Sero prevalence and Brucella species circulating among small ruminants and their attendants in Kasese and Rubirizi Districts, South-Western Uganda

Abstract

In Uganda, brucellosis is more widely studied in cattle than in other species of animals. A few studies conducted on Brucellosis in small ruminants suggest that there exists a significant association between caprine, ovine and human Brucellosis. In this study the sero prevalence of Brucella spp. infection, risk factors and Brucella spp. circulating among small ruminants and their attendants were investigated. A structured questionnaire was administered to farmers (n = 169) to determine community awareness and risk factors associated with zoonotic Brucellosis in July, 2018 of Kasese and Rubirizi districts. Blood samples drawn from humans (n = 169), goats (n = 399) and sheep (n = 92) were subjected to antibody test by Rose Bengal agglutination test and to polymerase chain reaction (PCR) to detect and speciate circulating Brucella species in the sero-positive samples (n = 137) using Bruce ladder PCR primers targeting the IS711 gene. The overall seroprevalence of Brucella infection was 15.5% (76/491) in small ruminants i.e. 9.8% (39/399) in goats, and 40.2% (37/92) in sheep. Meanwhile, the sero-prevalence was 36.1% (61/169) in humans. Using PCR, the prevalence of Brucella species was 4.4% (6/137) in humans and 19% (26/137) in the small ruminants. In the multiplex PCR, all the positive samples for Brucella genus were showing the same banding pattern as Brucella melitensis. Sharing communal water points and communal grazing areas are the major risk factors for Brucella infections in the animals. In addition, handling goats or sheep during delivery and consumption of inadequately cooked/roasted meat are risk factors for transmission in communities of Kasese and Rubirizi districts. The current study shows very high sero prevalence of Brucella species in humans and sheep. The main species of Brucella circulating among small ruminants and humans of Kasese and Rubirizi districts of Uganda is B. melitensis. There is need for further and bigger studies in the pastoral and agro-pastoral communities in the study area to study extent of the disease in the wider population of humans and animals. In addition, there is need for a robust control strategy against Brucellosis to reduce its transmission between humans and animals. Key words: Brucellosis, Rose Bengal agglutination test, Bruce ladder PCR, southwestern Uganda.