Identification of Plasmodium vivax sporozoites in mosquitoes using an enzyme-linked immunosorbent assay

A sandwich enzyme-linked immunosorbent assay (ELISA) for identifying Plasmodium vivax sporozoites in mosquitoes is described. Monoclonal antibodies produced against Thailand P. vivax sporozoites were used in an ELISA to detect and identify homologous sporozoites of Southeast Asian, Mexican and North Korean origin in extracts of frozen or dried infected mosquitoes. The assay was sensitive enough to detect 1 infected mosquito in a pool of 20 insects or 125-250 sporozoites per 30 microliter of mosquito extract. The use of a nonionic detergent and a single freeze-thaw to disrupt the circumsporozoite antigen significantly increased the sensitivity of the method.