Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia

G. A. Mekonnen; A. J.K. Conlan; S. Berg; B. T. Ayele; A. Mihret; A. Olani; H. Asgedom; J. L.N. Wood; G. Ameni; Abraham Aseffa; Bamlak Tessema; Bizuneh Belachew; Eshcolewyene Fekadu; Fantanesh Melese; Gizachew Gemechu; Hawult Taye; Rea Tschopp; Shewit Haile; Sosina Ayalew; Tsegaye Hailu; Adam Bekele; Chilot Yirga; Mulualem Ambaw; Tadele Mamo; Tesfaye Solomon; Solomon Gebre; Getachew Gari; Mesfin Sahle; Abde Aliy; Asegedech Sirak; Gizat Almaw; Mekdes Tamiru; Sintayehu Guta; Alan Clarke; Henrietta L. Moore; Catherine Hodge; R. Glyn Hewinson; Martin Vordermeier; Javier Nunez-Garcia; Berecha Bayissa; Aboma Zewude; Adane Worku; Lemma Terfassa; Mahlet Chanyalew; Temesgen Mohammed; Yemisrach Zeleke

doi:10.1017/S0950268821000480

Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia

G. A. Mekonnen, A. J.K. Conlan, S. Berg, B. T. Ayele, A. Mihret, A. Olani, H. Asgedom, J. L.N. Wood, G. Ameni, Abraham Aseffa, Bamlak Tessema, Bizuneh Belachew, Eshcolewyene Fekadu, Fantanesh Melese, Gizachew Gemechu, Hawult Taye, Rea Tschopp, Shewit Haile, Sosina Ayalew, Tsegaye HailuAdam Bekele, Chilot Yirga, Mulualem Ambaw, Tadele Mamo, Tesfaye Solomon, Solomon Gebre, Getachew Gari, Mesfin Sahle, Abde Aliy, Asegedech Sirak, Gizat Almaw, Mekdes Tamiru, Sintayehu Guta, Alan Clarke, Henrietta L. Moore, Catherine Hodge, R. Glyn Hewinson, Martin Vordermeier, Javier Nunez-Garcia, Berecha Bayissa, Aboma Zewude, Adane Worku, Lemma Terfassa, Mahlet Chanyalew, Temesgen Mohammed, Yemisrach Zeleke

Department of Veterinary Medicine

Research output: Contribution to journal › Article › peer-review

3 Citations (Scopus)

Abstract

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.

Original language	English
Article number	e69
Journal	Epidemiology and Infection
Volume	149
DOIs	https://doi.org/10.1017/S0950268821000480
Publication status	Published - 2021

Keywords

Apparent prevalence
Ethiopia
bovine tuberculosis
emerging dairy belts
incidence rate
positive reactors removal
risk factors

ASJC Scopus subject areas

Epidemiology
Infectious Diseases

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10.1017/S0950268821000480

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Mekonnen, G. A., Conlan, A. J. K., Berg, S., Ayele, B. T., Mihret, A., Olani, A., Asgedom, H., Wood, J. L. N., Ameni, G., Aseffa, A., Tessema, B., Belachew, B., Fekadu, E., Melese, F., Gemechu, G., Taye, H., Tschopp, R., Haile, S., Ayalew, S., ... Zeleke, Y. (2021). Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia. Epidemiology and Infection, 149, Article e69. https://doi.org/10.1017/S0950268821000480

Mekonnen, GA, Conlan, AJK, Berg, S, Ayele, BT, Mihret, A, Olani, A, Asgedom, H, Wood, JLN, Ameni, G, Aseffa, A, Tessema, B, Belachew, B, Fekadu, E, Melese, F, Gemechu, G, Taye, H, Tschopp, R, Haile, S, Ayalew, S, Hailu, T, Bekele, A, Yirga, C, Ambaw, M, Mamo, T, Solomon, T, Gebre, S, Gari, G, Sahle, M, Aliy, A, Sirak, A, Almaw, G, Tamiru, M, Guta, S, Clarke, A, Moore, HL, Hodge, C, Hewinson, RG, Vordermeier, M, Nunez-Garcia, J, Bayissa, B, Zewude, A, Worku, A, Terfassa, L, Chanyalew, M, Mohammed, T & Zeleke, Y 2021, 'Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia', Epidemiology and Infection, vol. 149, e69. https://doi.org/10.1017/S0950268821000480

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title = "Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia",

abstract = "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.",

keywords = "Apparent prevalence, Ethiopia, bovine tuberculosis, emerging dairy belts, incidence rate, positive reactors removal, risk factors",

author = "Mekonnen, {G. A.} and Conlan, {A. J.K.} and S. Berg and Ayele, {B. T.} and A. Mihret and A. Olani and H. Asgedom and Wood, {J. L.N.} and G. Ameni and Abraham Aseffa and Bamlak Tessema and Bizuneh Belachew and Eshcolewyene Fekadu and Fantanesh Melese and Gizachew Gemechu and Hawult Taye and Rea Tschopp and Shewit Haile and Sosina Ayalew and Tsegaye Hailu and Adam Bekele and Chilot Yirga and Mulualem Ambaw and Tadele Mamo and Tesfaye Solomon and Solomon Gebre and Getachew Gari and Mesfin Sahle and Abde Aliy and Asegedech Sirak and Gizat Almaw and Mekdes Tamiru and Sintayehu Guta and Alan Clarke and Moore, {Henrietta L.} and Catherine Hodge and Hewinson, {R. Glyn} and Martin Vordermeier and Javier Nunez-Garcia and Berecha Bayissa and Aboma Zewude and Adane Worku and Lemma Terfassa and Mahlet Chanyalew and Temesgen Mohammed and Yemisrach Zeleke",

note = "Publisher Copyright: {\textcopyright} 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.",

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doi = "10.1017/S0950268821000480",

language = "English",

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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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Dynamics and risk of transmission of bovine tuberculosis in the emerging dairy regions of Ethiopia

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