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

The vaccine, produced by an global scientific group, aims to prevent the severe disease caused by elephant endotheliotropic herpesvirus (EEHV), which is presently a leading cause of death in juvenile Asian elephants.

In tests that involved adult elephants at the facility, the vaccine was found to be safe and, crucially, to stimulate components of the immune system that helps combating 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 study will open the door to averting the fatalities of young elephants from the harmful disease caused by this virus.

Devastating Impact

EEHV has had a particularly devastating impact in captive environments. At Chester Zoo by itself, multiple young elephants have succumbed to it over the last decade. It has additionally been detected in natural populations and in some refuges and elephant orphanages.

It causes a haemorrhagic disease - uncontrolled bleeding that can be fatal within a day. It leads to death in over eighty percent of cases in young elephants.

Understanding the Threat

Why EEHV can be so lethal is still unknown. Many mature elephants host the virus - apparently with no adverse effects on their health. But it is thought that juvenile elephants are especially susceptible when they are being weaned, and when the protective defenses from the maternal nutrition decline.

At this stage, a calf's immune system is in a precarious balance and it can become overwhelmed. "It can cause extremely serious illness," a lead conservation scientist stated.

"It impacts elephants in nature, but we lack an exact number of how many deaths in total it has caused. For elephants in captivity however, there have been more than 100 deaths."

Vaccine Development

The research team, led by animal health experts, created the novel vaccine using a proven "scaffold". Essentially, the core design of this vaccine is identical to one routinely used to vaccinate elephants against a virus called a related virus.

The scientists incorporated this vaccine structure with proteins from EEHV - harmless bits of the virus that the elephant's immune system might identify and respond to.

In a world-first trial, the team tested the novel vaccine in several fit, mature elephants at the zoo, then analysed blood tests from the vaccinated animals.

Prof Steinbach stated that the findings, released in a scientific journal, were "better than we had hoped for".

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

Next Phases

The subsequent phase for the researchers is to try the vaccine in younger elephants, which are the animals most at risk to serious disease.

The current vaccination requires multiple shots to be given, so another aim is to determine if the same protective dose can be given in a more straightforward way - perhaps with less injections.

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

The project lead added: "We think this is a major step forward, and not just only for the elephants, but because it also shows that you can design and apply vaccines to assist threatened animals."