Immunization Advancement for Lethal Elephant Viral Disease

Scientists have achieved a major advance in creating a novel vaccine to combat a fatal virus that targets young elephants.

The inoculation, developed by an international research team, aims to stop the serious disease caused by EEHV, which is presently a primary cause of death in juvenile Asian elephants.

In tests that involved adult elephants at Chester Zoo, the vaccine was found to be harmless and, importantly, to stimulate components of the body's defenses that assists in fighting viruses.

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

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

Devastating Impact

EEHV has had a especially destructive effect in captive environments. At Chester Zoo alone, seven young elephants have succumbed to it over the last decade. It has also been found in wild elephant herds and in some refuges and elephant orphanages.

It causes a haemorrhagic disease - unchecked bleeding that can be deadly within 24 hours. It results in death in more than 80% of instances in juvenile elephants.

Understanding the Threat

Why EEHV can be so dangerous is still unknown. Numerous adult elephants host the virus - apparently with no negative impact on their well-being. But it is thought that young elephants are particularly vulnerable when they are being transitioned from milk, and when the immune-boosting defenses from the maternal nutrition decrease.

At this phase, a young elephant's immune system is in a delicate balance and it can become overwhelmed. "It may lead to extremely serious disease," a lead conservation scientist explained.

"It does affect elephants in nature, but we lack an precise count of how many fatalities in overall it has resulted in. For elephants in captivity though, there have been more than 100 deaths."

Vaccine Development

The research team, led by veterinary scientists, developed the novel vaccine using a tried and tested "scaffold". Basically, the core design of this vaccine is identical to one commonly employed to vaccinate elephants against a virus called cowpox.

The scientists seeded this immunization framework with components from EEHV - harmless parts of the virus that the elephant's immune system might recognise and react against.

In a world-first trial, the team tested the new vaccine in three fit, adult elephants at Chester Zoo, then examined blood samples from the innoculated animals.

The lead researcher stated that the findings, released in a scientific journal, were "better than we had hoped for".

"They showed, unequivocally that the vaccine was effective to stimulate the production of T cells, that are vital to fighting virus attacks."

Future Steps

The subsequent phase for the scientists is to test the vaccine in younger elephants, which are the animals most at risk to serious illness.

The present immunization involves four injections to be administered, so another aim is to work out if the same protective dose can be provided in a more straightforward way - perhaps with fewer jabs.

The conservation scientist explained: "Ultimately we aim to employ this vaccine in the elephants that are in danger, so we want to ensure that we can deliver it to where it's needed."

The project lead continued: "We believe this is a significant advancement, and not just only for the elephants, but because it additionally shows that you can design and use vaccines to assist endangered species."