Aedes aegypti (Diptera: Culicidae) production from non-residential sites in the Amazonian city of Iquitos, Peru

Abstract

Programmes for the surveillance of Aedes aegypti (L.) often focus on residential areas, ignoring non-residential sites. Between November 2003 and October 2004, pupal/demographic surveys were therefore conducted in non-residential sites in the Peruvian city of Iquitos. The sampled sites included schools, factories, ports, public markets, petrol stations, commercial zones, airports, government buildings, animal-production areas, and recreational areas. Compared with the residential sites that had been surveyed a few years earlier, the non-residential sites generally had fewer pupae/ha, even though pupae were found in a high percentage of the sites investigated. Nonetheless, although <56 pupae/ha were observed in the industrial, commercial, recreational and school sites, the river boats in the ports and the areas in and around public markets sometimes had pupal abundances (of 122–213 pupae/ha) that were comparable with those previously recorded in the residential sites.

When the relative production of Ae. aegypti was calculated by container type and characteristic (lidded/lidless, indoors/outdoors, and water-use patterns), no single container category was found to be a major producer of Ae. aegypti, with the exception of flower vases in cemeteries. In general, almost all (97%) of the pupae collected in the non-residential sites came from unlidded containers, although 91% of those collected in river boats came from lidded storage areas. With the exception of lumber mills, plant nurseries and markets (where only 39%–60% of the pupae were collected outdoors), >70% of pupal production was outdoors. In commercial areas, 41% of the pupae came from manually-filled containers, compared with <12% in residential sites.

These results indicate that non-residential sites can be highly productive for Ae. aegypti and that the role of such sites in dengue transmission requires further investigation.