Ingestion and development of Wuchereria bancrofti in Culex quinquefasciatus, Anopheles gambiae and Aedes aegypti after feeding on humans with varying densities of microfilariae in Tanzania.

Autor(es): McGreevy P B; Kolstrup N; Tao J; McGreevy M M; Marshall T F

Resumo: Laboratory observations were made on the transmission of Wuchereria bancrofti by Culex quinquefasciatus and Anopheles gambiae, natural vectors in East Africa, and by Aedes aegypti, an experimental vector. Mosquitoes were fed on human carriers with one to 2,667 microfilariae (mff/ml) of peripheral blood and the numbers of mff ingested were determined. The mosquitoes demonstrated a 'concentrating effect' and ingested 8.6 to 12-fold more mff than the expected number based on the density of mff in the carrier and the size of the blood meal. Studies on Culex showed that only 2.7 to 13% of the ingested mff developed into infective larvae (L3s). Emphasis was given to the transmission of Wuchereria from low density carriers with less than 10 mff/ml of peripheral blood-a value that approximates the threshold level of microfilaraemia detectable with conventional diagnostic techniques. By combining our laboratory data with published field data on the biting rates and longevity of mosquitoes in East Africa, we estimate that each low density carrier could serve as a source for nil to 15 L3s/year in Cx quinquefasciatus and 0.3 to 8 L3s/year in An. gambiae depending on the particular community. These estimates are relevant when formulating strategy to control bancroftian filariasis by mass chemotherapy with diethylcarbamazine. Experience with this drug has shown that a proportion of the carriers in a community continue to circulate mff at low levels after treatment. The present data demonstrate that these carriers serve as a reservoir of infection for mosquitoes

Palavras-Chave: Chemotherapy regimen; Diethylcarbamazine; Africa; Eastern; Anopheles; Culex Culicidae; Diagnostic techniques and procedures; Larva

Imprenta: Transactions of the Royal Society of Tropical Medicine and Hygiene, v. 76, n. 3, p. 288-296, 1982

Identificador do objeto digital:

Descritores: Aedes aegypti - Pathogenesis ; Aedes aegypti - Transmission ; Aedes aegypti - Public health

Data de publicação: 1982