Endemic bancroftian filariasis in Thailand: detection by Og4C3 antigen capture ELISA and the polymerase chain reaction.

Lymphatic filariasis, mainly caused by Wuchereria bancrofti and Brugia malayi, has been targeted for elimination by the World Health Organization by the year 2020. To achieve this goal, highly sensitive and specific diagnostic tests are necessary for close monitoring and evaluation of the control program. We employed an ELISA to detect the Og4C3 antigen and a polymerase chain reaction-based assay for diagnosis of W. bancrofti infection, among the Thai-Karen population in Tak province, Thailand. We found that this endemic area had a microfilarial rate of 10 per cent, while the antigen assay could detect cases about two fold as many (23%). The repeated PCR for the detection of Ssp I of W. bancrofti was positive in 12 per cent of the population under this study. Our data emphasize the need for using highly sensitive and specific assays for assessment of the real burden of the disease.