Geographic distribution of human  Blastocystis  subtypes in South America

Ramírez, Juan David; Sánchez, Angie; Hernández, Carolina; Flórez, Carolina; Bernal, María Consuelo; Giraldo, Julio Cesar; Reyes, Patricia; López, Myriam Consuelo; García, Lineth; Cooper, Philip J.; Vicuña, Yosselin; Mongi, Florencia; Casero, Rodolfo

doi:10.1016/j.meegid.2016.03.017

Cited by 180 publications

(169 citation statements)

References 24 publications

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“…Indeed, the studies reported thus far indicate that the majority of human infections with Blastocystis sp. are attributable to ST3 isolates (Özyurt et al 2008;Meloni et al 2011;Forsell et al 2012;Ramírez et al 2016), as was the case in the present study (60%). It is suggested that dominance of ST3 may be related to its human origin (Özyurt et al 2008;Meloni et al 2011;Yoshikawa et al 2016).…”

Section: Discussionsupporting

confidence: 79%

“…Recent studies have provided further information regarding ST distribution among human populations (Tan, 2008;Alfellani et al 2013); however, very few studies have been conducted in Latin America (Santín et al 2011). To date, a small number of studies subtyping Blastocystis (Malheiros et al 2011;David et al 2015;Ramírez et al 2016) (Garcia, 2001), considering positivity in at least one of the parasitological methods. Fifteen Blastocystis sp.-negative stool samples, determined by the parasitological methods, and 15 stool samples positive for other parasite infections (Ascaris lumbricoides, Entamoeba histolytica, Giardia lamblia, Endolimax nana and Entamoeba coli) were used as controls.…”

Section: Introductionmentioning

confidence: 99%

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Identification of Blastocystis subtypes in clinical stool samples from Sao Paulo City, Brazil

et al. 2017

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S U M M A R YBlastocystis sp. is a protozoan commonly found in human and animal stool samples. Several pathogenic and zoonotic aspects of this organism are still unknown. The aim of the present study was to investigate Blastocystis subtypes (STs) in samples from patients of the Hospital das Clínicas of the Faculdade de Medicina at the Universidade de São Paulo (HC-FMUSP), Brazil. Blastocystis sp.-positive stool samples diagnosed at the Section of Parasitology of the Central Laboratory (HC-FMUSP) were used for DNA isolation. Polymerase chain reaction (PCR) was performed using specific primers targeting the small-subunit rRNA gene. Direct DNA sequencing of the PCR products was performed and the DNA sequences were then aligned and compared with other sequences obtained from the GenBank database. Phylogenetic analysis was used to identify STs and determine the phylogenetic relationships between the sequences. Four STs were identified: ST1 (22·5%), ST2 (12·5%), ST3 (60%) and ST6 (5%). In conclusion, ST3 was the most prevalent ST among the human isolates followed by ST1. The present study is one of the few providing STs data from the human population in South America. Determining ST prevalence in human samples may contribute to the monitoring of Blastocystis sp. infection transmission in endemic regions.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Identification of Blastocystis subtypes in clinical stool samples from Sao Paulo City, Brazil

et al. 2017

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“…Similar ST1/3 frequencies have been reported recently in poor communities [57] and paediatric [83] and clinical [84] populations in the State of São Paulo, and in patients (and their relatives) attending a day-care hospital for the mentally ill in Rio de Janeiro [85]. Additionally, ST2 has been shown as a relevant Blastocystis subtype in asymptomatic patients [86] and the Amazonian Tapirapé indigenous people [87]. Explicit sex and age-related distribution of Blastocystis subtypes were noticed in the population investigated, with ST3 carriage being significantly more detected in males younger than 10 years-old and ST1 carriage in females in the age group of 10–14 years.…”

Section: Discussionsupporting

confidence: 77%

Prevalence of intestinal parasites, with emphasis on the molecular epidemiology of Giardia duodenalis and Blastocystis sp., in the Paranaguá Bay, Brazil: a community survey

et al. 2018

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BackgroundIntestinal 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.MethodsA 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.ResultsOverall, 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%).ConclusionsData 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.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3054-7) contains supplementary material, which is available to authorized users.

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“…In America, there is a high prevalence of ST1 and ST2, in Australia, Europe, and South Eastern Asia -ST1 and ST3, and in Europe -ST4 [10]. A recent study from SouthAmerica showed the presence of ST4 in humans [47] and latter STs 1, 2 and 3 were detected as the most frequent [48]. People are colonized mainly by ST1 through ST4, containing over 90% of assessments; but depending on the regions and countries, infection by ST5 through ST9 is also detected [10,20].…”

Section: Pathogenicity Of Blastocystis Sp Is a Relationship Possiblementioning

confidence: 99%

Genetic diversity and pathogenicity of Blastocystis

Skotarczak¹

2018

Ann Agric Environ Med.

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Blastocystis is a unicellular, anaerobic protist which lives in the intestinal tract of diverse animals, including humans. It was found that the host specificity and the pathogenic potential of different isolates are correlated with sequence variations in the SSU-rRNA gene. Identification of the organism to the species level is still an unresolved challenge. Genetic diversity revisions have led to the identification of 17 subtypes (STs) within the Blastocystis genus, and 9 (ST1 to ST9) have been reported in humans with varying prevalence. Since the members of the genus revealed a large genetic diversity, several molecular modalities of subtyping methods have been developed. Numerous studies on conveying the pathogenic potential to the molecular subtypes are available, but they could not be compared or analysed with the different molecular techniques employed. The use of different approaches may give false positives during diagnosis and the possibility of missed infections. A review of recent scientific literature indicates that the development of PCR assays is needed for molecular epidemiology and for mixed infections in health and disease cohorts, and also to help identify sources of Blastocystis transmission to humans, as well as to identify potential animal and environmental reservoirs. This review summarizes some of the recent progress and improvements in Blastocystis research on genetic diversity, taxonomy, molecular epidemiology, pathogenicity and subtyping methods.

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Geographic distribution of human Blastocystis subtypes in South America

Cited by 180 publications

References 24 publications

Identification of Blastocystis subtypes in clinical stool samples from Sao Paulo City, Brazil

Identification of Blastocystis subtypes in clinical stool samples from Sao Paulo City, Brazil

Prevalence of intestinal parasites, with emphasis on the molecular epidemiology of Giardia duodenalis and Blastocystis sp., in the Paranaguá Bay, Brazil: a community survey

Genetic diversity and pathogenicity of Blastocystis

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