The Colombian sera were collected in Buenaventura the main port on the Colombian Pacific Coast after human informed consent, during a cross sectional survey carried out from February to May 2002 within the framework of a project supported by the Colombian Research Council, COLCIENCIAS. The area has unstable transmission of both P. falciparum and P. vivax malaria. Ethical clearance to draw blood from human volunteers was Human purified antibodies were used at 5 mg/mL; IFAT was not performed on ring stages. 