Vectorial importance of triatominae bugs (Hemiptera: Reduviidae) in Guaymas, Mexico.

The study was conducted in Guaymas city, Sonora, in Northwestern Mexico. Triatomines were collected manually during daytime, within and around houses selected randomly, with one person searching for bugs during one hour per house. Collected bugs were identified and analyzed for Trypanosoma cruzi infection. From a total of 279 collected specimens there were 123 females, 65 males and 91 nymphs (entomological indexes: 63% infestation, 68.4% colonization, 8.5% density and 13.5% stacking). There were 251 (90%) triatominae bugs infected with T. cruzi, one of the highest natural infestation levels recorded in Mexico. The insects collected were identified as Triatoma rubida (91%) and T. recurva (9%). Previous reports for the same locality (1959) indicated the presence of T. rubida in the wild, we found T. rubida within houses, and T. recurva as a peridomestic bug. Unplanned housing developments in originally wild areas may have favored T. cruzi transmitters to migrate from the wild and into human dwellings.