In 1995-1996 we conducted an epidemiological survey in two communities (1656 individuals) on Qingshan island, Hunan province P.R. China, in order to determine the efficacy of current control strategies since their upgrading in 1991. In 1996, the overall prevalence for Schistosoma japonicum, Ascaris lumbricoides, Ancylostoma duodenale, and Trichuris trichiura had decreased moderately since 1991. The age-specific prevalence for S. japonicum for each of the representative age groups decreased slightly, but there was a significant reduction in these prevalences for the 5-9 (P < 0.01), 55-59 (P < 0.05) and the over 60 (P < 0.01) age groups. The 1996 intensities of infection for schistosomiasis were higher for all the age categories except for those aged 0-4 and 25-29 years of age. When the study population was further classified according to the percent uninfected, lightly infected (8-100 eggs/g (epg)), moderately infected (101-400 epg) and heavily infected (> 400 epg) for S. japonicum, there were fewer (5.6%) people infected in 1996 but the proportions of moderately (21.3 vs. 15.5%) and heavily (7.6 vs. 2.3%) infected individuals were higher than those observed in 1991. The reported cases of weakness and hepatomegaly (MSL > or = 3) were significantly lower (P < 0.01) in 1996 for both uninfected and infected (all intensities) individuals. General episodes of diarrhoea were also significantly lower in 1996 for those lightly (P < 0.05) and heavily (P < 0.01) infected. Likewise, the occurrence of splenomegaly (Hackett's > or = 2) was significantly lower among uninfected (P < 0.01) and heavily infected (P < 0.05) patients. In summary, although significant progress has been made in controlling schistosomiasis and other helminth infections in this highly endemic focus for schistosomiasis, there is still room for improvement. Chemotherapy for bovines and humans, mollusciding for Oncomelania control and health education should be initiated and upgraded if the health and well being of these island communities is to further improve.
PIP: The effectiveness of schistosomiasis control strategies implemented in 1991 were evaluated in a 1995-96 epidemiological study involving 1656 persons from two fishing villages on Qingshan Island in China's Hunan Province. In 1991, the prevalences of Schistosoma japonicum, Ascaris lumbricoides, A. duodenale, and Trichuris trichiura were 17.5%, 90.9%, 0.3%, and 46.5%, respectively. By 1996, these prevalences had dropped to 14.6%, 26.8%, 0.2%, and 4.0%, respectively. Despite an overall reduction in S. japonicum incidence, especially in the 5-9 and 55-59 year age groups, the proportion of moderate and heavy intensity infection was higher in 1996 than 1991, suggesting current dosages of praziquantel should be increased among the severely infected. Also recorded were reductions in S. japonicum-related morbidity--including weakness, hepatomegaly, diarrhea, and splenomegaly--among infected and uninfected persons. Since 1991, treatment coverage has increased for those aged 20 years and under and decreased among those older than 60 years. Recommended to ensure further public health advances are expanded treatment opportunities for humans, initiation of treatment of domestic animals and bovines, initiation of mollusciding in newly identified snail-positive habitats before the peak transmission period, and expanded health education programs.