Detection of DNA of W. bancrofti in blood samples by QC-PCR-ELISA-based

An internal control was used in a polymerase chain reaction PCR-ELISA-based technique to detect the DNA repeat of the filarial parasite W. bancrofti. The sensitivity of the test could detect as low as one single microfilaria added to 200 ul of blood. The assay was evaluated on field samples from persons living in areas endemic for filariasis. Examination of night blood of 113 individuals for the presence of microfilaria by filtration revealed 44 microfilaria carriers. All microfilaria carriers were positive in the PCR-ELISA and, in addition, 14 more samples were proven to contain parasite DNA. All the 58 proven cases had circulating filarial antigens in their serum samples. Assuming a sensitivity of PCR-ELISA on night blood of 100%, the sensitivity of night blood filtration was 74% and that of circulating filarial antigens is 100%. The data showed that the described PCR-ELISA method was capable of detecting the filarial infections. Consequently, this method facilitated the identification of the filarial endemic areas and the monitoring of control programs.