It is almost that time again, time to bring attention to the several million people who die from tuberculosis each year, and the subsequent impact on their families and community. World Tuberculosis Day is March 24th, commemorating the day that Robert Koch announced the discovery of the cause of tuberculosis, Mycobacterium tuberculosis. At times like these, I’m never sure if advocacy groups intend for the public to celebrate the occasion, or simply pay attention to the issue and leverage the publicity for action. So, my personal answer to the question “Do you celebrate World TB Day?” is no. I do not. Instead, I thought I would share the HALI team’s approach to addressing the problem of tuberculosis in Tanzania, and highlight what action is already underway.
Tuberculosis is an ancient disease, one that has afflicted humans since communities began to aggregate in larger groups. But tuberculosis does not just infect humans. TB is zoonotic, and there are a variety of Mycobacterium strains that are infectious to animals and people. In East Africa, one of these strains, Mycobacterium bovis, can infect and cause disease in wildlife, livestock, and people. In cattle, it is often recognized through abortions, or when animals are slaughtered for food by the presence of lesions in bodily tissues, sometimes the lungs or spleen. But M. bovis infection is rare in humans, unless you live in close proximity to animals and rely on them for your livelihood.
Throughout East Africa, communities like the Maassai, Turkana, Sukuma, Barabaig, and Dinka continue to practice traditional livestock husbandry, which for these pastoralist groups is characterized by a nomadic or semi-nomadic livestock production system reliant on extensive grazing and flexible movement of herds and households to available water sources and pasture. In these communities, risks for transmission of M. bovis from animal to people is especially high, as infection occurs when the bacterium is ingested, often through unpasteurized milk or raw or undercooked meat.
HALI has been working with pastoralists in the Ruaha ecosystem of Tanzania to better understand how animals and people are infected with M.bovis and other strains of TB, and how best to prevent exposure and disease in animals and people. Through a ‘healthy herds make healthy people’ approach, the project worked at first to understand the prevalence and transmission pathways of tuberculosis to cattle herds in the area, and investigated the underlying socio-economic challenges influencing household health and livelihoods.
Watch HALI’s field team test cattle for TB…
With a better understanding of the transmission dynamics behind tuberculosis in herds, HALI researchers then began investigating wildlife and environmental sources of infection, by collecting and analyzing samples from water and soil. Working with a team led by Elizabeth Wellington at the University of Warwick, new methods for detecting TB in the environment are now being investigated and validated. Concurrently, through funding from the National Institutes of Health, Goodluck Paul is leading a new effort to better understand TB transmission dynamics between herds and households through a partnership with the Tanzania National Institute of Medical Research and the University of California, San Francisco. This partnership is a true One Health collaboration, with medical doctors and veterinarians teaming up in the field and visiting pastoralist bomas. The teams are testing both animals and people for exposure to TB, research that when combined with the environmental transmission pathways research, will help inform better strategies to combat TB infection in animals and people and reduce the overall TB burden in the Ruaha area.
For more information on HALI’s NIH project or tuberculosis research, please contact the HALI team.
To learn more about World Tuberculosis Day, please visit USAID’s Global Health World TB Day site.
Click on the link to download USAID’s full FY2010 Report to Congress on the Global TB Context [PDF, 2.2MB].