Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Takeda, Kofu, Japan.
Trans R Soc Trop Med Hyg. 2011 Dec;105(12):711-6. doi: 10.1016/j.trstmh.2011.08.004. Epub 2011 Nov 1.
Limited information is available on the prevalence of waterborne pathogens in aquatic environments in developing countries. In this study, water samples were collected from nine shallow wells and a river in the Kathmandu Valley, Nepal, during the rainy season in 2009 and were subjected to detection of waterborne protozoa, viruses and coliphages using a recently developed method for simultaneous concentration of protozoa and viruses in water. Escherichia coli and total coliforms were also tested as indicator bacteria. At least one type of the five pathogens tested (Cryptosporidium, Giardia, human adenoviruses, and noroviruses of genogroups I and II) was detected in five groundwater samples (56%) (1000 ml each) from shallow wells. Compared with groundwater samples, the pathogens were more abundant in the river water sample (100ml); the concentrations of Cryptosporidium and Giardia were 140 oocysts/l and 8500 cysts/l, respectively, and the mean threshold cycle (Ct) values in real-time RT-PCR were 34.3, 36.8 and 34.0 for human adenoviruses and noroviruses of genogroups I and II, respectively. Genotyping of F-RNA coliphages by real-time RT-PCR was successfully used to differentiate human and animal faecal contamination in the samples. Moreover, for the groundwater samples, protozoa and viruses were detected only in E. coli-positive samples, suggesting that E. coli may be an appropriate indicator of pathogen contamination of valley groundwater.
发展中国家水生环境中水源性病原体的流行情况资料有限。本研究于 2009 年雨季在尼泊尔加德满都谷地采集了 9 口浅层井和一条河流的水样,采用最近开发的同时浓缩水中原生动物和病毒的方法,检测水源性原生动物、病毒和肠噬菌体。还测试了大肠杆菌和总大肠菌群作为指示菌。在来自浅层井的 5 个地下水样本(各 1000ml)中(56%)检测到了测试的 5 种病原体(隐孢子虫、贾第虫、人腺病毒和 I 组和 II 组诺如病毒)中的至少一种。与地下水样本相比,河流水样中的病原体更为丰富(100ml);隐孢子虫和贾第虫的浓度分别为 140 个卵囊/L 和 8500 个孢囊/L,实时 RT-PCR 的平均阈值循环(Ct)值分别为人腺病毒和 I 组和 II 组诺如病毒 34.3、36.8 和 34.0。通过实时 RT-PCR 对 F-RNA 噬菌体进行基因分型成功地用于区分样品中的人粪和动物粪污染。此外,对于地下水样本,仅在大肠杆菌阳性样本中检测到原生动物和病毒,表明大肠杆菌可能是山谷地下水病原体污染的合适指示菌。