Koalas with chlamydia could lead to vaccine for humans
TOORBUL, AUSTRALIA >> The first sign is the smell: smoky, like a campfire, with a hint of urine. The second is the koala’s rear end: If it is damp and inflamed, with streaks of brown, you know the animal is in trouble. Jo, lying curled and unconscious on the examination table, had both.
Jo is a wild koala under the purview of Endeavour Veterinary Ecology, a wildlife consulting company that specializes in bringing sick koala populations back from the brink of disease. Vets noticed on their last two field visits that she was sporting “a suspect bum,” as veterinarian Pip McKay put it. So they brought her and her 1-year-old joey into the main veterinary clinic.
McKay already had an inkling of what the trouble might be. “Looking at her, she probably has chlamydia,” she said.
Chlamydia — a pareddown, single-celled bacterium that acts like a virus — has been especially successful, infecting everything from frogs to fish to parakeets and humans.
This shared susceptibility has led some scientists to argue that studying, and saving, koalas may be the key to developing a longlasting cure for humans. “They’re out there, they’ve got chlamydia, and we can give them a vaccine; we can observe what the vaccine does under real conditions,” said Peter Timms, a microbiologist at the University of Sunshine Coast in Queensland. He has spent the past decade developing a chlamydia vaccine for koalas and is now conducting trials on wild koalas, in the hopes that his formula will soon be ready for wider release. “We can do something in koalas you could never do in humans,” Timms said.
How bad is chlamydia in humans? Consider that about 1 in 10 sexually active teenagers in the U.S. is already infected, said Dr. Toni Darville, chief of the division of pediatric infectious diseases at the University of North Carolina. Chlamydia is the most common sexually transmitted infection worldwide, with 131 million new cases reported each year.
Antibiotics exist, but they aren’t enough to solve the problem, Darville said. That’s because chlamydia is a “stealth organism,” producing few symptoms and often going undetected for years.
“We can screen them all and treat them, but if you don’t get all their partners and all their buddies at the other high schools, you have a big spring break party, and before you know it everybody’s infected again,” Darville said.
“So they have this longterm chronic smoldering infection, and they don’t even know it. And then when they’re 28, and they’re like, ‘Oh, I’m ready to have a baby,’ everything’s a mess.”