Arthritis in children: an occult manifestation of Bancroftian filariasis.

A form of unexplained arthritis, not attributable to known causes, seen in children (0-14 yrs) in this endemic zone of Bancroftian filariasis was investigated for its association with filariasis. Nineteen cases of undiagnosed arthritis were screened for filarial IgG antibodies to Wuchereria by Stick Enzyme Linked Immunosorbent Assay (ELISA). All had large joint involvement, the commonest joint affected being the knee joint. Involvement was monoarticular in 10 and binarticular in 9. Joint pain was present in 18 and effusion in 12. Five patients had recurrent episodes. Sixteen (84.2%) showed filarial antibodies of which only one (5.3%) was microfilaraemic. Patients with classical filariasis (16), disease controls (10), endemic normals (15) and non-endemic normals (10) were also subjected to ELISA to ascertain the sensitivity and specificity of the technique. Fifteen (93.8%) cases of classical filariasis and 1 (6.7%) of endemic normal were antibody positive, whereas none of disease controls and non-endemic normals had filarial antibodies. Nine cases of filarial arthritis reviewed after a course of Diethylcarbamazine showed satisfactory response to treatment.