Filarial antibody detection in suspected occult filariasis in children in an endemic area.

A study was conducted in filarial endemic area for diagnosis of occult filariasis in various clinical conditions in children. Thirty-five age- and sex-matched controls (endemic-15, non-endemic-10, disease control-10), 16 classical lymphatic filariasis, and 92 occult filariasis (clinical conditions which fall in the spectrum of occult filariasis and suspected to be filarial), were subjected to peripheral night blood smear examination for microfilaria (mf) and stick ELISA test using mf ES antigen for filarial antibodies. In the control group none showed mf and only 3 per cent (1/35) among endemic control were positive for filarial antibodies. In classical filariasis 1 per cent (2/16) showed mf and 94 per cent (15/16) had filarial antibodies. In suspected occult filariasis 1 per cent (one case of arthritis) showed mf and 62 per cent (57/92) showed filarial antibodies. These consisted of tropical pulmonary eosinophilia 63 per cent (15/24), arthritis where no cause could be ascertained on investigation 64 per cent (27/42), nephrotic syndrome 69 per cent (11/16), acute glomerulonephritis with ASO < 200 units 38 per cent (3/8), and cardiomyopathy 50 per cent (1/2). Correlation with age showed that 80 per cent (4/5) of cases of arthritis seen in 0-4 years of age group and 82 per cent (11/9) of nephrotic syndrome in the 10-14 years of age group were positive for filarial antibody. Arthritis due to other causes and minimal change nephrotic syndrome are uncommon in these respective age groups. It is concluded that the role of filariasis in endemic areas in these disease states cannot be denied and needs to be studied further.

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.