Rare Bacterium Behind Elephant Deaths In Botswana And Zimbabwe

In a significant breakthrough, scientists have determined the cause behind the tragic deaths of 350 elephants in Botswana’s Okavango Delta and 35 more at the bordering Hwange National Park and Victoria Falls in Zimbabwe in 2020. The findings, recently published in the esteemed Nature Communications journal, reveal that the fatalities in Zimbabwe were due to fatal septicaemia associated with Bisgaard taxon 45, an unnamed close relative of Pasteurella multocida.

Early in the investigation, poaching and deliberate poisoning were ruled out as potential causes. Infectious diseases, environmental poisoning, and increasing habitat stress due to ongoing drought and climate change were also dismissed. The researchers meticulously analyzed elephant carcasses and environmental samples, ruling out cyanobacterial or other intoxication. Instead, they discovered evidence of bacterial septicaemia akin to haemorrhagic septicaemia caused by Pasteurella multocida.

It’s worth noting that Pasteurella multocida had been previously suspected in the deaths of elephants in Botswana and Zimbabwe. This bacterium had also been responsible for the demise of 200,000 Kazakh antelopes in Kazakhstan in 2018 and can affect various animals, including cattle, buffalo, and chickens.

The presence of this bacteria in the Kavango-Zambezi (KAZA) transfrontier region, encompassing Zimbabwe, Botswana, Angola, Zambia, and Namibia, is deeply concerning. This area houses Africa’s largest elephant population, estimated at 227,900 as of 2022, with 58% residing in Botswana and 29% in Zimbabwe—both countries where the bacteria was detected.

Bisgaard taxon 45, the unidentified relative of Pasteurella multocida, represents a new phenomenon, presenting novel avenues of research for scientists. The source of infection and the route of transmission remain unknown, leading researchers to suspect that prior cases in the KAZA region might have been misdiagnosed as anthrax.

However, the research team faced bureaucratic challenges during their investigation in Zimbabwe and Botswana, hindering timely analysis. Delays in acquiring permits and sample transportation could have contributed to the delay in identifying Bisgaard taxon 45.

This discovery adds to the numerous health challenges threatening Southern Africa’s elephant population, including tuberculosis, anthrax, elephant endotheliotropic herpesvirus, encephalomyocarditis virus, floppy trunk syndrome, and malicious poisoning. Understanding these threats is essential for preserving the region’s iconic elephant population and ensuring their long-term survival.