Our work identified the insect that spreads the parasite Leishmania in Australia.
Leismaniasis is a devastating infection that can be fatal if left untreated.
Worldwide, leishmaniasis is an important disease of humans and other animals caused by the parasite Leishmania. Infection with Leishmania parasites can cause a range of symptoms, from ulcerative skin lesions to liver and spleen infection, and can be fatal. Australia was thought to be free of Leishmania parasites until 2003, when Leishmania infections were discovered in captive red kangaroos in the Northern Territory. Genetic analysis of the NT Leishmania revealed it was a new species, not found anywhere else in the world.
Since the initial identification of a Leishmania species in the NT, additional cases of cutaneous leishmaniasis have been identified. Clinical disease have now been found in other captive macropods including several northern wallaroos, a black wallaroo and agile wallabies.
A field investigation to identify the insect responsible for transmitting the disease was undertaken. After extensive trapping and screening of phlebotomine sandflies, we found no evidence that they were responsible for transmitting Leishmania. We then widened our investigation to include other blood sucking flies such as biting midges which are common in the area. Day feeding biting midges were found to be heavily infected with Leishmania parasites. This was an extremely significant finding as it is the first evidence anywhere in the world of transmission by an insect other than a phlebotomine sandfly.
Currently we are focusing our efforts on learning more about this midge species and the novel species of Australian Leishmania that they appear to transmit. Human infecting Leishmania species from other parts of the world are brought into Australia, most commonly by returning travellers or immigrants or asylum seekers from regions where the parasite is common. Further work is critical to assess the risk that both Australian and exotic Leishmania pose to wildlife and human health in Australia.
In 2005 Researchers from the Menzies won the prestigious Chief Minister’s Research and Innovation Award in the Northern Territory. The Leishmania Project Team were recognised for their work in identifying the insect that spreads the parasite Leishmania in Australia.
Staff: Deborah Holt
Collaborators: James Cook University,University of the Sunshine Coast, Taronga Conservation Society Australia, Xeroshield