Mysterious elephant deaths continue in Botswana

Preliminary investigations by Botswana’s Ministry of Environment, Natural Resources Conservation and Tourism into a fresh wave of elephant deaths in that country have ruled out anthrax and bacterial infections as the cause.

This follows the mysterious deaths of 39 elephants since January in the Moremi Game Reserve, according to a statement by the ministry. Poaching was also ruled out as the tusks of the elephants were found intact.

The latest deaths in the reserve occurred only months after hundreds of elephants died from ingesting toxic microorganisms. More than 300 elephant deaths had been reported near water sources in the Okavango Delta since May 2020.

The Moremi reserve lies about 100km east of Seronga, where last year’s deaths were reported.

At the time, the ministry ascribed the animals’ deaths to the ingestion of toxic microorganisms. In September 2020, it released a report that pointed to toxic microorganisms called cyanobacteria (blue-green algae) as the cause of death.

“Further laboratory analysis is ongoing. Extensive field and air investigations have not uncovered any mortality of other wildlife species within the area,” the ministry said.

Dr Markus Hofmeyr, a South African wildlife veterinarian, said at the time that it was difficult to ascertain whether the Botswana government’s diagnosis following the 2020 elephant deaths in Botswana had been accurate.

“Some of the elephants may have died from blue-green algae poisoning, but as far as I am aware no water samples were tested. It’s also extremely difficult to get a definitive diagnosis from older samples of a dead animal,” he added.

According to Hofmeyr, it was strange that no other animals had died from drinking the water. It was possible that the elephants had been exposed to a specific infectious agent and had infected each other.

Similar elephant deaths occurred in Zimbabwe at the same time. Some 25 elephant carcasses were found near water sources in that country last year, and authorities suspected the animals had succumbed to a bacterial infection.

Hofmeyr said Dr Chris Foggin, a veterinarian at the Victoria Falls Wildlife Trust, and other Zimbabwean veterinarians had managed to get fresh samples from the carcasses, which led to a more likely diagnosis of haemorrhagic septicaemia, caused by the bacteria Pasteurella hemocida.

The animals were also found with tusks intact, ruling out poaching and deliberate poisoning. Park authorities indicated that the elephants could have ingested the bacteria while searching for food. According to a report on france24.com, Foggin said that although the possibility of cyanobacteria had been considered, no evidence was found that it had caused the elephant deaths in Zimbabwe. – Annelie Coleman