Todayโs path rounds are on ๐๐ก๐ฅ๐๐ฆ๐ฒ๐๐ข๐จ๐ฌ๐ข๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ก๐ฅ๐๐ฆ๐ฒ๐๐ข๐จ๐ฌ๐ข๐ฌ is infection with ๐๐ก๐ฅ๐๐ฆ๐ฒ๐๐ข๐, a species of bacteria. Youโve probably heard of Chlamydia in people!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
While Chlamydia affects many species, today weโre going to talk about Chlamydia in koalas. Chlamydiosis is actually the most common infectious disease of koalas, and has a significant impact on the survival of the species.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Most cases of chlamydiosis in koalas are caused by ๐๐ก๐ฅ๐๐ฆ๐ฒ๐๐ข๐ ๐ฉ๐๐๐จ๐ซ๐ฎ๐ฆ, which is present in almost all free-ranging koala populations. In fact, some studies have shown that some groups of koalas have up to 100% of the population infected! Thankfully, not all koalas infected with the bacteria will show symptoms. This bacteria, similar to the human bacteria, is ๐ฌ๐๐ฑ๐ฎ๐๐ฅ๐ฅ๐ฒ ๐ญ๐ซ๐๐ง๐ฌ๐ฆ๐ข๐ญ๐ญ๐๐, but can also be passed to young koalas during birth or through the milk of the mother.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Chlamydia likes to live within cells, causing the immune system to target those cells for destruction to try and control the infection. This can lead to tissue damage. In particular, Chlamydia targets the ๐ฎ๐ซ๐จ๐ ๐๐ง๐ข๐ญ๐๐ฅ ๐ญ๐ซ๐๐๐ญ and the ๐๐จ๐ง๐ฃ๐ฎ๐ง๐๐ญ๐ข๐ฏ๐ (mucosa around the eye). Female koalas can develop ๐ฉ๐ฒ๐จ๐ฆ๐๐ญ๐ซ๐ (pus in the uterus), ๐ฆ๐๐ญ๐ซ๐ข๐ญ๐ข๐ฌ (infection of the uterus wall) and other infections. Male koalas can get infections of the testicles and prostate. These infections can be fatal in some cases. The conjunctiva typically shows redness and swelling, called ๐๐จ๐ง๐ฃ๐ฎ๐ง๐๐ญ๐ข๐ฏ๐ข๐ญ๐ข๐ฌ.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Typically the findings of conjunctivitis or urogenital infection are sufficient to diagnose the bacteria in koalas. However, if the veterinarian wants to confirm the diagnosis, they can do ๐๐๐ to detect the bacterial DNA directly.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐? ๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ๐๐?
Typically koalas are treated with antibiotics, particularly ๐๐จ๐ฑ๐ฒ๐๐ฒ๐๐ฅ๐ข๐ง๐. There is also a Chlamydia vaccine that has just entered the trial stage, designed to help reduce the severity of infection and allow the koala a better chance of survival.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-3) Examples of koalas with conjunctivitis from Chlamydia.
4) The uterus of a koala with pyometra, showing the severe expansion of the uterus with pus.
5) Little blue dit-dots of Chlamydia within some cells scraped off the conjunctiva.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Terio, KA, McAloose, D, St. Leger, J. Pathology of Wildlife and Zoo Animals. 2018.
Photos 1-5 ยฉ Noahโs Arkive contributors King, Rebar licensed under CC BY-SA 4.0.
