During August 1965, serum samples for the fluorescent-antibody test for malaria were obtained from 10 of the 35 patients involved in the Lake Vera, California, outbreak of P. vivax malaria in 1952–1953. Nine other persons who had also been at one of the Lake Vera camps during the summer of 1952 were likewise tested to serve as a normal reference. The results indicated that a low level of malarial antibody to P. vivax antigen persisted in the patient population 13 years after the original transmission of infection. This low level of malarial antibody was not detectable with the simian species P. fieldi as antigen.
Epidemic Intelligence Service Officer, Parasitic Diseases Section, Epidemiology Branch, Communicable Disease Center, Atlanta, Georgia. Present address: Parkland Memorial Hospital, Dallas, Texas.
Laboratory of Parasite Chemotherapy, NIAID-NIH, P.O. Box 190, Chamblee, Georgia.