Researchers Identify Cause of Enigmatic Elephant Deaths in Zimbabwe

An extensive investigation carried out by international scientific organizations has delved into the perplexing deaths of 35 African elephants in Zimbabwe, shedding light on a potential connection to a bacterium known as Bisgaard taxon 45, which has been linked to lethal septicaemia. This revelation underscores the escalating perils confronting African elephants, an already endangered species, and underscores the urgency of further research to unravel the root causes behind these fatalities, ultimately safeguarding the species from extinction.

It appears that a bacterium associated with severe septicemia may be accountable for the demise of six African elephants in Zimbabwe, with the possibility of affecting others in neighboring nations. This development has added infectious diseases to the ever-expanding roster of challenges confronting African elephants, a species that is perilously close to the brink of extinction.

In-Depth Examination

During this exceptional study, a collaborative effort involving scientists from the Victoria Falls Wildlife Trust, the Animal and Plant Health Agency UK, the University of Surrey, and laboratories in South Africa scrutinized the enigmatic deaths of 35 elephants, predominantly occurring between August and September 2020, within a 40 x 25 km radius in north-western Zimbabwe. This distressing incident followed the tragic demise of approximately 350 elephants in northern Botswana from May to June 2020, a disconcerting event that reverberated across international conservation circles.

African savanna elephants, with a mere 350,000 individuals remaining in the wild, are currently classified as an endangered species, experiencing ongoing losses estimated at a staggering eight percent annually. The implications of this discovery are profoundly disconcerting, as elephants already find themselves on the International Union for Conservation of Nature’s red list. Consequently, a thorough investigation into the causes behind these elephant deaths is imperative to ensure the continued existence of this majestic species.

Challenges on the Path to Understanding

Lead Investigator, Dr. Chris Foggin, a Wildlife Veterinarian at the Victoria Falls Wildlife Trust, remarked, “The investigation into this mortality in the wildlife areas of north-west Zimbabwe posed formidable challenges. The identification and timely access to carcasses for obtaining valuable samples are recurring obstacles in this line of work.”

He further added, “Moreover, the specific disease responsible for these deaths remained unknown initially, though we harbored suspicions of anthrax, a known presence in the region, or potentially another ailment with potential human health risks. Consequently, we exercised prudence while conducting post-mortem examinations on these colossal creatures, a feat in itself, especially considering the field conditions.”

Findings and Their Implications

Numerous postmortem examinations were meticulously conducted. The hypothesis of poaching was swiftly discarded, primarily due to the intact tusks of all the deceased elephants. Comprehensive toxicological analyses, encompassing immediate cyanide testing—a method occasionally employed for elephant poaching in Zimbabwe—alongside more sophisticated analyses conducted in the UK, unveiled no traces of poisons either in the elephant carcasses or near waterholes frequented by many of these animals.

Subsequent examinations undertaken by veterinarians and scientists revealed a septicaemic infection attributed to an obscure bacterium provisionally identified as Bisgaard taxon 45, an unclassified member of the Pasteurellaceae bacterial family, in six elephants. This identification was substantiated through bacterial isolation and genetic analysis. It’s worth noting that Pasteurella bacteria have previously been implicated in the sudden deaths of wild animals such as antelope, though their role in elephant fatalities was previously unsuspected.

Head of Virology at the Animal and Plant Health Agency (APHA), Professor Falko Steinbach, remarked, “The identification of this bacterium marks a significant stride in our quest to comprehend the reasons behind these elephant deaths, and I am gratified to have been part of the APHA team that corroborated these pivotal findings.”

He added, “Given the highly social nature of elephants and the potential link between this infection and the stress induced by extreme weather events like drought, which may heighten the likelihood of outbreaks, transmission of the bacterium cannot be ruled out. Further research is imperative to glean additional insights into the bacterium’s characteristics and its long-term implications for the African elephant population and other wildlife.”

Dr. Arnoud van Vliet, Senior Lecturer in Veterinary Microbiology at the University of Surrey, highlighted, “The international composition of our research team underscores the opportunities for conservation investigations into the diseases and deaths of free-ranging animals. Bisgaard taxon 45 has never been previously associated with bacterial septicaemia, adding yet another disease-related threat to elephant conservation.”

Reference: “Pasteurella sp. associated with fatal septicaemia in six African elephants” by Chris M. Foggin, Laura E. Rosen, Marijke M. Henton, Angela Buys, Toby Floyd, Andrew D. Turner, Jonathan Tarbin, Antony S. Lloyd, Columbas Chaitezvi, Richard J. Ellis, Helen C. Roberts, Akbar Dastjerdi, Alejandro Nunez, Arnoud H. M. van Vliet, and Falko Steinbach, 25 October 2023, Nature Communications. DOI: 10.1038/s41467-023-41987-z.

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More about Elephant Deaths

• Nature Communications Article: The original research article titled “Pasteurella sp. associated with fatal septicaemia in six African elephants” published in Nature Communications.
• Victoria Falls Wildlife Trust: The organization involved in the investigation of the elephant deaths in Zimbabwe.
• Animal and Plant Health Agency UK: The UK agency that played a role in the research and verification of findings.
• University of Surrey School of Veterinary Medicine: The institution where Dr. Arnoud van Vliet, one of the researchers, is affiliated.
• International Union for Conservation of Nature (IUCN): The organization that classifies and monitors the conservation status of species, including African elephants.