Field Monitoring of Cypermethrin Residual Effect on the Mortality Rates of the Phlebotomine Sand Fly Lutzomyia longipalpis in the State of Paraíba, Brazil

Abstract

In a visceral leishmaniasis endemic locality of northeast of Brasil where all settlements were treated with cypermethrin, a follow-up of Lutzomyia longipalpis populations was carried out by regular collections. The residual effect of the insecticide was studied using biological assays on three different types of walls. The results showed that the insecticides had an effect on intradomiciliar Lu. longipalpis populations limited to two months, and had no significant effect on peridomiciliar vector populations. The mortality rates of the tested sandflies were variable according to the type of wall. The decreasing of the insecticide effect was marked since the 3rd month, and mortality rates were identical whatever the type of wall since the 4th month. Unsufficient residual effect was detected after the 4th month

The impact of different sprayable surfaces on the effectiveness of indoor residual spraying using a micro encapsulated formulation of lambda-cyhalothrin against Anopheles gambiae s.s.

“…This study revealed that lambda-cyhalothrin residual efficacy on mud daub, limestone blocks, cement blocks, white wash and oil painted surface was below the threshold of ≥80% after 42–56 days post spraying. These findings are in line with previous studies that reported that limestone blocks and white wash, had shorter residual effect (60–120 days) with pyrethroids while wood, ceramic and thatched walls indicated longer residual effects (≥180 days) [30,31]. …”

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

“…Outdoor densities of Lu. longipalpis remained un-affected throughout the trial period (Passerat de Silans et al 1998).…”

Leishmaniasis sand fly vector density reduction is less marked in destitute housing after insecticide thermal fogging

“…Long-term studies looking at the population dynamics of SF vectors [11-18], and studies on insecticide based control of SF abundance [7] are limited. Insecticide control trials for New World sand flies have been carried out using organophosphates: Malathion [19]; organochlorines: DDT [20,21] and pyrethroids: cyfluthrin [22], cypermethrin [23,24], deltamethrin [25-30], lambdacyhalothrin [31-33]. Methods of insecticide application for SF control have included: fogging [19,22,34], residual spraying [21,23-27,31-33], insecticide diffusion devices [35], insecticide treated nets [28,29] and curtains [30].…”

“…Insecticide control trials for New World sand flies have been carried out using organophosphates: Malathion [19]; organochlorines: DDT [20,21] and pyrethroids: cyfluthrin [22], cypermethrin [23,24], deltamethrin [25-30], lambdacyhalothrin [31-33]. Methods of insecticide application for SF control have included: fogging [19,22,34], residual spraying [21,23-27,31-33], insecticide diffusion devices [35], insecticide treated nets [28,29] and curtains [30]. In general, these studies have shown that insecticide application at the household level seems to be the most effective SF control method [7], because it can suppress both SF abundance [7] and CL transmission over short [36] and long term [37] time scales.…”

“…Because CL transmission is ruled by ecological processes [42], how humans become part of a pathogen’s life cycle, especially in neglected tropical diseases like leishmaniasis, can be heavily influenced by social factors [43]. Even if recognized as an important factor for the success of insecticide applications in CL control [23,32], housing quality has been unaccounted for when evaluating the outcome of insecticide trials.…”