Botswana announced that he had discovered the cause of the deaths of hundreds of elephants in recent months: according to the results of investigations conducted by the government, the deaths were caused by toxins produced by bacteria present in the water drunk by the elephants.
Between spring and early summer 330 elephants had died in circumstances hitherto considered mysterious in northern Botswana, which is the southern African state that has the largest concentration of animals in the world. The news it had been filmed all over the world because such numbers were considered enormous for a community that was after all quite small: about 156 thousand elephants live in Botswana, and above all because it was feared that the cause of death, whatever it was, could extend and threaten the rest of the specimens.
The government announced in July that it had opened an investigation to try to explain the elephant deaths by collecting biological samples and also analyzing aerial images of the areas where the carcasses were found. In a press conference on Monday, Mmadi Reuben, veterinary officer with the Department of Wildlife and National Parks in Botswana, said the elephant’s death was caused by cyanobacteria, bacteria that carry out chlorophyll photosynthesis also known as blue algae, present in the water from which the elephants drank. Reuben explained that there are still many questions that are being answered, in particular why only elephants died and not other animals and why only in a certain area.
No other mass deaths had been recorded in the past few weeks – it seems that the surviving elephants had escaped from where the bodies were found, in the Okavango River Delta, the second largest inland river delta in the world – and the scientists had tried to understand what could have caused those identified in recent months. The hypothesis that the elephants had been killed with cyanide by ivory poachers was discarded because the dead specimens were found with their tusks still in place.
Christine Gosden, who teaches molecular medicine at the University of Liverpool, he had explained that she was interested in the case after reading about it Guardian, and had theorized that the elephant deaths were due to a neurotoxin called β-N-methylamino-L-alanine (or BMAA) produced by some algae. Gosden explained that he had noticed a certain correspondence between the strange behaviors observed in elephants shortly before they died – some specimens circled and then fell to the ground – with those of whales and dolphins that become ill due to the neurotoxin in question: “let’s talk of large mammals behaving in much the same way: they seem lost and bewildered, ”Gosden had explained. His conclusions therefore seem very similar to those of the Botswana health authorities.
Other scientists, on the other hand, were more skeptical and pointed out that BMAA is normally found in sea water, and that it was necessary to understand if the quantity present in the pools formed by the Okavango River was sufficient to kill an animal of enormous size like the elephant ( although thanks to their trunks, elephants can ingest hundreds of liters of water per day, thus potentially absorbing a significant amount of toxins). A second hypothesis considered was that the elephants had died from the virus that causes encephalomyocarditis, mainly carried by rodents. Animals of this kind could have frequented the same environments as elephants because in recent months there had been an increase in the cultivation of maize and sorghum.
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