Comparison between two artificial shelter units and timed manual collections for detecting peridomestic Triatoma infestans (Hemiptera : Reduviidae) in rural northwestern Argentina

A ne2 artificial shelter unit was compared with segments of bamboo cane lin ed with pleated filter paper for detecting peridomestic Triatoma infestans Klug at Amama and nearby rural villages in northwestern Argentina. The new shelter unit consisted of a black plastic, wide-mouthed jar with a screw ca p On the top, and a removable central structure made of pleated corrugated paper. In devices exposed from February to December 1999 at 24 sites positi ve for T infestans by timed manual collections with an irritant in April 19 99, the cumulative percentage of sites with any sign of infestation detecte d by the shelter unit increased from 71% after 2 mo to 96% after 10 mo, whe reas bamboo cane units concurrently detected only 12-42% of the sites. Sens itivity increased with time of exposure and the abundance of T infestans pe r site. In 19 sites negative for T. infestans by inspection. shelters incre asingly detected infestation at 16-63% of sites after 10 mo, whereas the ba mboo canes only detected one infestation. Shelter units inspected three tim es over an Ii-mo period were significantly more sensitive than a single man ual search with an irritant performed in March 2000. Our study provided con clusive field evidence that the shelter unit was more sensitive for detecti ng peridomestic T infestans than were timed manual searches, the standard r eference method, or bamboo cane units. Rapid timed searches by skilled bug collectors during the early surveillance phase overlooked many peridomestic populations that. in the absence of control, inevitably would increase in abundance and repopulate treated areas.