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.

Eco-bio-social determinants of dengue vector breeding: a multicountry study in urban and periurban Asia

“…21 Work by Focks et al 22 and subsequent multicentre studies [23][24][25] have reconfirmed the usefulness of pupal surveys to identify the types of containers that are epidemiologically important and to estimate adult vector abundance. A further limitation is that dengue vector studies usually focus either on house-holds or on defined public spaces 26,27 and therefore lack the analysis of vector production in defined geographical areas (spatial focus). Finally, even though the factors influencing dengue vector densities and ultimately viral transmission are ecological, biological and social (eco-bio-social), as illustrated in Fig.…”

House-to-house human movement drives dengue virus transmission

“…Consenting contacts residing in houses visited by febrile cases were diagnosed for recent DENV infection (contactsite cluster investigations; Methods). We focused on houses because previous work by our team measured very low mosquito abundances in many nonresidential spaces in Iquitos [e.g., schools, open-air markets, recreational areas (38)] and on visited households because a house-based study design was logistically tractable and previous work in Iquitos revealed that adult Ae. aegypti cluster strongly within single houses (25).…”

Aedes aegypti entomological indices in an endemic area for dengue in Sao Paulo State, Brazil

“…However, it is worth noting that the 0.15 pupae per inhabitant corresponded to the average value of this index for Jaguare. Although the spatial distribution of this index was not determined due to the already discussed diffi culty in estimating the size of population at risk for non-residential properties, 13 the spatialization of the other indices revealed the existence of a signifi cant spatial variation in the levels of Ae. aegypti infestation.…”

“…aegypti. 13 One limitation of using the number of pupae per inhabitant as a dengue risk index is the diffi culty in estimating the size of population at risk in non-residential properties. 13 One viable alternative for locations with these types of properties is the use of the number of pupae per hectare.…”