Blastocystis in humans and animals: new insights using modern methodologies

Prevalence of Blastocystis sp. in Morocco: Comparative assessment of three diagnostic methods and characterization of parasite forms in Jones' culture medium

Blastocystosis is an infection caused by Blastocystis sp., which colonizes the digestive tract of various hosts, including humans, although its pathogenicity is debated. It is crucial to detect and distinguish the different forms of Blastocystis to understand better its impact on human health and its epidemiological evolution. This study evaluated three diagnostic methods on 105 stool samples: direct examination, culture in Jones' medium, and conventional PCR. PCR is considered the gold standard and revealed a high prevalence of Blastocystis (67.62%) compared to direct examination (20.95%) and culture in Jones' medium (51.43%). Although the sensitivity of direct examination and culture was 31% and 76.1%, respectively, their specificity was 100%. No significant risk factors were identified. A statistically significant association was observed between Blastocystis infection and abdominal pain. Microscopic analysis revealed various morphological forms. Molecular diagnosis is an essential tool to determine the true prevalence of Blastocystis, and studying the different forms of this microorganism will contribute to a better understanding of its biological cycle and, therefore, the impact of this emerging infection on human health.

Blastocystis infection among diarrhea outpatients in Ningbo, Southeast China: A potential zoonotic health threat

BACKGROUND

Blastocystis is one of the important zoonotic parasites which can infect humans and various animals worldwide and has become a growing global public health concern. The study aims to obtain the data of Blastocystis infection and the information of the genetic characteristic.

METHODS

In the present study, 489 fecal samples were collected from diarrhea outpatients in Ningbo, Zhejiang province, and were examined the presence of Blastocystis by polymerase chain reaction combined with sequencing.

RESULTS

A total of 10 samples (2.04%, 10/489) were positive for Blastocystis with no significant difference among sex and age groups, respectively. Eight samples were successfully sequenced, and five zoonotic ST3 and three zoonotic ST1 with two new sequences were identified.

CONCLUSIONS

We first demonstrated the occurrence of Blastocystis infection in diarrhea outpatients in Ningbo, with two zoonotic subtypes (ST1 and ST3) and two new sequences being characterized. Meanwhile, mixed infection of Blastocystis and E. bieneusi was found which indicates the importance of investigation of multiple parasites. Finally, more extensive studies will be needed to better understand the transmission of Blastocystis at human-animal-environment interface and provide evidence for the development of one health strategies for the prevention and control of such diseases.

Blastocystis occurrence in water sources worldwide from 2005 to 2022: a review

There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.

Resistance of Blastocystis to chlorine and hydrogen peroxide

Blastocystis is a ubiquitous, widely distributed protist inhabiting the gastrointestinal tract of humans and other animals. The organism is genetically diverse, and so far, at least 28 subtypes (STs) have been identified with ST1-ST9 being the most common in humans. The pathogenicity of Blastocystis is controversial. Several routes of transmission have been proposed including fecal-oral (e.g., zoonotic, anthroponotic) and waterborne. Research on the latter has gained traction in the last few years with the organism having been identified in various bodies of water, tap water, and rainwater collection containers including water that has been previously filtered and/or chlorinated. Herein, we assessed the resistance of 11 strains maintained in culture, spanning ST1-ST9 to various chlorine and hydrogen peroxide concentrations for 24 h, and performed recovery assays along with re-exposure. Following the treatment with both compounds, all subtypes showed increased resistance, and viability could be visualized at the cellular level. These results are hinting at the presence of mechanism of resistance to both chlorine and hydrogen peroxide. As such, this pilot study can be the platform for developing guidelines for water treatment processes.

