[Analysis on morbidity and chemotherapy effects of Schistosoma japonicum infection in fishermen on Dongting Lake].
摘要
OBJECTIVE: To clarify and evaluate the morbidity of schistosome infection and the effectiveness of chemotherapy among fishermen on East Dongting Lake. METHODS: Information on water-contact, history of infection and of praziquantel (PZQ) treatment among fishermen was collected. Kato-Katz method and miracidium hatching test were applied to detect the pathogens in stool specimen. Serum antibodies against soluble egg antigen (SEA) were detected with ELISA and IHA. B-ultrasonic examination was used to determine the pathological changes of liver and spleen. Chemotherapy [PZQ 40 mg/(kg x d)] was given to the fishermen followed by a re-examination after a transmission season. RESULTS: The first investigation (six months before chemotherapy) showed that among 268 people inquired, 90.7% were frequently or intermittently contacting water, 24.0% were treated with PZQ each year, 39.4% had never been treated in the recent five years. Stool positive rate was 68.1% (111/163) and the geometric mean eggs per gram feces (EPG) were 48.77. Males had a higher infection rate (76.0%) and intensity (62.97 EPG) compared with that of females (58.7% infection rate and 30.42 EPG). The highest positive rate (83.3%) was in the age group of 11 to 20 years old. The prevalence of those who frequently or intermittently contacted water and were never treated before was 76.3% (106/139) and 79.7% (51/64), respectively. Serological positive rate was 88.0% (IHA) or 78.7% (ELISA). B-ultrasound revealed 77.4% (82/106) of the fishermen showing pathological changes in liver and/or spleen due to schistosomiasis. 37.7% of the patients showed II-III stage liver fibrosis (male: 53.0%, female: 15%), 58.5% hepatomegaly and 19.8% splenomegaly. The second investigation (six months after chemotherapy with PZQ) showed a stool positive rate of 35.4% and an average EPG 36.13 in the treatment group which were considerably lower than 56.5% infection rate and 68.47 EPG in the group without treatment. In 39 patients treated,