Malaria antibody titres as measured by the indirect fluorescent antibody test in relation to parasitaemia and treatment.

Two hundred and two sera from Orang Asli patients living in malarious areas were tested by the washed-cell, thick smear malaria IFA test. These patients were infected with P.vivax, P.falciparum and some with both parasites. Antibodies to the homologous antigens were detected at titres of 1 : 16-1 : 4096 about 60 days after onset of treatment. Eighteen months after cure antibody levels had fallen to lower levels of reactivity.