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Scientists have made a breakthrough in developing a new vaccine to prevent a fatal virus that targets juvenile elephants.

The vaccine, produced by an international research team, aims to prevent the serious disease caused by 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 safe and, importantly, to stimulate part of the body's defenses that helps combating viruses.

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

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

Devastating Impact

EEHV has had a particularly devastating impact in zoos. At Chester Zoo by itself, multiple young elephants have succumbed to it over the past ten years. It has also been detected in natural populations and in certain sanctuaries and care centers.

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

Understanding the Threat

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

At this phase, a calf's immune system is in a precarious balance and it can become overwhelmed. "It may lead to extremely serious illness," Dr Katie Edwards stated.

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

Immunization Creation

The research team, led by veterinary scientists, created the new vaccine using a proven "scaffold". Essentially, the core design of this vaccine is the same to one routinely used to vaccinate elephants against a virus called cowpox.

The researchers incorporated this vaccine structure with proteins from EEHV - harmless parts of the virus that the animal's immune system might recognise and respond to.

In a pioneering experiment, the team evaluated the new vaccine in three fit, mature elephants at the zoo, then analysed blood samples from the innoculated animals.

The lead researcher commented that the results, published in a scientific journal, were "better than we had hoped for".

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

Future Steps

The next step for the researchers is to try the vaccine in more juvenile elephants, which are the animals most vulnerable to serious disease.

The present immunization requires multiple shots to be given, so an additional objective is to determine if the equivalent effective amount can be provided in a simpler way - perhaps with fewer injections.

Dr Edwards clarified: "Ultimately we aim to use this vaccine in the elephants that are at risk, so we want to ensure that we can deliver it to where it's necessary."

Prof Steinbach added: "We believe this is a major step forward, and not just only for the elephants, but because it additionally shows that you can develop and use vaccines to help endangered species."