PDF(Pubmed)
Abstract：
Schistosomiasis is a parasitic disease affecting over 240-million people. World Health Organization (WHO) targets for Schistosoma mansoni elimination are based on Kato-Katz egg counts, without translation to the widely used, urine-based, point-of-care circulating cathodic antigen diagnostic (POC-CCA). We aimed to standardize POC-CCA score interpretation and translate them to Kato-Katz-based standards, broadening diagnostic utility in progress towards elimination. A Bayesian latent-class model was fit to data from 210 school-aged-children over four timepoints pre- to six-months-post-treatment. We used 1) Kato-Katz and established POC-CCA scoring (Negative, Trace, +, ++ and +++), and 2) Kato-Katz and G-Scores (a new, alternative POC-CCA scoring (G1 to G10)). We established the functional relationship between Kato-Katz counts and POC-CCA scores, and the score-associated probability of true infection. This was combined with measures of sensitivity, specificity, and the area under the curve to determine the optimal POC-CCA scoring system and positivity threshold. A simulation parametrized with model estimates established antigen-based elimination targets. True infection was associated with POC-CCA scores of ≥ + or ≥G3. POC-CCA scores cannot predict Kato-Katz counts because low infection intensities saturate the POC-CCA cassettes. Post-treatment POC-CCA sensitivity/specificity fluctuations indicate a changing relationship between egg excretion and antigen levels (living worms). Elimination targets can be identified by the POC-CCA score distribution in a population. A population with ≤2% ++/+++, or ≤0.5% G7 and above, indicates achieving current WHO Kato-Katz-based elimination targets. Population-level POC-CCA scores can be used to access WHO elimination targets prior to treatment. Caution should be exercised on an individual level and following treatment, as POC-CCAs lack resolution to discern between WHO Kato-Katz-based moderate- and high-intensity-infection categories, with limited use in certain settings and evaluations.
摘要：
血吸虫病是一种寄生虫病，影响了超过2.4亿人。世界卫生组织（WHO）消除曼氏血吸虫的目标是基于加藤-卡茨卵数，如果没有被广泛使用的翻译，基于尿液，即时循环阴极抗原诊断（POC-CCA）。我们旨在标准化POC-CCA评分解释，并将其转化为基于Kato-Katz的标准，在消除方面扩大诊断效用。贝叶斯潜在类别模型适用于治疗前至治疗后六个月四个时间点的210名学龄儿童的数据。我们使用1)Kato-Katz并建立了POC-CCA评分(否定，Trace,+,++和+++)，和2)加藤-卡茨和G-分数(一个新的，备选POC-CCA评分(G1至G10))。我们建立了Kato-Katz计数与POC-CCA评分之间的函数关系，和真实感染的评分相关概率。这与敏感度相结合，特异性，和曲线下面积，以确定最佳的POC-CCA评分系统和阳性阈值。用模型估计值参数化的模拟建立了基于抗原的消除目标。真实感染与POC-CCA评分≥+或≥G3相关。POC-CCA评分无法预测Kato-Katz计数，因为低感染强度会使POC-CCA盒饱和。治疗后POC-CCA敏感性/特异性波动表明卵排泄与抗原水平（活虫）之间的关系变化。消除目标可以通过群体中的POC-CCA得分分布来识别。人口≤2%++/+++,或≤0.5%G7及以上,表明实现了世卫组织卡托-卡茨的当前消除目标。人口水平的POC-CCA评分可用于在治疗前获得WHO消除目标。应在个人层面和治疗后谨慎行事，由于POC-CCA缺乏辨别基于WHOKato-Katz的中度和高强度感染类别的决心，在某些设置和评估中使用有限。
