title: Prevalence and genotyping of Giardia duodenalis isolated from sheep in Henan Province, central China.
abstract: Giardia duodenalis is a gastrointestinal protozoan that infects sheep. It is a well-known zoonotic pathogen and sheep have been implicated as a source of human infection. However, there have been few studies of its potential threat to public health in China. We used a multilocus analysis of the beta-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes to examine the occurrence and genotype distribution of G. duodenalis in sheep in China. In total, 716 fresh faecal specimens, including 89 from pre-weaned lambs (<3 months old) and 627 from post-weaned sheep (>3 months old) from nine intensive sheep farms in Henan Province, China, were examined for Giardia cysts with microscopy. Of these specimens, 6.65% (47/716; 99% CI: 6.2%-6.92%) from five farms were positive for G. duodenalis. The infection rate was significantly higher in pre-weaned lambs than in post-weaned sheep (12.36% versus 5.74%, respectively; P<0.05). Infection rates ranged from 2.8% to 17.2% on the G. duodenalis-positive farms. All G. duodenalis-positive samples were assayed with PCR followed by sequencing at the three gene loci investigated in this study. As a result, two assemblages were detected: assemblage A (n=5) and assemblage E (n=31), with some mixed E and A infections (n=3). The ratios of assemblage A to assemblage E on the different successfully sequenced G. duodenalis-positive farms were 0:1, 3:14, 1:4, and 1:12. Two new tpi sequences and one new gdh sequence were identified. Multilocus genotyping yielded seven multilocus genotypes (MLGs): one new assemblage A MLG and six assemblage E MLGs. In the phylogenetic analysis, the assemblage A MLG was more closely related to AI than to AII or AIII. The detection of G. duodenalis assemblage A in sheep has public health implications, although G. duodenalis assemblage E was predominant. The data provide basic information for control of giardiasis in human and sheep in Henan province, central China.
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China; Department of Animal Science, Henan Vocational College of Agriculture, Zhongmu 451450, Henan, PR China.
authors: Haiyan
authors: H
authors: Wang
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China.
authors: Meng
authors: M
authors: Qi
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China.
authors: Kaifang
authors: K
authors: Zhang
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China.
authors: Junqiang
authors: J
authors: Li
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China.
authors: Jianying
authors: J
authors: Huang
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China.
authors: Changshen
authors: C
authors: Ning
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, PR China. Electronic address: zhanglx8999@gmail.com.
authors: Longxian
authors: L
authors: Zhang
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D017125:Genes, Protozoan; D005838:Genotype; D016829:Giardia lamblia / Q000145:classification / Q000235:genetics*; D005873:Giardiasis / Q000662:veterinary*; D006801:Humans; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D015995:Prevalence; D017422:Sequence Analysis, DNA; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000469:parasitology*
keywords: Giardia; Host adaptation; Multilocus genotyping; Sheep