Bancroftian filariasis in Nepal: a survey for circulating antigenemia of Wuchereria bancrofti and urinary IgG4 antibody in two rural areas of Nepal.

Serum and urine samples were randomly collected from residents in two rural areas at different altitudes in Nepal, and were examined for Wuchereria bancrofti antigens and antibodies (IgG4) to filarial antigens, respectively. In Judigaun, located at 900 m in altitude, 25.2% of 238 serum samples were positive for antigen, and 50.8% of 244 urine samples were positive for antibody. The level of IgG4 antibodies was higher among antigen positive individuals than among the antigen negatives. In Kotyang, located at 1100-1300 m, the prevalence of antigenemia was 15.4% of 117 serum samples.