Botswana wants to draw a line under their elephant deaths – not so fast!
Pieter Kat
21st September 2020

In a press conference today, the Deputy Director and Chief Veterinary Officer of the Botswana Department of Wildlife and National Parks presented little convincing information to support their claim that “cyanotoxins” were responsible for well over 300 elephant deaths in a limited area of northern Botswana.

Crucial evidence was not presented as to the reasons and justification for their identification of Cyanobacteria occurring in eutrophic water holes as having caused the deaths of so many elephants. Also missing was any explanation as to why it was only elephants that died (apart from a weak suggestion that elephants “drink deep” from water holes and therefore might “suck up toxins”), why the elephants that died were limited to a relatively small area of northern Botswana (the same environment and waterholes are present across wide swathes of northern Botswana). Also, there was no discussion of which laboratories were sent samples and the capabilities of those laboratories, what samples were sent, the adequacy of those samples to perform tests (condition of the samples) and the diversity of samples that were sent (blood, internal organs, brain, stomach contents, etc).

So overall the case was not adequately made, despite being picked up quickly by Al Jazeera and Bloomberg reporting basically that the “mystery” was now solved…

Determining the presence of cyanotoxins is not a simple job. Cyanobacteria comprise a great diversity of species, some of which produce cyanotoxins while others do not. Also, among those that produce cyanotoxins, they do not always do so. Additionally, the toxins produced fall into a diversity of classes with different effects on the animal that ingests them.

The symptoms seen were neurotoxic, and those toxins are produced by a relatively small small group of Cyanobacteria. Detecting the presence of these cyanotoxins requires expertise and well-equipped laboratories, and tests relying on one particular method are not always reliable.

For those interested, there is a comprehensive publication by the EU on pros, cons, difficulties and limits of tests for cyanotoxins (…/c61665a1-45ab-11e7…/language-en). Their summary is as follows:

“In this report, attention is focused on the methodologies commonly used to detect cyanotoxins in water environments. These applications can be grouped in: I) microscopy analysis II) physicochemical methods III) molecular-based methods IV) biochemical based methods V) chemical methods. Each technique shows specific limitations in terms of sensitivity, reliability and limit of detection. The choice of the best one to use is determined in accordance with the information they provide, the availability of facilities and the technical expertise of the operators. Most of the research about cyanotoxins has been mainly focused on microcystins (MCs). The other cyanotoxins have been much less investigated and more tools need to be developed to overcome this problem. Notwithstanding there is no a single analytical application able to detect all cyanotoxin variants in an environmental sample.”

Microcystins are not neurotoxic.

So overall, the Botswana government has a long way to go to convince that the highly specific mortalities among elephants were directly related to neurotoxic cyanotoxins. Access should be provided to the laboratory reports, the specific methodologies used, the reliability of those methodologies and the quality of samples provided.

See news article here:

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