The variable prevalence of bovine tuberculosis among dairy herds in Central Ethiopia provides opportunities for targeted intervention
Creators: name: Almaw, Gizat
name: Conlan, Andrew J. K.
name: Ameni, Gobena
name: Gumi, Balako
name: Alemu, Alemseged
name: Guta, Sintayehu
name: Gebre, Solomon
name: Olani, Abebe
name: Garoma, Abebe
name: Shegu, Dereje
name: Yimesgen, Letebrhan
name: Nigussie, Demeke
name: Wood, James L. N.
name: Abebe, Tamrat
name: Mihret, Adane
name: Berg, Stefan
name: Consortium, The ETHICOBOTS
Publisher: name: Apollo - University of Cambridge Repository
Year: 2021
Subjects: Research Article
Medicine and health sciences
Biology and life sciences
People and places

description: Funder: This research was financially supported by the Ethiopia Control of Bovine Tuberculosis Strategies (ETHICOBOTS) project funded by the Biotechnology and Biological Sciences Research Council, the Department for International Development, the Economic &amp; Social Research Council, the Medical Research Council, the Natural Environment Research Council and the Defence Science &amp;Technology Laboratory, under the Zoonoses and Emerging Livestock Systems (ZELS) program.Stefan Berg was also funded by Defra, United Kingdom, ref: TBSE3294. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.; Grant(s): ref: BB/L018977/1
description: Funder: ETHICOBOTS; Grant(s): ref: BB/L018977/1
description: Bovine tuberculosis (bTB) is an important disease for dairy productivity, as well as having the potential for zoonotic transmission. Previous prevalence studies of bTB in the dairy sector in central Ethiopia have suggested high prevalence, however, they have been limited to relatively small scale surveys, raising concerns about their representativeness. Here we carried out a cross sectional one-stage cluster sampling survey taking the dairy herd as a cluster to estimate the prevalence of bTB in dairy farms in six areas of central Ethiopia. The survey, which to date is by far the largest in the area in terms of the number of dairy farms, study areas and risk factors explored, took place from March 2016 to May 2017. This study combined tuberculin skin testing and the collection of additional herd and animal level data by questionnaire to identify potential risk factors contributing to bTB transmission. We applied the single intradermal cervical comparative tuberculin (SICCT) test using &gt;4mm cut-off for considering an individual animal as positive for bTB; at least one reactor animal was required for a herd to be considered bTB positive. Two hundred ninety-nine dairy herds in the six study areas were randomly selected, from which 5,675 cattle were tested. The overall prevalence of bTB after standardisation for herd-size in the population was 54.4% (95% CI 48.7–60%) at the herd level, and it was 24.5% (95% CI 23.3–25.8) at the individual animal level. A Generalized Linear Mixed Model (GLMM) with herd and area as random effect was used to explore risk factors association with bTB status. We found that herd size, age, bTB history at farm, and breed were significant risk factors for animals to be SICCT positive. Animals from large herds had 8.3 times the odds of being tuberculin reactor (OR: 8.3, p-value:0.008) as compared to animals from small herds. The effect of age was strongest for animals 8–10 years of age (the oldest category) having 8.9 times the odds of being tuberculin reactors (OR: 8.9, p-value:&lt;0.001) compared to the youngest category. The other identified significant risk factors were bTB history at farm (OR: 5.2, p-value:0.003) and cattle breed (OR: 2.5, p-value: 0.032). Our study demonstrates a high prevalence of bTB in central Ethiopia but with a large variation in within-herd prevalence between herds, findings that lays an important foundation for the future development of control strategies.