PREVALENCE OF Blastocystis sp. IN CATTLE, GOAT AND SHEEP REARED BY DIFFERENT FARM MANAGEMENT SYSTEMS IN PAHANG, MALAYSIA

Blastocystis sp. is a familiar parasite in the gastrointestinal tract causing infection in humans and animals. The purpose of this study is to evaluate the Blastocystis sp. prevalence in three sorts of livestock; cattle, goats, and sheep in Pahang, Malaysia, which are reared under two management systems; intensive and semi-intensive farm management system. About 92, 96, and 65 cattle, goat, and sheep fecal samples respectively were collected from different farms around Kuantan, Bera, and Pekan. The fecal samples were cultured in Jones’ medium supplemented with 10% heat-inactivated horse serum and incubated at 37 ºC for 2 weeks, then observed under light microscopy daily. The total prevalence of Blastocystis sp. was 29.34% in cattle (27/92), 29.16% in goats (28/96), and 43.07% in sheep (28/65). Supported the results of this study, Blastocystis sp. prevalence was higher in sheep and livestock reared by a semi-intensive farm management system (44.38%). However, further study could be done for Blastocystis sp. subtypes identification to determine its genetic diversity. Notwithstanding, this study has provided additional knowledge on the prevalence of each livestock reared in farms around Pahang that serve as important information in understanding host-parasite relationships, besides determining the best farm management system to be applied by farmers.

Prevalence and Associated Factors of Blastocystis sp. Infection in Patients with Gastrointestinal Symptoms in Spain: A Case-Control Study

Blastocystis sp. is known to be the most prevalent parasite in fecal samples of humans worldwide. In the present report, a case–control study (1:9.89 (≈10)) was performed, by analyzing data from 3682 patients who attended a public hospital in the northern area of Spain showing gastrointestinal symptoms. Diagnosis was performed in human fecal samples by means of optical microscopy. The prevalence of Blastocystis sp. in patients with gastrointestinal symptoms was 9.18% (338/3682). Most of the Blastocystis sp.-infected patients tested negative for protozoa and helminths, and were underweight and foreign-born (26.4%), mainly from Africa and Central/South America. Gastrointestinal symptoms, such as abdominal pain, anorexia, halitosis, plus relative eosinophilia, as well as co-infections with pathogenic bacteria were associated with Blastocystis sp. infection. Both type 2 diabetes and treatment with immunosuppressive medicines at the time of Blastocystis sp. detection were associated with a higher proportion of infected patients. This is the first case–control study of Blastocystis sp. in humans in northern Spain and may contribute to surveillance and intervention strategies by public health authorities.

First Report of Blastocystis spp. Infection in Pet Birds in Henan Province, Central China

Blastocystis spp. are common intestinal parasites found in humans and many kinds of animals. Blastocystis spp. infection is associated with a variety of symptoms, including diarrhea, abdominal pain, and chronic urticaria, among which asymptomatic infection is the most common. Among the 11 potentially zoonotic subtypes of Blastocystis spp., 9 subtypes have been reported in bird species. The purpose of this study was to detect the infection rate and gene subtype distribution of Blastocystis spp. in pet birds in Henan Province, Central China, to provide a foundation for preventing and controlling Blastocystis spp. in pet birds. Fecal DNA was extracted from 382 fresh fecal samples of pet birds collected from five areas in Henan Province, Central China. Twenty-three species of pet birds from four orders, from local pet trading markets, parks, and individuals, were sampled. All DNA samples were investigated by PCR, and positive samples were sequenced to analyze the gene subtypes based on the small ribosomal subunit (SSU rRNA) gene. Blastocystis spp. was detected in 0.8% of the samples. Further DNA sequencing and phylogenetic analyses resulted in the identification of two known zoonotic subtypes, ST1 (n = 2) and ST7 (n = 1). As far as we know, this is the first time that ST1 subtype has been reported in Chinese birds. It is found that pet birds may be the hosts of zoonotic Blastocystis spp. subtypes, and the role of birds in transmitting Blastocystis spp. to humans needs to be further studied.

