Location: Mosquito and Fly Research Unit
Title: Comparison of two mosquito bioassay methods for the estimate of minimum effective dose in repellents Authors
|Gezan, Salvador -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2012
Publication Date: N/A
Technical Abstract: It is expected that laboratory-based repellent bioassays should reliably evaluate the efficacy of compounds that deter mosquito feeding behavior. The variety of repellent bioassays available allows for flexibility in design, but makes it difficult to compare any two methods, including in vitro and in vivo comparisons. The most reliable data come from skin assays; however, this exposes volunteers to chemicals and mosquito bites. In this study, four repellent active ingredients were used: DEET, IR3535, picaridin and para-menthane-3,8-diol. Results from bioassays with a module-based method were operated in vitro with a membrane and in vivo on the skin of the leg and were then compared to an in vitro method where repellent treated cloth is placed over an arm that is inserted into a cage of mosquitoes. Pooled data from six volunteers were used to estimate effective doses for four repellents at the 50, 95, and 99% levels (ED50, ED95, ED99) using a dose response curve with a probit model in the module tests. The ED99 was estimated with repellent-treated cloth as the concentration that prevented 99% of the mosquitoes from feeding. Based on the results of this study, cage-based tests appear to be a more reliable estimate of repellent activity on skin compared to module-based tests on membrane. However, with knowledge of the effective dose ratios, the module-based tests can be utilized for future repellent testing with infected vectors.