Integrated human-animal sero-surveillance of Brucellosis in the pastoral Afar and Somali regions of Ethiopia

Abstract

Background Brucellosis is widespread in Ethiopia with variable reported prevalence depending on the geographical area, husbandry practices and animal species. However, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock. Methodology We conducted an integrated human-animal brucellosis sero-surveillance study in two adjacent pastoral regions, Afar and Somali region (SRS). This cross-sectional study included 13 woredas (districts) and 650 households. Blood samples were collected from people and livestock species (cattle, camel, goats and sheep). Sera were analyzed with C-ELISA for camels and shoats (sheep and goats), with I-ELISA for cattle and IgG ELISA for humans. Descriptive and inferential statistics analyses were performed. Results A total of 5469 sera were tested by ELISA. Prevalence of livestock was 9.0% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0.0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one animal reactor. Overall, 4.1% of animals had a history of abortion. The proportion of animals with abortion history was higher in seropositive animals than in seronegative animals. Risk factor analysis showed that female animals were significantly at higher risk of being reactors (p = 0.013). Among the species, cattle had the least risk of being reactors (p = 0.014). In humans, there was a clear regional association of disease prevalence (p = 0.002). The older the people, the highest the odds of being seropositive. Conclusion Brucellosis is widespread in humans and animals in pastoral communities of Afar and SRS with the existence of geographical hotspots. No clear association was seen between human and particular livestock species prevalence, hence there was no indication as whether B. abortus or B. melitensis are circulating in these areas, which warrants further molecular research prior to embarking on a national control programs. Such programs will need to be tailored to the pastoral context.

Community Knowledge, Attitude, Practice and Prevalence of Brucellosis in In Livestock Owners in Northern Red Sea Region, Eritrea

“…In the previous study, the prevalence in the pastoralist community was (3•0%) and 4•5% in veterinary personnel [12]. Moreover, prevalence of the current study was very low compared to the results reported in a similar study conducted in Afar (48.3%) and in Somali (34.9%) regions, Ethiopia which has similar environmental setting and husbandry system to it [16]. In South Sudan the seroprevalence was 27.2 % as reported by the authors [18].…”

Bovine Brucellosis and Its Public Health Significance in Ethiopia

“…Therefore, the government has launched the National Brucellosis Technical Working Group (NBTWG) to spearhead collaborative efforts among government and private sectors, partners and universities, to coordinate and synergistically implement prevention and control efforts through the One Health approach [3]. Although the disease has widespread characteristics in humans and their livestock, particularly in occupational and pastoral communities, limited information is available regarding its prevalence, transmission and risk factors among communities [45].…”

“…Accordingly, a very recent study in Afar, "Integrated human-animal sero-surveillance of brucellosis in the pastoral Afar and Somali regions of Ethiopia," has reported an overall cattle brucellosis seroprevalence of 7.2% and 6.2% in Afar and Somali, respectively% [45] In the same year, Getahun reported an 0.6% prevalence in dairy cows with recent abortion history [47]. Another cross-sectional study in the Jimma Zone, Oromia Region, has reported an animal and herd level cattle prevalence of 16.4% and 4.3%, respectively [64].…”

“…In Ethiopia, brucellosis has widespread prevalence and endemic characteristics, and is among the major public health and economic problems among rural and urban areas [47], because associated risk factors and health interventions are not routinely determined, appropriate and effective diagnostic facilities are lacking, close contact between humans and their livestock is common, and the country has not yet started a coordinated prevention and control program [65]. According to several seroprevalence studies performed from the mid-2000s to 2021 (Fig 3 ), human brucellosis has been reported in various geographical areas of Ethiopia with a prevalence ranging from 2.15% to 48.3% [45,66].…”

Knowledge-attitude and practice of Anthrax and brucellosis: Implications for zoonotic disease surveillance and control in pastoral communities of Afar and Somali region, Ethiopia

“…In humans, brucellosis can cause adverse events during pregnancies and, if left untreated, may result in long-term cardiac, neurological or immunological complications [ 8 ]. Brucellosis is also considered endemic in Ethiopia [ 9 ].…”