Detection, Molecular Identification and Transmission of the Intestinal Protozoa Blastocystis sp. in Guinea from a Large-Scale Epidemiological Study Conducted in the Conakry Area

Blastocystis sp. is a single-celled parasite estimated to colonize the digestive tract of 1 to 2 billion people worldwide. Although it represents the most frequent intestinal protozoa in human stools, it remains still under-investigated in countries with a high risk of infection due to poor sanitary and hygiene conditions, such as in Africa. Therefore, the present study was carried out to determine the prevalence and subtype (ST) distribution of Blastocystis sp. in the Guinean population. For this purpose, fecal samples were collected from 500 individuals presenting or not digestive disorders in two hospitals of Conakry. Search for the parasite in stools was performed by real-time PCR targeting the small subunit rDNA gene followed by sequencing of the PCR products for subtyping of the isolates. A total of 390 participants (78.0%) was positive for Blastocystis sp. Five STs were identified in the Guinean cohort (ST1, ST2, ST3, ST4 and ST14) with varying frequency, ST3 being predominant. Among them, ST4 was found in only two patients confirming its global rarity in Africa whereas infections by ST14 were likely the result of zoonotic transmission from bovid. No significant association was detected between Blastocystis sp. colonization or ST distribution and the symptomatic status of Guinean subjects or the presence of digestive symptoms. In contrast, drilling water consumption represented a significant risk factor for infection by Blastocystis sp. Predominance of ST3 coupled with its low intra-ST diversity strongly suggested large-scale human-to-human transmission of this ST within this cohort. In parallel, the highest intra-ST diversity of ST1 and ST2 was likely correlated with various potential sources of infection in addition to anthroponotic transmission. These findings highlighted the active circulation of the parasite in Guinea as reported in some low-income African countries and the necessity to implement prevention and control measures in order to limit the circulation of this parasite in this endemic geographical area.

Prevalence and molecular subtyping of Blastocystis in domestic pigeons in Henan Province, Central China

Blastocystis is an anaerobic intestinal protozoan parasite found in humans and many kinds of animals that mainly causes diarrhea, abdominal pain and other clinical symptoms. At present, research on the prevalence and subtype diversity of Blastocystis in domestic pigeons is very limited. The purpose of this study was to detect the infection rate and gene subtype distribution of Blastocystis in domestic pigeons in Henan Province, Central China, to provide a foundation for preventing and controlling Blastocystis in domestic pigeons. Fecal DNA was extracted from 504 fresh fecal samples of pigeons collected from 4 areas in Henan Province, Central China. All DNA samples were investigated by polymerase chain reaction (PCR), and positive samples were sequenced to analyze the gene subtypes based on small ribosomal subunit (SSU rRNA) gene. The overall infection rate of Blastocystis in pigeons in Henan Province was 7.7% (39/504). Four subtypes (STs) of Blastocystis were identified including ST1 (2/39, 5.1%), ST3 (16/39, 41.0%), ST4 (1/39, 2.6%) and ST7 (20/39, 51.3%), all of which belonged to zoonotic subtypes, and ST7 was the dominant gene subtype. The results show that Blastocystis infection is common in domestic pigeons in Henan Province, Central China, and the pathogen were zoonotic subtypes. Particular attention should be given to reducing the risk of transmission of Blastocystis from domestic pigeons to humans.

Microbial Communities' Characterization in Urban Recreational Surface Waters Using Next Generation Sequencing

