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Researchers have achieved a major advance in developing a new immunization to prevent a deadly virus that targets young elephants.

The vaccine, developed by an global scientific group, aims to stop the severe illness caused by elephant endotheliotropic herpesvirus (EEHV), which is currently a leading cause of death in young Asian elephants.

In tests that included adult elephants at the facility, the vaccine was found to be harmless and, crucially, to stimulate part of the immune system that assists in fighting viruses.

A lead scientist called this as "a landmark moment in our work to protect Asian elephants".

It is anticipated that the result of this pioneering trial will open the door to preventing the fatalities of juvenile elephants from the harmful disease caused by this virus.

Severe Consequences

EEHV has had a especially devastating effect in captive environments. At Chester Zoo alone, multiple young elephants have died to it over the last decade. It has additionally been found in natural populations and in some refuges and elephant orphanages.

It causes a bleeding disorder - uncontrolled bleeding that can be deadly within 24 hours. It leads to death in more than 80% of cases in young elephants.

Understanding the Threat

Why EEHV can be so lethal is still unclear. Many adult elephants host the virus - apparently with no negative impact on their health. But it is thought that young elephants are particularly vulnerable when they are being transitioned from milk, and when the immune-boosting defenses from the mother's milk decrease.

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

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

Vaccine Development

The scientific group, headed by veterinary scientists, created the new vaccine using a proven "framework". Basically, the core design of this vaccine is the same to one routinely used to vaccinate elephants against a virus called cowpox.

The researchers seeded this immunization framework with proteins from EEHV - non-infectious parts of the virus that the animal's immune system might recognise and react against.

In a pioneering trial, the team evaluated the new vaccine in three healthy, mature elephants at the zoo, then examined blood samples from the innoculated animals.

Prof Steinbach commented that the findings, published in a research publication, were "more successful than anticipated".

"The results demonstrated, unequivocally that the vaccine was effective to stimulate the generation of T cells, that are vital to combating viral infections."

Future Steps

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

The present immunization involves multiple injections to be administered, so an additional objective is to determine if the same effective dose can be provided in a simpler way - perhaps with fewer jabs.

Dr Edwards explained: "Ultimately we aim to employ this vaccine in the elephants that are in danger, so we need to ensure that we can get it to where it's necessary."

Prof Steinbach added: "We believe this is a significant advancement, and not just only for the elephants, but because it additionally shows that you can design and apply vaccines to help threatened animals."