Bovine tuberculosis and brucellosis in livestock at the Greater Ruaha Ecosystem

Abstract

A cross-sectional study was conducted to determine the prevalence of bovine tuberculosis (BTB) and the seroprevalence of brucellosis in livestock at the Greater Ruaha Ecosystem in Tanzania. The study further characterized the Mycobacterium spp. from the slaughtered livestock. Survey conducted to assess potential herd-level risk factors for BTB and brucellosis revealed that the respondents’ ethnicity and herd mixing were the significant risk factors. Twenty-eight percent of 102 cattle herds had at least one positive or suspect BTB reactor. The overall prevalence of BTB infection in the cattle was 1.32% (18/1368). Forty-two percent of 93 flocks of the small ruminants had at least one brucellosis seropositive animal. The overall seroprevalence of brucellosis in the cattle and small ruminants was 6.6%. Although the prevalence of both diseases was relatively low for individual animals, herd-level prevalence was high, suggesting that infection is widespread in the study area and a significant number of households are at risk. Mycobacterium bovis strain identified via polymerase chain reaction (PCR) was confirmed by spoligotyping as spoligotype SB0133. This cattle strain of M. bovis was similar to previously reported involving wild animals in adjacent protected areas. Isolation of identical M. bovis from the wildlife and livestock and the demonstration of Brucella spp. seroprevalence in livestock in the same interface, strongly suggest livestock-wildlife interspecies sharing of these pathogens. Occurrence of the microorganisms poses a serious challenge to disease management strategies in pastoralist communities in the interface area.