MICROSCOPIC VISUALIZATION OF WUCHERERIA AND BRUGIA LARVAL STAGES IN INTACT CLEARED MOSQUITOS

Over the past several decades, epidemiologic data from filarial vector s typically has been obtained by mass dissection or by dissection of i ndividual specimens. The former is quick and easy to do on large numbe rs of insects but provides no information on the frequency distributio n of infection, presence of early developmental stages, or larval loca tion; the latter is labor-intensive and tedious. We describe a new tec hnique that can provide data comparable to those obtained by individua l dissection, including calculation of infection and infective rates, and this technique is easy enough to accommodate large numbers of inse cts. Brief treatment of ethanol-fixed, intact mosquitoes in sodium hyp ochlorite, followed by treatments in increasing concentrations of etha nol and an organic solvent allowed microscopic visualization of filari al larvae within the abdomen, thorax, head, and proboscis of Brugia ma layi-infected Aedes aegypti and Wuchereria bancrofti-infected Anophele s punctulatus. We compared the classic techniques to our technique usi ng Ae. aegypti infected by feeding on jirds with B. malayi microfilare mias. Comparisons of the infective rate, total number of infective sta ge larvae (L3s) observed, and locations of L3s showed that this new te chnique was comparable to the established methods, while being faster and more precise in determining the location of larvae.