Schistosomiasis is more prevalent than previously thought: what does it mean for public health goals, policies, strategies, guidelines and intervention programs?
Schistosomiasis is more prevalent than previously thought: what does it mean for public health goals, policies, strategies, guidelines and intervention programs?
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DOI：
10.1186/s40249-017-0275-5
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发表时间：
2017-03-22
影响因子：
8.1
通讯作者：
Campbell CH Jr
中科院分区：
文献类型：
--
作者：
Colley DG;Andros TS;Campbell CH Jr
三种主要寄生虫种（埃及血吸虫、埃及血吸虫）感染的定位和诊断。mansoni和S.日本血吸虫）的检测是用已知特异性的测定法进行的，但随着流行率的下降或在感染率已经很低的地区，这种测定法越来越不敏感。这对实现消灭血吸虫病的目标是一个真正的挑战，因为在蜗牛媒介中，寄生虫的生命周期的倍增部分有利于继续传播，只要即使是少数人也能保持少量的蠕虫在排泄物中传播卵。基于检测感染者尿液中的蠕虫抗原（循环阴极抗原- CCA;循环阳极抗原- CAA）的新作图工具具有高度灵敏度，据报道CAA测定具有高度特异性。在所有这三种寄生虫的低流行率地区使用这些工具已经证明，更多的人携带蠕虫而不是定期排泄虫卵，其水平可通过常规粪便检测（Kato-Katz）或尿液过滤检测到。在发病率极低的地区，这一数字有时高出6至10倍。面对似乎是一个相当大的人口“卵阴性/蠕虫阳性血吸虫病”，特别是在非常低的流行率的地区，国家NTD计划是困惑，他们应该制定什么指导方针和战略，如果他们继续朝着消除的目标。有一个关键的需要，继续评估所涉及的检测，并了解这种“卵阴性/蠕虫阳性血吸虫病”的个人发病率和社区传播的贡献。对于那些希望推进旨在消除的战略的国家NTD计划，也迫切需要基于使用这些更敏感的检测方法的新指南。本文的在线版本（doi：10.1186/s40249-017-0275-5）包含补充材料，可供授权用户使用。
Mapping and diagnosis of infections by the three major schistosome species (Schistosoma haematobium, S. mansoni and S. japonicum) has been done with assays that are known to be specific but increasingly insensitive as prevalence declines or in areas with already low prevalence of infection. This becomes a true challenge to achieving the goal of elimination of schistosomiasis because the multiplicative portion of the life-cycle of schistosomes, in the snail vector, favors continued transmission as long as even a few people maintain low numbers of worms that pass eggs in their excreta. New mapping tools based on detection of worm antigens (circulating cathodic antigen – CCA; circulating anodic antigen – CAA) in urine of those infected are highly sensitive and the CAA assay is reported to be highly specific. Using these tools in areas of low prevalence of all three of these species of schistosomes has demonstrated that more people harbor adult worms than are regularly excreting eggs at a level detectable by the usual stool assay (Kato-Katz) or by urine filtration. In very low prevalence areas this is sometimes 6- to10-fold more. Faced with what appears to be a sizable population of “egg-negative/worm-positive schistosomiasis” especially in areas of very low prevalence, national NTD programs are confounded about what guidelines and strategies they should enact if they are to proceed toward a goal of elimination. There is a critical need for continued evaluation of the assays involved and to understand the contribution of this “egg-negative/worm-positive schistosomiasis” condition to both individual morbidity and community transmission. There is also a critical need for new guidelines based on the use of these more sensitive assays for those national NTD programs that wish to move forward to strategies designed for elimination. The online version of this article (doi:10.1186/s40249-017-0275-5) contains supplementary material, which is available to authorized users.