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Randomized Controlled Trial
. 2006 May 27;332(7552):1247-52.
doi: 10.1136/bmj.332.7552.1247.

Effective control of dengue vectors with curtains and water container covers treated with insecticide in Mexico and Venezuela: cluster randomised trials

Axel Kroeger  1 , Audrey Lenhart, Manuel Ochoa, Elci Villegas, Michael Levy, Neal Alexander, P J McCall
Affiliations
Randomized Controlled Trial

Effective control of dengue vectors with curtains and water container covers treated with insecticide in Mexico and Venezuela: cluster randomised trials

Axel Kroeger et al. BMJ. .

Abstract

Objectives: To measure the impact on the dengue vector population (Aedes aegypti) and disease transmission of window curtains and water container covers treated with insecticide.

Design: Cluster randomised controlled trial based on entomological surveys and, for Trujillo only, serological survey. In addition, each site had a non-randomised external control.

Setting: 18 urban sectors in Veracruz (Mexico) and 18 in Trujillo (Venezuela).

Participants: 4743 inhabitants (1095 houses) in Veracruz and 5306 inhabitants (1122 houses) in Trujillo.

Intervention: Sectors were paired according to entomological indices, and one sector in each pair was randomly allocated to receive treatment. In Veracruz, the intervention comprised curtains treated with lambdacyhalothrin and water treatment with pyriproxyfen chips (an insect growth regulator). In Trujillo, the intervention comprised curtains treated with longlasting deltamethrin (PermaNet) plus water jar covers of the same material. Follow-up surveys were conducted at intervals, with the final survey after 12 months in Veracruz and nine months in Trujillo.

Main outcome measures: Reduction in entomological indices, specifically the Breteau and house indices.

Results: In both study sites, indices at the end of the trial were significantly lower than those at baseline, though with no significant differences between control and intervention arms. The mean Breteau index dropped from 60% (intervention clusters) and 113% (control) to 7% (intervention) and 12% (control) in Veracruz and from 38% to 11% (intervention) and from 34% to 17% (control) in Trujillo. The pupae per person and container indices showed similar patterns. In contrast, in nearby communities not in the trial the entomological indices followed the rainfall pattern. The intervention reduced mosquito populations in neighbouring control clusters (spill-over effect); and houses closer to treated houses were less likely to have infestations than those further away. This created a community effect whereby mosquito numbers were reduced throughout the study site. The observed effects were probably associated with the use of materials treated with insecticide at both sites because in Veracruz, people did not accept and use the pyriproxyfen chips.

Conclusion: Window curtains and domestic water container covers treated with insecticide can reduce densities of dengue vectors to low levels and potentially affect dengue transmission.

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Figures

Fig 1
Fig 1
Flow of households in Veracruz through study
Fig 2
Fig 2
Flow of households in Trujillo through study
Fig 3
Fig 3
Breteau and house indices in intervention and control clusters and in external control communities at baseline and end of studies in Veracruz (Mexico) and Trujillo (Venezuela), with monthly local rainfall data
See this image and copyright information in PMC

References

    1. PAHO. Dengue and dengue hemorrhagic fever in the Americas: guidelines for prevention and control. Washington: Pan American Health Organization, 1994. (Scientific Publication No 548.)
    1. Kay B, Vu SN. New strategy against Aedes aegypti in Vietnam. Lancet 2005;365: 613-7. - PubMed
    1. Vu SN, Nguyen TY, Tran VP, Truong UN, Le QM, Le VL, et al. Elimination of dengue by community programs using Mesocyclops (Copepoda) against Aedes aegypti in central Vietnam. Am Trop Med Hyg 2005;72: 67-73. - PubMed
    1. Parks W, Lloyd L. Planning social mobilization and communication for dengue fever prevention and control. Geneva: WHO, 2004. (WHO/CDS/WMC/2004.2.)
    1. Nathan BM, Knudsen AB. Aedes aegypti infestation characteristics in several Caribbean countries and implications for integrated community-based control. J Am Mosq Cont Ass 1991;7: 400-4. - PubMed

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