South African rhinos face widespread tuberculosis infection, in a natural refuge where they roam free.
In October 2020, the white rhinoceros was declared functionally extinct. This is so because, due to poaching, the species has not been able to recover from human pressure. On the contrary, the same phenomenon afflicts their biological cousins: black rhinos and other African cattle.
Recently, a team from Stellenbosch University in Cape Town discovered that these animals are also susceptible to bovine tuberculosis (Mycobacterium bovis). Especially those rhinos that inhabit South Africa’s Kruger National Park (KNP), which has historically been considered a refuge for its reestablishment as a species.
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According to researchers in South Africa, the survival of the African rhinoceros depends on three main factors:poaching, habitat loss and climatic effects«, as they write for Proceedings of the National Academy of Sciences (PNAS). Now, the species faces an equally deadly obstacle: bovine tuberculosis.
Formerly, the white rhinoceros was spread in two regions, mainly: North Africa, by the savannah from the Congo, Sudan and Uganda; and to the south, between South Africa, Botswana, Zimbabwe and Namibia. However, the populations that are recovering live in a ‘controlled freedom’, inside national parks such as the KNP.
Despite the care of the rangers and scientists who support its conservation, the species faces a new obstacle. This is how the authors describe it in the study:
“Our findings confirm a high, widespread infection burden in the rhino population of Kruger National Park, South Africa, and identify risk factors for infection. These findings provide a foundation for understanding the spread of bovine tuberculosis in complex ecosystems.”
Historically, this pathogen did not infect African rhinos. On the contrary, it is only recently that the species has become infected with tuberculosis. Scientists in Cape Town are concerned that this is a significant threat to their food security and conservationaccording to the results of their field studies.
Where do these deadly infections come from?
rhinos do not live in park on their own in the KNP. On the contrary, share habitat with other threatened species. One of them, explains Michele Miller, leader of the animal tuberculosis research group and author of the study, is the American buffalo:
“Infected buffalo most likely cough periodically; in this way, your saliva and respiratory secretions contaminate vegetation and habitat. Mycobacteria are very resistant and can survive in the environment for weeks or months.”
Due to the closeness that rhinoceroses have with cattle sick with tuberculosis, it is most likely that they have acquired the infection from ‘sick hosts’, as the researchers call them. Despite the seriousness of the matter, it is very difficult to know since when it began to spread among rhinos. Miller claims that there are cases since 2016.
However, all is not lost. On the contrary, the specialist assures that it is possible that the rhinoceroses contain tuberculosis and “possibly even remove it, if they are healthy«. Despite this, he acknowledges that figuring out how they are becoming infected and how to stop the infection could take years of study.
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