Vaccine Advancement for Lethal Elephant Viral Disease

Researchers have achieved a major advance in developing a novel immunization to prevent a deadly virus that targets young elephants.

The vaccine, developed by an international research team, aims to prevent the severe disease caused by EEHV, which is presently a leading cause of death in young Asian elephants.

In tests that involved mature elephants at Chester Zoo, the vaccine was found to be safe and, importantly, to activate components of the body's defenses that helps fighting viruses.

Prof Falko Steinbach described this as "a landmark moment in our work to protect Asian elephants".

It is anticipated that the outcome of this pioneering study will pave the way to averting the deaths of juvenile elephants from the dangerous disease caused by this virus.

Devastating Impact

EEHV has had a especially devastating effect in zoos. At one facility alone, seven young elephants have succumbed to it over the last decade. It has also been detected in wild elephant herds and in some sanctuaries and elephant orphanages.

It causes a haemorrhagic disease - unchecked bleeding that can be fatal within a day. It results in death in more than 80% of cases in juvenile elephants.

Understanding the Threat

Why EEHV can be so dangerous is remains unclear. Many mature elephants host the virus - apparently with no adverse effects on their health. But it is believed that juvenile elephants are particularly susceptible when they are being transitioned from milk, and when the immune-boosting antibodies from the mother's milk decrease.

At this phase, a young elephant's immune system is in a precarious state and it can become overwhelmed. "It may lead to really severe disease," a lead conservation scientist explained.

"It impacts elephants in nature, but we lack an precise count of how many deaths in total it has caused. For elephants in human care though, there have been more than 100 deaths."

Vaccine Development

The scientific group, led by animal health experts, created the new vaccine using a tried and tested "framework". Essentially, the basic structure of this vaccine is identical to one commonly employed to immunise elephants against a virus called cowpox.

The scientists incorporated this immunization framework with proteins from EEHV - non-infectious parts of the virus that the animal's immune system might identify and respond to.

In a world-first trial, the team tested the novel vaccine in three healthy, mature elephants at the zoo, then analysed blood tests from the innoculated animals.

The lead researcher commented that the results, released in a scientific journal, were "more successful than anticipated".

"They showed, clearly that the vaccine was able to stimulate the generation of immune cells, that are crucial to combating viral infections."

Next Phases

The subsequent phase for the scientists is to try the vaccine in more juvenile elephants, which are the creatures most vulnerable to severe illness.

The current immunization involves four shots to be given, so another aim is to work out if the same protective dose can be provided in a more straightforward way - possibly with fewer jabs.

Dr Edwards clarified: "Ultimately we aim to employ this vaccine in the elephants that are in danger, so we want to make sure that we can get it to where it's necessary."

The project lead continued: "We think this is a significant step forward, and not just only for the elephants, but because it additionally shows that you can develop and apply vaccines to help threatened animals."