To many it is a shock to hear that koalas can die of Chlamydia and that Chlamydia is threatening to wipe out entire populations of koalas. Chlamydia causes chronic infections in koalas, infections occurring in the urogenital and respiratory tracts, causing pneumonia, infertility, blindness and ultimately death. The visible symptoms are conjunctivitis, known as “pink eye”, and urinary tract infections causing incontinence, leading to a condition known as “dirty tail” or “wet bottom”.
The fact is that many koalas in the wild are living with Chlamydia (up to 70%). It is not until koalas become stressed and the koala’s immune system is unable to fight the virus that Chlamydia becomes dangerous, and fatal. Koalas are becoming more stressed due to habitat loss, habitat fragmentation, dogs, road trauma and bush fires. With increased urbanisation and insufficient planning, more and more koalas are now showing obvious signs of clinical Chlamydia. Koalas are especially prone to the dangers of Chlamydia when their home ranges are isolated due to fragmentation of habitat – females stop breeding and reproducing, and colonies die off.
When koalas are being monitored by scientists, they are captured briefly so that they can be given a health check for Chlamydia (and other health issues like cystitis and Koala Retrovirus, which we will talk more about later). Researchers used to wonder how koalas handled all these health issues, but now some are much more confident that koalas can look after themselves when they carry such viruses – what is definite is that koalas require healthy koala habitats and unlimited resources to maintain their immune systems, which is yet another reason why we have to rethink the way we use land in and near koala habitats.