Socio-economic modelling of rabies control in Flores Island, Indonesia

Abstract

Rabies is a zoonotic viral disease that can cause encephalomyelitis both in animals and humans. Since its introduction in Flores Island, Indonesia in 1997, it has been a serious public health threat with significant economic consequences. To control the disease, annual dog vaccination campaigns have been implemented to vaccinate all dogs free of any charge. Nevertheless, the campaigns have not been successful in eliminating rabies from the island. The main objective of this dissertation was to support future decisions on the control of rabies in Flores Island by providing insight into the role of socio-demographic and psychological factors of dog owners in the uptake of rabies control measures and by analyzing the cost-effectiveness of alternative mass dog vaccination strategies. By means of a cost accounting model, the costs of the currently applied rabies control measures in Flores Island were estimated at US$1.12 million (range: US$0.60–1.47 million) per year. The costs of culling roaming dogs resulted in the highest cost portion (39%), followed by the costs of post-exposure treatment (35%) and mass vaccination (24%). Risk factors associated with the uptake level of rabies control measures were analysed based upon an extensive survey among 450 dog-owners in the regencies of Sikka and Manggarai. Only 52% of these dog owners had at least one of their dogs vaccinated during the 2012 vaccination campaign. Vaccination uptake was significantly higher for dog owners who resided in Sikka, kept female dogs for breeding, had a monthly income of more than one million rupiah, and had easy access to their village. A study based on the Theory of Planned Behaviour demonstrated that the actual intention of dog owners to participate in a free-of-charge vaccination campaign was high (> 90%). The attitude item ‘vaccinating dogs reduces rabies cases in humans’, and the perceived behavioural control items ‘availability of time’ and ‘ability to confine dogs’ were shown to be significantly associated with this intention level. Relevant considerations to improve the participation level in future vaccination campaigns are therefore appropriate time management as well as the provision of skills to confine dogs during the vaccination. The cost-effectiveness of different mass dog vaccination strategies was evaluated by means of a deterministic model simulating transmission of rabies virus through the dog population of one village. Annual vaccination using a short-acting vaccine at a coverage of 50% was far from being cost-effective, suggesting that the currently applied rabies control in Flores Island is not an efficient investment in reducing human rabies burden. An increased investment in either an increase in the current coverage or in a switch from the short-acting vaccine to the long-acting vaccine type would certainly pay off.