Geospatial analysis and epidemiological aspects of human infections with Blastocystis hominis in Mazandaran Province, northern Iran

Blastocystis colonization and associations with population parameters in Thai adults

BACKGROUND

Blastocystis is a unicellular eukaryote commonly found in the intestinal tract of humans and other animals. The prevalence of Blastocystis has been investigated in both developed and developing countries, yet its occurrence and distribution in rural locations has been less studied. Herein, we aimed to examine the distribution of Blastocystis colonization in Thai adults representing background populations along a rural/peri-urban gradient, as well as associations between colonization and personal characteristics.

METHODOLOGY

A total of 238 participants were recruited from rural and peri-urban areas situated in three provinces. The presence of Blastocystis in feces was evaluated using PCR and qPCR. Information on gender, age, region (province), rural/peri-urban location, and body mass index (BMI) was collected.

PRINCIPAL FINDINGS

The overall rate of Blastocystis carriage was 67.2%. Univariate analysis revealed significant associations between Blastocystis carriage and region (p<0.05), location (p<0.001) and age group (p<0.05). Logistic regression analysis revealed that rural/peri-urban location and BMI were significantly associated with Blastocystis carriage. Nine subtypes (ST1-ST7, ST10 and ST23) were identified with ST3, ST7 and ST1 as the most abundant ones, in this order. The greatest diversity of subtypes, in terms of numbers, was found in the middle aged group (nine subtypes), while the least diversity was found in the young adult and obese (three subtypes each) groups.

CONCLUSIONS

This study increases the understanding of the epidemiology of Blastocystis colonization and its association with population parameters and characteristics in middle-income countries.

A 11-year-old boy with Blastocystis hominis infection, presents as immune thrombocytopenia

BACKGROUND

Some causes of first-line treatment failure for ITP are often closely related to infections. But parasitic infections are rarely mentioned and easily overlooked. The case is the first to describe a boy with immune thrombocytopenia associated with blastocystis hominis.

CASE PRESENTATION

The case involved a boy presenting with bleeding skin spots and ecchymosis and accompanied by intermittent epigastric pain and constipation. After a series of complete examinations, the platelet count was found to be decreased to 13 × 109/L and immune thrombocytopenia was diagnosed. After first-line treatment with gamma globulin and prednisolone, the thrombocytopenia remained unchanged. Blastocystis hominis was subsequently found in the patient's stool and then the treatment of metronidazole was provided. One week later, the patient's thrombocytopenia was completely relieved. He was followed up for six months and was found to have recovered well.

CONCLUSIONS

The screening for potential predisposing factors is very important for immune thrombocytopenia patients with poor response to first-line treatment, and the best treatment strategy should include the management of potential diseases.

Investigation of Blastocystis hominis Frequency in Patients with Diabetes by Microscopy and Conventional PCR Methods

Background

We aimed to determine the frequency and subtype of B. hominis in diabetic patients.

Methods

One hundred and fifty diabetic patients and 100 healthy people without any chronic disease were included in the study. Stool samples were analyzed by native-Lugol, condensation, trichrome staining and PCR methods.

Results

İn 150 patients with diabetes; B. hominis was detected in 38 (25.3%) by PCR, in 34 (22.7%) by native-Lugol and trichrome staining. In the control group, 14 (14%) out of 100 subjects were positive by PCR, and 10 (10%) were positive by native-Lugol and trichrome staining. In the statistical evaluation, a significant difference was found between gender (P=0.023), age (P=0.045; ≤35 and >35 comparison), duration of diabetes (P=0.04), the HbA1c value (P=0.023; <8 and ≥8 comparison), and B. hominis positivity. ST1 was determined in 76.9% of patients with diabetes, and ST2 was determined in 23.07%. Considering the 3 methods, B. hominis positivity was detected in 40 patients (26.7%) in diabetic group and in 14 participants (14%) in the control group (P=0.011).

Conclusion

B. hominis is a factor to be considered in patients with diabetes. Herein, the most common subtype detected in the patients with diabetes mellitus was ST1, but this result was not considered sufficient to reveal the importance of the subtype factor in the pathogenicity of B. hominis in patients with diabetes. In this context, there is a need for more comprehensive studies in both diabetic and other immunocompromised patient groups.

