Potential Transmission Cycles of Leishmania tropica in a Historic Disease Focus of Cutaneous Leishmaniasis in Southeast Tunisia

The transmission of Leishmania tropica (Wright) (Protozoa: Sarcomastigophora: Trypanosomatidae) was studied in a historic focus of the cutaneous leishmaniasis disease in southeast Tunisia. The sandfly Phlebotomus sergenti (Parrot) (Diptera: Psychodidae), the confirmed vector of L. tropica in humans. was the most abundant Phlebotomus species found in homes. Phlebotomus chabaudi s.l. (Croset) was the dominant species in the natural rocky habitats favored by the North African gundi, Ctenodactylus gundi (Rothman), which is a known putative rodent reservoir of L. tropica. Leishmania tropica MON-8 (Rioux. Lanotte and Pratlong) was the species isolated and identified from gundi, humans, and P. sergenti in the disease focus area. Based on these results, the North African gundi may serve at least as a maintenance host for L. tropica in this area of southeast Tunisia, even though L. tropica is commonly stated to be anthroponotic. These results also suggest that there may be two transmission cycles of L. tropica in this region, with P. sergenti transmitting L. tropica among humans inside and in peridomestic habitats and P. chabaudi s.l. transmitting the disease agent among gundi in their natural habitats. Phlebotomus chabaudi s.l. also may transmit to humans when humans venture into areas inhabited by gundi host reservoirs.