Koala vaccination campaign kicks off as species battles chlamydia epidemic


This year seems to be all about vaccination, not just for humans, but also for koalas. However, they are not doing this for COVID-19.

As part of a trial, around 400 koalas will be vaccinated against chlamydia – a sexually transmitted disease (STD) also found in humans that has spread widely among furbearing animals in parts of Australia. The researchers behind the initiative hope that the deployment of the vaccine will significantly improve the survival and reproduction of the animals.

Image credit: Creative Commons.

Wild koalas can become infected with chlamydia through sexual contact, and newborns can contract it by eat porridge, a type of nutritious excreta excreted by infected mothers (yes, koalas do). It is not clear why animals are so vulnerable to disease, with previous studies suggesting a virus from the same family as the human immunodeficiency virus (HIV) could be the reason.

While humans are affected by the bacteria Chlamydia trachomatis, koalas are targeted by Chlamydia pecorum – a different ‘race’ of chlamydia, although both can cause infertility and permanent blindness if left untreated. Antibiotics used in humans may also work for koalas, but the success rate varies and some antibiotics produce harmful side effects, disrupting the koalas’ gut bacteria.

The diet of wild koalas is based on eucalyptus leaves. Although nutritious, the leaves contain a compound called tanning which can be very toxic if not broken down by gut bacteria – and antibiotics appear to be the cause of this, leaving koalas unable to process their meals. This is why new antibiotics and even a vaccine have long been sought.

Try the new vaccine

The vaccine was developed by researchers from University of the Sunshine Coast (USC) in Australia. Professor Peter Timms has spent the last decade studying the impact of chlamydia in koalas and sequencing the koala genome, which has now led to the vaccine. It has already passed phase 1 and phase 2 trials, with over 250 koalas vaccinated.

Timms maintains that the vaccine is completely safe, with a good immune response and decreased levels of chlamydia infection identified in the trials. Now, for Phase 3, the plan is to vaccinate 400 animals, starting with the Australia Zoo Wildlife Hospital, Moggill Koala Rehabilitation Center and RSPCA Wildlife Hospital, and then continuing with the animals in the wild.

“We are now at the exciting stage of being ready to deploy the vaccine in large phase 3 trials”, Timms said in A declaration. “While this vaccination will directly benefit each animal, the trial will also focus on the protection offered by vaccination. All koalas will be microchipped and the hospital will register any animals that return for any reason. “

Ambert Gillett, a veterinarian at Australia Zoo Wildlife Hospital involved in the research, said chlamydia is a “cruel disease” for koalas, causing conjunctivitis, bladder infections and infertility. Having a vaccine will go a long way in preventing infection, she added. Chlamydia is the most common reason koalas are admitted to the Australian Zoo Wildlife Hospital.

In addition to chlamydia, koalas are also threatened by global warming and deforestation. Climate change is leading to a reduction in the range of koalas in Australia due to the decrease in the number of nutritious eucalyptus leaves available. At the same time, the expansion of agriculture is forcing koalas to spend more time on the ground to move from tree to tree.


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