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Scientists have made a major advance in creating a novel vaccine to prevent a fatal virus that affects young elephants.

The vaccine, developed by an international research team, is designed to stop the severe illness caused by elephant endotheliotropic herpesvirus (EEHV), which is currently a leading cause of death in young Asian elephants.

In trials that involved mature elephants at the facility, the vaccine was found to be safe and, crucially, to activate components of the immune system that helps combating viruses.

A lead scientist described this as "a landmark moment in our efforts to protect Asian elephants".

It is hoped that the outcome of this first-of-its-kind study will open the door to preventing the deaths of young elephants from the harmful disease caused by this virus.

Devastating Impact

EEHV has had a especially destructive effect in captive environments. At one facility by itself, multiple young elephants have died to it over the last decade. It has additionally been detected in natural populations and in certain refuges and elephant orphanages.

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

Understanding the Threat

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

At this phase, a calf's natural defenses is in a delicate balance and it can become overwhelmed. "It may lead to extremely serious disease," a lead conservation scientist stated.

"It impacts wild elephants, but we don't have an exact number of how many deaths in overall it has caused. For elephants in captivity though, there have been more than 100 deaths."

Vaccine Development

The research team, led by animal health experts, developed the new vaccine using a proven "framework". Essentially, the basic structure of this vaccine is identical to one routinely used to immunise elephants against a virus called a related virus.

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

In a world-first experiment, the team evaluated the new vaccine in several healthy, adult elephants at Chester Zoo, then examined blood samples from the vaccinated animals.

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

"They showed, clearly that the vaccine was effective to activate the generation of T cells, that are vital to combating virus attacks."

Future Steps

The subsequent phase for the researchers is to test the vaccine in younger elephants, which are the creatures most vulnerable to severe illness.

The current vaccination involves multiple shots to be administered, so an additional objective is to work out if the equivalent effective dose can be provided in a more straightforward way - possibly with fewer injections.

Dr Edwards clarified: "In the end we want to use this vaccine in the elephants that are at risk, so we want to make sure that we can deliver it to where it's necessary."

Prof Steinbach added: "We think this is a significant step forward, and not just solely for the elephants, but because it also shows that you can design and use vaccines to help endangered species."