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Scientists have achieved a breakthrough in developing a new vaccine to prevent a deadly virus that targets juvenile elephants.

The inoculation, developed by an global scientific group, is designed to prevent the serious illness caused by elephant endotheliotropic herpesvirus (EEHV), which is currently a primary cause of death in juvenile Asian elephants.

In tests that involved mature elephants at Chester Zoo, the vaccine was found to be harmless and, crucially, to activate part of the immune system that helps fighting viruses.

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

It is hoped that the outcome of this first-of-its-kind trial will pave the way to averting the fatalities of juvenile elephants from the dangerous condition caused by this virus.

Devastating Impact

EEHV has had a particularly destructive effect in zoos. At one facility alone, multiple baby elephants have died to it over the last decade. It has additionally been detected in natural populations and in some refuges and elephant orphanages.

It causes a bleeding disorder - uncontrolled bleeding that can be deadly 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 still unknown. Numerous mature elephants host the virus - seemingly with no negative impact on their health. But it is thought that young elephants are especially susceptible when they are being weaned, and when the immune-boosting antibodies from the mother's milk decrease.

At this stage, a young elephant's natural defenses is in a delicate state and it can become overwhelmed. "It can cause extremely serious illness," a lead conservation scientist explained.

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

Immunization Creation

The scientific group, led by veterinary scientists, created the new vaccine using a proven "framework". Essentially, the core design of this vaccine is identical to one commonly employed to vaccinate elephants against a virus called cowpox.

The researchers incorporated this vaccine structure with components from EEHV - harmless bits of the virus that the animal's defense system might recognise and react against.

In a world-first trial, the team tested the new vaccine in several healthy, mature elephants at Chester Zoo, then analysed blood tests from the innoculated animals.

Prof Steinbach commented that the findings, published in a scientific journal, were "more successful than anticipated".

"They showed, clearly that the vaccine was able to stimulate the production of immune cells, that are vital to fighting viral infections."

Future Steps

The next step for the scientists is to test the vaccine in younger elephants, which are the creatures most at risk to serious disease.

The current vaccination requires four injections to be administered, so another aim is to work out if the same protective dose can be given in a simpler way - possibly with less jabs.

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

Prof Steinbach added: "We think this is a major step forward, and not just solely for the elephants, but because it also demonstrates that you can develop and apply vaccines to help threatened animals."