Evaluation of deltamethrin‐impregnated bednets and curtains against phlebotomine sandflies in Valle del Cauca, Colombia

Abstract

The effectiveness of bednets and curtains (nylon mesh 64 per cm2) impregnated with deltamethrin at 26 mg a.i./m2 in reducing the biting nuisance caused by three phlebotomine sandfly species: Lutzomyia columbiana, Lu.lichyi and the predominant Lu.youngi (Diptera: Psychodidae), was evaluated at La Guaira, a rural settlement in Valle de Cauca near Cali, Colombia. Pairs of volunteers collected sandflies under impregnated bednets, in rooms protected by impregnated curtains or in unprotected rooms in a randomized matched design. Collections were made in three houses per night on three consecutive nights, so that each house was sampled under each of the three treatments. This routine was repeated at 2-week intervals for 6 months. There was no significant difference between the overall numbers of sandflies collected in rooms with or without impregnated curtains. Only 0.14 sandflies/man-hour were caught on human bait under impregnated bednets, significantly fewer than the numbers collected on human bait outside the nets in the same room (1.91) or in unprotected rooms (3.29). In a second set of experiments carried out in La Guaira and the neighbouring community of Jiguales, the effect of deltamethrin impregnation was evaluated by comparing numbers of sandflies collected on human bait under treated and untreated nets. Significantly fewer were collected under the impregnated nets (0.25 v. 0.69/man-hour). Wild-caught female Lu.youngi exposed to treated netting for 2 min in the laboratory all died with 24 h. The impact of deltamethrin-impregnated bednets was considered to be useful against Lu.youngi and other potential vectors of leishmaniasis in such communities.

Fatores sócio-econômicos e atitudes em relação à prevenção domiciliar da leishmaniose tegumentar americana, em uma área endêmica do sul da Bahia, Brasil

“…Mosquiteiros impregnados com inseticida funcionaram melhor do que as cortinas impregnadas na proteção contra flebotomíneos (Alexander et al, 1995) e podem ser confeccionados com tecido de malha larga, proporcionando relativa ventilação, fator importante para as noites quentes na região tropical (Oliveira Filho et al, 1994). Mesmo com rasgões, a impregnação com altas doses de inseticida de um mosquiteiro com até 2% de sua área danificada, garantiu, pelo efeito excito-repelente, a eficácia contra anofelinos na proteção contra a malária (Carnevale et al, 1992).…”

Domestic and peridomestic transmission of American cutaneous leishmaniasis: changing epidemiological patterns present new control opportunities

“…Insecticide-treated bednets have also previously been demonstrated to protect users against the bites of the ACL vector Lu. youngi in Colombia (Alexander et al 1995), and may therefore reduce domestic ACL transmission. Taken together, these results raise hopes for insecticide-based interventions in many foci.…”

Avaliação de medidas de controle de flebotomíneos no norte do Estado do Paraná, Brasil

“…In 2001 average captures in 1996-1997and 1997-1998Numerosos trabalhos de controle de flebotomíneos têm dado um enfoque para o uso de inseticidas químicos em paredes de casas e anexos (abrigos de animais, silos) 3,4,5,6,7,8,9 , em ambientes silvestres 10,11,12 e impregnados em mosquiteiros 13,14,15,16,17 . Essas medidas apesar de atrativas não são permanentes 18 , além do que, a precariedade das habitações, a descontinuidade e/ou o uso em épocas inapropriadas e os riscos ambientais advindos da aplicação de inseticidas em ambientes silvestres, constituem fatores limitantes para o controle de flebotomíneos 15,19,20,21 .…”