The role of the peridomiciliary area in the elimination of Triatoma infestans from rural Argentine communities

CECERE MC; GÜRTLER RE; CANALE D; CHUIT R; COHEN J

REVISTA PANAMERICANA DE SALUD PúBLICA

Año: 1997 vol. 1 p. 273 - 279

1020-4989

The purpose of this study was to identify theorigin of Triatoma infestans reinfestation and study its dynamics following spraying with deltamethrin inside and around 94 housesin three rural communities in northwestern Argentina. The effectivenesso f the spraying was evaluated immediately alter the houses were sprayed and two months la ter. In addition, five residual peridomiciliary foci were found and sprayed, as well as three preexisting ones that had not been sprayed. Yo monitor reinfestation, biosensors were placed in the houses and each family was also asked to capture triatomines and keep them in plastic bags; in addition, triatomines were searched for in and around houses, using an aerosol that dislodged them from their hiding places. Selective sprayings were carried out only where a colony of T. infestans was found. During the 30 months of follow-up, the percentage of houses in which any T. infestans were captured varied between3 % and 9%. In six housesT, . infestans were captured during more than one evaluation. The number of peridomiciliary areas found to be infested (19) was double the number of infested houses (9). Colonies of T. infestans were found only in the peridomiciliary areas, where the number of T. infestans captured was six times higher than in the houses. Chickens were the host most frequently associated with peridomiciliary foci. Yhis area was the origin and principal source of reinfestation. Yo reduce the speed of reinfestation and the frequency with which sprayings are needed, the following environmental and chemical control methods must be combined in the peridomiciliary area: reduce the number of hiding places of triatomines; restrict the raising of birds to structures that cannot be colonized by triatomines; apply an insecticide that is less likely to be degraded by exposure to the elements, or perform a second spraying 6 to 12 months after the first; and employ a device for early detectionof the presence of T. infestans around houses.