- Accelerating Bovine Tuberculosis Control in Developing Countries-Ethiopia (ABTBCD Project)
Scope: To determine the direct efficacy of BCG vaccine in cattle, onward transmission and duration of BCG vaccinal immunity and revaccination interval experimental study will be conducted on cross bred cattle. The filed performance of defined antigen skin test will be determined by cross-sectional study in dairy farms
The objective of the Project
- To develop and validate a new fit-for- purpose DIVA skin test for the detection of bovine tuberculosis infected cattle, and
- To determine the efficacy of BCG vaccination in protecting cattle against the disease and reducing onward transmission.
- To determine the duration of BCG vaccinal immunity and revaccination interval
Expected Outcome from the project
Built the capacity of AHI in terms of skilled man-power and laboratory equipment for the diagnosis of bovine tuberculosis. Established experimental animal research facility at AHI.
- The study is expected to generate scientific information on the diagnostic performance of DST as compared to the traditional Comparative Cervical Tuberculin (CCT) test.
- The study will generate scientific information about the direct efficacy of BCG and onward transmission and
- Will generate information useful to determine the duration of BCG vaccinal immunity and revaccination interval
Progress
- The experimental research on BCG efficacy and onward transmission was conducted for two years and completed. Currently the manuscript entitled on “BCG vaccination of cattle reduces transmission of bovine tuberculosis, improving the prospect of elimination” was accepted for publication on Science journal.
- The experiment on the “Duration of immunity of Bacillus Calmette–Guérin (BCG) vaccination in holstein-zebu cross breed calves under natural transmission setting and the role of revaccination in protection of bovine tuberculosis” is also completed.
- The other research to assess the field performance of defined antigen skin test (DST) was also completed. Currently the data analysis and manuscript writing in ongoing. The research title is “Evaluation of the field performance of defined antigen skin test (DST) for the diagnosis of bovine tuberculosis, a latent class analysis”
- Field assessment of the effectiveness and feasibility of implementing test-and-cull and test-and-segregation approaches at a pilot level was conducted in two government owned dairy farms for around 18 months. Currently the manuscript entitled on “Assessing the feasibility of test-and-cull and test-and-segregation approaches for the control of bovine tuberculosis in Ethiopian dairy farms” is submitted for publication
Research project implementers
Animal Health Institute (AHI), Pennsylvania State University (USA), Aklilu Lemma Institute of Pathobiology (Addis Ababa University), Armauer Hansen Research Institute (AHRI), Animal and Plant Health Agency (UK), and Cambridge University (UK)
Project start and end date: 2017-2024
Funded by: Bill & Melinda Gates Foundation and the Department for International Development (UK)
Project PI at AHI: Dr. Getnet Abie (DVM, PhD)
- BCG vaccination of cattle reduces transmission of bovine tuberculosis, improving the prospect of elimination (under ABTBCD Project)
This is ongoing research project implemented in collaboration with Pennsylvania State University of USA, Addis Ababa University Aklilu Lemma Institute of Pathobiology and Armauer Hansen Research Institute (AHRI).
The project has the following main objectives:
- To enable the development and validation of a new fit-for- purpose DIVA skin test for the detection of bTB infected cattle in Ethiopia that may be used in the future implementation of a national bTB control program.
- Determination of the safety, potency in eliciting an immune response, and efficacy of BCG in providing protection and reduction of onward transmission of M. bovis in controlled and field trials in cross-bred cattle in Ethiopia.
- To evaluate the performance of BCG re-vaccination in protecting bovine tuberculosis in Holstein-Zebu cross breed calves under natural transmission setting.
Besides, other related researches on bTB control options are also ongoing with the following objectives:
- To assess the effectiveness and feasibility of implementing test-and-cull and test-and-segregation approaches on a pilot scale in intensively raised dairy cattle settings in Ethiopia.
- To establish a “test-negative herd” with calves born from cows that are positive for bovine tuberculosis (bTB) using Bang’s Method.
Major achievements:
- The experimental research on BCG efficacy and onward transmission was conducted for two years and completed. Currently the manuscript entitled on “BCG vaccination of cattle reduces transmission of bovine tuberculosis, improving the prospect of elimination” was accepted for publication on Science journal.
- The experiment on the “Duration of immunity of Bacillus Calmette–Guérin (BCG) vaccination in holstein-zebu cross breed calves under natural transmission setting and the role of revaccination in protection of bovine tuberculosis” is also completed. Currently, remaining with culture and molecular test related works. This experiment was divided in four Batches during implementation (containing 71 calves total at the start of the experiment and 35 seeders). The animals were grouped in to three in each batche (control group, vaccinate group and Revaccinate group). The experimental study was conducted for 24 months after exposure with BTB positive seeders and the revaccinate group took the second vaccination after a year of the first vaccination. The animals were tested for IGRA and skin test every two month and four months of post exposure with seeders respectively then PM was done on all the experimental animals and the histopathology analyses was completed. Currently data analysis and manuscript writing on the immunological analyses of the experiment is ongoing.
- The other research to assess the field performance of defined antigen skin test (DST) was also completed. Currently the data analysis and manuscript writing in ongoing. The research title is “Evaluation of the field performance of defined antigen skin test (DST) for the diagnosis of bovine tuberculosis, a latent class analysis”
- Field assessment of the effectiveness and feasibility of implementing test-and-cull and test-and-segregation approaches at a pilot level was conducted in two government owned dairy farms for around 18 months. Currently the manuscript entitled on “Assessing the feasibility of test-and-cull and test-and-segregation approaches for the control of bovine tuberculosis in Ethiopian dairy farms” is submitted for publication.
- The study to establish a “test-negative herd” with calves born from cows that are positive for bovine tuberculosis (bTB) using Bang’s Method is ongoing.