RESUMO
Reduced fenitrothion susceptibility in Haitian Anopheles albimanus is documented using time/mortality measurements from otherwise standard World Health Organization (WHO) bioassays. Survival beyond a time threshold in bioassays is shown to be highly correlated with elevated non-specific esterase levels. A shift in resistance incidence from less than 20 to over 60% in a six-month period is documented using both the bioassay and microassay procedures, showing the potential of microplate assay methods in early detection of resistance. Conventional 24-hour reading of WHO bioassay data failed to detect resistance until the level reached 60%. Resistance appeared to be focal, with an increase in intensity coinciding with a fenitrothion spray cycle for malaria control.
Assuntos
Anopheles , Fenitrotion , Animais , Bioensaio , Resistência a Medicamentos , HaitiRESUMO
A one-year study of the biting and resting habits of the malaria vector Anopheles albimanus was carried out in four rural villages of northern Haiti. Man-biting rates and nightly biting cycles were determined by the use of all-night man-biting captures inside and outside houses. Seasonal changes in density and behavior were determined by repeating the captures on a bimonthly basis throughout one year. Exophily was demonstrated in these anopheline populations by a comparison of inside-biting with inside-resting densities. These behavior characteristics are discussed in relation to malaria transmission and to the choice of malaria control methods.
Assuntos
Anopheles/fisiologia , Animais , Comportamento Alimentar , Haiti , Humanos , Mordeduras e Picadas de Insetos , Estações do AnoRESUMO
Three methods of capturing Anopheles albimanus mosquitoes were compared during a field study in four villages in northern Haiti. Updraft ultraviolet (UV) light traps proved to be more effective than biting collections, regardless of season or whether the tests were done indoors or outdoors. Biting collections were in turn more effective than the Centers for Disease Control (CDC) miniature light traps. Updraft UV light traps and biting collections yielded more An. albimanus outdoors than indoors; the reverse was found for the CDC miniature light traps. The updraft UV light traps caught An. albimanus on 86% of the occasions used outside and 75% of the occasions inside. The biting collections were equally as successful as the traps in catching mosquitoes outside but caught An. albimanus only on 64% of the occasions when used inside houses. The CDC miniature light traps were successful in collecting An. albimanus on 33% of the occasions outside and 60% of the occasions inside.