Zoonotic Transmission of Blastocystis Subtype 1 among People in Eastern Communities of Thailand: Organic Fertilizer from Pig Feces as a Potential Source

Blastocystis sp. remains a public health problem among people, particularly in rural areas of many developing countries. The infection usually reflects poor sanitation in communities by waterborne, zoonotic, and person-to-person transmission.

Subtype distribution and molecular characterization of Blastocystis from hemodialysis patients in Turkey

Introduction: The aim of this study was to determine the Blastocystis prevalence and subtypes in hemodialysis patients in Turkey. Methodology: Eighty-four patients diagnosed with end-stage renal failure who were undergoing hemodialysis and 20 healthy volunteers were enrolled. Blastocystis presence was investigated by native-Lugol, trichrome staining, PCR using STS primers, and DNA sequencing analysis. Results: Among the stool samples from the hemodialysis patients, 9.52% (8/84) were found to be Blastocystis-positive with the native-Lugol and trichrome staining. Seven of the eight Blastocystis isolates were subtyped using STS primers. Blastocystis subtype distribution was as follows: one had ST1, two had ST2, two had ST3, two had ST3+ST6, and one was not subtyped. Blastocystis positivity was detected in two healthy control (2/20, %10), one subject had ST1, and the other was not subtyped. All subtypes identified by PCR were confirmed by the sequencing analysis. In the two samples that had mixed subtypes (ST3+ST6) when using the STS primers, only ST3 was detected in the sequencing analysis. Although some patients have multiple symptoms, the most common symptoms in Blastocystis positive patients were bloating (5/8), diarrhea (4/8), nausea and vomiting (2/8), and gas and weight loss (1/8). Also, only one patient had Giardia intestinalis. Conclusions: This was the first study to determine the Blastocystis subtypes in hemodialysis patients. A rare subtype, ST6, was identified in two of the patients. Thus, the ST6 infections were attributable to transmission from poultry infections. The presence of this unusual subtype suggests the need for further extensive studies of hemodialysis patients.

Relative Frequency of Blastocystis Subtypes 1, 2, and 3 in Urban and Periurban Human Populations of Arequipa, Peru

Blastocystis is one of the most common protozoa found in the human gut and are genetically diverse and widely distributed around the world. Nonspecific and inconsistent symptoms have been associated with this protozoon; thus, its clinical importance remains controversial. Our aim was to estimate the relative frequency of Blastocystis subtypes 1, 2, and 3, which are the predominant subtypes reported in South America, based on conserved regions of SSU rDNA sequences and determine the factors associated with them. A total of 116 Blastocystis-positive stool samples were processed using conventional PCR with Blastocystis-specific primers. We identified subtype 1 (10.3%), subtype 2 (7.8%), subtype 3 (25.0%), and mixed subtype infections (8.7%). However, we could not identify any Blastocystis subtypes in 48.3% of the samples; therefore, it is likely that other subtypes were present in the area. No association was found between any gastrointestinal symptom and single or mixed Blastocystis subtypes. We found a statistically significant association between Blastocystis subtype 2 and irritable bowel syndrome (OR = 17.8, 95% CI = 1.5–408.4, p = 0.039); however, the number of samples with IBS was small (n= 4). There was no association between the Blastocystis subtypes and any epidemiological variable studied. In rural populations, we only identified subtype 1, while in urban and periurban populations, we identified subtypes 1, 2, and 3.

Distribution and molecular analysis of Blastocystis subtypes from gastrointestinal symptomatic and asymptomatic patients in Iran

Introduction: Blastocystis is a common intestinal parasite of human and animal hosts. The parasite has 17 subtypes, and among those at least nine subtypes (ST1-ST9) are found in human hosts. Objective: The aim of the present study was to investigate the presence of different subtypes of Blastocystis spp. among the patients referred to Velayat hospital of Qazvin province, Iran. Methods: Overall, 864 stool samples were examined by using formalin-ethyl acetate concentration method and Trichrome staining. All specimens were cultured in clotted fetal bovine medium. Later, DNA extraction and PCR amplification of 18S ribosomal RNA gene region was conducted and phylogenetic tree constructed. Results: The results revealed 7.9% (68/864) of the study population were infected with Blastocystis. Intestinal symptoms were observed in 61% (36/59) of individuals positive for Blastocystis, with abdominal pain in 58% (21/36) of cases which was more frequent than other intestinal signs. No significant relationship was observed among the study variables. By molecular and phylogenetic analysis, three subtypes ST1 (45%), ST2 (30%) and ST3 (23%) of parasite were identified. Conclusion: This study showed ST1 subtype was the predominant subtype among the positive specimens, meanwhile the highest haplotype and nucleotide diversity were clarified in ST3 subtype. Keywords: Blastocystis, subtype, Phylogenetic analysis, Iran.