One in seven rhinos in the Kruger National Park are infected with the pathogen that causes bovine tuberculosis, according to new research.
Scientists tested samples from 437 rhinos, collected from 2016 to 2020, and found the Mycobacterium bovis germ in 15.4% of them.
But this does not mean the animals are diseased or dying. Stellenbosch University animal TB research group leader Michele Miller said their immune systems were keeping it in check.
“They are not losing weight or coughing, and if you looked at a group of 400 rhinos you wouldn’t be able to pick out those that are infected. They can potentially live for years with infection if it is contained,” said Miller.
The study, published in the Proceedings of the National Academy of Sciences, also involved the SA National Parks (SANParks) veterinary wildlife services and San Diego Zoo Wildlife Alliance.
Senior author Carmel Witte, from San Diego, said bovine TB occurs in wildlife systems throughout the world
“In the US, spillover of infection from cattle has spread to white-tailed deer in Michigan. This, in turn, can create spillback of infection into livestock, and carries a risk of spread to other wildlife and people,” said Witte.
Miller said the research showed most of the rhinos can contain the infection if they are otherwise healthy. “It can be compared to humans who are infected with Covid-19 or have latent TB, but are asymptomatic,” she said.
Witte said that the eventual population-level health effects of bovine TB are unknown. “Continued surveillance of rhinoceros, as well as other animals, can help us understand the long-term impact of this infection in wildlife and prevent catastrophic population losses and further disease spread,” she said.
Wynand Goosen, from Stellenbosch, added: “To avoid the next pandemic in people, livestock and wildlife will have to be actively monitored for various infectious pathogens with zoonotic potential.”
The study identified proximity to buffalo herds and drought as risk factors for infection. A significant cluster of cases was detected near Mpumalanga farms on Kruger’s south-western border, where livestock herds have historically been implicated in the spillover of bovine TB to the park’s wildlife in Kruger, especially buffalo.
Kruger’s chief vet, Peter Buss, said bovine TB is prevalent in at least 15 other species in the park and the new research had significant implications for SANParks’ rhino conservation and management strategy.