Booth M, Guyatt H L, Li Y, Tanner M
Department of Public Health and Epidemiology, Swiss Tropical Institute, Basel, Switzerland.
Trop Med Int Health. 1996 Oct;1(5):646-54. doi: 10.1111/j.1365-3156.1996.tb00090.x.
In common with other helminth infections, symptoms associated with Schistosoma japonicum infection have a low specificity, and many infections are asymptomatic. The presence of the parasite in a sick individual from an endemic area does not mean that S. japonicum is the aetiological agent. However, estimates of the proportion of all symptomatic episodes in a community attributable to S. japonicum infection can be used to determine its public health impact. Using parasitological and morbidity survey data from 3 villages in China, the fractions of diarrhoea, bloody stool, and abdominal pain episodes that were attributable to S. japonicum infection were estimated. The association between hepatomegaly and S. japonicum infection was also assessed. For all morbidity indicators, it was found that individuals with higher infection intensities were at greater risk of morbidity. The highest risk indicator of morbidity associated with S. japonicum infection was bloody stools. Logistic regression revealed that factors related to village and sex were important confounders of the relation between infection and the risk of morbidity. The fraction of the population in each village estimated to be suffering morbidity attributable to S. japonicum infection was low, due to the low prevalence of infection. However, the results suggest that some sick individuals may have been diagnosed as false negatives for S. japonicum infection.
与其他蠕虫感染一样，日本血吸虫感染相关症状的特异性较低，许多感染者并无症状。在流行地区，患病个体体内存在该寄生虫并不意味着日本血吸虫就是病因。然而，可通过估算社区中所有由日本血吸虫感染引起的症状性发作的比例，来确定其对公共卫生的影响。利用来自中国3个村庄的寄生虫学和发病率调查数据，估算了腹泻、血便和腹痛发作中由日本血吸虫感染所致的比例。同时还评估了肝肿大与日本血吸虫感染之间的关联。对于所有发病率指标，研究发现感染强度较高的个体发病风险更高。与日本血吸虫感染相关的最高发病风险指标是血便。逻辑回归分析显示，与村庄和性别相关的因素是感染与发病风险之间关系的重要混杂因素。由于感染率较低，每个村庄中估计因日本血吸虫感染而发病的人口比例较低。然而，结果表明，一些患病个体可能被误诊为日本血吸虫感染的假阴性病例。
