Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
Water Res. 2013 Apr 1;47(5):1726-40. doi: 10.1016/j.watres.2012.12.027. Epub 2012 Dec 27.
There has been no large-scale systematic molecular epidemiological investigation of the waterborne protozoans, Cryptosporidium or Giardia, in southeastern Australia. Here, we explored, for the first time, the genetic composition of these genera in faecal samples from animals in nine Melbourne Water reservoir areas, collected over a period of two-years. We employed PCR-based single-strand conformation polymorphism (SSCP) and phylogenetic analyses of loci (pSSU and pgp60) in the small subunit (SSU) of ribosomal RNA and 60-kDa glycoprotein (gp60) genes to detect and characterise Cryptosporidium, and another locus (ptpi) in the triose-phosphate isomerase (tpi) gene to identify and characterise Giardia. Cryptosporidium was detected in 2.8% of the 2009 samples examined; the analysis of all amplicons defined 14 distinct sequence types for each of pSSU and pgp60, representing Cryptosporidium hominis (genotype Ib - subgenotype IbA10G2R2), Cryptosporidium parvum (genotype IIa - subgenotypes IIaA15G2R1, IIaA19G2R1, IIaA19G3R1, IIaA19G4R1, IIaA20G3R1, IIaA20G4R1, IIaA20G3R2 and IIaA21G3R1), Cryptosporidium cuniculus (genotype Vb - subgenotypes VbA22R4, VbA23R3, VbA24R3, VbA25R4 and VbA26R4), and Cryptosporidium canis, Cryptosporidium fayeri, Cryptosporidium macropodum and Cryptosporidium ubiquitum as well as six new pSSU sequence types. In addition, Giardia was identified in 3.4% of the samples; all 28 distinct ptpi sequence types defined were linked to assemblage A of Giardia duodenalis. Of all 56 sequence types characterised, eight and one have been recorded previously in Cryptosporidium and Giardia, respectively, from humans. In contrast, nothing is known about the zoonotic potential of 35 new genotypes of Cryptosporidium and Giardia recorded here for the first time. Future work aims to focus on estimating the prevalence of Cryptosporidium and Giardia genotypes in humans and a wide range of animals in Victoria and elsewhere in Australia. (Nucleotide sequences reported in this paper are available in the GenBank database under accession nos. KC282952-KC283005).
在澳大利亚东南部，还没有对水源原生动物、隐孢子虫或贾第鞭毛虫进行大规模系统的分子流行病学调查。在这里，我们首次探索了在墨尔本水水库地区的动物粪便样本中这些属的遗传组成，这些样本是在两年的时间内收集的。我们采用基于 PCR 的单链构象多态性 (SSCP) 和小亚基 (SSU) 核糖体 RNA 和 60kDa 糖蛋白 (gp60) 基因中的基因座 (pSSU 和 pgp60) 和三磷酸甘油醛异构酶 (tpi) 基因中的 (ptpi) 的系统发育分析来检测和表征隐孢子虫，并用另一个基因座 (ptpi) 来鉴定和表征贾第鞭毛虫。在 2009 年检查的 200 个样本中，检测到 2.8%的样本中存在隐孢子虫；所有扩增子的分析为每个 pSSU 和 pgp60 定义了 14 个不同的序列类型，代表了隐孢子虫同源物（基因型 Ib-亚基因型 IbA10G2R2）、隐孢子虫 parvum（基因型 IIa-亚基因型 IIaA15G2R1、IIaA19G2R1、IIaA19G3R1、IIaA19G4R1、IIaA20G3R1、IIaA20G4R1、IIaA20G3R2 和 IIaA21G3R1）、隐孢子虫 cuniculus（基因型 Vb-亚基因型 VbA22R4、VbA23R3、VbA24R3、VbA25R4 和 VbA26R4）以及隐孢子虫犬属、隐孢子虫 fayeri、隐孢子虫 macropodum 和隐孢子虫 ubiquitum 以及六个新的 pSSU 序列类型。此外，在 3.4%的样本中鉴定出了贾第鞭毛虫；所有定义的 28 个独特的 ptpi 序列类型都与十二指肠贾第鞭毛虫的 A 群有关。在所鉴定的 56 个序列类型中，有 8 个和 1 个之前分别在人类的隐孢子虫和贾第鞭毛虫中记录过。相比之下，我们对首次在这里记录的 35 种新的隐孢子虫和贾第鞭毛虫的人畜共患病潜力一无所知。未来的工作旨在重点估计在维多利亚州和澳大利亚其他地区的人类和各种动物中隐孢子虫和贾第鞭毛虫基因型的流行率。（本文报道的核苷酸序列可在 GenBank 数据库中以登录号 KC282952-KC283005 获得）。
