Papers

Insecticide impregnated curtains to control domestic transmission of cutaneous leishmaniasis in Venezuela: cluster randomised trial

Axel Kroeger, professor of international community health, ^a Elci Villegas Avila, lecturer, ^b Linda Morison, lecturer in medical statistics. ^c

^a School of Tropical Medicine, Liverpool L3 5QA, ^b Research Centre "José W Torrealba," Núcleo Universitario "Rafael Rangel" Universidad de los Andes, Trujillo, Venezuela, ^c London School of Hygiene and Tropical Medicine, London WC1E 7HT

Correspondence to: A Kroeger A.Kroeger{at}liverpool.ac.uk

Objective: To measure the impact on transmission of leishmaniasis of curtains impregnated with insecticide.
Design: Cluster randomised controlled trial: household interview survey, observational study of people's behaviour, entomological study with light trap captures of sandflies inside houses.
Setting: 14 urban sectors in Trujillo, Venezuela.
Participants: 2913 inhabitants of 569 houses.
Intervention: Sectors were paired according to their 12 month cumulative incidence of cutaneous leishmaniasis, one sector in each pair was randomly allocated to receive polyester curtains impregnated with lambdacyhalothrin (intervention group) while the other sector received curtains without insecticide or no curtains (control groups). After 12 months a follow up household survey was conducted.
Main outcome measures: Reduction in abundance of sandflies indoors and 12 month incidence of clinical cases of cutaneous leishmaniasis.
Results: Transmission of cutaneous leishmaniasis occurred mainly in the domestic setting, with the incidence over 12 months of 4%. The mean number of sandflies per trap per night was 16. After follow up the 12 month incidence of cutaneous leishmaniasis was 0% in the intervention group and 8% in the six pairs in the control group that received unimpregnated curtains (mean difference 8, 95% confidence interval 4.22 to 11.78; P=0.001). There were significantly fewer sandflies in the intervention group (2 v 15, mean difference 13 sandflies per trap; 9 to 17; P<0.001).
Conclusion: Curtains impregnated with insecticide provide a high degree of protection against indoor transmission of cutaneous leishmaniasis.

What is already known on this topic The transmission of cutaneous leishmaniasis is increasingly in urban and domestic settings House spraying, space spraying, and insecticide treated material reduce the number of vectors What this paper adds Pyrethroid impregnated curtains can considerably reduce the incidence rate of cutaneous leishmaniasis in areas where indoor transmission is predominant