Methods in Anopheles Research - MR4

Chapter 3 : Specific Anopheles Techniques3.4 Mosquito AnesthesiaPage 2 of 4TriethylamineThis chemical is used for Drosophila quite successfully because it is extremely safe. It is available for thispurpose from Carolina Biological Supply as “FlyNap.” Our limited experience with this is that it‘anesthetizes‘ Anopheles mosquitoes irreversibly. In this regard, it is similar to chloroform but would be agood choice when extended immobilization but not recovery is acceptable. Normal biological activities ofseveral types during anesthesia have been confirmed in Culex (Kramer et al. 1990), but we are not awareof similar observations of Anopheles.ChillingFigure 3.4.2. A small Peltier cold table on whichdamp filter paper is placed to conduct cold andprevent mosquitoes from sticking to thecondensation.All mosquitoes with which I have had experience willwithstand some degree of chilling on ice followed byresting on a near-freezing surface. Shown is a smallchilling table that can be used for this purpose. Formosquitoes it is usually necessary to cover the coldsurface with a thin piece of damp paper to prevent themosquitoes from sticking to the condensate on thebare platform. Being slightly damp makes the paperadhere uniformly to the plate and increases heattransfer. Even this must be changed frequently as itbecomes sticky. Entire cages or cups of mosquitoescan be placed briefly in a freezer in order to knockthem down and then transferred to a chilled surface,but make the time as short as possible since mostanophelines will not survive total freezing.Ether and Chloroform SafetyExposure to ether and chloroform should beminimized by keeping containers sealed, dispensingminimum amounts, and using them for the shortestpossible durations of time.Diethyl ether should be stored in a flammable storagecabinet or an explosion proof refrigerator not longerthan 3 - 6 months. This cabinet should not be used tostore oxidizing agents. Explosive peroxides can formwith long term storage, so purchase and store onlyenough for immediate needs. The occupationalexposure limit is 400 ppm as a time-weighted average(TWA, 8 hour exposure) and it has a short term limitexposure (15 minutes) of 500 ppm. Keep theanesthesia chamber closed as much as possible. Review the specific MSDS of the manufacturer youpurchase ether from for any additional handling and storage recommendations, as well other relevanthealth and safety information. Some manufacturers recommend that you do not open unless contentsare at room temperature or below, and that after opening the container, any unused ether be discarded ordisposed of after 2-3 days. Only dispense ether in a chemical fume hood. Avoid agitation and sparksduring all phases of use.Chloroform is considered a known animal carcinogen with unknown relevance to humans. Itsoccupational exposure limit for an 8-hour TWA exposure is 10 parts per million (ppm). However,exposures to chloroform should never exceed 50 ppm at any time. This is referred to as OSHA’s ceilingoccupational exposure limit. Chloroform has a low odor threshold of 85 ppm, so by the time you smellchloroform the ceiling concentration would have already been exceeded. Anesthetizing procedures