Scientists from South Africa and Pakistan have pooled their expertise in an effort to understand why more than 350 elephants in Botswana have died in just two months.

The research team comprises Assistant Professor Dr Shahan Azeem of the University of Veterinary and Animal Sciences in Lahore, Pakistan; Dr Roy Bengis, retired Chief State Veterinarian of the Kruger National Park; Professor Rudi van Aarde, Emeritus Professor and Conservation Ecology Chair at the University of Pretoria’s (UP) Department of Zoology and Entomology; and Professor Armanda Bastos, Head of the Department of Zoology and Entomology at UP and an affiliate of UP’s Centre for Veterinary Wildlife Studies.

Their commentary – titled “Mass die-off of African elephants in Botswana: pathogen, poison or a perfect storm?” – was published this week in the African Journal of Wildlife Research. “The article attempts to identify possible causes of these deaths and is a result of Dr Azeem initiating the commentary out of concern that a similar event could affect Asian elephants,” said Prof Bastos.

Image by Professor Rudi van Aarde.

Botswana has reported the death of 350 African elephants (Loxodonta africana) in just two months, sparking speculation among conservationists and the public around the cause. Carcasses were first found in the Okavango Panhandle region. There are now reports that these deaths could be attributed to a naturally occurring toxin, but there are no definite answers. The team has not been directly involved in the research into the deaths, with samples being tested by other scientists in Zimbabwe, the USA and at UP’s Faculty of Veterinary Science.

“The die-off in Botswana has broader implications because elephant populations are heterogenous – some countries have many, whereas others have very few, and will not withstand the loss of so many animals,” Dr Azeem explained. “Without definite answers around the cause of these deaths, it is not clear whether mitigation is necessary or possible in Botswana, and it will not be possible to prevent future mass deaths.”

Although the loss of so many elephants is small in comparison to the total number of elephants in Botswana  – which is estimated to be about 130 000 – Prof Van Aarde cautions that there is a risk of localised elephant extinction if a die-off of similar scale were to occur elsewhere. “This is because elephant numbers differ substantially by region, country and even within a country. More than 50% of African elephants occur in the southern Africa region.”

Prof Bastos explained that the elephant population in the Kruger National Park is about 20 000, whereas there are about 600 elephants in Addo Elephant National Park in the Eastern Cape. “A die-off of similar scale could be ‘absorbed’ in Kruger, but would be devastating for Addo. It is therefore urgent that the cause of the current die-off is identified so that conservationists are better prepared, as it is the only way to prevent similar losses of susceptible elephants elsewhere.”

Image by Professor Rudi van Aarde.

In the paper, the team observes that the death of the elephants in Botswana “was indiscriminate in line with their age and gender, while death for some was sudden as elephants were found collapsed forward onto their chests, tusks in the ground, rather than on their sides”.

What distinguishes these deaths from past mortalities is that they occurred in an area that is inhabited by elephants, humans and livestock, rather than in a protected area, leading to initial speculation that direct human action was the cause. However, elephant carcasses were found with tusks intact and no other species were affected, making malicious poisoning and poaching unlikely. This led to suggestions in the media that either disease, environmental bio-intoxication or starvation could be to blame. All of this was considered by the researchers in their commentary, together with indirect human effects that are specific to the Seronga area. This area is artificially high in elephant densities due to fencing, as well as crops that concentrate elephants and rodents to the same area.

They point out that anthrax infection has been ruled out as the cause of death. “It is unlikely to be the cause of the current mass elephant die-offs, as clinical signs that are consistent with anthrax, including haemorrhagic discharge from body orifices, were not reported in these elephants,” Dr Bengis explained. “Furthermore, the carcasses of other species were not found during the outbreak.”

Starvation was also an unlikely cause as northern Botswana experienced late heavy rains and bumper crops.

The team is calling for thorough and speedy epidemiological studies to explore disease transmission dynamics in local environmental settings, along with in-depth laboratory investigation. “We desperately need an answer to this so that we can recognise the ‘clues’ faster if there is a next time, identify appropriate preventative steps and implement these rapidly so that the loss is not on the scale seen in Botswana,” said the scientists.

Image by Professor Rudi van Aarde.

They stress that local communities have an important role to play in rapid response to wildlife losses/crises. “Scientists cannot do this alone. The future of wildlife conservation relies on local community engagement and integration into conservation plans.” The team recommends that government and non-governmental organisations assist in investigating the deaths by working with local communities to find fresh carcasses for sampling and “to assist with sampling of possible reservoirs of infection, such as rodents and mosquitoes”.

Only once contributing factors to the cause of the mass death of Botswana’s elephants have been established will it become clear whether this is a self-limiting, non-contagious/contagious agent, or an epidemic, they said.