Longitudinal Analysis of Plasmodium Falciparum-Specific Immunity in Travelers and Immigrants From Malaria Endemic Areas to the United States

Objectives

Anecdotal evidence suggests clinical immunity to malaria wanes within months to years after an immune individual leaves an endemic area. A detailed, systematic description of the quality and longevity of the P. falciparum-specific humoral and cellular immune responses in such individuals over time in the absence of ongoing exposure is lacking.

This protocol will attempt to fill this knowledge gap through comprehensive longitudinal immunological analyses of two populations of healthy adult volunteers: 1) naive travelers returning from malaria endemic areas recently treated (within 2 weeks) for acute P. falciparum malaria and referred from hospitals in the metropolitan Washington DC area; and 2) immigrants from malaria endemic areas living in the metropolitan Washington DC area with serologic evidence of past P. falciparum exposure.

The primary objective is to estimate the quality and longevity of P. falciparum-specific humoral and cellular immune responses in the absence of ongoing P. falciparum exposure in both returned travelers and immigrants. The secondary objective is to compare the P. falciparum-specific humoral and cellular immune response in naive travelers and immigrants to individuals in malaria-endemic areas enrolled in ongoing protocols in Mali.