Schistosoma japonicum infection among migrant fishermen in the Dongting Lake region of China

An epidemiological survey of Schistosoma japonicum infection was made among 316 persons, fishermen and their family members, in 5 sites of the Dongting Lake region. Their medical history was taken and physical and stool examinations were carried out. The infected persons were divided into 3 groups; 2 were treated with one or 2 doses of praziquantel and one, the control group, was given no treatment. The results showed a high overall prevalence of 41% with an intensity of infection of 34 eggs per gram (epg) in a single stool specimen. The individuals with a history of treatment had a lower prevalence (45/167, 26.9%) than those with no history of treatment (85/149, 57%) (P < 0.01). The mean intensity of infection of the treated group, 27.8 epg, was also lower than that of the untreated group, 39.1 epg (P < 0.01). Symptoms within the past 2 weeks were reported by 31% of the individuals surveyed. Individuals excreting eggs had a higher rate of symptoms (56.2%) than those not excreting eggs (13.4%) (P < 0.01). The proportions of those not excreting eggs in the treated groups were 77.8% and 84.1%, compared with 14.6% in the control group. The survey revealed relatively high endemicity among fishermen and their family members. Treatment and health education of fishermen should be encouraged to control transmission.