About This Project

Botswana recently experienced severe, highly publicized mortality of elephant, which authorities attribute to a natural toxin. Neighboring northwest Zimbabwe, including Hwange National Park, has a similar climate and topography and holds the country’s largest elephant population. In the past, elephant have also died suddenly at waterholes in Hwange. This project aims to test seasonal waterholes for natural toxins to predict episodes of mortality and better manage this problem.

Ask the Scientists

What is the context of this research?

Zimbabwe and Botswana hold approximately 60% of remaining African savannah elephants. From March-May 2020 at least 350 elephant in Botswana died of a mysterious neurological condition attributed to a natural toxin. Most of these elephant died close to seasonal waterholes (pans). Similar, but fewer deaths have occurred close to pans in northwest Zimbabwe, but the animals are usually found too late to collect useful samples from the carcasses.

One hypothesis is that the ‘natural toxin’ may originate from harmful algal blooms (HABs) of cyanobacteria in the water in pans; also that elephant may have an unusual sensitivity to such a toxin. HABs occur in these pans because of the high organic content of the water deposited by elephant and other species that utilize this water source.

What is the significance of this project?

Finding toxins in these water bodies could provide clues on the emergence of this disease, which has the potential to threaten this critical population of an iconic African species. Zimbabwe and Botswana have limited financial and technical resources and neither country can do sophisticated analyses for natural environmental toxins: for wildlife and people. Sending samples for testing at international laboratories is almost impossible because of cost, import restrictions and the current COVID-19 pandemic.

This project would establish a relatively novel and simple diagnostic approach that is feasible in Zimbabwe and doesn’t require access to fresh carcasses. Such analysis should give a semi-quantitative assessment to authorities of whether pans are likely to prove lethal to elephant.

What are the goals of the project?

This project will set up PCR testing for genes coding for cyanobacterial toxins at the Victoria Falls Wildlife Trust Laboratory. Water and sediment samples will be collected in northwest Zimbabwe, both from pans continuously fed by borehole water and filled only by seasonal rains. At least 25 pans will be sampled during the dry season (October) and again after the rains (December/January). If available, fresh stomach contents of any elephant found dead close to such pans will be collected.

This analysis will determine if these genes are present in the pans and whether these is a difference between dry and wet season presence. Results will be correlated with the presence of elephant carcasses at the pans and also if deaths of fish, also seen in past seasons in Hwange, have occurred.