Result of a first step toward community-based surveillance of transmission of Chagas' disease with appropriate technology in rural areas.

Abstract

The objective of this work was to develop an effective methodology for the surveillance of Chagas' disease vectors in rural areas. It was based on the use of sensor boxes and portable mini-pumps to be integrated into the regular health promotion activities of the Primary Health Care (PHC) agents. The proposed methodology involves a continuous passive intradomiciliary detection of triatomines by sensor boxes that are monitored quarterly by PHC agents. Insecticidal treatment of the houses was performed immediately after the detection of triatomines. The more conventional method of vertical surveillance involves a direct entomologic evaluation conducted by trained professionals. The entire house is searched and there is a mandated treatment of the positive houses. The results of the followups obtained in the county of Rio Hondo in Santiago del Estero Province during a 36-month evaluation period immediately following attack phase application of insecticides were analyzed. The initial high domiciliary and peridomiciliary infestations decreased abruptly after the insecticidal treatment in both areas. When the performances of both types of surveillance were compared, the PHC agent method showed a lower percentage of houses reinfested, with fewer triatomines in the former, and a decrease in their rate of Trypanosoma cruzi infection. Evaluations of reinfestations using the man/hour method and the senor box method showed the same sensitivity. A higher sensitivity for detection of low densities of vector populations was achieved using the sensor boxes. The cost of PHC agent/sensor boxes surveillance was five times lower than the classic one. The proposed strategy for the continuous surveillance of Chagas' disease vectors has demonstrated effectiveness, allows community participation, and seems suitable for large scale application.