DIAGNOSIS OF MALARIA BY ACRIDINE-ORANGE FLUORESCENT MICROSCOPY IN AN ENDEMIC AREA OF VENEZUELA

Fluorescent (acridine orange) microscopical examination of capillary c entrifuged blood (quantitative buffy coat [QBC(R)] analysis) and Giems a stained thick blood smears (GTS) were compared for diagnosis of mala ria in blood specimens from adults living in malaria transmission area s of the States of Bolivar and;Amazonas in southeastern and south Vene zuela, respectively. Of a total of 198 GTS examined, 95 subjects (48%) showed parasitaemia. Among the 95 blood films with a positive GTS, 94 were judged positive by the QBC. However positive QBC tubes were foun d in 29 out of 103 blood specimens with a negative GTS. Thus, relative to a GTS standard, the sensitivity and specificity of the QBC-test wa s 99.2% and 72%, respectively. Young trophozoites of Plasmodium vivax and P. falciparum could not be distinguished with certainty. It is con firmed that the QBC offers many advantages compared with the standard diagnosis of malaria parasites, specifically in the speed of staining and ease of interpretation. However in places where P falciparum and P . vivax occur species and stage differentiation should be confirmed wi th the GTS.