22nd September 2020
A sudden massive die-off among elephants in Botswana has been pinned on toxins created by algae common in South African dams.
The Botswana government recorded 330 dead elephants and said that the toxic algae were found in the watering holes that they visited.
"Mortality event characteristics and the field, clinical, postmortem, histopathological, and laboratory findings suggest the elephants died from neurotoxic cyanobacterium (blue-green alga) toxicosis associated with a toxic bloom of cyanobacterium in seasonal pans in the region," Botswana's Department of wildlife and national parks acting director Cyril Taolo told The Tshwana Times.
As to why the cyanobacteria only affected elephants remain to be answered but, evidence that fits the neurological symptoms observed in elephants and the cyanobacteria explains why the deaths stopped when seasonal drinking holes dried up.
Botswana has thus revealed the intent to test watering holes for the toxic algae to prevent a repeat event in the future.
The same mission could be more difficult to achieve in South Africa, where 50% of the country's dams host the same blue-green algae that killed off elephants and can affect humans.
The cyanobacteria thrive off warm, nutrient-rich water fed by sewage or fertilizer run-off from farmlands.
This makes it difficult to get rid of the algae once it has established itself in a water body and its presence makes treating the water for human consumption difficult.