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

The inoculation, produced by an international research team, aims to prevent the severe disease caused by EEHV, which is currently a leading cause of death in young Asian elephants.

In trials that involved mature elephants at Chester Zoo, the vaccine was found to be safe and, crucially, to activate part of the immune system that assists in fighting viruses.

A lead scientist described this as "a pivotal step in our efforts to protect Asian elephants".

It is anticipated that the result of this pioneering trial will pave the way to averting the deaths of young elephants from the harmful disease caused by this virus.

Severe Consequences

EEHV has had a especially devastating impact in captive environments. At Chester Zoo alone, seven young elephants have succumbed to it over the last decade. It has additionally been found in wild elephant herds and in certain sanctuaries and care centers.

It causes a haemorrhagic disease - uncontrolled hemorrhaging that can be fatal within 24 hours. It results in death in more than 80% of cases in juvenile elephants.

Understanding the Threat

Why EEHV can be so lethal is still unclear. Many mature elephants carry the virus - seemingly with no adverse effects on their health. But it is thought that juvenile calves are particularly susceptible when they are being transitioned from milk, and when the protective antibodies from the mother's milk decrease.

At this stage, a young elephant's immune system is in a precarious state and it can become overwhelmed. "It may lead to really severe disease," a lead conservation scientist explained.

"It impacts wild elephants, but we don't have an precise count of how many fatalities in overall it has resulted in. For elephants in human care however, there have been more than 100 deaths."

Vaccine Development

The research team, led by veterinary scientists, developed the new vaccine using a proven "scaffold". Basically, the core design of this vaccine is identical to one routinely used to immunise elephants against a virus called a related virus.

The researchers seeded this vaccine structure with components from EEHV - non-infectious parts of the virus that the elephant's defense system might identify and respond to.

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

The lead researcher stated that the findings, published in a research publication, were "better than we had hoped for".

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

Future Steps

The subsequent phase for the researchers is to test the vaccine in younger elephants, which are the creatures most vulnerable to severe illness.

The present immunization requires four injections to be administered, so an additional objective is to determine if the same protective amount can be provided in a more straightforward way - perhaps with less injections.

Dr Edwards explained: "In the end we want to use this vaccine in the elephants that are in danger, so we want to ensure that we can deliver it to where it's necessary."

The project lead continued: "We believe this is a significant advancement, and not necessarily solely for the elephants, but because it additionally demonstrates that you can design and use vaccines to help threatened animals."