Is Leishmaniasis extending its range?

The recent report of leishmaniasis in people in East Timor raises a number of important issues. In November 1999, a medicosurgical group from Europe, forming part of the International Force for East Timor (INTERFET), identified 46 patients who had cutaneous lesions characteristic of leishmaniasis. Diagnosis was made on the basis of clinical presentation and direct microscopical examination of lesion specimens. The samples were transported to Europe for further speciation, the results of which have yet to be published. If confirmed, this finding represents the emergence of a serious vector-borne parasitic disease in a region distant from known endemic foci. It not only poses a ‘new' threat to local residents, refugees and visitors to the area, but also has the potential to spread. It is important that parasites isolated from these cases are quickly characterized by appropriate molecular techniques. Speciation in cases of leishmaniasis can be very important in providing a prognosis and predict the course of subsequent disease. Such information would also help to determine the origin of the aetiological agent. Clearly, if proven, the report must stimulate further investigations in the area to identify the epidemiological factors that led to the infection of these people. Awareness of the occurrence and significance of leishmaniasis must be heightened as it presents rarely in Southeast Asia and Australia. The report also highlights the need for enhanced surveillance of such vector-borne diseases in the region, and for determining the distribution of known and potential phlebotomine vectors. Very little is known about the vectorial capability of phlebotomine sandflies in Indonesia and Australia. A number of Phlebotomus spp have been recorded in Australia but the consensus opinion is that none feed on mammals. However, this information is dated and new studies must be considered to determine which species are present in Australia and East Timor and what their feeding preferences are. Indeed, there might be foci of leishmaniasis transmission in parts of Southeast Asia. For example, an infant from southern Thailand was recently diagnosed with visceral leishmaniasis and a human-biting species of phlebotomine flies has been identified in central Thailand. Clearly, there is a need to establish appropriate mechanisms for the rapid dissemination of materials and information in such situations, so that countries at risk can activate their mechanisms of preparedness and respond appropriately