Evaluation of methods for the laboratory diagnosis of malaria in Guyana

RESUMO

When 297 blood samples taken from patients attending a fever clinic in Georgetowm Public Hospital were examined microscopically, after thick and thin blood films had been stained with Giemsa, one hundred and forty-two (47.8 per cent ) were microscopically positive for malaria. After processing the patients' serum samples by the Indirect Fluourescent Antibody (IFA) technique, specific IgG and IgM antibodies were detected in 239 (81.3 per cent ) and 179 (60.1 per cent ), respectively, of the sera. Based on the microscopical findings, the IFAT gave positive and negative values of 54.4 per cent and 81.8 per cent (IgG), and 57.5 per cent and 67.8 per cent (IgM), suggesting that the IgM would be more useful than the IgG in the diagnosis of current malaria. An odds ratio analysis showed that the presence of symptoms, IgG or IgM antibodies, as well as visits to endemic regions, could be good indicators of current malaria. Age and occupation are not. The microscopical method will continue to be the gold standard - the best available criterion for the validation of our tests - for our diagnosis of acute malaria.