Coupe Stephane, Delabre Karine, Pouillot Regis, Houdart Stephanie, Santillana-Hayat Maud, Derouin Francis
Laboratoire de Parasitologie-Mycologie, UFR Faculté de Médecine Denis Diderot, Paris, France.
FEMS Immunol Med Microbiol. 2006 Aug;47(3):351-9. doi: 10.1111/j.1574-695X.2006.00098.x.
Accidental ingestion of natural waters while bathing carries a risk of infection by waterborne protozoa such as Cryptosporidium, Giardia and, possibly, microsporidia. In order to evaluate this risk, we conducted a one-year prospective study of two recreational lakes and three river sites located near Paris, where bathing and boating are frequent. Twenty-litre water samples were collected monthly from each site. Concentrated samples were submitted to immunomagnetic separation followed by immunofluorescence (IMS-IF) for Cryptosporidium and Giardia detection. PCR and PCR restriction fragment length polymorphism (PCR-RFLP) were used for the genetic characterization of Cryptosporidium species on IMS-IF-positive samples. PCR were systematically performed to detect Enterocytozoon bieneusi. Bacteria counts were also determined. IMS-IF revealed low counts of Giardia cysts and Cryptosporidium oocysts in the recreational lakes, with occasional peaks (max. 165 cysts/10 L and 9 oocysts/10 L). By contrast, the river sites were consistently and sometimes heavily contaminated throughout the year. Enterocytozoon bieneusi was found in only two river samples. PCR-RFLP genotyping showed the presence of C. hominis and C. parvum. No correlation was found between the presence or counts of parasites and bacteria, except between the presence of Giardia and high counts of Escherichia coli and enterococci. Based on a previously developed model for quantitative risk assessment of waterborne parasitic infections, we estimated that the mean risk of infection by Cryptosporidium and Giardia associated with swimming was <10(-4) in the recreational lakes, and frequently higher at the river sites.
沐浴时意外摄入天然水存在感染水源性原生动物的风险，如隐孢子虫、贾第虫，以及可能的微孢子虫。为评估此风险，我们对巴黎附近两个休闲湖泊和三个河段进行了为期一年的前瞻性研究，这些地方常有人们进行沐浴和划船活动。每月从每个地点采集20升水样。浓缩后的样本先进行免疫磁珠分离，然后采用免疫荧光法（IMS-IF）检测隐孢子虫和贾第虫。对IMS-IF检测呈阳性的样本，使用聚合酶链反应（PCR）和PCR限制性片段长度多态性分析（PCR-RFLP）对隐孢子虫种类进行基因特征分析。系统地进行PCR以检测比氏肠胞微孢子虫。同时也测定细菌数量。IMS-IF检测发现休闲湖泊中贾第虫包囊和隐孢子虫卵囊数量较少，偶尔出现峰值（最高165个包囊/10升和9个卵囊/10升）。相比之下，河段全年持续受到污染，有时污染严重。仅在两份河流水样中发现比氏肠胞微孢子虫。PCR-RFLP基因分型显示存在人隐孢子虫和微小隐孢子虫。除了贾第虫的存在与大肠杆菌和肠球菌的高数量之间存在关联外，未发现寄生虫的存在或数量与细菌之间存在相关性。基于先前开发的水源性寄生虫感染定量风险评估模型，我们估计在休闲湖泊中与游泳相关的隐孢子虫和贾第虫感染平均风险<10^(-4)，而在河段该风险通常更高。
