Date Published: February 21, 2018
Publisher: Public Library of Science
Author(s): Tariku Jibat Beyene, Monique C. M. Mourits, Abraham Haile Kidane, Henk Hogeveen, Brecht Devleesschauwer.
In developing countries where financial resources are limited and numerous interests compete, there is a need for quantitative data on the public health burden and costs of diseases to support intervention prioritization. This study aimed at estimating the health burden and post-exposure treatment (PET) costs of canine rabies in Ethiopia by an investigation of exposed human cases. Data on registered animal bite victims during the period of one year were collected from health centers in three districts, i.e. Bishoftu, Lemuna-bilbilo and Yabelo, to account for variation in urban highland and lowland areas. This data collection was followed by an extensive case search for unregistered victims in the same districts as the registered cases. Victims were visited and questioned on their use of PET, incurred treatment costs and the behavioral manifestations of the animal that had bitten them. Based on the collected data PET costs were evaluated by financial accounting and the health burden was estimated in Disability-Adjusted Life Years (DALYs). In total 655 animal bite cases were traced of which 96.5% was caused by dog bites. 73.6% of the biting dogs were suspected to be potentially rabid dog. Annual suspected rabid dog exposures were estimated per evaluated urban, rural highland and rural lowland district at, respectively, 135, 101 and 86 bites, which led, respectively, to about 1, 4 and 3 deaths per 100,000 population. In the same district order average costs per completed PET equaled to 23, 31 and 40 USD, which was significantly higher in rural districts. Extrapolation of the district results to the national level indicated an annual estimate of approximately 3,000 human deaths resulting in about 194,000 DALYs per year and 97,000 exposed persons requiring on average 2 million USD treatment costs per year countrywide. These estimations of the burden of rabies to the Ethiopian society provide decision makers insights into the potential benefits of implementing effective interventions.
Rabies is a viral infection that infects all mammals. Estimations on the global burden of rabies indicate a health impact of 59,000 human deaths per year, a loss of 3.7 million DALYs per year and about 8.6 billion USD of economic losses mainly due to premature deaths (productivity losses) and post-exposure treatment (PET) costs .
This study aimed to assess the burden of rabies in Ethiopia in terms of DALYs and PET costs while accounting for variation across different agro-ecologies. We recorded an average annual human mortality rate due to rabies between 0.7 (in Bishoftu) and 4.2 (in Lemuna-bilbilo) cases per 100,000 population with exposure rates ranging from 19–137 per 100,000 population with the highest number in Lemuna-bilbilo. Our evaluated numbers of exposures and deaths were higher than previous national estimates  consisting of 12 exposure cases per 100,000 population and 1.6 rabies deaths per 100,000 population, respectively. These estimates were calculated from confirmed exposure cases that were reported to health centers. Our estimates could have overestimated the actual number of bite cases by rabid dog as suspected cases were determined by the six-criterion method and not by laboratory confirmation techniques. The six criteria method has, however, been reported to be rather accurate (94.6%)  in the clinical diagnosis of rabies. Moreover, this retrospective study occurred up to a year after patients or family members had been bitten and were asked to provide details about the bite and the dog. Hence, responses could have been subjected to recall bias which would imply an under or over estimate of the burden. Recall error increases with the length of the recall period. Rabies is, however, one of the most feared diseases with almost 100% fatality rate. For this reason it was expected that the bite victims were rather accurate in remembering rabies exposures within the selected time frame of a calendar year.