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Guerin, Patrick

Nom
Guerin, Patrick
Affiliation principale
Site web
Fonction
Professeur associé
Email
patrick.guerin@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/310

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  • Publication
    Accès libre
    Fabrication of an olfactometer for mosquito behavioural studies
    (2010)
    Omrani, S. M.
    ;
    Vatandoost, H.
    ;
    Oshaghi, M. A.
    ;
    Shokri, F.
    ;
    Guerin, Patrick 
    ;
    Ershadi, M. R. Y.
    ;
    Rassi, Y.
    ;
    Tirgari, S.
    Background & objectives: Olfaction is the major sensory modality involved in the resource searching behaviour of insects including vector mosquitoes (Diptera: Culicidae). To date, our current country-wide knowledge on the host-seeking behaviour of Iranian mosquitoes is mainly confined to host preference which has exclusively come from field studies. Olfactometer is a scientific tool by which more naive aspects of man-vector contact can be clarified under controlled and less biased conditions. Methods: The wind tunnel and stimulus delivery system was constructed from acrylic materials based on previously introduced models with some modifications. Air supply and required light were ensured by a powerful compressor and incandescent bulbs, respectively. Desired level of temperature was maintained by controllable heating radiators. For humidity production a unique in-built piezo system was devised in the course of the air flow. Fine regulators facilitated the continuous generatation of the humidity at a preset level. Results: Titanium tetrachloride smoke plus monitoring of the wind speed revealed that the flow of air was proper and invariable. A desired level of humidity and temperature could be set up in just 10 and 15-45 min, respectively. These physical parameters varied only +/-2% (humidity) and +/-0.15 degrees C (temperature) in a typical 20 min duration. Conclusion: The first sophisticated olfactometer in the field of medical entomology in Iran is reported here. Fast set up and stability of physical parameters are its salient features. It is expected that with the aid of this olfactometer further information on the physiological principles of the host-seeking behaviour of mosquitoes become available soon.
  • Publication
    Métadonnées seulement
    An in Vitro Assay for Testing Mosquito Repellents Employing a Warm Body and Carbon Dioxide as a Behavioral Activator
    (2010)
    Kroeber, Thomas 
    ;
    Kessler, Sébastien 
    ;
    Frei, Jérôme
    ;
    Bourquin, Martine 
    ;
    Guerin, Patrick 
    We describe here an in vitro behavioral assay for testing mosquito repellents applied in a dose-based manner to a warm body (34 C) in test cages. The system was used to assess the sensitivity of 4-6-day-old Anopheles gambiae to the insect repellent diethyl methyl benzamide (deet). These tests were made in the absence and presence of additional carbon dioxide (CO(2)) applied as a pulse to activate mosquitoes in the cages. In the absence of the CO(2) pulse the mosquitoes hardly responded to the warm body. Increasing the CO(2) level in the cage by 1,000 parts per million caused a 25-fold increase in the number of landings by mosquitoes on the warm body in 2-min tests. This mosquito activation allowed the measurement of a significant reduction in the number of landings to bite on the warm body with increasing doses of deet (0.4 to 3.8 mu g/cm(2)). An asymptotic nonlinear model fitted to the repellency data in the presence of CO(2) allowed estimation of the effective dose of deet that reduced landings to bite by 50% (ED(50)) at 0.95 mu g/cm(2) (5 nmol/cm(2)) and the corresponding ED(95) at 4.12 mu g/cm(2) (21.5 nmol/cm(2)). This in vitro bioassay has the advantage of permitting a fast throughput of test products under standardized conditions and is suitable for screenings designed for the purpose of discovering lead products with as yet unknown human toxicological and dermatological profiles.