Garcia-R Juan C, French Nigel, Pita Anthony, Velathanthiri Niluka, Shrestha Rima, Hayman David
Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Palmerston North, New Zealand.
Institute of Veterinary, Animal & Biomedical Sciences, Massey University, Palmerston North, New Zealand.
PLoS Negl Trop Dis. 2017 Jul 13;11(7):e0005736. doi: 10.1371/journal.pntd.0005736. eCollection 2017 Jul.
Cryptosporidiosis and giardiasis are recognized as significant enteric diseases due to their long-term health effects in humans and their economic impact in agriculture and medical care. Molecular analysis is essential to identify species and genotypes causing these infectious diseases and provides a potential tool for monitoring. This study uses information on species and genetic variants to gain insights into the geographical distribution and spatial patterns of Cryptosporidium and Giardia parasites. Here, we describe the population heterogeneity of genotypic groups within Cryptosporidium and Giardia present in New Zealand using gp60 and gdh markers to compare the observed variation with other countries around the globe. Four species of Cryptosporidium (C. hominis, C. parvum, C. cuniculus and C. erinacei) and one species of Giardia (G. intestinalis) were identified. These species have been reported worldwide and there are not unique Cryptosporidium gp60 subtype families and Giardia gdh assemblages in New Zealand, most likely due to high gene flow of historical and current human activity (travel and trade) and persistence of large host population sizes. The global analysis revealed that genetic variants of these pathogens are widely distributed. However, genetic variation is underestimated by data biases (e.g. neglected submission of sequences to genetic databases) and low sampling. New genotypes are likely to be discovered as sampling efforts increase according to accumulation prediction analyses, especially for C. parvum. Our study highlights the need for greater sampling and archiving of genotypes globally to allow comparative analyses that help understand the population dynamics of these protozoan parasites. Overall our study represents a comprehensive overview for exploring local and global protozoan genotype diversity and advances our understanding of the importance for surveillance and potential risk associated with these infectious diseases.
隐孢子虫病和贾第虫病被认为是重要的肠道疾病，因为它们对人类健康有长期影响，并且在农业和医疗保健方面具有经济影响。分子分析对于识别引起这些传染病的物种和基因型至关重要，并提供了一种潜在的监测工具。本研究利用物种和基因变异信息来深入了解隐孢子虫和贾第虫寄生虫的地理分布和空间格局。在这里，我们使用gp60和gdh标记描述了新西兰存在的隐孢子虫和贾第虫基因型组的种群异质性，以将观察到的变异与全球其他国家进行比较。鉴定出了四种隐孢子虫（人隐孢子虫、微小隐孢子虫、兔隐孢子虫和刺猬隐孢子虫）和一种贾第虫（肠贾第虫）。这些物种在全球范围内都有报道，并且在新西兰没有独特的隐孢子虫gp60亚型家族和贾第虫gdh组合，这很可能是由于历史和当前人类活动（旅行和贸易）的高基因流动以及大量宿主种群的持续存在。全球分析表明，这些病原体的基因变异广泛分布。然而，数据偏差（例如序列被忽视提交到基因数据库）和低采样率低估了基因变异。根据累积预测分析，随着采样工作的增加，可能会发现新的基因型，尤其是对于微小隐孢子虫。我们的研究强调了全球范围内对基因型进行更大规模采样和存档的必要性，以便进行有助于理解这些原生动物寄生虫种群动态的比较分析。总体而言，我们的研究代表了对探索本地和全球原生动物基因型多样性的全面概述，并推进了我们对这些传染病监测的重要性以及潜在风险的理解。
