Estimate of Plasmodium Falciparum Sporozoite Content of Anopheles Stephensi used to Challenge Human Volunteers

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  • Center for Vaccine Development, Department of Medicine, University of Maryland School of Medicine, Department of Medical and Molecular Parasitology, New York University Medical Center, Baltimore, Maryland

Plasmodium falciparum infected Anopheles stephensi, taken from a group of mosquitoes which had been used to challenge recipients of (NANP)3-TT vaccine, were tested for P. falciparum sporozoite content by an immunoradiometric assay. Seventy-six percent were infected with mean and median sporozoite equivalents per mosquito of 220,994 and 217,398, respectively (SD = 54,911). This sporozoite density is greater than that usually found in the field. These data suggest that this challenge for evaluating P. falciparum sporozoite vaccines is a demanding test of immunity.