The parasite Leishmania was previously discovered as the cause of skin lesions in captive red kangaroos in the Northern Territory in 2004. Prior to this, Australia and the Antarctic were thought to be the only continents in the world free of Leishmania parasites and its insect carriers. Leishmania species are single-celled parasites that are transmitted by biting flies. Leishmaniasis is the disease caused by infection with this parasite. Approximately 20 species of Leishmania are known to cause disease in humans and other mammals. Leishmania species maintain a lifecycle that involves dogs, small rodents, or reptiles (the reservoir host), and a sandfly species that transmits the infection (the vector).

The host range, lifecycle, and zoonotic potential of the Australian Leishmania parasite are unknown. Current data indicates that the Leishmania isolated in the red kangaroos is a new species, which is likely to be endemic in the Top End. This study aims to investigate the life cycle of Leishmania in the Top End by determining the transmitting vector (sand fly) and the natural hosts of the parasite in the wild. This study will help to assess the risks to both wildlife and human health.

The World Health Organisation (WHO) considers leishmaniasis to be a globally significant parasitic disease. Leishmaniasis is also included on The Office International des Epizooties (OIE – World Organisation for Animal Health) List B, which contains “transmissible diseases that are considered to be of socio-economic and/or public health importance within countries and that are significant in the international trade of animals and animal products”.

Previous risk assessments regarding incursions of Leishmania into Australia have been based on the premise that no suitable sand fly species existed in Australia to act as vectors. The presence of a vector capable of transmitting Leishmania infection among red kangaroos in the NT raises the possibility that imported pathogenic species of Leishmania could become endemic in Australia.