Prevalence of brucellosis and associated risk factors in dairy cattle in Maekel and Debub Regions, Eritrea.

Introduction: Brucellosis is a zoonotic disease with worldwide distribution. It is considered endemic in Eritrea, however, the current prevalence status and related risk factors in animals are unknown. The objective of this study was to determine the prevalence of and risk factors for brucellosis in dairy cattle in Maekel and Debub regions, Eritrea. Methods: A cross sectional study was conducted between August 2021 and February 2022. A total of 2,740 dairy cattle from 214 herds in 10 sub-regions of Eritrea were selected for blood and data collection. Blood samples were tested using Rose Bengal Plate Test (RBPT) and positive samples were confirmed using competitive (c-ELISA). Data on risk factors was collected using questionnaire and analyzed using logistic regression. Results: In total, 34/2740 animals tested positive by RBPT. Of these, 29 were confirmed positive by c-ELISA, giving an apparent and estimated true individual-level prevalence of 1.1% (95% CI: 0.7, 1.5%) and 1.3% (95% CI: 0.9, 1.8%), respectively. Sixteen herds (7.5%) tested positive by RBPT and of these 15 herds (7.0%) were confirmed positive by c-ELISA, giving an estimated true herd-level prevalence of 7.0% (95% CI: 4.0, 10.7). Animal and herd-level apparent prevalence was 1.6 and 9.2% in Maekel, while in Debub it was 0.6 and 5.5%, respectively. Multivariable regression analysis indicated that non-pregnant lactating cows (adjusted odds ratio [aOR] = 3.35; p = 0.042) were more likely to be Brucella sero-positive. History of abortion on the farm (aOR = 5.71; p = 0.026) and larger number of cows in the herd (aOR = 1.14; p < 0.001) were associated with brucellosis sero-positivity in herds. Conclusion: Brucellosis prevalence was low in the study areas. Nonetheless, this low prevalence may increase if the disease is not controlled. Therefore, testing animals before movement, good farming practices, sanitary measures, and an awareness raising program on brucellosis are recommended.

Prevalence of bovine tuberculosis in cattle, goats, and camels of traditional livestock raising communities in Eritrea.

BACKGROUND: The aim of the current study was to assess the prevalence of bovine tuberculosis (BTB) in cattle, goats, and camels, and its zoonotic potential within the traditional livestock raising communities in four regions of Eritrea. The Single Intradermal Comparative Tuberculin Test (SICTT) as indicator of M. bovis infection was conducted on 1077 cattle, 876 goats, and 195 camels. To elucidate possible risk factors for BTB transmission between animals and its potential zoonotic implication, questionnaire based face-to-face interviews were conducted in households of which 232 raised cattle, 128 goats, and 29 camels. RESULTS: The results of the SCITT were interpreted using the OIE standard (> 4 mm cut-off) for positive responses. In cattle, individual animal (n = 1077) and herd (n = 413) prevalences were 1.2% (n = 13) [Confidence Interval (CI) 95% CI, 1.0-1.3%] and 3.2% (n = 13) (95% CI, 3.0-3.4%), respectively. In goats (n = 876), none of the animals was positive. In camels, individual animal (n = 195) and herd (n = 70), BTB prevalences were 1.5% (n = 3) (95% CI,1.4-1.6%) and 2.9(n = 2) (95% CI, 0.9-4.6%), respectively. Overall, male animals were more at risk (OR = 2.6; 95% CI:1.0-8.7) when compared to females. Sharing of water points, introduction of new animals into herds and migration of animals over large distances were common events that may contribute to intra and inter-species transmission of BTB. Consumption of raw milk, lack of BTB transmission awareness, and low levels of education were common in the farming communities. CONCLUSION: The current study highlighted a low prevalence of M. bovis in cattle, goats and camels in extensive traditional livestock in Eritrea. Despite this, the spatial distribution of affected animals across most of the sampled regions and consumption of unpasteurized milk warrants surveillance, cautious and timely control measures for the disease.

Prevalence and risk factors of bovine tuberculosis in dairy cattle in Eritrea.

BACKGROUND: The prevalence of bovine tuberculosis (BTB) in dairy cattle in the three major milk producing regions of Eritrea was assessed by subjecting 15,354 dairy cattle, 50 % of Eritrea's dairy cattle population, to the single intradermal comparative tuberculin test (SICTT). Skin test results were interpreted according to guidelines of the World Organization for Animal Health (OIE) with >4 mm as cutoff in skin thickness increase. In addition, we studied the relation between 'physiological' variables related to pregnancy and lactation, and the variable 'region' on the probability to be skin test positive. RESULTS: The BTB prevalences at animal and herd levels were: 21.5% and 40.9% in Maekel, 7.3% and 10% in Debub, and 0.2% and 1.6% in the Anseba region, respectively. Overall, in the regions included, prevalence was 11.3% (confidence interval (CI) 95% CI, 11.29 - 11.31%) and 17.3% (95% CI, 17.27-17.33%), at animal and herd level, respectively. Considering positive herds only, the animal BTB prevalence was 36.8%, 30.1%, and 1.8%, in Maekel, Debub and Anseba, respectively, and the overall animal prevalence within these herds was 32%. In adult dairy cattle the probability of positive reactivity in the SICTT test was highest in pregnant animals as compared to the other categories. CONCLUSION: This study reports persistent prevalence of BTB as defined by positive SICTT in the dairy sector of Eritrea, especially in the regions of Maekel and Debub that are located in the central highlands of the country. To our understanding this is the first report that has encompassed all the major dairy farms in Eritrea and it will be instrumental in advocating future BTB control programs in the dairy sector.