Australia’s Koalas Have Chlamydia, But a New Vaccine Could Save Them

The sexually transmitted disease threatens the health of one of Australia’s iconic marsupials

two koalas
Marco Simoni/Robert Harding World Imagery/Corbis

Koalas, the marsupials best known for snacking on eucalyptus leaves and napping for up to 18 hours a day, are under threat from chlamydia. But now the fuzzy beasties have a new hope: Researchers based in Queensland have announced that they have a working vaccine.

Koalas stricken with chlamydia can become blind, infertile and die. The sexually transmitted disease has hit the koala population hard. There are an estimated 80,000 to 43,000 koalas left in the wild: according to BBC News, koala numbers have dropped by 80 percent during the past decade in some areas. (Chlamydia's not the only threat that's contributed to this drop—hunting until the late 1920s, habitat destruction and road accidents haven't helped koalas, either.)

The new vaccine has been under development for the past five years has now completed its first successful field trial. 

In their tests, the researchers fitted 60 koalas with radio collars. Half the animals received the vaccine; the other half did not. Some of those given the vaccine were already infected, and the researchers found that they did go on to develop the full symptoms of the disease. Of the eight vaccinated koalas that had eye infections, seven showed improvement. 

Three of the untreated koalas caught chlamydia. 

“It’s all very promising and it’s not just that [the vaccine is] doing the right thing from an immune response point of view, but it’s actually protecting a significant number of them out in the wild climbing around trees,” Peter Timms told The Japan Times. The paper also reports:

Timms hopes to continue the trial, such as through the possible vaccination of entire communities of koalas — about 50 to 100 animals each — in areas where they could be at risk.

Koalas temporarily admitted to sanctuaries or hospitals could also be vaccinated before they are returned to the wild.

“We hope to specifically show a positive effect of the vaccine on disease, not just infection, as well as female reproductive rates,” Timms said.

With luck, the vacccine could change those population numbers. Then we might hear the male koalas’ bellow from tree tops as frequently as they did before.

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