Leishmaniasis is a fatal or disfiguring disease caused by a protozoan parasite transmitted by hematophagous sand flies. Globally, 350 million people are estimated to be at risk, resulting in ~1 million cases per year. There are two major forms of the disease: visceral leishmaniasis (VL), which is always treated, otherwise case fatality is ~80%; and cutaneous leishmaniasis (CL), for which the decision to treat is more complicated. The disease is an important diagnostic consideration in travelers from Latin America, the Middle East, North or East Africa, and has been reported in the Southern United States (1). Populations at risk include immunosuppressed persons, immigrants, military and foreign service personnel, and staff or volunteers from non-governmental organizations (1).
Given the toxicity of anti-leishmanial drugs, a confirmed laboratory diagnosis is required prior to starting therapy (2). The decision to treat CL depends upon clinical factors - patient immune status; number, size, duration, and anatomic location of lesions – and the species of parasite (2). While many cutaneous cases of “Old World” Leishmania spp (OWL) will be treated, small, isolated lesions of L. tropica may resolve spontaneously. Among “New World” Leishmania spp (NWL), the Viannia subgenus members have a propensity for mucocutaneous involvement (MCL) and dissemination and thus require treatment to prevent profound disfigurement.
Our Leishmania PCR assay offers highly sensitivity molecular identification of Leishmania spp that infect humans, with a limit of detection of a single organism per reaction. When Leishmania parasites are detected by the assay, sequencing identifies the causative organism to the species or species-complex. This test can be ordered as a stand-alone assay and is performed reflexively if broad-range fungal PCR detects Leishmania sp as an incidental finding.
