EEHV vaccine breakthrough
Learn how the elephants here at the zoo were vital to the development of the vaccine
EEHV vaccine breakthrough
Learn how the elephants here at the zoo were vital to the development of the vaccine
You may have already read about the EEHV vaccine breakthrough achieved by the team here at Chester Zoo, alongside the University of Surrey and the Animal and Plant Health Agency (APHA), but we’re about to share with you the untold story of the vaccine trial’s most important contributors – the elephants themselves and the trusted team behind-the-scenes.
Back in October, we shared the news that our six-year study involving a small group of three elephants, Aung Bo, Sundara Hi Way, and Maya, confirmed that we had found a safe and effective vaccine that could stimulate a protective immune response for the Asian elephants in our care against EEHV – a disease that can kill Asian elephants in just 24 hours.
Asian elephants are already listed as Endangered on the IUCN (International Union for Conservation of Nature) Red List, with fewer than 40,000 individuals remaining in the wild. Fatal cases of EEHV have been documented across India, Nepal, Myanmar, Thailand, and beyond - with the disease affecting both wild populations and vital conservation breeding programmes, like ours here in Chester, and in zoos worldwide.
A NEW CHAPTER
Having previously lost elephants to EEHV, and seeing Indali Hi-Way come back to full health following a rapid response and intensive treatment back in 2019, elephant conservationists around the world are celebrating the positive step forward in preventing this devastating disease from claiming more lives in the future.
With the help of the entrusted elephant team here at the zoo, the three elephants that were at the heart of this ground-breaking study showed there is a way to help the thousands of elephants across Asia and in zoos and sanctuaries across the world through this new vaccination.
A NEW CHAPTER
Having previously lost elephants to EEHV, and seeing Indali Hi-Way come back to full health following a rapid response and intensive treatment back in 2019, elephant conservationists around the world are celebrating the positive step forward in preventing this devastating disease from claiming more lives in the future.
With the help of the entrusted elephant team here at the zoo, the three elephants that were at the heart of this ground-breaking study showed there is a way to help the thousands of elephants across Asia and in zoos and sanctuaries across the world through this new vaccination.
Trust & collaboration
Completing the six-year study was very much a collaboration between our team of vets, our expert elephant team, and the elephants themselves. Working with such powerful and intelligent animals is built on trust and strong communication, which some of our keepers have been building with the elephants over decades together.
How do we hand vaccinate an elephant that can grow to over 4 tonnes?
- The actual amount required for such a large animal is relatively low at around 2-3ml per dose and only a small needle is needed to penetrate the elephant’s thick skin.
- Positive reinforcement is at the heart of the process and the team use their tried and trusted communication techniques, body language, and the use of target sticks to get the elephants into the best position.
- Working through specially designed protective barriers, the elephants receive the vaccination through their rump. Hand injections are used to create as little discomfort as possible and the elephants receive reassuring pats both before and after the injection.
- The process is completed with a favourite selection of fruit, with apples, bananas, and melons at the top of the list!
In the weeks following the vaccination, our teams were regularly monitoring and taking blood from the elephants to identify at what point the elephant’s immune system began to respond. The 'ingredients' in the vaccine focus on activating the body’s T-cells – the immune system’s 'generals' that identify and destroy infected cells. So far, we’ve proven that the vaccine was able to stimulate the elephants to produce these T-cells that are crucial to fighting off EEHV.
How do we hand vaccinate an elephant that can grow to over 4 tonnes?
- The actual amount required for such a large animal is relatively low at around 2-3ml per dose and only a small needle is needed to penetrate the elephant’s thick skin.
- Positive reinforcement is at the heart of the process and the team use their tried and trusted communication techniques, body language, and the use of target sticks to get the elephants into the best position.
- Working through specially designed protective barriers, the elephants receive the vaccination through their rump. Hand injections are used to create as little discomfort as possible and the elephants receive reassuring pats both before and after the injection.
- The process is completed with a favourite selection of fruit, with apples, bananas, and melons at the top of the list!
In the weeks following the vaccination, our teams were regularly monitoring and taking blood from the elephants to identify at what point the elephant’s immune system began to respond. The 'ingredients' in the vaccine focus on activating the body’s T-cells – the immune system’s 'generals' that identify and destroy infected cells. So far, we’ve proven that the vaccine was able to stimulate the elephants to produce these T-cells that are crucial to fighting off EEHV.
VULNERABLE CALVES
Many elephants carry the EEHV virus with no impact on their health, but it appears that elephant calves face a particularly vulnerable time while they are being weaned from their mother’s milk, and they are losing the immune-boosting antibodies they have been receiving since birth. This time is a delicate balance as the immune system is still in its infancy and can be overwhelmed.
Since the study began, a further two young elephants, Riva Hi Way and Elizabeth, have received protection through the vaccination, helping them progress through their younger, more vulnerable years as their immune system grows stronger.
As the new herd here at Chester grows and bonds in the future, the vaccination will be a key part of their care, with elephants around the world soon to have the same opportunity for protection from the deadly disease.
After witnessing the rapid decline that EEHV can cause, it feels like a really optimistic time among the team as we see the results of this study offering such hope for the future. The care and time that goes into monitoring the elephants here at the zoo, with regular trunk swabs and blood tests to test for EEHV among the herd is a vital part of the fight against this disease and the success of the vaccine is the next level of protection for the elephants.
Richard Fraser, Elephants Team Manager here at the zoo
