TY - JOUR
T1 - Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia
AU - Mekonnen, G. A.
AU - Conlan, A. J.K.
AU - Berg, S.
AU - Ayele, B. T.
AU - Mihret, A.
AU - Olani, A.
AU - Asgedom, H.
AU - Wood, J. L.N.
AU - Ameni, G.
AU - Aseffa, Abraham
AU - Tessema, Bamlak
AU - Belachew, Bizuneh
AU - Fekadu, Eshcolewyene
AU - Melese, Fantanesh
AU - Gemechu, Gizachew
AU - Taye, Hawult
AU - Tschopp, Rea
AU - Haile, Shewit
AU - Ayalew, Sosina
AU - Hailu, Tsegaye
AU - Bekele, Adam
AU - Yirga, Chilot
AU - Ambaw, Mulualem
AU - Mamo, Tadele
AU - Solomon, Tesfaye
AU - Gebre, Solomon
AU - Gari, Getachew
AU - Sahle, Mesfin
AU - Aliy, Abde
AU - Sirak, Asegedech
AU - Almaw, Gizat
AU - Tamiru, Mekdes
AU - Guta, Sintayehu
AU - Clarke, Alan
AU - Moore, Henrietta L.
AU - Hodge, Catherine
AU - Hewinson, R. Glyn
AU - Vordermeier, Martin
AU - Nunez-Garcia, Javier
AU - Bayissa, Berecha
AU - Zewude, Aboma
AU - Worku, Adane
AU - Terfassa, Lemma
AU - Chanyalew, Mahlet
AU - Mohammed, Temesgen
AU - Zeleke, Yemisrach
N1 - Publisher Copyright:
© The Author(s), 2021. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution- NonCommercial-NoDerivatives licence (http:// creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use or in order to create a derivative work.
PY - 2021
Y1 - 2021
N2 - The Ethiopian government has several initiatives to expand and intensify the dairy industry; however, the risk of bovine tuberculosis (bTB) spread is a challenge. To assess the rate of expansion and risk factors for transmission of bTB within-herds, we carried out a repeated cross-sectional survey at two time points, 2016/17 and 2018, in three regional cities, namely, Gondar, Hawassa and Mekelle, representing the emerging dairy belts of Ethiopia. The total number of herds involved was 128, comprising an average of 2303 cattle in each round. The Single Intradermal Comparative Cervical Tuberculin (SICCT) test was used to identify reactor status and data on herd-level risk factors were collected using a structured questionnaire. In the first survey, the apparent prevalence of bTB, as measured by the SICCT test, was 4.5% (95% CI 3.7–5.4%) at the individual animal-level and 24% (95% CI 17.5–32%) at the herd-level. There was no statistically significant change in the overall apparent prevalence or regional distribution at the second survey, consistent with the infection being endemic. The incidence rate was estimated at 3.6 (95% CI 2.8–4.5) and 6.6 (95% CI 3.0–12.6) cases/ 100 cattle (or herd)-years at the animal- and herd-levels, respectively. Risk factors significantly associated with the within-herd transmission of bTB were age group and within-herd apparent prevalence at the start of the observation period. We noted that farmers voluntarily took steps to remove reactor cattle from their herds as a consequence of the information shared after the first survey. Removal of reactors between surveys was associated with a reduced risk of transmission within these herds. However, with no regulatory barriers to the sale of reactor animals, such actions could potentially lead to further spread between herds. We therefore advocate the importance of setting up regulations and then establishing a systematic bTB surveillance programme to monitor the impact prior to implementing any control measures in Ethiopia.
AB - The Ethiopian government has several initiatives to expand and intensify the dairy industry; however, the risk of bovine tuberculosis (bTB) spread is a challenge. To assess the rate of expansion and risk factors for transmission of bTB within-herds, we carried out a repeated cross-sectional survey at two time points, 2016/17 and 2018, in three regional cities, namely, Gondar, Hawassa and Mekelle, representing the emerging dairy belts of Ethiopia. The total number of herds involved was 128, comprising an average of 2303 cattle in each round. The Single Intradermal Comparative Cervical Tuberculin (SICCT) test was used to identify reactor status and data on herd-level risk factors were collected using a structured questionnaire. In the first survey, the apparent prevalence of bTB, as measured by the SICCT test, was 4.5% (95% CI 3.7–5.4%) at the individual animal-level and 24% (95% CI 17.5–32%) at the herd-level. There was no statistically significant change in the overall apparent prevalence or regional distribution at the second survey, consistent with the infection being endemic. The incidence rate was estimated at 3.6 (95% CI 2.8–4.5) and 6.6 (95% CI 3.0–12.6) cases/ 100 cattle (or herd)-years at the animal- and herd-levels, respectively. Risk factors significantly associated with the within-herd transmission of bTB were age group and within-herd apparent prevalence at the start of the observation period. We noted that farmers voluntarily took steps to remove reactor cattle from their herds as a consequence of the information shared after the first survey. Removal of reactors between surveys was associated with a reduced risk of transmission within these herds. However, with no regulatory barriers to the sale of reactor animals, such actions could potentially lead to further spread between herds. We therefore advocate the importance of setting up regulations and then establishing a systematic bTB surveillance programme to monitor the impact prior to implementing any control measures in Ethiopia.
KW - Apparent prevalence
KW - Ethiopia
KW - bovine tuberculosis
KW - emerging dairy belts
KW - incidence rate
KW - positive reactors removal
KW - risk factors
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U2 - 10.1017/S0950268821000480
DO - 10.1017/S0950268821000480
M3 - Article
C2 - 33622436
AN - SCOPUS:85101585626
SN - 0950-2688
VL - 149
JO - Epidemiology and Infection
JF - Epidemiology and Infection
M1 - e69
ER -