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Scientists have achieved a breakthrough in creating a novel immunization to combat a deadly virus that targets juvenile elephants.

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

In tests that included adult elephants at the facility, the vaccine was found to be harmless and, crucially, to stimulate part of the immune system that assists in fighting viruses.

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

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

Severe Consequences

EEHV has had a particularly devastating effect in captive environments. At Chester Zoo alone, multiple young elephants have died to it over the last decade. It has additionally been detected in natural populations and in certain sanctuaries and elephant orphanages.

It causes a haemorrhagic disease - unchecked bleeding that can be fatal within a day. It leads to death in more than 80% of instances in young elephants.

Understanding the Threat

Why EEHV can be so lethal is still unclear. Many mature elephants host the virus - apparently with no negative impact on their well-being. But it is believed that juvenile elephants are especially vulnerable when they are being weaned, and when the immune-boosting antibodies from the maternal nutrition decrease.

At this stage, a calf's natural defenses is in a delicate balance and it can become overpowered. "It can cause really severe illness," a lead conservation scientist explained.

"It does affect elephants in nature, but we don't have an exact number of how many deaths in total it has caused. For elephants in human care though, there have been over a hundred 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 vaccinate elephants against a virus called a related virus.

The researchers incorporated this immunization framework with proteins from EEHV - non-infectious parts of the virus that the elephant's defense system might recognise and respond to.

In a pioneering experiment, the team tested the novel vaccine in several fit, adult elephants at the zoo, then analysed blood samples from the innoculated animals.

The lead researcher commented that the findings, released in a research publication, were "better than we had hoped for".

"They showed, clearly that the vaccine was able to stimulate the production of immune cells, that are vital to combating virus attacks."

Next Phases

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

The current vaccination involves four shots to be given, so an additional objective is to determine if the same effective dose can be provided in a simpler way - possibly with fewer injections.

Dr Edwards explained: "In the end we want to use 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."

Prof Steinbach added: "We think this is a significant step forward, and not just only for the elephants, but because it additionally demonstrates that you can design and use vaccines to assist threatened animals."