rabies; and iii) assess potential community-driven activities to optimize rabies control and surveillance.MethodsConducted between February and June 2011, the study combined a questionnaire (n = 300; CI = 95 %; error margin = 5 %) and focus group discussions (FGDs) in 10 villages in the Denpasar, Gianyar, and Karangasem regencies. The questionnaire included a Likert scale to assess community knowledge and attitudes. For the knowledge assessment, three points were given for a correct answer, while wrong answers and uncertain answers were given zero points. For the attitudes assessment, three points were given for a positive answer, two points for a neutral answer, and one point for a negative answer. Respondent knowledge was categorized as good (score >40), fair (score 20–40), or poor (score <20), based on a maximum total score 60. Respondent attitudes were categorized as positive (score >26), neutral (score 13–26), or negative (score <13), based on a maximum total score of 39. Mixed-gender FGDs in each sub-village (banjar) were conducted, each involving 7–15 participants to complement the questionnaire results. On a follow-up research trip in mid-2013, the data analysis was triangulated and validated using semi-structured interviews. Questionnaire data were analyzed descriptively using SPSS 17.0, while qualitative data from interviews and FGDs were analyzed manually according to accepted methods of coding and memo writing. The chi-square test was then used to analyze the statistical relationships between knowledge and attitudes of the respondents.ResultsOut of the total 300 respondents, most were predominantly male (82 %), Hindu (99 %), married (96 %), older than 30 years of age (92 %), and owned dogs (72 %). Dog ownership was motivated by culture, personal taste, and function, with dogs was being used as guards (85 %) and companion animals (27 %), and was sometimes related to religious or traditional obligations (2 %). Relating to their culture and local beliefs, and eventually becoming their way of life, 79 % of respondents kept free-roaming dogs. With the rabies outbreak in Bali and Western breeds becoming more popular, more responsible dog ownership (leashing, confining, regular feeding) became more acceptable and changed community perceptions on keeping dogs, even though the sustainability of this practice cannot be gauged. In addition, the economic situation posed major problems in rural areas. The level of community knowledge about rabies and its associated c...

Maintaining high vaccination coverage is key to successful rabies control, but mass dog vaccination can be challenging and population turnover erodes coverage. Declines in rabies incidence following successive island-wide vaccination campaigns in Bali suggest that prospects for controlling and ultimately eliminating rabies are good. Rabies, however, has continued to circulate at low levels. In the push to eliminate rabies from Bali, high coverage needs to be maintained across all areas of the island. We carried out door-to-door (DTD) questionnaire surveys (n = 10,352 dog-owning households) and photographic mark–recapture surveys (536 line transects, 2,597 observations of free-roaming dogs) in 2011–2012 to estimate dog population sizes and assess rabies vaccination coverage and dog demographic characteristics in Bali, Indonesia. The median number of dogs per subvillage unit (banjar) was 43 (range 0–307) for owned dogs estimated from the DTD survey and 17 (range 0–83) for unconfined dogs (including both owned and unowned) from transects. Vaccination coverage of owned dogs was significantly higher in adults (91.4%) compared to juveniles (<1 year, 43.9%), likely due to insufficient targeting of pups and from puppies born subsequent to vaccination campaigns. Juveniles had a 10–70 times greater risk of not being vaccinated in urban, suburban, and rural areas [combined odds ratios (ORs): 9.9–71.1, 95% CI: 8.6–96.0]. Free-roaming owned dogs were also 2–3 times more likely to be not vaccinated compared to those confined (combined Ors: 1.9–3.6, 95% CI: 1.4–5.4), with more dogs being confined in urban (71.2%) than in suburban (16.1%) and rural areas (8.0%). Vaccination coverage estimates from transects were also much lower (30.9%) than household surveys (83.6%), possibly due to loss of collars used to identify the vaccination status of free-roaming dogs, but these unconfined dogs may also include dogs that were unowned or more difficult to vaccinate. Overall, coverage levels were high in the owned dog population, but for future campaigns in Bali to have the highest chance of eliminating rabies, concerted effort should be made to vaccinate free-roaming dogs particularly in suburban and rural areas, with advertising to ensure that owners vaccinate pups. Long-lasting, cheap, and quick methods are needed to mark vaccinated animals and reassure communities of the reach of vaccination campaigns.

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