The use of wide-mesh gauze impregnated with lambda-cyhalothrin covering wall openings in huts as a vector control method in Suriname

Abstract

An alternative vector control method, using lambda-cyhalothrin impregnated wide-mesh gauze covering openings in the walls of the houses was developed in an area in the Eastern part of the interior of Suriname. Experimental hut observations showed that Anopheles darlingi greatly reduced their biting activity (99-100%) during the first 5 months after impregnation. A model assay showed high mortality both of mosquitoes repelled by the gauze as well as of those that succeeded in getting through it. A field application test in 270 huts showed good acceptance by the population and good durability of the applied gauze. After introducing the method in the entire working area, replacing DDT residual housespraying, the malaria prevalence, of 25-37% before application dropped and stabilized at between 5 and 10% within one year. The operational costs were less than those of the previously used DDT housespraying program, due to a 50% reduction in the cost of materials used. The method using wide-mesh gauze impregnated with lambda-cyhalothrin strongly affects the behavior of An. darlingi. It is important to examine the effect of the method on malaria transmission further, since data indirectly obtained suggest substantial positive results.

PIP: Field application testing in Suriname confirmed that use of wide-mesh gauze impregnated with lambda-cyhalothrin to cover openings in the walls of Bush Negro homes represents an effective, acceptable, and low-cost vector control method. In experimental hut observations in the Eastern part of the interior of Suriname, this method reduced the biting activity of Anopheles darlingi by 99-100% in the first 5 months after impregnation. A model assay showed high mortality among mosquitoes repelled by the gauze and 100% mortality in insects that were able to cross through the mesh. A field application test in 270 huts showed good acceptance by the population, with no conflicts with local cultural customs, and excellent durability. After replacement of DDT residual house-spraying (associated with a malaria prevalence of 25-37%) with the impregnated gauze method, malaria prevalence dropped to 5-10% and material costs were halved. When the Suriname Government resumed responsibility for health care in the interior in 1992 when political strife stopped, use of this vector control method was not continued despite its demonstrated benefits.