Abstract：
Giardia duodenalis, Cryptosporidium spp., and Blastocystis sp. are common intestinal eukaryotic parasites affecting children in developed and resource-limited countries. Lack of information on the epidemiology and long-term stability in asymptomatic children complicates interpretation of transmission and pathogenesis. To assess the occurrence, genetic diversity, and temporal dynamics of intestinal eukaryotic parasites in young children, 679 stool samples from 125 toddlers attending six public day-care centres in Central Spain were collected bimonthly within a 1-year period. Detection and identification of species/genotypes were based on PCR and Sanger sequencing methods. Four eukaryotic species were identified: G. duodenalis (2.5‒31.6%), Cryptosporidium spp. (0.0‒2.4%), Blastocystis sp. (2.5‒6.4%), and Entamoeba dispar (0.0‒0.9%). Entamoeba histolytica and Enterocytozoon bieneusi were undetected. Sequence analyses identified assemblage A (63.6%) and B (36.4%) within G. duodenalis (n = 11), C. hominis (40%), C. parvum (40%), and C. wrairi (20%) within Cryptosporidium spp. (n = 5), and ST1 (3.8%), ST2 (46.2%), ST3 (15.4%), and ST4 (34.6%) within Blastocystis sp. (n = 26). Giardia duodenalis sub-assemblage AII/AIII was detected in a toddler for 10 consecutive months. Stable carriage of Blastocystis ST2 allele 9, ST3 allele 34, and ST4 allele 42 was demonstrated in five toddlers for up to 1 year. Conclusions: Giardia duodenalis and Blastocystis sp. were common in toddlers attending day-care centres in Central Spain. Long-term infection/colonization periods by the same genetic variant were observed for G. duodenalis (up to 10 months) and Blastocystis sp. (up to 12 months). What is Known: • Asymptomatic carriage of G. duodenalis and Blastocystis sp. is frequent in toddlers. • The epidemiology and long-term stability of these eukaryotes in asymptomatic young children is poorly understood. What is New: • Long-term colonization/infection periods by the same genetic variant were described for Blastocystis sp. (up to 12 months) and G. duodenalis (up to 10 months).
摘要：
十二指肠贾第虫,隐孢子虫。,和囊胚。是影响发达国家和资源有限国家儿童的常见肠道真核寄生虫。缺乏有关无症状儿童的流行病学和长期稳定性的信息会使对传播和发病机理的解释复杂化。为了评估发生，遗传多样性,以及幼儿肠道真核寄生虫的时间动态，在1年内每两个月收集一次来自西班牙中部六个公共日托中心的125名幼儿的679份粪便样本。物种/基因型的检测和鉴定基于PCR和Sanger测序方法。确定了四种真核生物：十二指肠球藻（2.5-31.6％），隐孢子虫。（0.0-2.4%），囊胚。（2.5-6.4%），和Entamoebadispar（0.0-0.9%）。未检测到溶组织内阿米巴和肠孢子虫。序列分析确定了十二指肠氏杆菌内的组合A（63.6％）和B（36.4％）（n=11），C.人类(40%)，C.parvum(40%)，和隐孢子虫中的C.wrairi（20％）。（n=5），和ST1（3.8%），ST2（46.2%），ST3（15.4%），和ST4（34.6％）在囊胚菌属中。（n=26）。连续10个月在幼儿中检测到十二指肠贾第鞭毛虫亚组AII/AIII。在五个幼儿中证明了囊胚ST2等位基因9，ST3等位基因34和ST4等位基因42的稳定携带长达1年。结论：十二指肠贾第鞭毛虫和囊胚。在西班牙中部日托中心的幼儿中很常见。观察到十二指肠芽孢杆菌（长达10个月）和芽囊原虫的相同遗传变异的长期感染/定殖期。（长达12个月）。什么是已知的：•无症状的十二指肠G和囊胚的携带。在幼儿中很常见。•对这些真核生物在无症状幼儿中的流行病学和长期稳定性了解甚少。新增内容:•对于囊胚菌属描述了相同遗传变异的长期定植/感染时期。（长达12个月）和十二指肠G（长达10个月）。
