April 10, 2013
Why Do Koalas Get Chlamydia?
Michael Harper for redOrbit.com — Your Universe Online
Blame it on their small stature. Blame it on their soft fur. For what could be a myriad of reasons, Koalas would almost certainly win the “Most Cuddly” award amongst all of the familiar marsupials.
Sadly, like all other creatures — cute and ugly alike — Koalas also have a tendency to get sick from time to time. According Dr. Adam Polkinghorne and a host of researchers with Queensland University of Technology (QUT), these small creatures are even susceptible to diseases such as Chlamydia and the Koala Retrovirus, or KoRV.
For years it has been a mystery why some Koalas catch these diseases and some do not. Now, Dr. Polkinghorne and a team of researchers have discovered what they´re calling the “holy grail” of genetic data which explains the immune system of these beloved marsupials. The research was carried out in conjunction with The Australian Museum and is the world´s first project to map the Koala genome.
Professor Peter Timms, another QUT researcher, says discovering the koala interferon gamma (IFN-g) gene could both explain why some koalas become vulnerable to these diseases.
"We know koalas are infected with various strains of Chlamydia, but we do not know why some animals go on to get severe clinical disease and some do not," said Professor Timms in a statement explaining their findings.
"We also know that genes such as IFN-g are very important for controlling chlamydial infections in humans and other animals. Identifying these in the koala will be a major step forward in understanding and controlling diseases in this species.”
Before the QUT team could begin mapping out the Koala´s genes, they first needed access to several tissues from a specimen.
The researchers found this tissue in Birke, a Koala who had recently been put down after an unfortunate run-in with a local dog. It was in Birke´s tissues that the researchers found the so-called genetic holy grail. In addition to locating the IFN-g gene, they were also able to uncover the sequences of some 390 other immune-related genes, providing them with a wealth of data.
These immune related genes only made up about 1.8 percent of the total tissue samples from Birke but were still able to shed light on how koalas are able to protect themselves against pathogens.
"Virtually nothing is known about the immune system of the koala and the absence of information has been a major hindrance to our efforts to understand how Chlamydia and KoRV infections lead to such debilitating disease in this native species," said Dr. Polkinghorne.
Now that they have this information at their disposal, the research team has created a molecular test that can measure the expression of IFN-g in a Koala´s blood stream. With this test, scientists will be able to understand which koalas are more likely to stand up to diseases like Chlamydia and KoRV. Dr. Polkinghorne and professor Timms have already begun to test the koalas in the Australia Zoo Wildlife Hospital who are suffering from ocular and reproductive health issues.
Professor Timms is already putting their findings to good use working on a Chlamydia vaccine. This vaccine will be sent out to koalas in South East Queensland.
This wealth of data will also benefit a number of other creatures from Down Under. The wolverine, for instance, shares many of the same genetic sequences with koalas. Professor Timms has said that while this isn´t surprising, it is good news for biologists working in the field who want to protect as many animals as possible.
"This promises to benefit gene discovery and the development of immunological tools that will help us to fight diseases in our other threatened and endangered wildlife species."
Dr. Polkinghorne, Professor Timms and the rest now plan to hold a workshop to discuss the best ways to analyze this new data and better protect the cute and cuddly koala.