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

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

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

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

It is anticipated that the result of this pioneering study will open the door to averting the fatalities of juvenile elephants from the dangerous disease caused by this virus.

Devastating Impact

EEHV has had a especially devastating impact in zoos. At Chester Zoo by itself, seven young elephants have died to it over the last decade. It has also been detected in natural populations and in some sanctuaries and care centers.

It causes a bleeding disorder - uncontrolled bleeding that can be deadly within 24 hours. It leads to death in more than 80% of instances in young elephants.

Understanding the Threat

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

At this stage, a calf's immune system is in a precarious state and it can become overpowered. "It can cause really severe disease," Dr Katie Edwards explained.

"It does affect elephants in nature, but we lack 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."

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 commonly employed to vaccinate elephants against a virus called a related virus.

The scientists seeded this immunization framework with proteins from EEHV - non-infectious parts of the virus that the animal's immune system might recognise and react against.

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

The lead researcher stated that the findings, published in a research publication, were "more successful than anticipated".

"They showed, unequivocally that the vaccine was able to stimulate the production of immune cells, that are crucial to fighting virus attacks."

Next Phases

The next step for the researchers is to test the vaccine in younger elephants, which are the animals most at risk to serious illness.

The current vaccination requires multiple shots to be given, so another aim is to work out if the equivalent protective dose can be given in a more straightforward way - perhaps with fewer jabs.

Dr Edwards 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 necessary."

Prof Steinbach added: "We believe this is a major advancement, and not just solely for the elephants, but because it also shows that you can design and use vaccines to help threatened animals."