Filariasis in Colombia: prevalence of Mansonella ozzardi in the Departamento de Meta, Intendencia del Casanare, and Comisaría del Vichada.

The prevalence and distribution of filarial infections among the inhabitants of adjacent regions of the Departamento del Meta, Intendencia del Casanare, and Comisaría del Vichada in northeastern Colombia was determined by collection and examination of blood samples using the Knott's method. Mansonella ozzardi, the only species detected, was found in 2.5% of the samples collected in Meta (6/243), in 4.9% from Casanare (12/247) and in 2.5% from Vichada (3/137). All of the microfilaria carriers were Indians who had migrated from other parts of eastern Colombia, principally from the interior of Meta and Vichada. These results indicate that filariases are not endemic in the regions examined, and suggest that influx of microfilaria carriers with sufficiently high microfilaremia could establish new foci of transmission in areas where appropriate vectors are abundant.