Microbial communities in surface waters used for recreational purposes are indicators of contamination and risk of contact with human pathogens. Hence, monitoring microbial communities in recreational waters is important for potential public health threats to humans. Such monitoring is rare in Colombia, even in its capital, Bogotá, the most populous city in the country. This city encompasses metropolitan and linear parks with recreational water bodies that are used frequently by the public, and the presence of pathogens can compromise the health of the citizens. Therefore, we examined the bacterial, and eukaryotic communities in urban recreational lakes (URL) in four metropolitan parks in Bogotá, Colombia. Samples from four metropolitan parks (Los Novios, Simon Bolivar, El Tunal, and Timiza) and one stream contaminated with sewage from a linear park (El Virrey) were collected. We used amplicon next-generation sequencing of the 16S-rRNA gene and 18S-rRNA gene to characterize microbial communities followed by bioinformatics analyses. In addition, general water quality parameters-pH, hardness, acidity, alkalinity, dissolved oxygen, and nitrites-were recorded using a commercial kit. Genera of pathogens, including Legionella, Pseudomonas, Mycobacterium, Candida, and Naegleria, were found in lake waters. The stream El Virrey was, however, the only surface water that showed an abundance of fecal bacteria, often associated with low oxygen concentrations. All water bodies showed a predominance of fungal phyla, except for the lake at Timiza. This lake showed the highest pH, and its ecological dynamics are likely different from other water bodies. Likewise, some URLs displayed a greater abundance of cyanobacteria, including toxin-producing species. Algal genera associated with eutrophication were predominant among primary producing microorganisms. This study shows for the first time the description of the bacterial and eukaryotic communities of some URLs and a stream in Bogotá. The URLs and the stream harbored various pathogens that might pose a risk to the citizen's health.

Colorectal cancer and Blastocystis sp. infection

BACKGROUND

Blastocystis sp. is a common intestinal protozoan found worldwide. Based on gene analysis, 17 subtypes (STs, ST1-ST17) have been identified, 9 of which have been isolated from humans. Differences in clinical consequences may depend on differences among the STs. Here, we evaluated the prevalence of Blastocystis sp. in patients with colorectal cancer (CRC) compared to a control group and assessed the relationships between Blastocystis sp. infection and sex; age; and CRC grade, stage, and location.

METHODS

The study included 107 CRC patients (41 women and 66 men, median age 65 years); 124 subjects without colorectal cancer or a history of oncological disease comprised the control group (55 women and 69 men, median age 63). Stool samples were collected from patients before oncological treatment and examined using light microscopy (iodine-stained smear). Additionally, PCR-based identification of Blastocystis sp. was performed in 95 stool samples from CRC patients and 76 stool samples from the control group.

RESULTS

Light microscopy showed that the prevalence of Blastocystis sp. was significantly higher in CRC patients than in the control group (12.15% and 2.42%, respectively; p = 0.0041). Multivariate analysis showed that the odds of Blastocystis sp. infection were fivefold higher in the CRC group than in the control group. PCR-based molecular examinations demonstrated that the proportion of patients infected with Blastocystis sp. was significantly higher in the CRC group than in the control group (12.63% and 2.63%, respectively; p = 0.023). The predominant ST in the CRC group was ST3, detected in nine patients (75%), followed by ST1 (2 patients, 16.7%) and ST2 (1 patient, 8.3%). No association was found between Blastocystis sp. infection and age, sex, or CRC stage, grade, or location.

CONCLUSIONS

The results showed that CRC was associated with an increased risk of opportunistic Blastocystis sp. infection, even before oncological treatment. To the best of our knowledge, this is the first report estimating the prevalence of Blastocystis sp. infection in CRC patients before oncological treatment in Europe.

Subtyping Blastocystis in pigs and humans revealed unusual avian-specific subtype ST6 in humans in Serbia

Blastocystis is a common protist colonizing the gastrointestinal tract of humans and various animals. The first subtyping of Blastocystis isolates in pigs and humans in Serbia revealed unusual avian-specific subtype ST6 in humans. In total, 48 pig faecal specimens collected on seven pig farms and 50 human faecal specimens positive to Blastocystis by microscopic examination were selected for the study. Eleven randomly selected PCR-positive pig samples and 10 samples from human patients (with gastrointestinal complaints) were subjected to SSU rDNA sequencing. Three subtypes were identified (ST3, ST5 and ST6) by phylogenetic analysis. ST5 was found in all pig samples; while in human samples, we detected ST3 and ST6. The latter subtype is relatively uncommon in Europe and highly adapted to avian hosts; therefore, the possibility of sporadic zoonotic transmission to human patients should not be ignored.

