Comparison of indoor searches with whole house demolition collections of the vectors of Chagas disease and their indoor distribution

Abstract

The number of Triatoma dimidiata found per man-hour of collection in each of the three mud-walled houses were 4,1 and 37. In the third house 8 of T. nitida were also collected. When the walls of these houses were dismantled, an additional 114,141 and 307 of T. dimidiata were collected along with 34 of T. nitida in the third house. In the palm-thatch roofed huts only Rhodnius prolixus were collected. The numbers per man-hour collected were 11,27 and 26. When the roofs were dismantled and searched 75,449 and 978 bugs were found in the respective houses. These results indicate that the numbers collected by the traditional method did not accurately reflect the population density in the houses. The collections indicate that the hiding places of T. dimidiata and R. prolixus were very limited within the houses. An average of 31% of T. dimidiata were collected in only two dismantled block sections (2m^2) which were close to the beds and chicken nest and 40% of R. prolixus in the last house were obtained in the lower section of the palm-thatched roofs just above a bed. This area occupied only 4.2% area in total space of the house. These results suggest that insecticidal treatments would be most effective if they focused on the places where more bugs concentrate.