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 DC, USA

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

The elimination of Triatoma infestans, the main vector of Chagas’ disease is compounded by great difficulties in controlling bug populations in the peridomestic environment. Peridomestic sites are the first to be recolonized by T. infestans and are considered the main source of community reinfestation following control interventions. Knowledge about flight dispersal of triatomine bugs is thus essential for understanding the reinfestation process of rural communities.  Based on an empirical model of flight initiation, coupled with data from a longitudinal field study, flight of T. infestans was predicted to peak in summer. To test this prediction, longitudinal light trap collections were conducted during March (late summer), July (winter) and November (spring) in a rural community of northwestern Argentina. Following each collection period, all peridomestic sites around light traps were 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 compounds with at least one peridomestic site infested by T. infestans, with goat and pig corrals the most probable sources of dispersing bugs. The arrival of bugs to light traps 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 information can be used by vector control agencies to efficiently target control actions against T. infestans.