Koalas — those adorable marsupials from Down Under — don’t seem to have much in common with people. But they’re very susceptible to the same infection that wreaks havoc in humans.

Chlamydia is the world’s most common sexually transmitted infection. In people, chlamydia can smolder in the reproductive tract for years, causing inflammation, scarring and — ultimately — infertility.

Chlamydial organisms are very similar in koalas, but infections hit them harder, causing excruciating inflammation and other urogenital trauma. As a result, chlamydia is a big reason why koala populations have plummeted by 80 percent over 20 years.

But now, researchers in Australia are conducting studies of a chlamydia vaccine in wild koalas. If trials are successful, information gathered may help to develop a similar vaccine for people.