Seasonal variations in active dispersal of natural populations of Triatoma infestans (Hemiptera: Reduviidae) in rural northwestern Argentina

VAZQUEZ-PROKOPEC GM; CEBALLOS LA; MARCET PL; CECERE MC; CARDINAL MV; KITRON U; GÜRTLER RE

Washington, EEUU

Congreso; 54th Annual Meeting of the American Society of Tropical Medicine and Hygiene.; 2005

American Society of Tropical Medicine and Hygiene.

The elimination of Triatoma infestans, the main vector of Chagas’ disease, has shown great difficulties in the peridomestic environment. Peridomestic sites are the first to be recolonized by T. infestans and are considered the main source of community reinfestation after control interventions. Knowledge about flight dispersal of triatomine bugs is thus essential for understanding the reinfestation process of rural communities.  An empirical model of flight initiation, coupled with data from a longitudinal study predicted that flight of T. infestans would peak in summer. To test this prediction, we conducted longitudinal light trap collections during 3-8 nights in March (late summer), July (winter) and November (spring) 2003, and in March 2004 in a rural community of northwestern Argentina. Each date, all peridomestic sites around light traps were later inspected to assess the relative abundance and nutritional status of T. infestans at each site. A total of 26 T. infestans (14 males, 7 females, 4 V and 1 IV instar nymphs), and 15 sylvatic triatomine bugs (Triatoma guasayana and Triatoma garciabesi) were collected in 96 light trap-nights. Collection of T. infestans bugs peaked in summer surveys (10-14 bugs) in comparison to spring (2 bugs) and winter (no bugs). All positive light traps were located in houses with at least one peridomestic site infested by T. infestans, being goat and pig corrals the more likely source of dispersants. The arrival of bugs to light traps when winds were lower than 5 km/h was significantly associated with maximum temperature and relative humidity. This is the first field report of seasonal variations in flight dispersal activity of T. infestans. This basic information may help vector control agencies to efficiently target control actions against T. infestans.