TY - JOUR
T1 - Evaluation of the Efficacy of BCG in Protecting Against Contact Challenge With Bovine Tuberculosis in Holstein-Friesian and Zebu Crossbred Calves in Ethiopia
AU - The ETHICOBOTS consortium
AU - Bayissa, Berecha
AU - Sirak, Asegedech
AU - Worku, Adane
AU - Zewude, Aboma
AU - Zeleke, Yemisrach
AU - Chanyalew, Mahlet
AU - Gumi, Balako
AU - Berg, Stefan
AU - Conlan, Andrew
AU - Hewinson, R. Glyn
AU - Wood, James L.N.
AU - Vordermeier, H. Martin
AU - Ameni, Gobena
N1 - Funding Information:
This work was funded by the Biotechnology and Biological Sciences Research Council, the Department for International Development, the Economic and Social Research Council, the Medical Research Council, the Natural Environment Research Council, and the Defense Science and Technology Laboratory, under the Zoonoses and Emerging Livestock Systems (ZELS) program, ref: BB/L018977/1. JW was supported by The ALBORADA Trust. RH holds a Sêr Cymru II Research Chair funded by the European Research Development Fund and Welsh Government. SB, RH, and HV were also funded by Defra, UK, ref: TBSE3294. The funding bodies had no direct role in the design of the study and collection, analysis, and interpretation of data and in writing the article.
Funding Information:
The authors are grateful to the management of Aklilu Lemma Institute of Pathobiology (ALIPB) and Addis Ababa University (AAU) and the members of the Ethiopia Control of Bovine Tuberculosis Strategies (ETHICOBOTS) project at ALIPB. In addition, the authors acknowledge the individuals and institutions that positively contributed to the success of this research project including the National Animal Health Diagnostic and Investigation Center (NAHDIC). The members of the Ethiopia Control of Bovine Tuberculosis Strategies (ETHICOBOTS) consortium are as follows: Abraham Aseffa, Adane Mihret, Bamlak Tessema, Bizuneh Belachew, Eshcolewyene Fekadu, Fantanesh Melese, Gizachew Gemechu, Hawult Taye, Rea Tschopp, Shewit Haile, Sosina Ayalew, and Tsegaye Hailu, all from Armauer Hansen Research Institute, Ethiopia; Rea Tschopp from Swiss Tropical and Public Health Institute, Switzerland; Adam Bekele, Chilot Yirga, Mulualem Ambaw, Tadele Mamo, and Tesfaye Solomon, all from Ethiopian Institute of Agricultural Research, Ethiopia; Tilaye Teklewold from Amhara Regional Agricultural Research Institute, Ethiopia; Solomon Gebre, Getachew Gari, Mesfin Sahle, Abde Aliy, Abebe Olani, Asegedech Sirak, Gizat Almaw, Getnet Mekonnen, Mekdes Tamiru, and Sintayehu Guta, all from National Animal Health Diagnostic and Investigation Centre, Ethiopia; James Wood, Andrew Conlan, and Alan Clarke, all from Cambridge University, UK; Henrietta L. Moore and Catherine Hodge, both from University College London, UK; Constance Smith at University of Manchester, UK; R. Glyn Hewinson, Stefan Berg, Martin Vordermeier, and Javier Nunez-Garcia, all from Animal and Plant Health Agency, UK; Gobena Ameni, Berecha Bayissa, Aboma Zewude, Adane Worku, Lemma Terfassa, Mahlet Chanyalew, Temesgen Mohammed, and Yemisrach Zeleke, all from Addis Ababa University, Ethiopia. Funding. This work was funded by the Biotechnology and Biological Sciences Research Council, the Department for International Development, the Economic and Social Research Council, the Medical Research Council, the Natural Environment Research Council, and the Defense Science and Technology Laboratory, under the Zoonoses and Emerging Livestock Systems (ZELS) program, ref: BB/L018977/1. JW was supported by The ALBORADA Trust. RH holds a S?r Cymru II Research Chair funded by the European Research Development Fund and Welsh Government. SB, RH, and HV were also funded by Defra, UK, ref: TBSE3294. The funding bodies had no direct role in the design of the study and collection, analysis, and interpretation of data and in writing the article.
Publisher Copyright:
© Copyright © 2021 Bayissa, Sirak, Worku, Zewude, Zeleke, Chanyalew, Gumi, Berg, Conlan, Hewinson, The ETHICOBOTS Consortium, Wood, Vordermeier and Ameni.
