Abstract
BackgroundWith worldwide distribution and importance for veterinary medicine, Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi have been found in a wide variety of vertebrate hosts. At present, few available molecular data can be used to understand the features of genetic diversity of these pathogens in areas without or less intensive farming. Dominated by grazing, Tibet is a separate geographic unit in China and yaks are in frequent contact with local herdsmen and necessary for their daily life. Therefore, to investigate the distribution of these pathogens in yaks of Tibet, 577 fecal specimens were screened using nested PCR for the presence and genotypes of the three intestinal pathogens.ResultsThe overall prevalence of Cryptosporidium spp., G. duodenalis, and E. bieneusi were 1.4% (8/577), 1.7% (10/577), and 5.0% (29/577), respectively. Cryptosporidium andersoni (n = 7) and Cryptosporidium bovis (n = 1) were detected by sequence analysis of the SSU rRNA gene. Genotyping at the SSU rRNA and triosephosphate isomerase genes suggested that all G. duodenalis positive specimens belonged to assemblage E. Sequence analysis of the internal transcribed spacer gene identified six known E. bieneusi genotypes: BEB4 (n = 11), I (n = 6), D (n = 5), J (n = 2), CHC8 (n = 1), and BEB6 (n = 1). One subtype (A5,A4,A2,A1) for C. andersoni and three multilocus genotypes for E. bieneusi were identified by multilocus sequence typing.ConclusionsWe report for the first time the status of three enteric pathogens infection simultaneously for grazing yaks in Tibet. Yaks in our study are likely to impose a low zoonotic risk for humans. The molecular epidemiology data add to our knowledge of the characteristics of distribution and transmission for these pathogens in Tibet and their zoonotic potential and public health significance.
Highlights
With worldwide distribution and importance for veterinary medicine, Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi have been found in a wide variety of vertebrate hosts
Among 13 genotypes detected in yaks from the three studies available, genotypes BEB4 and J were reported to be the dominant E. bieneusi genotypes in yaks, which were clustered into group 2
Cryptosporidium Among 577 samples (62 from Mainling, 125 from Gongbo’gyamda, 262 from Bayi District, 56 from Gyaca, and 72 from Xaitongmoin), Cryptosporidium spp. were detected in eight (1.4%, 8/577) specimens based on the SSU Small subunit rRNA (rRNA) gene
Summary
With worldwide distribution and importance for veterinary medicine, Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi have been found in a wide variety of vertebrate hosts. As the commonly considered causes of human cryptosporidiosis, giardiosis, and microsporidiosis, Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi have been found in a wide variety of vertebrate hosts. These pathogens can present several typical clinical symptoms, varying from asymptomatic infection to acute or chronic diarrhea. In terms of genetic variation, molecular biological analyses have shown that G. duodenalis has at least eight genotypes or assemblages (A-H), with A and B mainly infecting humans and animals and C to H being restricted to nonhuman host species [3, 11]. Genotypes CHN11, CHN12, CHN14, and WCY1 belonged to group 1 and the remainder belonged to group 2 [15,16,17]
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