Field evaluation of a lethal ovitrap against dengue vectors in Brazil

Abstract

Field evaluation of a "lethal ovitrap" (LO) to control dengue vector Aedes mosquitoes (Diptera: Culicidae), was undertaken in two Brazilian municipalities, Areia Branca and Nilopolis, in the State of Rio de Janeiro. The LO is designed to kill Aedes via an insecticide-treated ovistrip (impregnated with deltamethrin). In each municipality, the intervention was applied to a group of 30 houses (10 LOs/house) and compared to 30 houses without LOs in the same neighbourhood. Five LOs were put outside and five LOs inside each treated house. Three methods of monitoring Aedes density were employed: (i) percentage of containers positive for larvae and/or pupae; (ii) total pupae/house; (iii) total adult females/house collected by aspirator indoors. Weekly mosquito surveys began during the month before LO placement, by sampling from different groups of 10 houses/week for 3 weeks pre-intervention (i.e. 30 houses/month) and for 3 months post-intervention in both treated and untreated areas. Prior to LO placement at the end of February 2001, Aedes aegypti (L) densities were similar among houses scheduled for LO treatment and comparison (untreated control) at each municipality. Very few Ae. albopictus (Skuse) were found and this species was excluded from the assessment. Post-intervention densities of Ae. aegypti were significantly reduced for most comparators (P < 0.01), as shown by fewer positive containers (4-5 vs. 10-18) and pupae/house (0.3-0.7 vs. 8-10) at LO-treated vs. untreated houses, 3 months post-treatment at both municipalities. Numbers of adult Ae. aegypti females indoors were consistently reduced in LO-treated houses at Areia Branca (3.6 vs. 6.8/house 3 months post-intervention) but not at Niloplis (approximately 3/house, attributed to immigration). These results demonstrate sustained impact of LOs on dengue vector population densities in housing conditions of Brazilian municipalities.

Multiple insecticide resistance in Aedes aegypti (Diptera: Culicidae) populations compromises the effectiveness of dengue vector control in French Guiana

“…Recent work has successfully identified methods to increase the efficiency of current vector control by using a mixture of larvicides and/or adulticides and/or synergists (Darriet & Corbel 2006, lucia et al 2009), treating at different times during the year (Chung et al 2001(Chung et al , lothrop et al 2008 or using geographic information system technology to optimise spraying operations (Mak et al 2007). Pull-to-kill strategies (Perich et al 2003, Williams et al 2007) also produced promising results by reducing Aedes spp density while targeting them specifically. This advantageous method consists of attracting females to specific, insecticide-containing breeding sites.…”

Evaluación de estrategias comunitarias para el control de Aedes aegypti en Cali, Colombia

“…quinquefasciatus and Ae. aegypti because they permanently maintain water (19,23). In this study, the catch basins evaluated were highly positive for larvae and pupae of Cx.…”

“…The LO has been found effective against Ae. aegypti in the laboratory (18) and in the field (19). The LO is designed to attract and kill gravid Ae.…”

“…The LO is designed to attract and kill gravid Ae. aegypti females (18,19). Females depositing eggs contact the deltamethrin-treated paper strip and obtain a lethal dose of insecticide.…”

“…Larvae were left in the containers during the intervention period to avoid a reduction in the mosquito population. Sampling of adult mosquitoes inside each house was accomplished with modified electric manual aspirators (Insect Vac aspirator, Bioquip) as described by Perich et al (19). Captured mosquitoes from each house were placed in a separate cage and transported to the laboratory for identification.…”