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Researchers have made a major advance in creating a new vaccine to combat a deadly virus that affects juvenile elephants.

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

In tests that included mature elephants at Chester Zoo, the vaccine was found to be harmless and, importantly, to activate components of the body's defenses 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 open the door to averting the fatalities of juvenile elephants from the dangerous condition caused by this virus.

Severe Consequences

EEHV has had a particularly destructive effect in captive environments. At one facility alone, seven baby elephants have succumbed to it over the last decade. It has also been detected in natural populations and in certain refuges and care centers.

It causes a bleeding disorder - unchecked hemorrhaging that can be deadly within a day. It results in death in more than 80% of instances in young elephants.

Understanding the Threat

Why EEHV can be so dangerous is still unclear. Many adult elephants carry the virus - seemingly with no negative impact on their well-being. But it is thought that young elephants are especially susceptible when they are being transitioned from milk, and when the protective defenses from the maternal nutrition decrease.

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

"It impacts wild elephants, but we lack an exact number of how many fatalities in overall it has caused. For elephants in human care however, there have been over a hundred deaths."

Immunization Creation

The research team, led by veterinary scientists, developed the new vaccine using a proven "scaffold". 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 vaccine structure with proteins from EEHV - non-infectious bits of the virus that the elephant's defense system might recognise and react against.

In a pioneering experiment, the team evaluated the new vaccine in three healthy, adult elephants at Chester Zoo, then examined blood tests from the innoculated animals.

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

"The results demonstrated, unequivocally that the vaccine was effective to activate the generation of T cells, that are crucial to fighting viral infections."

Next Phases

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

The present vaccination involves multiple shots to be administered, so another aim is to determine if the equivalent effective dose can be provided in a simpler way - possibly with fewer injections.

The conservation scientist explained: "Ultimately we want to employ 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 believe this is a major advancement, and not necessarily solely for the elephants, but because it additionally shows that you can design and apply vaccines to help threatened animals."