Molecular prevalence and subtype distribution of Blastocystis spp. among children who have diarrheia or are asymptomatic in Wenzhou, Zhejiang Province, China

Abstract

Blastocystis sp., a significant zoonotic parasite with a global distribution, was the focus of this study, which aimed to investigate its prevalence and genetic diversity among diarrheic and asymptomatic children in Wenzhou, China. We collected 1,032 fecal samples from Yuying Children’s Hospital, Wenzhou, China, comprising 684 from children with diarrhea and 348 from asymptomatic children. Genomic DNA extracted from these samples was used to detect Blastocystis spp. by PCR, targeting the small subunit ribosomal RNA gene. Subsequently, a phylogenetic tree was constructed, applying the maximum likelihood method. Blastocystis spp. were detected in 67 (6.5%) of the fecal samples. The prevalence rate of Blastocystis spp. in diarrheic children (8.8%; 60/684) was significantly higher than that in asymptomatic children (2.0%; 7/348) (χ 2 = 17.3, p < 0.001). Sequence analysis of the SSU rRNA gene identified five known Blastocystis spp. subtypes, ST1 (n = 12), ST2 (n = 5), ST3 (n = 35), ST4 (n = 12), and ST7 (n = 3). ST1 and ST3 were present in both diarrheic and asymptomatic children, while ST2, ST4, and ST7 were exclusive to diarrheic children. Intra-subtype genetic polymorphisms were identified, comprising four variations in ST1 (ST1-1 to ST1-4), five in ST3 (ST3-1 to ST3-5), two in ST4 (ST4-1 and ST4-2), and two in ST7 (ST7-1 and ST7-2). Notably, ST1-2 to ST1-4, ST3-3 to ST3-5, and ST7-1 and ST7-2 represent newly identified variations. The composition and genetic characteristics of subtypes among children in this region suggest various sources of infection, including human-to-human and animal-to-human transmission.

Molecular investigation of Blastocystis sp. infections in wild rodents from the Inner Mongolian Autonomous Region and Liaoning province, China: High prevalence and dominance of ST4

“…ST4 is also prevalent in humans worldwide, with a global occurrence rate of 5.9% and Europe accounts for a significant proportion of human cases, reaching up to 19.8% [ 14 ]. In China, cases of ST4 infection in humans have been reported in multiple provinces including Zhejiang, Henan, and Yunnan [ 5 , 28 ]. Meanwhile, ST4 has also been identified in various rodent species in China, including coypus, bamboo rats, porcupines, civets, and brown rats [ 29 ].…”

“…Until now, at least 25 subtypes (ranging from ST1 to ST17, ST21, ST23 to ST26, ST30, ST31, and ST39) have been identified [ 5 , 13 , 24 – 27 , 30 ]. Notably, subtypes ST1 to ST9, ST12, and ST14 were shared by both humans and animals [ 5 , 13 , 28 , 30 ]. Despite this knowledge, there is still a lack of data on Blastocystis infection in wild rodents in China [ 20 , 23 ].…”

Molecular prevalence, subtype distribution, and zoonotic potential of Blastocystis sp. in wild rodents and shrews inhabiting Zhejiang province of China

“…Further, they have also been detected in children, individuals with diarrhea, patients with human immunodeficiency virus among men who have sex with men, and in the water sources of other cities ( 15 – 17 ). Blastocystis has been consistently detected in humans in Zhejiang Province, China ( 18 , 19 ). However, the cause of the human infection has not been fully understood.…”