The Health for Animals and Livelihood Improvement (HALI) Project is engaged in the surveillance and prevention of zoonotic diseases in livestock in the pastoral communities of the Pawaga and Idodi Divisions of Iringa District, Tanzania.
HALI Coordinator, Dr. Harrison Sadiki with Mama Joshua at her home near Tungamalenga village. (Photo by D. Wolking)
HALI team members are collecting and testing livestock for the presence of zoonotic diseases. In collaboration with local slaughterhouses/slabs, traders and pastoralist groups, HALI collects tissue and blood from slaughtered cattle and small ruminants, and milk and blood and feces from live cattle, sheep and goats. These samples are cultured for bovine tuberculosis (BTB) at Sokoine University of Agriculture (SUA). Any Mycobacterium species isolated by culture has the strain type confirmed using biochemical testing and polymerase chain reaction (PCR).
At pastoralist households, we are using the single comparative intradermal skin test to test cattle for exposure to tuberculosis. Sera from livestock and wildlife are tested for exposure to bovine tuberculosis, brucellosis, leptosporosis, and toxoplasmosis. Fecal samples from adult and neonatal livestock are being examined for the presence of Cryptosporidium and Giardia.
The majority of disease testing is done by Sokoine University of Agriculture in order to continue building the University’s capacity as a leading diagnostic lab in Tanzania and to ensure that results are obtained in a timely fashion for the most rapid analysis and dissemination to stakeholders.
Maasai women running with her livestock. (Photo by P. Coppolillo)
Second, HALI team members are gathering information to determine if there are common characteristics of cattle, or households that may put them at greater risk for disease.
The HALI team talks to each household we work with about preventing disease transmission from livestock to people. We plan to use this data to assess which households, or which practices may be associated with a higher risk of disease in both livestock and people.
The subject of bovine tuberculosis transmitted to human tuberculosis is a fascinating subject. I think it is especially interesting in the study of ancient epidemiology. There has been debates as to whether “human pathogenic strains of tuberculosis’ evolved from the mutation of the more ancient strains of Mycobacterium (e.g. M.bovine). One hypothesis states that M. bovine mutated into a human pathogen when ancient nomadic civilizations began to live closely with their livestock. What really adds to the fun of this subject is that this theory is supported or disputed through preserved mummy tissue found in Egypt and Europe.
Tuberculosis is protected by a capsule which enables it to lie dormant for many years before becoming actively pathogenic. This same capsulated property has made the bacterium able to survive for thousands of years in mummy tissue. With the aid of polymerase chain reaction and DNA replication we now are able to map the mutations of the bacterium from ancient mummy tissues. This has created milestones in modern medical research and in the understanding of how Mycobacterium strains mutate and become resistant to antibiotics. Antibiotic resistance makes human tuberculosis one of the most dangerous reemerging infectious diseases. All this modern science was possible through ancient research. To me that is fascinating.
Hi Barbara – agreed that is fascinating. Thanks for your comment. Do you have any additional references regarding the bovine TB evolution hypothesis that you could recommend. I had heard this before. Thanks so much – Deana