CHANGES IN ANTI-FILARIAL ANTIBODY AFTER CONTROL OF FILARIASIS IN SHANDONG PROVINCE

The changes in anti filarial antibody level at different periods in di fferent population groups of various controlled areas were studied by indirect fluorescent antibody test (IFT) using frozen sections of Brug ia malayi adult worms as antigen. The positive rates by IFAT in former ly hyper-, moderate- and low endemic areas decreased to the level as t hose in non-endemic areas 15, 10 and 10 years respectively after the c ontrol of filariasis. In the children born after the control of filari asis, the IFAT positive rate was less than 1%. An analysis of IFAT pos itive cases showed that the positive rate was lowest in children under 10 years old and highest in those aged 20-40 and decreased progressiv ely with the increasing of age. In addition, the IFAT positive rates o f microfilaremia cases, the residents in currently endemic area and co ntrol group from non-endemic area were 91.4%, 33.9% and 4.5% respectiv ely. These data demonstrated the present distribution pattern of anti- filarial antibody.