Wang Xian-Hong, Wu Xiao-Hua, Zhou Xiao-Nong
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai 200025, China.
Int J Parasitol. 2006 Jul;36(8):895-902. doi: 10.1016/j.ijpara.2006.04.003. Epub 2006 May 24.
A Bayesian approach to overcome the imperfections of an immunological test (an antibody-based ELISA) and a parasitological test (Kato-Katz) in the detection of Schistosoma japonicum infection, was used to estimate community prevalences of S. japonicum infection in China. At the same time, the similarity between the prevalence estimates based on data from ELISA alone and those using data from both ELISA and Kato-Katz tests was explored. The database from the third nationwide sampling survey of schistosomiasis in China, 2004, was used for analysis, in which a total of 239 endemic villages were sampled from seven endemic provinces through a stratified cluster sampling technique and 250,987 residents aged from 6 to 65 years, were examined by ELISA followed by a Kato-Katz test applied to the seropositives. Bayesian hierarchical models incorporating random effects to reflect the nested data structure and uncertainty about test properties were employed to analyse the data. Our analysis suggested that using data from ELISA alone or both ELISA and Kato-Katz tests resulted in similar prevalence estimates, probably owing to the lack of sensitivity of Kato-Katz and the fact that Kato-Katz was only applied to the seropositives. We conclude that it is feasible to employ only ELISA, instead of combined ELISA and Kato-Katz tests, to estimate prevalence of S. japonicum infection in large-scale epidemiological settings. This study confirmed heterogeneity in the prevalence of S. japonicum infection in space by the fact that the estimated prevalences of S. japonicum infection in the sampled villages ranged from 0.02% to about 56% (posterior median). It is indicated that the disease remains a threat in some areas along the Yangtze River, although great achievements have been made in the control programme of schistosomiasis in China.
采用贝叶斯方法克服免疫检测（基于抗体的酶联免疫吸附测定法，ELISA）和寄生虫检测（加藤厚涂片法，Kato-Katz）在日本血吸虫感染检测中的不足，以估计中国社区日本血吸虫感染率。同时，探讨了仅基于ELISA数据的感染率估计值与使用ELISA和Kato-Katz两种检测数据的感染率估计值之间的相似性。分析使用了来自2004年中国第三次全国血吸虫病抽样调查的数据库，通过分层整群抽样技术从七个血吸虫病流行省份抽取了239个流行村，对250987名6至65岁居民进行ELISA检测，随后对血清反应阳性者进行加藤厚涂片法检测。采用纳入随机效应以反映嵌套数据结构和检测特性不确定性的贝叶斯分层模型对数据进行分析。我们的分析表明，仅使用ELISA数据或同时使用ELISA和Kato-Katz检测数据得出的感染率估计值相似，这可能是由于加藤厚涂片法缺乏敏感性，且该方法仅应用于血清反应阳性者。我们得出结论，在大规模流行病学调查中，仅采用ELISA而非ELISA与加藤厚涂片法联合检测来估计日本血吸虫感染率是可行的。本研究证实了日本血吸虫感染率在空间上存在异质性，抽样村的日本血吸虫感染率估计值范围为0.02%至约56%（后验中位数）。这表明，尽管中国在血吸虫病防治工作中取得了巨大成就，但长江沿线一些地区的血吸虫病仍然构成威胁。
