The seroepidemiology of malaria in Middle America. IV. Passage of malaria antibodies from mothers to infants.

In an area of El Salvador moderately endemic for malaria, use of the indirect fluorescent antibody test (IFA) showed that 44% of the infants born to mothers who had IFA responses to Plasmodium vivax of 1:20 or higher during the latter part of their pregnancy had positive IFA responses of 1:10 or higher to this antigen. No serum from an infant was positive in the absence of some level of malarial response in the mother.