Cases of Plasmodium vivax malária have been recorded in a region known as Aldeia dos Índios, Municipality of Peruíbe (24.19ºS and 47.00ºW), in the South Coastal Region of the State São Paulo, Brazil, for the last twenty years. Symptomless, parasitologically subpatent infections persist in that area. The vectors, Anopheles (Kerteszia) cruzii and A. (K.) bellator breed on epiphytic Bromeliaceae, on the top of tall trees. Serological surveys for malaria antibodies, by means of indirect immunofuorescence test, are being performes since the second half of the year 1984, to evaluate P. vivax antibody levels, and to identify possible sources of infection not detected by haemoscopy. Information is being put together to compose an adequate picture of dynamics of malaria transmission in that region, wich comprises ten localities with a total population of about 3,000. As economical activities predominate the cultivation of banana and cacao in addition to that for subsistence. Input data for microcomputer processing were age, sex, and titer. The results were associated to sex, age-groups and the geometric means of the serological titers. A low-endemicity frequency distribution pattern os serological titers was found in connection with the population studied. A predominance of serological cases in age-groups above 15 years was observed. In some cases, haemoscopic positivity was preceded by serological reactivity. The use of the combination haemoscopy/ serology was accordingly indicated. Further investigation was proposed, such as a longitudinal study of haemoscopical and/or serological cases, submitted or not to radical treatment; a research on serological titers of the human population tested using as antigens simian plasmodia potentially infective to man, and an investigation on the installation and persistence of the focus from the viewpoint of human geography.
vivax malaria - seroepidemiology