Prevalence of Select Intestinal Parasites in Alabama Backyard Poultry Flocks

Simple Summary

As biosecurity is generally low in backyard chicken flocks, infections with various pathogens are common. This puts other poultry nearby, including commercial flocks, at risk. Some chicken pathogens can also infect humans and cause disease. In this study, backyard poultry flocks were tested for parasites. Eighty-four fecal samples, 82 from chickens and two from turkeys, from 64 backyard flocks throughout the state of Alabama were collected in the summers of 2017 and 2018. The most frequently observed parasites were coccidia, unicellular parasites capable of causing diarrhea. Eggs of various roundworms were observed in 20.3–26.6% of the flocks. These parasites were usually present in low numbers only. Other detected parasites were the flagellates Histomonas meleagridis and Tetratrichomonas gallinarum in 4.7% and 18.8% of flocks. Both can cause severe disease in poultry. Detected parasites that can cause disease in humans were Cryptosporidium spp. in 18.8% of the flocks and Blastocystis spp. in 87.5% of the flocks. The results will help to provide information that can be used to design outreach programs to improve the health and wellbeing of birds in backyard flocks.

Abstract

Keeping chickens as backyard pets has become increasingly popular in the United States in recent years. However, biosecurity is generally low in backyard flocks. As a consequence, they can serve as reservoirs for various pathogens that pose a risk for commercial poultry or human health. Eighty-four fecal samples, 82 from chickens and two from turkeys, from 64 backyard flocks throughout the state of Alabama were collected in the summers of 2017 and 2018. Coccidia oocysts were seen in 64.1% of flocks with oocyst counts in most samples below 10,000 oocysts per gram. Eggs of Ascaridia spp. or Heterakis gallinarum were observed in 20.3% of the flocks, and eggs of Capillaria spp. in 26.6% of the flocks. Egg counts were low, rarely exceeding 1000 eggs per gram. DNA extracted directly from fecal samples was investigated by PCR for other relevant parasites. The results showed that 4.7% of flocks were positive for Histomonas meleagridis, 18.8% of flocks for Tetratrichomonas gallinarum, 18.8% of flocks for Cryptosporidium spp. and 87.5% of flocks for Blastocystis spp. The results will help to provide information that can be used to design outreach programs to improve health and wellbeing of birds in backyard flocks.

Molecular detection and subtype distribution of Blastocystis in farmed pigs in southern China

Blastocystis is one of the most common causative agents of intestinal diseases, which can cause enteric diseases in animals and humans. However, limited data is available on the prevalence or subtypes of Blastocystis infections in farmed pigs in southern China. In this study, a total of 396 fecal samples were collected from farmed pigs in three provinces in southern China in 2016, and screened for Blastocystis by PCR amplification of the small subunit rRNA (SSU rRNA) gene fragment. One hundred and seventy (42.93%) of the examined fecal samples were detected Blastocystis-positive, and two known zoonotic subtypes ST1 and ST5 were identified, with ST5 being the predominate subtype. Moreover, gender, age and region were considered as risk factors that associated with Blastocystis infection in farmed pigs. The present study revealed the prevalence and subtypes of Blastocystis infections in farmed pigs in southern China, which provided essential data for the control of Blastocystis infections in pigs, other animals and humans in China.

