A comparison of the Og4C3 antigen capture ELISA, the Knott test, an IgG4 assay and clinical signs, in the diagnosis of Bancroftian filariasis.

To compare methods for diagnosing Bancroftian filariasis, six hundred and seventy four people from rural areas of Papua New Guinea were screened using microfilaraemia, the Og4C3 antigen capture ELISA, an ELISA to detect IgG4 specific antibodies and clinical examination. Both ELISA tests detected around twice the number of positive cases than those detected by the presence of microfilariae alone. No correlation was found with clinical signs and laboratory tests. This study raises concern over the underestimation of the prevalence of filariasis due to ineffective diagnostic criteria. The two ELISA tests should be of value in epidemiological surveys and for monitoring filariasis control programs.