Poster Presentation 64th International Conference of the Wildlife Disease Association 2015

Occurrence of the Koala Retrovirus (KoRV) and Chlamydia pecorum in the Mount Lofty Ranges koala population (#141)

Jessica Fabijan 1 , Nishat Sarker 2 , Gregory Simmons 2 , Courtney Waugh 3 , Adam Polkinghorne 3 , Peter Timms 3 , Wayne Boardman 1 , Farhid Hemmatzadeh 1 , Katherine Natasha Speight 1 , Darren Trott 1
  1. School of Animal and Veterinary Science, The University of Adelaide, Roseworthy, South Australia, Australia
  2. School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
  3. Faculty of Science, Health, Education and Engineering, The University of the Sunshine Coast, Maroochydore, Queensland, Australia

Two key infectious pathogens of koalas (Phascolarctos cinereus) are the koala retrovirus (KoRV) and Chlamydia pecorum. High KoRV viraemia is associated with lymphoid neoplasia and immuno-compromise in infected koalas, leading to secondary infections with opportunistic pathogens such as Chlamydia, which cause ocular, respiratory and urogenital tract disease.

Both pathogens are highly prevalent in eastern Australian populations, however the prevalence in the South Australian Mt Lofty Ranges koala population is unknown and thought to be low. This study identified the occurrence of KoRV and C. pecorum in the Mt Lofty Ranges and whether there is an association between KoRV and Chlamydia.

Blood samples were collected prior to euthanasia from 21 euthanised koalas submitted for necropsy. Haematology and KoRV status as determined by PCR were assessed. Dry swabs of the conjunctiva and urogenital sinus were collected for chlamydial detection using Clearview Chlamydia MF test and q-PCR. An additional 10 samples were collected from hospitalised koalas that were released.

The occurrence of KoRV-provirus was 77.4% (24/31) with 12.5% of affected koalas having lymphoma (3/24). Chlamydia pecorum was identified at32.3% (10/31) with half of these koalas showing clinical disease (5/10) and the remainder subclinical carriage (5/10). Reproductive tract disease was the most common presentation of chlamydial disease. A trend towards significant association was identified between KoRV and Chlamydialinfection(P=0.083).

The high occurrence of KoRV and chlamydial infection in rescued koalas indicates these pathogens are significant in the Mt Lofty Ranges koala population, requiring further investigation to determine the true prevalence in this population.