Perz J F, Le Blancq S M
Division of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA.
Appl Environ Microbiol. 2001 Mar;67(3):1154-62. doi: 10.1128/AEM.67.3.1154-1162.2001.
Cryptosporidium, an enteric parasite of humans and a wide range of other mammals, presents numerous challenges to the supply of safe drinking water. We performed a wildlife survey, focusing on white-tailed deer and small mammals, to assess whether they may serve as environmental sources of Cryptosporidium. A PCR-based approach that permitted genetic characterization via sequence analysis was applied to wildlife fecal samples (n = 111) collected from September 1996 to July 1998 from three areas in lower New York State. Southern analysis revealed 22 fecal samples containing Cryptosporidium small-subunit (SSU) ribosomal DNA; these included 10 of 91 white-tailed deer (Odocoileus virginianus) samples, 3 of 5 chipmunk (Tamias striatus) samples, 1 of 2 white-footed mouse (Peromyscus leucopus) samples, 1 of 2 striped skunk (Mephitis mephitis) samples, 1 of 5 racoon (Procyon lotor) samples, and 6 of 6 muskrat (Ondatra zibethicus) samples. All of the 15 SSU PCR products sequenced were characterized as Cryptosporidium parvum; two were identical to genotype 2 (bovine), whereas the remainder belonged to two novel SSU sequence groups, designated genotypes 3 and 4. Genotype 3 comprised four deer-derived sequences, whereas genotype 4 included nine sequences from deer, mouse, chipmunk, and muskrat samples. PCR analysis was performed on the SSU-positive fecal samples for three other Cryptosporidium loci (dihydrofolate reductase, polythreonine-rich protein, and beta-tubulin), and 8 of 10 cloned PCR products were consistent with C. parvum genotype 2. These data provide evidence that there is sylvatic transmission of C. parvum involving deer and other small mammals. This study affirmed the importance of wildlife as potential sources of Cryptosporidium in the catchments of public water supplies.
隐孢子虫是人类和许多其他哺乳动物的肠道寄生虫，给安全饮用水供应带来了诸多挑战。我们开展了一项野生动物调查，重点关注白尾鹿和小型哺乳动物，以评估它们是否可能作为隐孢子虫的环境来源。一种基于聚合酶链反应（PCR）的方法被应用于野生动物粪便样本（n = 111），该方法通过序列分析允许进行基因特征鉴定。这些粪便样本于1996年9月至1998年7月从纽约州下游的三个地区采集。Southern印迹分析显示，有22份粪便样本含有隐孢子虫小亚基（SSU）核糖体DNA；其中包括91份白尾鹿（弗吉尼亚鹿）样本中的10份、5份花栗鼠样本中的3份、2份白足鼠样本中的1份、2份条纹臭鼬样本中的1份、5份浣熊样本中的1份以及6份麝鼠样本中的6份。所有15个测序的SSU PCR产物均被鉴定为微小隐孢子虫；其中两个与基因型2（牛型）相同，其余属于两个新的SSU序列组，分别命名为基因型3和4。基因型3包含四个来自鹿的序列，而基因型4包括来自鹿、小鼠、花栗鼠和麝鼠样本的九个序列。对SSU阳性粪便样本针对其他三个隐孢子虫基因座（二氢叶酸还原酶、富含多苏氨酸蛋白和β-微管蛋白）进行了PCR分析，10个克隆的PCR产物中有8个与微小隐孢子虫基因型2一致。这些数据提供了证据，表明微小隐孢子虫存在涉及鹿和其他小型哺乳动物的野生动物传播。这项研究证实了野生动物作为公共供水流域中隐孢子虫潜在来源的重要性。
