Rabies Control Situation in Bali Deteriorates

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Recent news reports from Bali indicate that human deaths from the rabies virus are on the rise again. Bali, an island province in Indonesia of around 4.2 million people, and a very popular tourist destination, was historically rabies-free. Cases of rabies in humans and dogs were first reported in late 2008. The site of the original infections was a peninsula on the southern coast of the island, and good surveillance coupled with a timely, effective intervention around that location would likely have prevented the epidemic that ensued.

Control efforts started in December 2008 and involved mass culling of dogs and emergency vaccination at fixed posts. Vaccination (with a local vaccine that required boosting after 3 months) was estimated to reach around 40% of the dogs, with only 25% receiving the required boosters. This was not sufficient to control the epidemic which spread across the whole island within 2 years. In 2010, 82 people died of rabies.

A rabies prevention bylaw enacted in 2009 stipulates that dog owners have to keep their pets at home and have them vaccinated regularly, but this is not proving practical in a culture where most owners cannot easily restrain their dogs and have always let them roam freely.

Island-wide concerted rabies control efforts focussed on mass dog vaccination reached more than 70% of dogs in 2010 and 2011. The high-quality vaccine used did not require boosting, and reduced the burden of human deaths dramatically, but did not fully eliminate the disease from the dog population. As a result of the programme, human rabies cases were reduced from eleven per month in 2010 to just one per month the following year. Following a mass vaccination of dogs, there was another major reduction in 2012 and 2013, bringing the number of reported cases down to only one human case in all of 2013.

However, recently the human death toll has been rising again. From just one human death reported in 2013, there were 3 deaths in 2014, and 7 deaths in the first six months of 2015, according to Head of the Bali Provincial Health Office, Dr. Ketut Suarjaya quoted in the Bali Times. An original target of a rabies-free Bali by 2015 is now impossible, and to make the revised target date of 2020 will require a 2-year period without human or dog cases of rabies.

Shortages of human rabies vaccines are being reported as the government has apparently run out of money to buy more. Last month it was reported that none of the major public and private hospitals had vaccine supplies, and a return to dog culling has occurred. Whilst owned and community dogs are allowed to roam free, there is the risk that vaccinated dogs are also being culled, and residents have been insisting that their vaccinated (and collared to demonstrate this) dogs have been rounded up and culled.

Clearly, rabies will exploit any breach in control measures. It is disheartening to see the immense progress in reducing both human and animal deaths start to slip away, and the resultant rise in deaths that could have been prevented. Culling of dogs is universally agreed to be an ineffective means to control rabies, can destroy vital community support for more effective control interventions and encourages dog population turnover. In the case of Bali, this situation is also potentially resulting in the removal of vaccinated dogs that would otherwise be protecting their communities. Free roaming dogs that are effectively vaccinated do not pose a rabies risk, and are in fact the most important dogs to vaccinate to stop the spread of the rabies virus.

Sustained, intensive dog vaccination campaigns with high quality vaccine that reach over 70% of the population are known to be highly effective, and have been shown to be so on Bali in recent years. If these are reinvigorated quickly, further human deaths can be prevented and could achieve rabies elimination remarkably quickly in an island situation where the importation of dogs is controlled. The goal of a rabies-free Bali by 2020 is still within reach.

Written by Louise Taylor, from the following sources. Putra et al (2013): Response to a rabies epidemic, Bali, Indonesia, 2008-2011, FAO website: Bali Serves as a Model for Control of Rabies, Jakarta Post: June 27th 2014, York Times: March 24th, 2015, Bali Times: June 15th 2015, Letter to Jakarta Post: June 19th, 2015.