Identification of blood meals in Aedes aegypti by antibody sandwich enzyme-linked immunosorbent assay.

A comparative study of 3 ELISA protocols was performed for host blood meal identification in Aedes aegypti. In the sandwich-B ELISA, which used a combination of heavy and heavy+light chain conjugates, specificity was improved to such a degree that conjugates no longer required cross-adsorption with heterologous sera. Using the sandwich-B assay, human blood meals in laboratory reared Ae. aegypti could be detected longer after feeding (100% at 32 h and 80% at 42 h) than with a direct assay (100% at 20 h). Efficacy of the sandwich-B and direct ELISAs in field analyses was studied in parallel) using 80 field collected mosquitoes from Thailand. The sandwich-B assay was superior (88% detection rate) to the direct assay (41% detection rate) and was thus selected as the method of choice for future field studies.