Symptoms and signs of illness in koalas

If you notice behavioural anomalies in a koala, or you can see it has swollen eyes, cloudy eyes, or wet bottom, call NSW WIRES on 1300 094 737 or go online. Experienced, trained handlers will advise what should be done to assist the koala. If you are unsure if a koala needs help, it is wise to seek advice from a trained professional.

When recording a sighting on the Koala Register, a question will appear that asks if the koala is sick or injured. Your answer could be 'yes', 'no', or 'unsure'. Often the latter is the answer that comes back, however additional comments provided have helped us to identify several individuals that may actually have been in need of assistance and direct the observer to contact local wildlife carers.

While entering a 'yes' value in the response field in an observation record will not trigger Council to contact to wildlife carers, the information is of interest to see the extent of issues. It can also be a good reminder for you, as the observer, to take action and help our wildlife. You don't need to be a trained professional to know what to look for - a keen eye is all you need!

There are a range of reasons a koala may be sick, and these may manifest in sluggishness or a change in their behaviour. One of the most common causes of illness in koalas is Chlamydia, which is a sexually transmitted infection. Chlamydia can cause conjunctivitis (which may in turn result in blindness), urinary tract infections, reproductive system infections (which may in turn result in infertility), pneumonia, and death. While the infection itself or its symptoms of infertility and pneumonia cannot be easily identified by a casual observer, there are some signs that you can easily detect.

Urinary tract infections resulting from Chlamydia can cause a lack of control of the bladder, a sign known as wet bottom, which is visible as a brown discolouration on the bottom. Note, however, that koalas can frequently get a discoloured bottom from sitting on a gummy branch, or sitting in mud after a wander to a creek. If the discharge is really dark and in a broad area with some crusting from prolonged urine dripping, then help is required.

Koalas that have conjunctivitis, a common symptom of chlamydia, will have pink and swollen eyes, sometimes with discharge. Even just a slightly pink rimmed eye calls for attention. Conjunctivitis can cause blindness if not caught early, which can be seen from cloudy eyes. If a koala has become blind, then this symptom may manifest in behavioural changes such as a lack of fear response to the presence of humans, an inability to navigate climbing a tree, a tendency to stand on the ground rather than seeking height, and slower movement than usual.

While infection from chlamydia can cause the death of a koala in the wild, if caught early and treated, they can make a full recovery.

See below for some examples of the signs to look for. Please note that some of the images are graphic and may cause distress.

If the images do not appear, click the header of the article (or here) to view it in full.

A male koala emerging from a territorial fight, showing signs of wet bottom.

A male koala, nicknamed Barlaagany, was picked up by WIRES carers after showing signs of wet bottom.

A male koala, nicknamed Barlaagany, was picked up by WIRES carers after showing signs of blindness through cloudy vision, lack of fear when approached and difficulty navigating the landscape.

A male koala, nicknamed Ramornie Bob, was picked up by WIRES carers after showing signs of conjunctivitis. Ramornie Bob was later released back into the wild after a round of antibiotics.