Limitation of using synthetic human odours to test mosquito repellents

Okumu, F. O., Titus, E., Mbeyela, E., Killeen, Gerry ORCID: https://orcid.org/0000-0002-8583-8739 and Moore, S. J. (2009) 'Limitation of using synthetic human odours to test mosquito repellents'. Malaria Journal, Vol 8.

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Abstract

Background: Gold-standard tests of mosquito repellents involve exposing human volunteers to host-seeking mosquitoes, to assess the protective efficacy of the repellents. These techniques are not exposure-free and cannot be performed prior to toxicological evaluation. It is postulated that synthetic lures could provide a useful assay that mimics in-vivo conditions for use in high-throughput screening for mosquito repellents. Methods: This paper reports on a semi-field evaluation of repellents using a synthetic blend of human derived attractants for the malaria vector, Anopheles gambiae sensu stricto Different concentrations of known repellents, N, N diethyl-3-methylbenzamide (deet) and Para-methane-3, 8, diol (PMD) were added into traps baited with the synthetic blend, and resulting changes in mosquito catches were measured. Results: All test concentrations of deet (0.001% to 100%) reduced the attractiveness of the synthetic blend. However, PMD was repellent only at 0.25%. Above this concentration, it significantly increased the attractiveness of the blend. There was no relationship between the repellent concentrations and the change in mosquito catches when either deet (r(2) = 0.033, P = 0.302) or PMD (r(2) = 0.020, P = 0.578) was used. Conclusion: It is concluded that while some repellents may reduce the attractiveness of synthetic human odours, others may instead increase their attractiveness. Such inconsistencies indicate that even though the synthetic attractants may provide exposure-free and consistent test media for repellents, careful selection and multiple-repellent tests are necessary to ascertain their suitability for use in repellent screening. The synthetic odour blend tested here is not yet sufficiently refined to serve as replacement for humans in repellent testing, but may be developed further and evaluated in different formats for exposure free repellent testing purposes.

Item Type:	Article
Uncontrolled Keywords:	Mosquito Repellents, Mosquito, Toxicological Evaluation, Anopheles, Synthetic Lures
Subjects:	QV Pharmacology > Drug Standardization. Pharmacognosy. Medicinal Plants > QV 771 Standardization and evaluation of drugs QV Pharmacology > Toxicology > General Toxicology > QV 600 General works QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes QX Parasitology > Insects. Other Parasites > QX 650 Insect vectors QX Parasitology > Insects. Other Parasites > QX 515 Anopheles
Digital Object Identifer (DOI):	https://doi.org/10.1186/1475-2875-8-150
Depositing User:	Users 183 not found.
Date Deposited:	05 Mar 2010 09:50
Last Modified:	24 Jan 2022 15:13
URI:	https://archive.lstmed.ac.uk/id/eprint/353

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