PDF(Pubmed)
Abstract：
Despite decades of interventions, 240 million people have schistosomiasis. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity, affected treatment efficacy and reinfection rate estimates. The point-of-care circulating cathodic antigen (referred to from here as POC-CCA+) test is advocated as an improvement on the Kato-Katz method, but improved estimates are limited by ambiguities in the interpretation of trace results.
We collected repeated Kato-Katz egg counts from 210 school-aged children and scored POC-CCA tests according to the manufacturer\'s guidelines (referred to from here as POC-CCA+) and the externally developed G score. We used hidden Markov models parameterized with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding trace interpretations.
Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79%-92%), 99% (POC-CCA+; 97%-100%) and 98% (G-Score; 95%-100%). Post-treatment, 93% (Kato-Katz; 88%-96%), 72% (POC-CCA+; 64%-79%) and 65% (G-Score; 57%-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27%-42%), 51% (POC-CCA+; 41%-62%) and 44% (G-Score; 33%-55%) were estimated to have been reinfected by 9-weeks.
Treatment impact was shorter-lived than Kato-Katz-based estimates alone suggested, with lower clearance and rapid reinfection. At 3 weeks after treatment, longer-term clearance dynamics are captured. At 9 weeks after treatment, reinfection was captured, but failed clearance could not be distinguished from rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.
We collected repeated Kato-Katz egg counts from 210 school-aged children and scored POC-CCA tests according to the manufacturer\'s guidelines (referred to from here as POC-CCA+) and the externally developed G score. We used hidden Markov models parameterized with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding trace interpretations.
Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79%-92%), 99% (POC-CCA+; 97%-100%) and 98% (G-Score; 95%-100%). Post-treatment, 93% (Kato-Katz; 88%-96%), 72% (POC-CCA+; 64%-79%) and 65% (G-Score; 57%-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27%-42%), 51% (POC-CCA+; 41%-62%) and 44% (G-Score; 33%-55%) were estimated to have been reinfected by 9-weeks.
Treatment impact was shorter-lived than Kato-Katz-based estimates alone suggested, with lower clearance and rapid reinfection. At 3 weeks after treatment, longer-term clearance dynamics are captured. At 9 weeks after treatment, reinfection was captured, but failed clearance could not be distinguished from rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.
摘要：
尽管进行了数十年的干预，2.4亿人患有血吸虫病。感染不能直接观察,基于鸡蛋的加藤-卡茨厚涂片缺乏敏感性，影响治疗效果和再感染率估计。提倡即时循环阴极抗原（此处称为POC-CCA）测试是对Kato-Katz方法的改进，但是改进的估计受到跟踪结果解释中的歧义的限制。
我们从210名学龄儿童中收集了重复的Kato-Katz鸡蛋计数，并根据制造商的指南（此处称为POC-CCA+）和外部开发的G评分对POC-CCA测试进行了评分。我们使用了用Kato-Katz、Kato-Katz和POC-CCA+以及Kato-Katz和G分数参数化的隐马尔可夫模型，通过对这些诊断进行比以前更正式的统计核对，推断六个月内四个时间点的潜伏清除和再感染概率。我们的方法需要关于痕迹解释的最小但可靠的假设。
与Kato-Katz模型相比，基于抗原的模型估计所有时间点的感染率更高，对应于较低的清除率和较高的再感染估计。具体来说,治疗前的患病率估计为85%(Kato-Katz；95%CI：79%-92%)，99%(POC-CCA+;97%-100%)和98%(G评分;95%-100%)。后处理,93%（加藤-卡茨；88%-96%），估计有72％（POC-CCA；64％-79％）和65％（G评分；57％-73％）的感染者可以清除感染。在那些清除感染的人中，35%（加藤-卡茨；27%-42%），估计有51％（POC-CCA；41％-62％）和44％（G评分；33％-55％）在9周内再次感染。
治疗效果比Kato-Katz单独估计的时间短，具有较低的清除率和快速的再感染。治疗后3周，较长期的清除动态被捕获。治疗后9周，再次感染被捕获，但清除失败无法与快速再感染区分开来。因此,需要频繁的采样来了解这些重要的流行病学动态。
我们从210名学龄儿童中收集了重复的Kato-Katz鸡蛋计数，并根据制造商的指南（此处称为POC-CCA+）和外部开发的G评分对POC-CCA测试进行了评分。我们使用了用Kato-Katz、Kato-Katz和POC-CCA+以及Kato-Katz和G分数参数化的隐马尔可夫模型，通过对这些诊断进行比以前更正式的统计核对，推断六个月内四个时间点的潜伏清除和再感染概率。我们的方法需要关于痕迹解释的最小但可靠的假设。
与Kato-Katz模型相比，基于抗原的模型估计所有时间点的感染率更高，对应于较低的清除率和较高的再感染估计。具体来说,治疗前的患病率估计为85%(Kato-Katz；95%CI：79%-92%)，99%(POC-CCA+;97%-100%)和98%(G评分;95%-100%)。后处理,93%（加藤-卡茨；88%-96%），估计有72％（POC-CCA；64％-79％）和65％（G评分；57％-73％）的感染者可以清除感染。在那些清除感染的人中，35%（加藤-卡茨；27%-42%），估计有51％（POC-CCA；41％-62％）和44％（G评分；33％-55％）在9周内再次感染。
治疗效果比Kato-Katz单独估计的时间短，具有较低的清除率和快速的再感染。治疗后3周，较长期的清除动态被捕获。治疗后9周，再次感染被捕获，但清除失败无法与快速再感染区分开来。因此,需要频繁的采样来了解这些重要的流行病学动态。
