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

Abstract

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.

Keywords: Bovine tuberculosis; Camels; Eritrea; Goats; Mixed crop-livestock system; Pastoral system; Single intradermal comparative tuberculin test (SICTT).

Fig. 1

Map of Eritrea depicting the study areas (n = 31) and water points (n = 4, shared by animals from 11 study areas), having skin test reactors with > 4 mm-cut-off (red dots) and those with no reactors using > 4 mm (black dots) in the selected study areas within the traditional livestock husbandry system in Eritrea. The numbers (1–6) indicated on the map show the six administrative regions of Eritrea (1 = Maekel; 2 = Debub; 3 = Anseba; 4 = Gash Barka; 5 = Northern Red Sea; 6 = Southern Red Sea) (Adapted using: Loecher and Ropkins [54]. RgoogleMaps and loa: Unleashing R Graphics Power on Map Tiles. Journal of Statistical Software 63(4), 1–18. URL http://www.jstatsoft.org/v63/i04/)