Wu Yanchen, Yao Lan, Chen Hongshuang, Zhang Weizhe, Jiang Yanyan, Yang Fengkun, Liu Aiqin, Shen Yujuan
Department of Parasitology, Harbin Medical University, Harbin, 150081, Heilongjiang, China.
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, China.
Parasit Vectors. 2022 May 11;15(1):165. doi: 10.1186/s13071-022-05269-9.
Giardia duodenalis is a common parasitic diarrheal agent in humans, especially in developing countries. The aim of this study was to investigate the prevalence and multilocus genetic characterization of G. duodenalis in patients with diarrhea and animals in northeastern China, and to assess the epidemiological role of animals in the transmission of human giardiasis.
A total of 1739 fecal specimens from 413 diarrheal patients and 1326 animals comprising 16 mammal species were collected in Heilongjiang Province of China and screened for G. duodenalis by PCR and sequencing of the SSU rRNA gene. All G. duodenalis-positive specimens were subtyped by PCR and sequencing of the bg, tpi, and gdh genes. To detect additional mixed infections of different assemblages, assemblage A/B/E-specific PCRs were performed to amplify the tpi gene.
Sequence analysis of the SSU rRNA gene determined the prevalence of G. duodenalis (5.81%, 24/413) in diarrheal patients, with a peak in minors aged 5-17 years, and identified assemblages A and B. MLG-AII and MLG-B1 were obtained based on concatenated nucleotide sequences of the bg, tpi, and gdh genes, with MLG-AII being identical to a cat-derived isolate reported previously. By sequence analysis of the SSU rRNA gene, G. duodenalis was detected in 214 (16.14%) animals belonging to 11 mammal species, with the prevalence ranging from 1.69 to 53.85%, and assemblages A to G were identified. Sequence analysis of the bg, tpi, and gdh genes from 46 specimens produced 31 MLGs, including MLG-AI (n = 1), MLG-B2-B8 (n = 18), and MLG-E1-E23 (n = 27).
The finding of G. duodenalis in diarrheal patients enhances consciousness of detecting G. duodenalis in clinical practice and emphasizes the importance of health education in local inhabitants, especially in the age group of 5-17 years. The identification of seven assemblages (A to G) and 33 MLGs reveals genetic heterogeneity of G. duodenalis in the investigated areas. Due to insufficient homology data on the zoonotic transmission of G. duodenalis, the precise epidemiological role that animals play in the transmission of human giardiasis needs to be assessed by more large-scale molecular epidemiological investigations of local humans and animals.
十二指肠贾第虫是人类常见的寄生性腹泻病原体，在发展中国家尤为常见。本研究旨在调查中国东北地区腹泻患者和动物中十二指肠贾第虫的流行情况及多位点基因特征，并评估动物在人类贾第虫病传播中的流行病学作用。
在中国黑龙江省共收集了413例腹泻患者和1326只动物（包括16种哺乳动物）的1739份粪便标本，通过PCR和SSU rRNA基因测序筛查十二指肠贾第虫。所有十二指肠贾第虫阳性标本通过PCR和bg、tpi和gdh基因测序进行亚型分析。为检测不同组合的其他混合感染，进行了组合A/B/E特异性PCR以扩增tpi基因。
SSU rRNA基因序列分析确定腹泻患者中十二指肠贾第虫的流行率为5.81%（24/413），在5 - 17岁的未成年人中达到峰值，并鉴定出组合A和B。基于bg、tpi和gdh基因的串联核苷酸序列获得了MLG - AII和MLG - B1，其中MLG - AII与先前报道的猫源分离株相同。通过SSU rRNA基因序列分析，在属于11种哺乳动物的214只动物（16.14%）中检测到十二指肠贾第虫，流行率在1.69%至53.85%之间，并鉴定出组合A至G。对46份标本的bg、tpi和gdh基因进行序列分析，产生了31个MLG，包括MLG - AI（n = 1）、MLG - B2 - B8（n = 18）和MLG - E1 - E23（n = 27）。
在腹泻患者中发现十二指肠贾第虫提高了临床实践中检测十二指肠贾第虫的意识，并强调了对当地居民，特别是5 - 17岁年龄组进行健康教育的重要性。鉴定出七种组合（A至G）和33个MLG揭示了所调查地区十二指肠贾第虫的遗传异质性。由于关于十二指肠贾第虫人畜共患病传播的同源性数据不足，需要通过对当地人和动物进行更大规模的分子流行病学调查来评估动物在人类贾第虫病传播中的确切流行病学作用。