PY - 2021/7/22
Y1 - 2021/7/22
N2 - Bovine tuberculosis (bTB) is prevalent in intensive dairy farms in Ethiopia. Vaccination could be an alternative control approach given the socio-economic challenges of a test-and-slaughter control strategy. The efficacy of the BCG was evaluated on 40 Holstein-Friesian (HF) and zebu crossbred calves recruited from single intradermal cervical comparative tuberculin (SICCT) test negative herds and randomly allocated into two groups. Twenty-two calves were vaccinated within 2 weeks of age, and 18 were kept as a control. Six weeks post-vaccination, the two groups were exposed and kept mixed with known SICCT test positive cows for 1 year. Immune responses were monitored by interferon gamma (IFN-γ) release assay (IGRA), SICCT test, and antibody assay. Vaccinated calves developed strong responses to the SICCT test at the sixth week post-vaccination, but did not respond to ESAT-6/CFP-10 peptide antigen-based IGRA. During the exposure, IFN-γ response to the specific peptide cocktail [F(2.44, 92.67) = 26.96; p < 0.001] and skin reaction to the specific proteins cocktail [F(1.7, 64.3); p < 0.001] increased progressively in both groups while their antibody responses were low. The prevalence of bTB was 88.9% (95% CI: 65.3–98.6) and 63.6% (95% CI: 40.7–83.8) in the control and vaccinated calves, respectively, based on Mycobacterium bovis isolation, giving a direct protective efficacy estimate of 28.4% (95% CI: −2.7 to 50.1). The proportion of vaccinated calves with lesion was 7.0% (34/484) against 11.4% (45/396) in control calves, representing a 38% (95% CI: 5.8–59.4) reduction of lesion prevalence. Besides, the severity of pathology was significantly lower (Mann–Whitney U-test, p < 0.05) in vaccinated (median score = 2.0, IQR = 0–4.75) than in control (median score = 5, IQR = 3.0–6.25) calves. Moreover, survival from M. bovis infection in vaccinated calves was significantly (log-rank test: χ2 = 6.749, p < 0.01) higher than that of the control calves. In conclusion, the efficacy of BCG was low, but the reduced frequency and severity of lesion in vaccinated calves could suggest its potential role in containing onward transmission.
AB - Bovine tuberculosis (bTB) is prevalent in intensive dairy farms in Ethiopia. Vaccination could be an alternative control approach given the socio-economic challenges of a test-and-slaughter control strategy. The efficacy of the BCG was evaluated on 40 Holstein-Friesian (HF) and zebu crossbred calves recruited from single intradermal cervical comparative tuberculin (SICCT) test negative herds and randomly allocated into two groups. Twenty-two calves were vaccinated within 2 weeks of age, and 18 were kept as a control. Six weeks post-vaccination, the two groups were exposed and kept mixed with known SICCT test positive cows for 1 year. Immune responses were monitored by interferon gamma (IFN-γ) release assay (IGRA), SICCT test, and antibody assay. Vaccinated calves developed strong responses to the SICCT test at the sixth week post-vaccination, but did not respond to ESAT-6/CFP-10 peptide antigen-based IGRA. During the exposure, IFN-γ response to the specific peptide cocktail [F(2.44, 92.67) = 26.96; p < 0.001] and skin reaction to the specific proteins cocktail [F(1.7, 64.3); p < 0.001] increased progressively in both groups while their antibody responses were low. The prevalence of bTB was 88.9% (95% CI: 65.3–98.6) and 63.6% (95% CI: 40.7–83.8) in the control and vaccinated calves, respectively, based on Mycobacterium bovis isolation, giving a direct protective efficacy estimate of 28.4% (95% CI: −2.7 to 50.1). The proportion of vaccinated calves with lesion was 7.0% (34/484) against 11.4% (45/396) in control calves, representing a 38% (95% CI: 5.8–59.4) reduction of lesion prevalence. Besides, the severity of pathology was significantly lower (Mann–Whitney U-test, p < 0.05) in vaccinated (median score = 2.0, IQR = 0–4.75) than in control (median score = 5, IQR = 3.0–6.25) calves. Moreover, survival from M. bovis infection in vaccinated calves was significantly (log-rank test: χ2 = 6.749, p < 0.01) higher than that of the control calves. In conclusion, the efficacy of BCG was low, but the reduced frequency and severity of lesion in vaccinated calves could suggest its potential role in containing onward transmission.
KW - Ethiopia
KW - bovine tuberculosis
KW - crossbred cattle
KW - efficacy of BCG
KW - natural transmission
UR - http://www.scopus.com/inward/record.url?scp=85112665190&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85112665190&partnerID=8YFLogxK
U2 - 10.3389/fvets.2021.702402
DO - 10.3389/fvets.2021.702402
M3 - Article
AN - SCOPUS:85112665190
SN - 2297-1769
VL - 8
JO - Frontiers in Veterinary Science
JF - Frontiers in Veterinary Science
M1 - 702402
ER -