Determinants of hepato- and spleno-megaly in Hunan, China: cross-sectionalsurvey data from areas endemic for schistosomiasis

In order to understand the determinants of schistosome-related hepato- and spleno-megaly better, 14 002 subjects aged 3-60 years (59% male; mean age = 32 years) were randomly selected from 43 villages, all in Hunan province, C hina, where schistosomiasis caused by Schistosoma japonicum is endemic. The abdomen of each subject was examined along the mid-sternal (MSL) and mid-c lavicular lines, for evidence of current hepato- and/or spleno-megaly, and a questionnaire was used to collect information on the medical history of e ach individual. Current infections with S. japonicum were detected by stool examination. Almost all (99.8%) of the subjects were ethnically Han by descent and most (77%) were engaged in farming. Although schistosomiasis appeared common (42 % of the subjects claiming to have had the disease), only 45% of the subjec ts said they had received anti-schistosomiasis drugs. Overall, 1982 (14%) o f the subjects had S. japonicum infections (as revealed by miracidium-hatch ing tests and/or Katon Katz smears) when examined and 22% had palpable hepa tomegaly (i.e. enlargement of at least 3 cm along the MSL), although only 2 .5% had any form of detectable splenomegaly (i.e. a Hackett's grade of at l east 1). Multiple logistic regression revealed that male subjects, fisherme n, farmers, subjects aged greater than or equal to 25 years, subjects with a history of schistosomiasis, and subjects who had had bloody stools in the previous 2 weeks were all at relatively high risk of hepato- and/or spleno -megaly. In areas moderately endemic for Schistosoma japonicum, occupational exposur e and disease history appear to be good predictors of current disease statu s among older residents. These results reconfirm those reported earlier in the same region.