Use of a semi-field system to evaluate the efficacy of topical repellents under user conditions provides a disease exposure free technique comparable with field data

Malaria Journal

Methodology

Emmanuel Simfukwe¹  Hassan Ngonyani¹  Daniel Lugiko¹  Dickson Lweitojera¹  Japhet Kihonda¹  Edgar Mbeyela¹  Marta Maia²  Sarah Moore²  Onyango Sangoro³ 

[1] Ifakara Health Institute, Box 74, Bagamoyo, Tanzania;Ifakara Health Institute, Box 74, Bagamoyo, Tanzania;Department of Health Interventions, Swiss Tropical and Public Health Institute, Socinstrasse, 57, CH-4002, Basel, Switzerland;University of Basel, Petersplatz 1, 4003, Basel, Switzerland;Ifakara Health Institute, Box 74, Bagamoyo, Tanzania;Disease Control Department, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK;

关键词: Repellent;    Anopheles arabiensis;    Semi-field system;    Efficacy;    N, N;   

DOI  :  10.1186/1475-2875-13-159

 received in 2013-12-04, accepted in 2014-04-21,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundBefore topical repellents can be employed as interventions against arthropod bites, their efficacy must be established. Currently, laboratory or field tests, using human volunteers, are the main methods used for assessing the efficacy of topical repellents. However, laboratory tests are not representative of real life conditions under which repellents are used and field-testing potentially exposes human volunteers to disease. There is, therefore, a need to develop methods to test efficacy of repellents under real life conditions while minimizing volunteer exposure to disease.MethodsA lotion-based, 15% N, N- Diethyl-3-methylbenzamide (DEET) repellent and 15% DEET in ethanol were compared to a placebo lotion in a 200 sq m (10 m × 20 m) semi-field system (SFS) against laboratory-reared Anopheles arabiensis mosquitoes and in full field settings against wild malaria vectors and nuisance-biting mosquitoes. The average percentage protection against biting mosquitoes over four hours in the SFS and field setting was determined. A Poisson regression model was then used to determine relative risk of being bitten when wearing either of these repellents compared to the placebo.ResultsAverage percentage protection of the lotion-based 15% DEET repellent after four hours of mosquito collection was 82.13% (95% CI 75.94-88.82) in the semi-field experiments and 85.10% (95% CI 78.97-91.70) in the field experiments. Average percentage protection of 15% DEET in ethanol after four hours was 71.29% (CI 61.77-82.28) in the semi-field system and 88.24% (84.45-92.20) in the field.ConclusionsSemi-field evaluation results were comparable to full-field evaluations, indicating that such systems could be satisfactorily used in measuring efficacy of topically applied mosquito repellents, thereby avoiding risks of exposure to mosquito-borne pathogens, associated with field testing.

【 授权许可】

CC BY   
© Sangoro et al.; licensee BioMed Central Ltd. 2014