A Review of the Economics of the Prevention and Control of Rabies

Abstract

Although rabies in domestic and wild animals represents a significant threat to public health and can cause economic losses among livestock, there are very few studies that examine the economics of rabies in animals. The literature that does exist can be characterised as poorly documented estimates of costs, with insufficient information to allow replication of the analyses. Most papers have numerous 'violations' of the standard recommended procedures for assessing burden of disease and the cost and benefits of interventions. For example, most studies do not distinguish between financial charges and true economic costs. Further, despite the fact that controlling rabies in animal populations is often a multi-year task, only a few papers contain a multi-year framework, complete with discounting of future costs and benefits. Globally, dog-transmitted rabies represents the largest threat to human health. In order to prevent the transmission of rabies in a dog population, it is theoretically necessary to vaccinate a minimum of 60 to 70% of the dogs. Even countries with potentially sufficient resources, however, do not often meet and sustain these rates. One reason for such failure might be that individual dog owners might feel that it is too expensive to vaccinate their pets. Recent estimates in the US of the cost of vaccinating dogs range from $US16 to $US24 per dog. In developing countries, estimates range from $US0.52 in Thailand, to $US1.19 in the Philippines, to $US2.70 in Malawi. None of these estimates include indirect costs accured by the pet owners. Lethal methods of dog population control are even more expensive, and attempting to control rabies by reducing dog populations has not worked for any extended period. Rabies in livestock is often reported, but the impact in the US and most developed countries appears relatively small. Vampire bat-transmitted rabies in Latin America appears to be the most serious rabies problem in livestock. The largest cost due to wildlife rabies is the cost of vaccinating domestic animals, both large and small. In the US, domestic animals face multiple sources of wildlife rabies. Attributing the entire cost of vaccinating domestic animals to 1 species can result in the over estimation of the benefits of immunising a given wildlife population via vaccine-laden baits. For example, despite a definite decline in the number of rabid foxes, it has been difficult to obtain the promised benefits of using oral vaccines in Europe to control fox rabies. Other authors maintain that the use of oral vaccines to control fox rabies is cost beneficial, but there are no convincing data supporting that claim. Additionally, vaccinating raccoons with an oral vaccine requires approximately 4 times more vaccine-laden baits vaccinating foxes, which makes it highly questionable if it would be cost beneficial to use oral vaccine to attempt raccoon rabies elimination in areas where it is already enzootic. The economics of using oral vaccines to prevent raccoon rabies invading uninfected areas has yet to be examined.