Asian elephants (Elephas maximus indicus) are by far the largest land mammal on the Asian continent, measuring up to 11 feet and weighing up to 5 tons. Their habitat covers 13 countries in South and Southeast Asia, but despite a relatively large spread, they are under serious threat from poaching and habitat destruction. To make matters even worse, there’s even a deadly virus threatening them. Now, a zoo in the UK wants to address this by working on a potentially life-saving vaccine for elephants.

Together with University of Surrey researchers, the Chester Zoo has long been looking at the Elephant endotheliotropic herpesvirus (EEHV), a type of herpes virus that can cause hemorrhagic disease when transmitted to young elephants. When the virus is detected in the blood or symptoms appear, it’s usually too late to treat the disease.  

EEHV can affect any elephant, from young to adults. It’s known to have caused deaths in at least eight countries, including Nepal, Thailand, Cambodia, Laos, Myanmar, and Sri Lanka. Asian elephants are now listed are endangered by the International Union for the Conservation of Nature’s (IUCN), with all hopes placed on a vaccine solution. 

The virus has been detected in zoos, sanctuaries, safari parks, and, more worryingly, in wild elephants. A study by veterinary scientist Sonia Jesus Fontes estimated that EEHV caused 52% of the deaths of Asian elephants in European zoos since 1985. In North America, the virus was accounted to have caused 50% of the deaths since 1980. 

The team at Chester Zoo, including veterinarians, keepers, and immunologists, is now officially starting the trial of the vaccine, after long years of research. The backbone of the vaccine is the same as the one used to immunize elephants against the cowpox virus. Groups around the world have studied the EEHV virus but Chester Zoo is now taking a big step forward. 

“The only long-term solution to beating EEHV is to find a vaccine. Without zoos caring for the species it would be almost impossible to achieve that but, thankfully, we’re now making remarkable progress. The global conservation community is today a step closer to finding a viable vaccine,” Mike Jordan, head of Animals and Plants at the zoo, said in a statement. 

First steps of the vaccine

A healthy 20-year-old male elephant named Aung Bo is the first one to participate in the trials of the vaccine, with early tests showing an immune response. The trial was only possible due to the elephant’s willingness to participate. Vets test the elephants regularly for the virus, so they got used to providing blood samples on a regular basis.

Tanja Maehr, lead researcher at the University of Surrey, described this as an important moment in the team’s research, with “real optimism” to find a safe vaccine that works. While the initial results from the trials are positive, with the vaccine stimulating an immune response, these are still the early days on the road to an approved vaccine. 

“It’ll be several months until the first stage of our work to select the best candidate vaccine and determine optimal dosages and frequencies is complete. Then, if successful, further trials in zoos and in the field will need to take place to fully ascertain its efficacy,” Maehr, also a conservation fellow at the zoo, said in a statement.