Molecular epidemiology of imported cases of leishmaniasis in Australia from 2008 to 2014

Abstract

Leishmaniasis is a vector borne disease caused by protozoa of the genus Leishmania. Human leishmaniasis is not endemic in Australia though imported cases are regularly encountered. This study aimed to provide an update on the molecular epidemiology of imported leishmaniasis in Australia. Of a total of 206 biopsies and bone marrow specimens submitted to St Vincent's Hospital Sydney for leishmaniasis diagnosis by PCR, 55 were found to be positive for Leishmania DNA. All PCR products were subjected to restriction fragment length polymorphism analysis for identification of the causative species. Five Leishmania species/species complexes were identified with Leishmania tropica being the most common (30/55). Travel or prior residence in a Leishmania endemic region was the most common route of acquisition with ~47% of patients having lived in or travelled to Afghanistan. Cutaneous leishmaniasis was the most common manifestation (94%) with only 3 cases of visceral leishmaniasis and no cases of mucocutaneous leishmaniasis encountered. This report indicates that imported leishmaniasis is becoming increasingly common in Australia due to an increase in global travel and immigration. As such, Australian clinicians must be made aware of this trend and consider leishmaniasis in patients with suspicious symptoms and a history of travel in endemic areas. This study also discusses the recent identification of a unique Leishmania species found in native kangaroos and a potential vector host which could create the opportunity for the establishment of a local transmission cycle within humans.

Fig 1. Digestion of amplified ITS1 regions with the restriction endonuclease HaeIII of different species of Leishmania from isolates from this study on a 4% agarose gel.

Lane 1: L. tropica, lane 2: L. major, lane 3: L. donovani complex, lane 4: L. braziliensis complex, lane 5: L. mexicana. A 100bp ladder was used as the molecular size marker (M).