Estimating the distribution of worm burden and egg excretion of Schistosoma japonicum by risk group in Sichuan Province, China
Estimating the distribution of worm burden and egg excretion of Schistosoma japonicum by risk group in Sichuan Province, China
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DOI：
10.1017/s003118200200207x
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发表时间：
2002-09-01
期刊：
影响因子：
2.4
通讯作者：
Spear, RC
中科院分区：
文献类型：
--
作者：
Hubbard, A;Liang, S;Spear, RC
2000年秋季，对四川省西南部安徽河谷的20个村庄的约4000名村民进行了日本血吸虫病流行情况的广泛横断面调查。两个程序被用来评估感染状况，加藤-卡茨厚涂片程序和毛滴虫孵化试验。虽然Kato-Katz程序提供了有关患病率和强度的信息，但孵化试验只提供了患病率数据，尽管大便的体积要大得多。此外，我们对15个个体的子集进行了加藤-卡茨涂片检查。在更大的横断面调查中，孵化试验和Kato-Katz阳性个体的比例为25%。这项研究的目的是使用孵化和加藤-卡茨检验来估计卵子和蠕虫在风险组中的分布，这些测试来自横断面数据和来自纵向数据集的重复加藤-卡茨涂片。作为参数估计的前奏，根据自然村和职业将个体分为危险组；加藤-卡茨阳性者在危险组中的比例从10%到60%不等。我们使用了de Vlas et at的统计模型。(1992)和贝叶斯技术，以得出蠕虫和卵分布参数的估计和推断。参数估计意味着(1)每克粪便中有相似的鸡蛋(例如)每对蠕虫与先前的估计相比，(2)风险组之间的蠕虫负担范围以及(3)组内风险异质性的估计对关于人内排卵变异性的先前信息很敏感。
During autumn 2000 an extensive cross-sectional survey of the prevalence of Schistosomiasis japonicum was conducted among about 4000 villagers within 20 villages in the Arming River Valley located in the southwestern Sichuan Province. Two procedures were used to assess infection status, the Kato-Katz thick smear procedure and a miracidia hatch test. Whereas the Kato-Katz procedure provides information on both prevalence and intensity, the hatch test provides only prevalence data, albeit on a much larger volume of stool. In addition, we performed Kato-Katz smears for IS consecutive samples on a subset of 15 individuals. The proportion of both hatch-test and Kato-Katz positive individuals in the larger cross-sectional survey was 25%. The goal of the study was to estimate both the egg and worm distributions among risk groups using both the hatch and Kato-Katz tests from the cross-sectional data and the repeated Kato-Katz smears from the longitudinal data sets. As a prelude to parameter estimation, individuals were classified into risk groups by natural village and occupation; the proportion of Kato-Katz positive subjects among the risk groups varied from 10% to 60%. We used the statistical model of de Vlas et at. (1992) and Bayesian techniques to derive both estimates of and inference about the worm and egg distribution parameters. The parameter estimates imply (1) similar eggs per gram stool (e.p.g.) per worm pair compared with earlier estimates, (2) a range of worm burdens among the risk groups and (3) estimates of risk heterogeneity within groups is sensitive to prior information on the within-person variability in egg excretion.