Scientists are vaccinating wild koalas against chlamydia IG News

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as it happens6:01Scientists are vaccinating wild koalas against chlamydia

Scientists are trying to save koalas from a disease that is making their lives miserable and threatening the very existence of their species.

Researchers in Australia have developed a chlamydia vaccine specially formulated for furry marsupials, and they’re hoping it will help stop the mass spread of the sexually transmitted disease.

In an ambitious new field trial, which began in March, they are vaccinating wild koalas in the state of New South Wales.

“Koalas are an iconic Australian species,” said Samuel Phillips, a molecular biologist at the University of the Sunshine Coast who helped develop the vaccine. as it happens Host Neil Koksal.

“They do a lot not only for Australian tourism, but also for the maintenance of the bush. They help clear leaves to stop a lot of wildfires from spreading. They really help the ecosystem of Australian forests.” are important in.”

a species in danger

Koalas may appear, at first glance, to lead lives of leisure. They sleep more than 20 hours a day, and spend many of their waking hours perched on treetops chewing eucalyptus leaves.

But in reality, being a koala is not easy. As of 2022, they are listed as Endangered in Eastern Australia. And last year an Australian government inquiry found that without urgent action to protect them, they could be extinct in New South Wales by 2050.

They face habitat loss from development and wildfire. They are often hit by cars or attacked by dogs.

But one of their biggest threats is chlamydia, which can lead to blindness, widespread infertility and fatal kidney failure.

In New South Wales alone, about 80 percent of koalas are infected with the disease, according to Matthew Crowther, a conservation biologist at the University of Sydney who monitors the condition in koala populations.

A bespectacled man in a lab coat smiles at what looks like a stack of silver-colored pills and test tubes in a glass container.  His nametag reads: "Sam"
Samuel Phillips poses for a photo in the lab where he is making vaccine doses for wildlife vaccine trials at the University of the Sunshine Coast. (Ton Stewart / Samuel Phillips / The Associated Press)

The origin of chlamydia in koalas has not been confirmed, but many scientists suspect that they initially caught it from exposure to feces from infected sheep and cattle. It is now transmitted sexually, or passed from mother to child.

But their unique biology makes them resistant to treatment.

“Koalas are exceptionally good at detoxification agents, including antibiotics. So we have to give doses up to four times that of a normal animal, and longer doses,” Phillips said.

“It wipes out the koala’s microbiome in their gastrointestinal tract, which is really important to koalas. They use the bacteria in their gut to detoxify the eucalyptus leaves and also help with digestion. This Without the bacteria, they starve to death.”

catch, kill and release

So instead of trying to cure chlamydia in sick koalas, scientists are now trying to prevent it in healthy ones. And they have already had some luck.

Phillips said veterinarians at Wildlife Rescue Centers in Queensland have already successfully tested the single-shot vaccine on a few hundred koalas that were brought in because of other afflictions.

But there are limits to that approach. Because the critters were often treated for multiple conditions, Phillips says it’s been hard to properly monitor vaccine effectiveness.

“Just vaccinating the koala [brought into] Wildlife hospitals only vaccinate about two percent of koalas,” he said. “And we estimate that we need to get at least 20 to 40 percent of the koala population vaccinated to at least reduce the disease.”

A koala in a tree, squinting at a leaf with its eyes squinting.
Chlamydia is one of the many threats koalas face every day. (Mark Baker / The Associated Press)

So this time, they are aiming to eat up to half the koalas in the Northern Rivers region of New South Wales. That’s about 50 animals.

Researchers use binoculars to find koalas in eucalyptus trees, then build circular enclosures around the base of the trees, with doors leading to the cages. After a few hours or days, koalas will eventually hop from tree to tree in search of tasty leaves, and wander into harmless nets.

After checking the animals to make sure they are in good condition, the researchers administer anesthesia, inject them, then monitor them for 24 hours after they wake up to confirm there are no unexpected side effects.

Each vaccinated koala is marked with pink paint to ensure they are not trapped more than once, as well as microchips and ear tags, to track their progress over time.

“We’ve done a bit of modeling to show that hopefully if we vaccinate 50 per cent of the population, we can achieve a 70 per cent reduction in chlamydia infection rates within these cols,” Phillips said.

look | Koala downgraded from vulnerable to endangered:

Koala declared endangered in eastern Australia

Australia’s much-loved koalas have been moved from a vulnerable species to an endangered species as disease and habitat loss threaten their survival.

If it works, the vaccine could not only help boost the koala population in Australia, but also dramatically reduce their suffering.

Chlamydia can infect koalas’ eyes, leaving them blind and unable to climb trees to find food or escape predators. It can also infect their urogenital tract, causing bacterial infection, inflammation of the bladder or kidney failure.

Female koalas often develop cysts on their ovaries and become infertile.

Rebecca Johnson, chief scientist at the Smithsonian’s National Museum of Natural History in Washington, DC, previously led the Koala Genome Consortium in Australia. He told The Associated Press that seeing the effects of the disease up close was heartbreaking.

A necropsy of a koala with advanced chlamydia that had been euthanized found “ovaries completely enclosed in cysts” and “intestines filled with hard lumps of food, evidence that she had not digested food properly”. Could,” she said.

“She was clearly barren and in pain.”