PCR-ELISA FOR THE DETECTION OF BRUGIA-MALAYI INFECTION USING FINGER-PRICK BLOOD

A polymerase chain reaction assay based on the enzyme-linked immunosor bent assay (PCR-ELISA) has been developed to detect Brugia malayi infe ction in an area of low endemicity in Malaysia. Blood samples from 239 subjects were tested: 192 amicrofilaraemic individuals, 14 microfilar aemic persons and 3 chronic elephantiasis cases from endemic areas and 30 city-dwellers (non-endemic controls). PCR products were examined b y ELISA and Southern hybridization. In the PCR-ELISA, digoxigenin-labe lled PCR products were hybridized to a biotin-labelled probe. This was followed by incubation in streptavidin-coated microtitre wells and de tection using anti-digoxigenin-peroxidase and ABTS(TM) [2,2'-azinobis( 3-ethylbenzthiazoline-6-sulphonic acid)]. All microfilaraemic samples were positive by PCR-ELISA and Southern hybridization and all samples from non-endemic subjects and chronic elephantiasis patients were nega tive. The PCR-ELISA detected 12 times as many B. malayi infections as did thick blood film examination. Nineteen of the 194 samples from the endemic area gave positive results by both PCR-ELISA and Southern hyb ridization, and an additional 5 samples were positive by PCR-ELISA onl y. The PCR-ELISA was specific and sensitive, detected more infections, and was more reproducible than Southern hybridization.