Stellenbosch doctoral study can help prevent spreading of bovine TB in African buffalo



Published Apr 4, 2023


Cape Town – A researcher at Stellenbosch University (SU) has found an innovative way to diagnose bovine Tuberculosis (TB) in African buffalo and identify infected animals more accurately and rapidly.

Dr Charlene Clarke from the Centre of Excellence for Biomedical Tuberculosis Research in the Faculty of Medicine and Health Sciences at SU said it could help to prevent the spread of the disease in one of the continent’s most iconic and high-valued species.

“It is essential to diagnose bovine TB quicker and to accurately identify infected buffaloes early because these animals keep the disease-causing bacteria in the ecosystem, which can cause infection of other species such as lions, wild dogs, rhinos, elephants, and antelopes,” she said.

Clarke obtained her PhD in Molecular Biology last week at an SU graduation ceremony.

For her doctorate, Clarke combined molecular and immune-based tests to help improve the diagnosis of bovine.

As part of her study, Clarke collected tissue and swab samples from the mouths and noses (oronasal) of infected animals while they were immobilised.

She also collected oronasal swabs from buffaloes that tested negative for bovine TB. These swabs allowed her to identify and characterise nontuberculous mycobacteria (NTMs) species in buffaloes. All the swab samples were stored in a medium that inactivates all pathogens and stabilises the DNA, thereby rendering them safe to handle.

She said that her study is important given the factors that complicate accurate diagnosis in buffaloes, such as the confirmation of infection by mycobacterial isolation from tissue grown in a laboratory, which relies on time-consuming methods with limited sensitivity; exposure of buffaloes to more than 250 NTMs that are closely related to M. bovis; and the inappropriate interpretation of diagnostic tests.

“The presence of NTMs, for example, can cause false-positive test results which can lead to the unnecessary loss of animals due to culling, and quarantine of the farm on which ‘positive’ animals were identified.”

Going forward, there's a need to continuously improve the diagnostic tools for accurately identifying infected buffaloes at early stages of infection, before they shed bacteria and transmit it to other animals, she said.

Cape Times