Ono K, Tsuji H, Rai S K, Yamamoto A, Masuda K, Endo T, Hotta H, Kawamura T, Uga S
Division of Microbiology, Hyogo Prefectural Institute of Public Health, Kobe University School of Medicine, Kobe, Japan.
Appl Environ Microbiol. 2001 Sep;67(9):3832-6. doi: 10.1128/AEM.67.9.3832-3836.2001.
In Japan, only a few rivers have been inspected for Cryptosporidium parvum contamination, and the methods used had low sensitivity. In 1998 and 1999, we used a method with higher sensitivity to examine all large rivers used as sources of water supply in one prefecture (which we divided into four areas) in western Japan for Cryptosporidium oocysts. One sample was collected at each of 156 sites along 18 rivers, and samples were tested for Cryptosporidium oocysts by immunomagnetic separation. Samples were classified as being obtained on an island with livestock and fishing industries, a densely populated urban area, a western region including farming villages, or a still more rural northern area with agriculture and fishing. Restriction fragment length polymorphism analysis was used for identification of the C. parvum found as the bovine or human type. C. parvum was detected in at least one sample from 13 of the 18 rivers and in 47% (74 of 156) of the samples. One-third to all of the samples from each area contained C. parvum oocysts. The number of C. parvum oocysts per 20 liters of river water varied in the same pattern as the number of cattle kept in the four kinds of areas (as determined by the Mantel extension test). Oocysts isolated were of the bovine type; the C. parvum detected in rivers probably came from cattle kept in that valley. As we had expected, when tested with a more sensitive method, river water in western Japan was found to be greatly contaminated with C. parvum oocysts, as reported in other countries.
在日本，仅对少数几条河流进行过微小隐孢子虫污染情况的检测，且所采用的方法灵敏度较低。1998年和1999年，我们运用一种灵敏度更高的方法，对日本西部一个县（我们将其划分为四个区域）内所有用作供水水源的大型河流进行微小隐孢子虫卵囊检测。沿着18条河流的156个位点各采集了一份样本，并通过免疫磁珠分离法对样本进行微小隐孢子虫卵囊检测。样本按采集地点分为有畜牧业和渔业的岛屿、人口密集的市区、包括乡村的西部地区或农业与渔业更为发达的北部乡村地区。采用限制性片段长度多态性分析来鉴定所发现的微小隐孢子虫是牛型还是人型。在18条河流中的13条河流的至少一份样本中检测到了微小隐孢子虫，在156份样本中有47%（74份）检测到该虫。每个区域三分之一至全部样本中都含有微小隐孢子虫卵囊。每20升河水中微小隐孢子虫卵囊的数量变化模式与这四类地区所饲养牛的数量变化模式相同（经曼特尔扩展检验确定）。分离出的卵囊为牛型；在河流中检测到的微小隐孢子虫可能来自该流域所饲养的牛。正如我们所预期的，使用更灵敏的方法检测时，发现日本西部的河水受到微小隐孢子虫卵囊的严重污染，其他国家也有类似报道。
