The Bali Rabies Outbreak

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A summary of the recent outbreak of rabies on Bali in Indonesia has been published. It shows the scale of the problem and offers lessons about the management of such emergencies.

Bali was historically rabies-free, but in 2008 rabies was detected on a peninsula on the South of the island, probably introduced by infected dogs travelling on fishermen’s boats. At this point the island had no policies for rabies PEP and no dog bite surveillance, rabies diagnostic facilities, or vaccines for dogs. Despite culling efforts and vaccination attempts in 2008-9, the infection spread across the whole island. More than 130 people died and more than 130,000 were given post-exposure treatment for dog bites with control efforts costing over $17million.

Early vaccination attempts by the government were hampered by the difficulty in handling the free-roaming dog population, covering only 40% of the dog population initially, and only 25% with a necessary booster 3 months later. Panic lead to demand for emergency culling of dogs in some areas, but many communities objected. Dog culling may have even helped to spread rabies as vaccinated dogs were culled, new puppies replaced those culled and there was evidence of dog movement to avoid culls.

Consequently, these measures failed to contain the infection, but surveillance efforts set up with the help of the Australian government provided critical data to track the infection spread.

In 2009 the Australian government donated longer lasting vaccines and a local NGO, the Bali Animal Welfare Association (BAWA) with the support of the World Society for the Protection of Animals (WSPA) stepped up to implement mass vaccination campaigns. Better dog catching techniques allowed them to reach the necessary 70% vaccination coverage almost everywhere they vaccinated.

From Oct 2010 to April 2011, an island-wide mass vaccination campaign was completed by the government, BAWA and WSPA and from May to December 2011 a second was implemented by the government with the support of FAO. These finally brought the epidemic under control. The monthly number of confirmed dog rabies cases fell from 44.7 before mass vaccination to 10.8 during the first mass vaccination campaign, to 6.0 during the second mass vaccination campaign. The number of dogs culled fell from >108,000 to 40,000 to 14,000 over the same timeframes, but long term dog population management in Bali remains uncertain. Monthly human rabies deaths fell from 4.3 and 4.8 to 1.1 respectively. By December 2011, all but 30 villages (4.1%) were considered rabies free, with no new dog cases in 6 months.  Although rabies incidence has been substantially reduced, the article urges that vaccination must continue until rabies is eliminated from the dog population.

A recent new report states that it has been almost one year since the last reported human rabies death. There are hopes that Bali will again be declared rabies free, a target set for by 2015, but this will require two consecutive years without a single occurrence of rabies in either animals or humans. Currently 2% of dog bites are reported to be from rabid dogs. Stage four of the government’s free mass dog vaccination for the all 300,000 dogs in Bali will start mid-April and run until June this year. However, residents are expected to bring their dogs for vaccination, and there are concerns that attitudes towards responsible pet ownership have not improved significantly.

Summarised by Louise Taylor from an article by Putra et al. in Emerging Infectious Diseases, April 2013 and a Jakarta Post article from March 28th 2013.