DNA research aims to give insight into bovine TB
WORLD TB Day is marked on March 24, and throughout this month Stellenbosch University will be highlighting this important issue.
Tuberculosis in humans is a wellknown disease. Less well known, but equally severe, is TB that occurs in cattle and wildlife, called bovine TB (BTB).
Unlike TB in humans, which is mostly confined to the developing world, BTB is a worldwide problem.
In South Africa BTB threatens not only the wildlife and farming industries, but may also be transmitted to humans that consume infected animal products.
“This is particularly concerning in areas with a high HIV prevalence, as people with HIV are at a much higher risk of contracting TB,” says Dr Nikki le Roex, a molecular biologist with Stellenbosch University’s Faculty of Medicine and Health Sciences (FMHS).
Although the African buffalo is the species most commonly affected by BTB in South Africa, it has also been detected in baboons, leopards, cheetah, impala, kudu, warthogs and lions.
“The existence of BTB in our country could result in major economic, ecological and public health impacts, on other wildlife species as well as the surrounding livestock and farming communities,” says Le Roex.
In cattle and African buffalo, BTB is transmitted between members of a herd through inhalation (breathing, coughing and sneezing), and infection may cause weight loss, fever, coughing and a general decline in health.
Predators become infected either by eating infected prey or through transmission during prey capture.
Buffalo may develop lung lesions, but their symptoms are less pronounced or absent while other species, such as lions, become very ill and may even die.
“Lions can be severely and fatally infected by BTB, and as a key predator species this may have consequences for the ecosystem,” says Le Roex.
In an effort to address the issue of BTB, researchers at Stellenbosch University are looking at why some buffalo become infected with BTB, while others in the same herd don’t.
For this they are examining the DNA of individual animals to determine whether their genetic makeup plays a role in whether the animal is resistant or susceptible to the disease.
According to Professor Eileen Hoal-Van Helden, also with the FMHS Division of Molecular Biology and Human Genetics, this type of investigation could reveal valuable information about susceptibility and resistance to this disease.
“Investigating the DNA to find what makes some buffalo more susceptible could enable us to find and perhaps select animals that are more resistant to disease,” says Hoal-Van Helden.
Stassen is a journalist for the Faculty of Medicine and Health Sciences at the Stellenbosch University.