Fluorescent Antibody Reactions against Six Species of Simian Malaria in Monkeys from India and Malaysia

Sera from 45 Malaysian and 51 Indian monkeys were tested for fluorescent antibody response to antigens of Plasmodium fieldi, P. gonderi, P. inui, P. coatneyi, P. knowlesi, and P. cynomolgi bastianellii. A total of 17 Malaysian and 33 Indian monkey sera had positive antibody responses with the larger number reacting with P. fieldi and P. gonderi. The results suggest the possibility of prior malaria infection or of nonspecific antibody to other parasites. The intensity of this response to heterologous or common antigens may be sufficient to mask a species-specific response. The use of monkeys having no initial fluorescent antibody titer for Plasmodium is suggested for studies involving antibody in monkey malaria.