Understanding the impact of Bovine Tuberculosis on lion populations in Kruger National Park

The Minister of Forestry, Fisheries, and the Environment, Dr. Dion George, has responded to growing concerns about the prevalence of Bovine Tuberculosis (BTb) among lions in Kruger National Park (KNP). 

The issue was raised following statements from Wildlife Ranching South Africa.

According to reports, BTb prevalence in the park’s lion population varies across regions, with the southern region reporting infection rates ranging from 37% to 70.5%, the central region showing a range of 18% to 78%, and the northern region having infection rates between 0% and 41%. 

Despite these varying rates, George confirmed that BTb does not pose a significant threat to the lion population’s overall viability. 

"Lions are resilient and adapt by shifting their prey preferences," George said, emphasising that prey biomass, rather than disease prevalence, plays a more crucial role in their survival. 

He added that while early predictions suggested a potential long-term decline in the lion population due to BTb, these forecasts have not come to pass. 

"Lions have been able to adapt their diet, preferring buffalo and kudu, and the transmission of BTb within the lion population is unsustainable without repeated infections from prey."

The exact number of lions dying annually from BTb remains unknown, but George stated that these deaths are not significant enough to affect the park’s overall lion population. "Lions currently occupy most of the available habitat in the park," he explained. 

He said in response to suggestions of introducing captive-bred lions to bolster the population, South African National Parks (SANParks) firmly rejected this idea, affirming that there is no need for additional lions in KNP.

The Minister also referred to the last significant decline in lion numbers, which occurred between 1974 and 1975.

During this period, 62 lions were culled as part of a study on the blue wildebeest population, prompted by a sharp drop in wildebeest numbers due to the fencing of KNP’s western boundary, which blocked wildebeest migration routes.

Isaac Phaala, spokesperson for Kruger National Park, echoed George’s sentiment, explaining that while BTb remains a concern, the lion population in the park is healthy and growing, as reflected in the latest census figures. 

"BTB is not negatively affecting the viability of the lion population, as the animals have developed a tolerance to the disease, allowing them to live longer."

He also highlighted that prey availability plays a more significant role in lion survival than disease prevalence. 

"The latest census shows an increase in all plains game populations, ensuring an adequate food source for the lions." 

With a growing lion population, Phaala assured that "food availability is not a concern."

Regarding the management of BTb, Phaala explained that KNP is managed as naturally as possible, given the park's vast two-million-hectare area. 

"KNP is being managed as naturally as possible, with its vast two-million-hectare area encompassing diverse topographies," he said. 

"Trying to vaccinate or manage BTB is not only going to be impossible but extremely expensive."

Instead, he noted, SANParks focuses on monitoring the disease, capturing lions for specimen collection when opportunities arise, and using these findings to guide conservation efforts.

For conservation efforts, understanding lion numbers is crucial. Alison Govaerts, a doctoral student at Stellenbosch University, is leading efforts to count lion populations in the central regions of KNP. 

This census, in collaboration with the Endangered Wildlife Trust (EWT) and SANParks, aims to gather essential data to guide future conservation strategies.

"We must know how many lions there are and where they are," Govaerts explained.

"Once we have this data, we can focus on connectivity between parks to ensure gene flow and allow for adaptation to climate changes and prey fluctuations."

Although lion populations across Africa are generally in decline, areas like KNP have shown stability. 

Govaerts stressed the importance of regularly monitoring lion populations to prevent irreversible declines, stating, "If we don’t engage surrounding communities, our conservation efforts won’t succeed."

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