During the period of 2002 to 2003, there were collected sand flies in two areas of Amazon State (Forest Combat Training Base - BI1 and Tarumã-Mirim). Were collected the 1440 L. (Nyssomyia) umbratilis female. Lu. umbratilis is the main responsible for the transmission of American Tegumentary Leishmaniasis (ATL) in the northern of Amazon River. Only 15 specimens (or 1,04%) presented natural infection with trypanosomatids, being 12 at Bl1 and 3 at Tarumã-Mirim. The infection rate was 1,66% (12 of the 720 collected at BI1) and 0,42% (3 of the 720 at Tarumã-Mirim). These results confirm the previous informations described by other authors that insects have low rates of natural infection by trypanosomatids even in high endemic areas for Leishmaniasis.
Natural infection; Lutzomyia umbratilis; American Tegumentary Leishmaniasis; Trypanosomatidae; mensal variation