P. Fischer et al., SENSITIVITY OF A POLYMERASE CHAIN REACTION-BASED ASSAY TO DETECT ONCHOCERCA-VOLVULUS DNA IN SKIN BIOPSIES, Parasitology research, 82(5), 1996, pp. 395-401
A polymerase chain reaction (PCR) of a 150-bp tandem repeat of Onchoce
rca volvulus (O-150) combined with Southern-blot hybridization to spec
ies-specific DNA probes was employed for DNA detection. O-150 was ampl
ified from parasites originating from Uganda, Benin, Cameroon, Liberia
, Ghana, Burkina Faso, Mali, and Zaire and was successfully hybridized
to digoxigenin-labeled oligonucleotides. To investigate the sensitivi
ty of the PCR, 2 skin biopsies were taken from each of 227 persons fro
m Uganda with proven O. volvulus infections but with low microfilaria
(mf) densities due to ivermectin treatment. One biopsy was tested by P
CR and the other was digested using collagenase to assess the total nu
mber of mf. The PCR revealed 76.2% of the samples to be positive, and
the collagenase method showed that 78.9% were positive, indicating sim
ilar sensitivity for the two methods. It is probable that for both tec
hniques the biopsy must contain at least one live mf or fragments of a
dead mf. In this study, no free or circulating O. volvulus DNA could
be detected in skin biopsies by PCR.