Prevalence of occult filariasis was studied among the patients attending the outpatient department (OPD) of Raja Mirasudar Hospital, Thanjavur, an endemic area for filariasis in Tamil Nadu using the Sevafilacheck test system for detection of filarial antibody against a purified microfilarial excretory secretary antigen (ES) fraction. The common clinical presentations of positive patients before Diethylcarbamazine (DEC) treatment were analysed. A total of 34 patients (15.5%) out of 220 showed filarial antibody in their serum, with arthritis (52.9%), tropical pulmonary eosinophilia (23.5%), joint pain-knee (17.6%) generalized myalgia and low back pain (5.9%) as common symptoms. All the 34 patients positive for filarial antibody were treated with DEC (6mg/kg body weight/day for 21 days each month for three months). The patients so treated showed a dramatic clinical relief.
