Brucellosis prevention and control in small ruminants using a test and slaughter strategy in the pastoral Afar Region of Ethiopia: A pilot study.

Abstract

BACKGROUND: Brucellosis is a neglected tropical zoonosis with substantial health and economic impact in developing countries. Despite its endemicity in Ethiopia, there is currently no surveillance or control in livestock. The study objective was to assess the effect of animal segregation and elimination as a brucellosis control strategy in small ruminants in the pastoral Afar region of Ethiopia. METHODS: The study was conducted over 2 years. All small ruminants, older than 5 months originally in the herd and those subsequently entering the herd were ear tagged with unique ID numbers. All animals were tested for brucellosis every six months using Rose Bengal Testing and ELISA for confirmation. Purchased animals and animals that had aborted were segregated and tested before joining the herd. Sero-positive animals were eliminated and owners compensated. A herd-book was kept for all animals and households visited each week. A mathematical transmission model was developed to assess the change of prevalence under different intervention scenarios. RESULTS: Cumulatively, 15,489 small ruminant samples were tested for brucellosis, of which 889 reactors were eliminated. Brucellosis prevalence declined from 12 % to 1 % over the study period and no more animal abortions were recorded by the end of the study. The mathematical model showed that the removal of positive reactors in that specific context clearly decreases the sero-prevalence and eventually leads to the elimination of brucellosis. CONCLUSION: Segregation and test-and-slaughter strategy can effectively reduce brucellosis prevalence in animals, thus alleviating the disease burden on the public health sector. A strong inter-disciplinary and trans-disciplinary approach is required taking into account epidemiological context and pastoralist culture.