Molecular epidemiology and subtyping of Blastocystis sp. and its subtypes in celiac patients; a case control study

Blastocystis sp. is a common intestinal protist, reported from symptomatic and asymptomatic subjects. Blastocystis sp. has been reported from a broad spectrum of gastrointestinal disorders. Celiac disease (CD) is an autoimmune disorder of the small intestine, which leads to the lack of tolerance against gluten. Long-term following of gluten-free diet in CD patients decreases the gut microbiota restoration and probably decreases the chance of Blastocystis sp. colonization. The current study aimed to investigate the prevalence of Blastocystis sp. and its subtypes in CD patients in comparison to healthy subjects. Stool samples were collected from 238 participants including 92 confirmed CD patients and 146 healthy subjects. upon DNA extraction, the presence of Blastocystis sp. was evaluated using amplification of discriminative regions of the small ribosomal RNA (ssu rRNA) gene. To characterize subtypes and alleles, amplified fragments were sequenced. Phylogenetic trees were constructed to visualize subtype correlation. Our findings showed that 21% (50) of samples including 16.3% (15/92) and 23.97% (35/146) were positive for Blastocystis sp. in CD patients and healthy controls, respectively. Except family relationship, other variables were not statistical correlated with the presence of Blastocystis sp.. Totally, 25 samples were successfully sequenced. Accordingly, ST1, ST2, and ST3 were present in 8 (32%), 9 (36%), and 8 (32%) of the samples, respectively. Allele discrimination showed that all ST1 were allele 4; alleles 11, 9, and 12 were retrieved from ST2, and alleles 34, 36, and 38 were observed in ST3. The relationship between colonization of Blastocystis sp. and alteration in the gut microbiota composition is indeterminate, however, this hypothesis that lower prevalence of Blastocystis sp. in CD patients who follow a gluten-free diet affect the colonization of Blastocystis sp. via alteration in the gut microbiota composition could be interesting for further investigations.

The Coexistence of Blastocystis spp. in Humans, Animals and Environmental Sources from 2010-2021 in Asia

Blastocystis spp. are controversial unicellular protists that inhabit the gastrointestinal tract of humans and a wide range of animals worldwide. This review provides an overview of the prevalence and distribution of Blastocystis spp. and their subtypes throughout Asia. Research articles reporting on the presence of Blastocystis spp. in locations within Asia, between 1 January 2010, and 10 May 2021, were obtained from Scopus, PubMed, and Google Scholar. In 427 articles, the prevalence of Blastocystis spp. in 31 countries within the last decade was revealed. Isolates were found in humans, various mammals, birds, reptiles, insects, water sources, vegetables, and ambient air. Prevalence of Blastocystis spp. varied widely across host categories. Subtypes identified throughout Asia were STs 1-14, and ST18-22 (novel subtypes). ST1, ST2, ST3, ST4 were the most frequently isolated in humans; ST5 in pigs; ST10 and ST14 in goats, sheep, and cattle; and ST6 and ST7 in chickens. ST1 and ST3 were most common in water samples. ST1, ST2, ST3, ST4, ST5 and ST6 were shared by humans, animals, and water sources. There is a growing interest in the study of Blastocystis spp. and their subtypes in Asia. Due to the isolation of Blastocystis spp. from biotic and abiotic sources in Asia, the application of the One Health (OH) approach to the study of Blastocystis spp. is proposed for improved perception of this organism.

Epidemiology and subtype distribution of Blastocystis in humans: A review

Blastocystis is a commonly encountered gastrointestinal protozoan in humans and animals with uncertain pathogenicity. Despite its potential public health impact, epidemiological data regarding the prevalence and molecular subtype (ST) distribution of Blastocystis have been rarely reported. Among Blastocystis STs, ST1-ST4 are common in humans, including healthy and immunodeficient populations. According to the Chi-squared (χ²) association based on the data compiled for this cross-sectional study, the presence of ST1 is associated with asymptomatic infection, whereas the presence of ST4 is associated with symptomatic infection. However, cross-sectional studies cannot clarify the potential pathogenicity of Blastocystis, unlike in vivo and in vitro studies. Poor hygiene, poor sanitation and zoonotic transmission are possible factors associated with high Blastocystis prevalence, although this protozoan may be part of the normal healthy human gastrointestinal microbiota. This review covers the prevalence, STs and distribution of Blastocystis infection in humans. Thus, future epidemiological and subtyping studies could reveal new STs in humans as well as possible associations of STs with disease, drug resistance and related mechanisms such as protease activity. These associations with proper ST identification may facilitate the control of potential threats to host health, including the direct pathogenic effects of Blastocystis or alterations of the gastrointestinal microbiome.

In vitro susceptibility of human Blastocystis subtypes to simeprevir

Introduction and aim

Blastocystis is a common enteric parasite, having a worldwide distribution. Many antimicrobial agents are effective against it, yet side effects and drug resistance have been reported. Thus, ongoing trials are being conducted for exploring anti-Blastocystis alternatives. Proteases are attractive anti-protozoal drug targets, having documented roles in Blastocystis. Serine proteases are present in both hepatitis C virus and Blastocystis. Since drug repositioning is quite trendy, the in vitro efficacy of simeprevir (SMV), an anti-hepatitis serine protease inhibitor, against Blastocystis was investigated in the current study.

Methods

Stool samples were collected from patients, Alexandria, Egypt. Concentrated stools were screened using direct smears, trichrome, and modified Ziehl-Neelsen stains to exclude parasitic co-infections. Positive stool isolates were cultivated, molecularly subtyped for assessing the efficacy of three SMV doses (100,150, and 200 μg/ml) along 72 hours (h), on the most common subtype, through monitoring parasite growth, viability, re-culture, and also via ultrastructure verification. The most efficient dose and duration were later tested on other subtypes.

