Department of Microbiology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Trans R Soc Trop Med Hyg. 2013 Aug;107(8):511-7. doi: 10.1093/trstmh/trt042. Epub 2013 Jun 4.
Cryptosporidium and Giardia in water supplies is acknowledged as a public health problem. In the present study, we applied immunofluorescence assay (IFA), PCR and loop-mediated isothermal amplification (LAMP) for the detection of the two protozoa.
Over a period of 12 months, surface water samples were collected from two rivers in the north of Iran, and filtrated by 142 mm membrane filters. At each sampling point 10 L water were used for IFT and the10 L were analysed using molecular methods.
In 15/40 samples, (oo)cysts were detected by one of the IFA, PCR or LAMP methods. Five samples that were Cryptosporidium-negative by IFA were positive by LAMP. A total of 10 out of 13 samples that were Giardia-positive by IFA were also positive by PCR. IFA revealed high levels of Giardia, with 1-1800 cysts and 1-16 Cryptosporidium oocysts detected per 10 L.
The study reveals that the investigated water supplies were contaminated by Cryptosporidium and Giardia. The LAMP assay has advantages for detection and screening of these protozoa at relatively low concentration in water samples. The three assays applied are complimentary but no single one will give the true prevalence of these parasites in surface water samples. However, each method has its own advantages and disadvantages dependent of the aim and the study design; a combination of detection methods should be applied to discover whether water is, or is not, contaminated with (oo)cysts. This is the first report on the occurrence of (oo)cysts in Iranian surface waters to compare the results of parasite detection obtained with the different methods.
水中的隐孢子虫和贾第鞭毛虫被认为是一个公共卫生问题。在本研究中，我们应用免疫荧光检测（IFA）、聚合酶链反应（PCR）和环介导等温扩增（LAMP）来检测这两种原生动物。
在 12 个月的时间里，从伊朗北部的两条河流中采集地表水样本，并通过 142mm 膜过滤器进行过滤。在每个采样点，使用 10L 水进行 IFT，其余 10L 水用于分子方法分析。
在 40 个样本中的 15 个样本中，通过 IFA、PCR 或 LAMP 方法中的一种检测到（oo）囊。通过 LAMP 检测到 5 个 IFA 检测为阴性的 Cryptosporidium 样品。通过 IFA 检测为阳性的 13 个 Giardia 样本中，有 10 个样本也通过 PCR 检测为阳性。IFA 显示贾第鞭毛虫的水平较高，每 10L 水检测到 1-1800 个囊和 1-16 个 Cryptosporidium 卵囊。
本研究表明，所调查的供水受到 Cryptosporidium 和 Giardia 的污染。LAMP 检测法具有在水样中相对较低浓度下检测和筛选这些原生动物的优势。应用的三种检测方法是互补的，但没有一种方法能准确反映地表水样本中这些寄生虫的真实流行率。然而，每种方法都有其自身的优缺点，取决于检测的目的和研究设计；应结合应用多种检测方法来确定水样是否受到（oo）囊的污染。这是首次报道伊朗地表水（oo）囊的发生情况，比较了不同方法检测寄生虫的结果。
