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Researchers have achieved a major advance in developing a new vaccine to combat a deadly virus that affects young elephants.

The inoculation, developed by an international research team, aims to prevent the serious illness caused by elephant endotheliotropic herpesvirus (EEHV), which is currently a leading cause of death in young Asian elephants.

In trials that included adult elephants at Chester Zoo, the vaccine was found to be harmless and, importantly, to activate part of the immune system that helps fighting viruses.

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

It is hoped that the result of this pioneering study will pave the way to averting the deaths of young elephants from the harmful condition caused by this virus.

Severe Consequences

EEHV has had a particularly devastating effect in zoos. At Chester Zoo by itself, seven baby elephants have died to it over the last decade. It has also been detected in wild elephant herds and in some refuges and care centers.

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

Comprehending the Danger

Why EEHV can be so lethal is remains unclear. Numerous adult elephants carry the virus - apparently with no adverse effects on their health. But it is thought that juvenile calves are particularly vulnerable when they are being weaned, and when the immune-boosting defenses from the maternal nutrition decline.

At this stage, a young elephant's natural defenses is in a delicate state and it can become overpowered. "It can cause really severe illness," Dr Katie Edwards explained.

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

Vaccine Development

The scientific group, led by veterinary scientists, developed the novel vaccine using a tried and tested "scaffold". Essentially, the core design of this vaccine is the same to one commonly employed to vaccinate elephants against a virus called cowpox.

The researchers incorporated this vaccine structure with proteins from EEHV - non-infectious parts of the virus that the elephant's defense system might recognise and react against.

In a pioneering trial, the team tested the new vaccine in several fit, mature elephants at the zoo, then analysed blood tests from the vaccinated animals.

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

"The results demonstrated, clearly that the vaccine was able to stimulate the generation of immune cells, that are vital to combating virus attacks."

Next Phases

The subsequent phase for the researchers is to test the vaccine in more juvenile elephants, which are the creatures most vulnerable to serious disease.

The current immunization involves four injections to be administered, so another aim is to determine if the equivalent effective amount can be provided in a more straightforward way - perhaps with fewer jabs.

The conservation scientist explained: "In the end we aim to use this vaccine in the elephants that are at risk, so we need to ensure that we can get it to where it's needed."

The project lead added: "We think this is a significant advancement, and not necessarily solely for the elephants, but because it also demonstrates that you can develop and apply vaccines to assist endangered species."