The young elephant girl Indali stands here closely embraced by another baby elephant. She may already be relieved about a new vaccine against a deadly elephant herpes virus. The elephant girl from Chester Zoo in Great Britain is one of the first proboscideans to be vaccinated against the Elephant Endotheliotropic Herpesvirus (EEHV).
For the first time, an international team led by Tanja Maehr from the University of Surrey was able to show that a vaccination triggers a strong immune response in the giants. The prototype could therefore be an important step towards protecting the endangered Asian elephants. “The next step could be to test the vaccine on calves and in affected countries so we can start protecting the animals most at risk,” says Maehr.
During the vaccination, the researchers used a viral vector – a harmless virus that serves as a transport vehicle to introduce EEHV genes into the cells. These then produce certain proteins that identify the virus. The immune system can then recognize the virus from these and develop a targeted immune response. The researchers also used a booster vaccination to further strengthen the response.
To find out how well the new vaccination works, Maehr and her team analyzed the elephants’ blood counts, including using complete transcriptome sequencing. This is a method to examine all active genes in immune cells at once. This allowed the researchers to see exactly which defense mechanisms are activated by the vaccination and how the immune system reacts to the vaccine. This is the first time such systematic sequencing has been done on elephants.
Further analysis showed that the vaccination activated several antiviral defense pathways. “EEHV has claimed the lives of so many elephants, both in captivity and in the wild, but this vaccine gives hope. We can’t say yet that this will be the end of EEHV deaths, but we have taken a big step in that direction,” said Katie Edwards, senior conservation scientist at Chester Zoo.