Botswana: Mysterious Elephant Deaths Caused by Cyanobacteria

Toxins produced by microscopic algae in the water caused the previously inexplicable deaths of hundreds of elephants in Botswana, wildlife officials say.

Botswana is home to a third of Africa’s declining elephant population.

The alarm arose when elephant carcasses were seen in the country’s Okavango Delta between May and June.

Authorities say a total of 330 elephants are now known to have died from ingesting cyanobacteria. Poaching has been ruled out as a cause of death.

Cyanobacteria are toxic bacteria that can appear naturally in standing water and sometimes grow into large flowers known as blue-green algae.

Scientists warn that climate change may be making these incidents, known as toxic blooms, more likely because they favor hot water.

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The findings come after months of testing in specialized laboratories in South Africa, Canada, Zimbabwe and the United States.

Many of the dead elephants were found near watering holes, but until now wildlife authorities had doubted bacteria were to blame because flowers appear on the edges of ponds and elephants tend to drink from the environment.

“Our latest tests have found that cyanobacterial neurotoxins are the cause of deaths. These are bacteria found in water,” Department of Wildlife and National Parks Chief Veterinary Officer Mmadi Reuben said at a conference Monday. press.

The deaths “ceased at the end of June 2020, coinciding with the drying of [water] pans “, AFP quotes him.

Reports from June noted that the tusks had not been removed, meaning that poaching was not considered a likely explanation.

Anthrax poisoning has also been ruled out, according to senior wildlife department official Cyril Taolo.

But questions remain about the deaths, Reuben told reporters.

“We still have a lot of questions to answer, like why only elephants and why only that area. We have a number of hypotheses that we are investigating.”

Hundreds of bodies were detected with the help of aerial reconnaissance earlier this year.

Dr Niall McCann of the UK-based charity National Park Rescue previously told the BBC that local conservationists first alerted the government in early May after they took a flight over the delta. .

“They detected 169 in a three-hour flight,” he said. “Being able to see and count so many in a three-hour flight was extraordinary.”

Twenty-five elephants recently died in a group in neighboring Zimbabwe. Test samples have been sent to the UK for analysis.

Source: WHO