Pioneering study of tuberculosis in rhino

Ilse Bigalke of Stellenbosch University's Faculty of Medicine and Health Sciences describes a recent detailed study of the prevalence of bovine tuberculosis in rhinoceros populations in the Kruger National Park.

- Ilse Bigalke

The largest study ever to be conducted on a free-ranging population of rhinoceros has revealed that one in every seven rhino in the Kruger National Park (KNP) is infected with Mycobacterium bovis, the pathogen that causes bovine tuberculosis (TB).

The study was conducted by Stellenbosch University's (SU) Animal Tuberculosis (TB) Research Group, South African National Parks (SANParks), and the San Diego Zoo Wildlife Alliance in the US.

The researchers tested samples from 437 rhino collected from 2016 to 2020 in the KNP, and found an estimated prevalence of M. bovis infection of 15,4% in black and white rhino populations in the park. While these results are worrying, the evidence provided by the study is crucial to the effective conservation of the already vulnerable rhino population.

In addition to this, scientists with the Animal TB Research Group, situated within SU's Faculty of Medicine and Health Sciences, have developed a novel diagnostic test to detect M. bovis in rhino, which will greatly aid conservation efforts.

INFECTED, BUT ASYMPTOMATIC

The researchers emphasise that the presence of infection does not mean that the animals are diseased or dying. Prof Michele Miller, who leads the Animal TB Research Group and is the National Research Foundation's research chair in animal TB, says their research shows that most of the rhino can contain the infection if they are otherwise healthy.

"It can be compared with humans who are infected with COVID-19 or have latent TB, but are asymptomatic. The infected rhino are harbouring the bacteria, but their immune systems are keeping it in check. They're not losing weight or coughing, and if you look at a group of 400 rhino, you won't be able to pick out those that are infected. They can potentially live for years with infection if it is contained."