AN EVALUATION OF SCHISTOSOMA-JAPONICUM INFECTIONS IN 3 VILLAGES IN THE DONGTING LAKE REGION OF CHINA .1. PREVALENCE, INTENSITY AND MORBIDITY BEFORE THE IMPLEMENTATION OF ADEQUATE CONTROL STRATEGIES

We examined three Chinese villages (one farming village and two fishin g villages) in an area highly endemic for schistosomiasis japonica in order to study the prevalence, intensity of infection and the associat ed morbidities before the implementation of adequate control strategie s. Socio-economic status, medical histories including the frequency an d type of water contact, physical examinations, parasitological examin ations and questionnaires relevant to the knowledge of schistosomiasis were performed on a random sample of 1542 individuals (45% female; 55 % male). The prevalence of Schistosoma japonicum was 9.4% in the fanni ng village and 16.5 and 26.2% in the fishing villages. Eighty-three pe rcent of the infected population had light infections (8-100 eggs per gram stool (epg)) and only 6% had heavy infections (>400 epg). Both th e prevalence and intensity of infection varied significantly (P<0.01) with the frequency of water contact. All the morbidity indicators (wea kness, inability to work, diarrhoea, hepatomegaly and splenomegaly) we re significantly higher (P<0.01) among those infected with S. japonicu m. Knowledge of schistosomiasis, in general, was unsatisfactory in all three villages; 12.4% of the population was infected when their knowl edge of schistosomiasis was good, whereas 26.6% of the population was infected when their knowledge was poor. Further, it appears that schis tosomiasis control based on selective chemotherapy (praziquantel) of r andomly selected stool-positive individuals was ineffective in signifi cantly reducing the prevalence of S. japonicum and its associated clin ical manifestations in the villages under study. (C) 1997 Elsevier Sci ence B.V.