[Observation on negative changes of indirect hemagglutination assay in chronic schistosomiasis patients]

A total of 135 chronic schistosomiasis patients were investigated with indirect hemagglutination assay (IHA) kit for schistosomiasis issued by the national authority, and the titer > or = 1 : 10 was deemed as positive. The IHA positive patients were investigated with Kato-Katz technique and the hatching method, and the water contact survey was performed every year and the re-infection patients were excluded. In the fourth year, 93.65 per thousand of the patients became IHA negative. In conclusion, the schistosome antibody levels of the population by IHA test can be one of important indexes to judge whether the epidemic situation relapses in the process of continuous schistosomiasis surveillance.