Department of Pharmacy, Pharmaceutical Technology and Parasitology, Parasitology Area, Faculty of Pharmacy, Valencia University, Avda. Vicent Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain.
Department of Basic Pathology, Biological Sciences Area, Paraná Federal University, Av. Cel. Francisco H. dos Santos 100, Curitiba, 19031, Brazil.
Parasit Vectors. 2018 Aug 30;11(1):490. doi: 10.1186/s13071-018-3054-7.
Intestinal protozoan parasites are major contributors to the global burden of gastrointestinal disease causing significant socioeconomic consequences. Children living in resource-poor settings with restricted access to water and sanitary services are particularly at risk of these infections.
A prospective, community-based, cross-sectional survey was conducted in Paraná (southern Brazil) between May 2015 and May 2016. A total of 766 stool samples were individually collected from volunteers (male/female ratio: 0.99; age range: 0-76 years) and used for investigating the presence of intestinal helminth and protozoan species by routine microscopic procedures including the Kato-Katz and modified Ritchie concentration methods and the Ziehl-Neelsen stain technique. Quantitative real-time PCR confirmed microscopy-positive samples for Giardia duodenalis and the assemblages and sub-assemblages determined by multilocus sequence-based genotyping of the glutamate dehydrogenase (gdh) and β-giardin (bg) genes of the parasite. Identification of Blastocystis subtypes was carried out by amplification and sequencing of a partial fragment of the small-subunit ribosomal RNA gene (SSU rDNA) of this heterokont microorganism.
Overall, 46.1% (353/766) of the participants were infected/colonised by at least one intestinal parasite/commensal species. Protozoan and helminth species were detected in 42.7% and 10.1% of the surveyed population, respectively. Blastocystis sp. (28.2%), Endolimax nana (14.9%), and Giardia duodenalis (11.0%) were the most prevalent species found among protozoans and Ascaris lumbricoides (5.0%), Trichuris trichiura (4.6%) and hookworms (1.0%) among helminths. A total of 38 G. duodenalis-positive samples were genotyped at gdh and bg markers, revealing the presence of the sub-assemblages AII (47.4%), AII/AIII (2.6%), BIII (5.3%), BIV (26.3%) and BIII/BIV (13.1%). Two samples (5.3%) were only identified as assemblage B. AII was predominantly found in females aged 5-9 years and was associated with a higher likelihood of reporting gastrointestinal symptoms. A total of 102 Blastocystis-positive samples were successfully subtyped at the SSU rRNA gene revealing the presence of ST1 (36.3%), ST2 (15.7%), ST3 (41.2%), ST4 (2.9%), ST6 (1.0%) and ST8 (2.9%).
Data presented here indicate that enteric parasites still represent a pressing health concern in Paraná, Brazil, probably due to sub-optimal water, sanitation and hygiene conditions. A mostly anthroponotic origin is suspected for G. duodenalis and Blastocystis sp. infections.
肠道原生动物寄生虫是导致全球胃肠道疾病负担的主要因素，给社会经济带来了重大影响。生活在资源匮乏、用水和卫生设施受限地区的儿童特别容易受到这些感染的影响。
本研究于 2015 年 5 月至 2016 年 5 月在巴西南部的巴拉那州进行了一项前瞻性、基于社区的横断面调查。共采集了 766 份志愿者的粪便样本（男/女比例：0.99；年龄范围：0-76 岁），并使用常规显微镜检查方法（包括加藤法和改良瑞特氏染色浓缩法）和齐尔-尼尔森染色技术，对肠道蠕虫和原生动物物种的存在情况进行调查。聚合酶链反应（PCR）技术用于对粪便样本进行 Giardia duodenalis 和其他寄生虫的检测，同时还使用多位点序列基于基因分型的谷氨酸脱氢酶（gdh）和β-微管蛋白（bg）基因对寄生虫进行鉴定。通过扩增和测序 Blastocystis 微生物的小亚基核糖体 RNA 基因（SSU rDNA）的部分片段，对 Blastocystis 亚型进行鉴定。
总体而言，766 名参与者中有 46.1%（353 人）感染/定植了至少一种肠道寄生虫/共生物种。在所调查的人群中，分别检测到 42.7%和 10.1%的原生动物和蠕虫物种。其中，最常见的原生动物为 Blastocystis sp.（28.2%）、Endolimax nana（14.9%）和 Giardia duodenalis（11.0%），最常见的蠕虫为 Ascaris lumbricoides（5.0%）、Trichuris trichiura（4.6%）和钩虫（1.0%）。对 38 份 G. duodenalis 阳性样本进行了 gdh 和 bg 标记基因的基因分型，结果显示存在亚群 AII（47.4%）、AII/AIII（2.6%）、BIII（5.3%）、BIV（26.3%）和 BIII/BIV（13.1%）。有 2 份样本（5.3%）仅被鉴定为亚群 B。AII 主要见于 5-9 岁的女性，且与报告胃肠道症状的可能性增加有关。对 102 份 Blastocystis 阳性样本的 SSU rRNA 基因进行了成功的亚型分析，发现存在 ST1（36.3%）、ST2（15.7%）、ST3（41.2%）、ST4（2.9%）、ST6（1.0%）和 ST8（2.9%）。
本研究表明，肠道寄生虫仍然是巴西巴拉那州的一个紧迫的健康问题，这可能是由于用水、卫生和卫生条件不理想造成的。G. duodenalis 和 Blastocystis sp.感染可能主要是人为来源。
