Leishmaniasis and Human Trafficking

By Carol A. Kemper, MD, FACP

Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center

Dr. Kemper does research for Abbott Laboratories and Merck. This article originally appeared in the July 2011 issue of Infectious Disease Alert. At that time it was peer reviewed by Timothy Jenkins, MD, Assistant Professor of Medicine, University of Colorado, Denver Health Medical Center. Dr. Jenkins reports no financial relationship to this field of study.

Source: Cannella AP, et al. A cluster of cutaneous Leishmaniasis associated with human smuggling. Am J Trop Med Hyg 2011;84:847-850.

Physicians at the University of California-San Diego (UCSD) report a cluster of 5 cases of cutaneous Leishmaniasis in illegal immigrants from East Africa, which surprisingly turned out to be consistent with New World Leishmaniasis, although all 5 had come from an area endemic for Old World Leishmaniasis. How did this occur?

Four Somali and one Ethiopian were brought to the Emergency Room at UCSD by Immigration and Custom Enforcement Agents. They had all been found being smuggled across the U.S.-Mexico border about 20 miles south of the city, and had been held in custody for up to 60 days. They each presented with one small cutaneous ulcer, either nodular or pustular, in different locations on the body (thumb, ear, foot, etc.) and in different stages of development. Initially thought to be MRSA folliculitis, prison officials had attempted administration of trimethoprim-sulfamethoxazole and doxycycline without response. The patients were then referred to UCSD for further care.

Skin biopsies were obtained, and the histology was consistent with leishmaniasis, although the presence of a number of features, such as large vacuoles, was more consistent with New World Leishmaniasis. Cultures yielded a Leishmania spp. and isoenzyme analysis confirmed L. panamensis, which is a member of the Viannia group of Leishmania. Confirmatory PCR was performed at the Centers for Disease Control and Prevention. All of the patients responded to liposomal amphotericin, although one patient relapsed, requiring a second course of therapy.

The story of how they had arrived at the Mexican border from East Africa was not readily forthcoming, but eventually it was learned that all 5 individuals had been smuggled at different times along an identical route from Djibouti to Dubai to Moscow to Havana, Cuba, and then to Quito, Ecuador, through Colombia, and then by ground via Panama to the U.S.-Mexico border. The trip through Panama required foot travel, and the individuals slept outdoors on the ground at night in sleeping bags. They described many insect bites.

New World Leishmaniasis occurs throughout Central and South America and is caused by the bite of a sand fly. Only a small number of the 76 sand fly species in Ecuador, Colombia, and Panama can transmit Leishmaniasis, and recent data suggest that up to 1% of female Lutzomyia sand flies are infected. Within 2-8 weeks of a sand fly bite, a small pustule develops, which progresses to a painless ulcer. Fourteen different species of Leishmania exist in the New World, a number of which can cause mucocutaneous involvement, including L. panamensis. More aggressive therapy with amphotericin is therefore warranted.

Subsequent to this event, 3 individuals from East Africa presented to the physicians in Tacoma, WA, with a similar story. They had been smuggled along the identical route, and skin biopsies yielded the same organism. The discovery of two clusters of Leishmaniasis, in San Diego and in Tacoma, suggest that human trafficking from East Africa through this route must be fairly common with important public health implications for U.S. residents.