Results

Results revealed that Blastocystis was detected in 54.17% of examined samples. Molecularly, ST3 predominated (62%), followed by ST1 (8.6%) and ST2 (3.4%). Ascending concentrations of SMV progressively inhibited growth, viability, and re-culture of treated Blastocystis, with a non-statistically significant difference when compared to the therapeutic control metronidazole (MTZ). The most efficient dose and duration against ST3 was 150 µg/ml for 72 h. This dose inhibited the growth of ST3, ST1, and ST2 with percentages of 95.19%, 94.83%, and 94.74%, successively and viability with percentages of 98.30%, 98.09%, and 97.96%, successively. This dose abolished Blastocystis upon re-culturing. Ultra-structurally, SMV induced rupture of Blastocystis cell membrane leading to necrotic death, versus the reported apoptotic death caused by MTZ. In conclusion, 150 µg/ml SMV for 72 h proved its efficacy against ST1, ST2, and ST3 Blastocystis, thus sparing the need for pre-treatment molecular subtyping in developing countries.

Comparing spatio-temporal distribution of the most common human parasitic infections in Iran over two periods 2007 to 2012 and 2013 to 2018: A systematic quantitative literature review

This study analyses the spatio-temporal trend of the prevalence of the four most prevalent parasitic diseases in Iran over two periods, 2007 to 2012 and 2013 to 2018, indicating high-risk and low-risk areas. Out of 19 126 articles, we selected 220 articles for data extraction and calculated the pooled prevalence for cutaneous leishmaniasis, human toxoplasmosis, giardiasis and blastocystosis for all 31 provinces in the country. Anselin local Moran's I was used to identify clusters and outliers in the prevalence rates. The mean prevalence of cutaneous leishmaniasis patients was found 35.12 per 100 000 in 2007 to 2012 but fell to 19.12 per 100 000 in the 2013 to 2018 period. The mean prevalence of acute and chronic toxoplasmosis was 2.36% and 32.5%, respectively, in 2007 to 2012, which changed to 2.28% and 31.14% in 2013 to 2018. The total prevalence of giardiasis declined from 9.8% in 2007 to 2012 to 4.8% in 2013 to 2018, while the mean prevalence of blastocystosis declined from 8.9% in 2007 to 2012 to 6.76% in the 2013 to 2018 period. There was only one high-high cluster in 2007 to 2012 and that was due to giardiasis, while there were two in 2013 to 2018, one for blastocystosis and one for chronic toxoplasmosis. The total prevalence of blastocystosis, giardiasis and cutaneous leishmaniasis in Iran has continually declined since 2007. In contrast, the prevalence of toxoplasmosis in pregnant Iranian women has not been changed. Iran's Midwest has more parasitic infections compared to the Mideast, which may be explained by the existence of vast deserts and consequently dry and hot climate in the latter part of the country.

Improving Hashimoto's thyroiditis by eradicating Blastocystis hominis: Relation to IL-17

BACKGROUND

Hashimoto's thyroiditis (HT) is a common autoimmune disorder that causes significant morbidity. Interleukin (IL)-17 was identified as a major contributing factor in the pathogenesis of HT. Blastocystis hominis (BH) is a very common infection and has been shown to be associated with several diseases. Our aim was to determine serum IL-17 level in HT patients with and without BH infection and the effect of eradicating BH in patients with HT.

METHODS

A prospective cohort study was conducted on 20 HT patients not infected with BH (group I), 20 HT patients infected with BH (group II), and 20 healthy patients (group III). Serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH), thyroid peroxidase antibodies (anti-TPO), and IL-17 were performed by ELISA method and were repeated in group II after 6 weeks of eradication of BH.

RESULTS

Patients with HT showed a significantly higher serum IL-17 compared with controls. IL-17 was significantly higher in HT patients infected with BH compared with HT patients not BH infected (mean 6.93 ± 2.83 pg/ml versus 3.25 ± 1.55 pg/ml, p = 0.003). After BH eradication TSH, anti-TPO, and IL-17 were significantly decreased (mean 14.76 ± 11.11 µIU/ml versus 9.39 ± 7.11 µIU/ml, p < 0.001; mean 308 ± 175.6 IU/ml versus 295.4 ± 167.1 IU/ml, p = 0.006; and mean 6.93 ± 2.83 pg/ml versus 6.45 ± 2.48 pg/ml, p < 0.001), respectively. Multivariate analysis after treating BH infection showed that IL-17 was significantly negatively correlated with FT3 (adjusted p = 0.002) and significantly positively correlated with anti-TPO (adjusted p = 0.045).

CONCLUSION

Treatment of BH infection ameliorates HT through reduction in IL-17, anti-TPO, and TSH.

CLINICAL TRIAL REGISTRATION NUMBER

PACTR201909495111649.