What does soil-transmitted helminth elimination look like? Results from a targeted molecular detection survey in Japan
What does soil-transmitted helminth elimination look like? Results from a targeted molecular detection survey in Japan
复制标题
DOI：
10.1186/s13071-019-3875-z
复制
发表时间：
2020-01-08
影响因子：
3.2
通讯作者：
Hamano, Shinjiro
中科院分区：
文献类型：
--
作者：
Hasegawa, Mitsuko;Pilotte, Nils;Hamano, Shinjiro
背景日本是为数不多的几个被认为已经消灭了土传蠕虫的国家之一。1949年，全国蛔虫患病率为62.9%，由于基础设施、社会经济状况的改善和国家性传播感染控制措施的实施，这一比例在1973年下降到0.6%。《寄生虫病防治法》于1994年终止，日本停止了人口水平的筛查；因此，日本目前的STH传播状况并不是很好。STH感染的零星病例继续被报告，这增加了STH感染大规模复发的可能性。鉴于传统的显微镜检测方法对低强度的STH感染不敏感，我们使用敏感的基于PCR的分析方法进行了有针对性的患病率调查，以评估当前的STH传播状况，并描述日本据信已实现历史上STH消除的地区的流行病学特征。方法采集日本6个STH高发区的682名学龄前儿童和学龄儿童的粪便标本。参与者的照顾者完成了一份问卷，以确定获得水、卫生设施和个人卫生(洗涤)的机会，以及可能暴露在环境污染中。在粪便检测方面，采用多重平行实时荧光聚合酶链式反应检测蛔虫、美洲钩虫、十二指肠钩虫和鞭虫的感染。结果在682名儿童中，没有发现阳性样本，参与者报告洗涤标准很高。结论据我们所知，这是日本第一个使用敏感分子技术进行STH检测的STH监测研究。结果表明，STH感染没有复发，而且在采样地区流行率持续下降。这些发现表明，将患病率降低到消除阈值以下是可能的，这暗示着传播中断。此外，这项研究还提供了间接证据，证明多重并行实时聚合酶链式反应方法适用于评估STH患病率极低地区的消除状况。
Background Japan is one of the few countries believed to have eliminated soil-transmitted helminths (STHs). In 1949, the national prevalence of Ascaris lumbricoides was 62.9%, which decreased to 0.6% in 1973 due to improvements in infrastructure, socioeconomic status, and the implementation of national STH control measures. The Parasitosis Prevention Law ended in 1994 and population-level screening ceased in Japan; therefore, current transmission status of STH in Japan is not well characterized. Sporadic cases of STH infections continue to be reported, raising the possibility of a larger-scale recrudescence of STH infections. Given that traditional microscopic detection methods are not sensitive to low-intensity STH infections, we conducted targeted prevalence surveys using sensitive PCR-based assays to evaluate the current STH-transmission status and to describe epidemiological characteristics of areas of Japan believed to have achieved historical elimination of STHs. Methods Stool samples were collected from 682 preschool- and school-aged children from six localities of Japan with previously high prevalence of STH. Caregivers of participants completed a questionnaire to ascertain access to water, sanitation and hygiene (WASH), and potential exposures to environmental contamination. For fecal testing, multi-parallel real-time PCR assays were used to detect infections of Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale and Trichuris trichiura. Results Among the 682 children, no positive samples were identified, and participants reported high standards of WASH. Conclusions To our knowledge, this is the first STH-surveillance study in Japan to use sensitive molecular techniques for STH detection. The results suggest that recrudescence of STH infections has not occurred, and that declines in prevalence have been sustained in the sampled areas. These findings suggest that reductions in prevalence below the elimination thresholds, suggestive of transmission interruption, are possible. Additionally, this study provides circumstantial evidence that multi-parallel real-time PCR methods are applicable for evaluating elimination status in areas where STH prevalence is extremely low.