Prevalence and Subtypes Distribution amongst Syrian Refugee Communities Living in North Lebanon

Molecular data concerning the prevalence and subtype (ST) distribution of the intestinal parasite Blastocystis sp. remain scarce in the Middle East. Accordingly, we performed the first molecular epidemiological survey ever conducted in the Syrian population. A total of 306 stool samples were collected from Syrian refugees living in 26 informal tented settlements (ITS) subjected or not to water, sanitation, and hygiene (WASH) interventions in North Lebanon, then screened for the presence of Blastocystis sp. by real-time polymerase chain reaction followed by subtyping. The overall prevalence of the parasite was shown to reach 63.7%. Blastocystis sp. colonization was not significantly associated with gender, age, symptomatic status, abdominal pain or diarrhea. In contrast, WASH intervention status of ITS was identified as a risk factor for infection. Among a total of 164 subtyped isolates, ST3 was predominant, followed by ST1, ST2, and ST10. No particular ST was reported to be associated with age, gender, symptomatic status, digestive disorders, or WASH intervention status of ITS. Intra-ST diversity of ST1 to ST3 was low suggesting large-scale anthroponotic transmission. Moreover, comparative analysis of ST1 to ST3 genotypes revealed that the circulation of the parasite between Syrian refugees and the host population was likely limited.

Prevalence and Subtype Analysis of Blastocystis hominis Isolated from Patients in the Northeast of Iran

Blastocystis hominis is the most common intestinal parasite found in humans and many other hosts. Pathogenicity of Blastocystis spp. remains controversial, and it has been suggested that it may be associated with specific subtypes of the organism. This study identified the B. hominis subtypes and their prevalence rates in the northeast of Iran. A total of 1878 samples were collected from the northeast of Iran from January to December 2017. The patients' demographic details were recorded. Samples were examined by a wet mount, and genomic DNA was extracted from positive samples. Also, PCR was done on the positive samples, and sequencing and phylogenetic analysis were subsequently performed. From 1878 collected stool samples, 152 (8.1%) Blastocystis samples were detected by the microscopic method. Of the 152 samples, Blastocystis spp. were found in 53.6% of the men and 28.9% of the women who showed clinical gastrointestinal symptoms, and a significant relationship was observed between gender and clinical symptoms (P = 0.002). A meaningful relationship was found between the season and infection with this parasite (P value = 0.003). The results of the sequencing of 22 PCR products showed the dominance of ST3, which was isolated from 10 (45.45%) patients, while ST1, ST2, and ST7 were found in 4 (18.19%), 7 (31.81%), and 1 (4.55%) patients, respectively. In this study, ST7 had a low prevalence in the northeast of Iran, and similar to previous studies, ST3 was the dominant subtype.

Epidemiology of Blastocystis infection from 1990 to 2019 in China

Background

Blastocystis is ubiquitous presence in animals and humans worldwide and has a high level genetic diversity. The aim of this study was to conduct a summary of Blastocystis prevalence, subtypes (STs) in humans and animals in China and depict their distribution.

Methods

We searched for the articles related to epidemiology of Blastocystis in humans and animals throughout China which published from January 1, 1990, to July 31, 2019 in the following databases: PubMed, China National Knowledge Infrastructure (CNKI) and Wanfang database. The keywords were Blastocystis and one of the following ones: STs, subtypes, distribution, epidemiology, prevalence, infection, molecular, geographic, intestinal parasites, genetic diversity and characterization.

Results

In recent years, various molecular epidemiological studies have been carried out in some provinces/regions of China to identify subtypes of Blastocystis. Infants and young children, school students, hospitalized diarrhea patients, HIV/AIDS patients, tuberculosis patients, and cancer patients as respondents had been included. ST1–ST7 and ST12 were the main subtypes in Chinese population. Moreover, surveys of Blastocystis infection in animal were also conducted in some provinces of China. A variety of animals were investigated including pigs, cattle, sheep, yak, giant panda, and crested ibis (Nipponia nippon) with the main subtypes of ST1–ST8, ST10, ST12–ST14.

Conclusions

In recent years, some provinces/regions in China have conducted various molecular epidemiological studies to identify the Blastocystis subtypes. It is important to focus on new subtypes and mixed subtypes of infection, while increasing data on ribosomal alleles. We encourage the scientific community to start research on humans and surrounding animals (including domestic and wild animals) to better understand the possibility of Blastocystis transmission between humans and animals. We call for action among researchers studying intestinal parasitic diseases (Blastocystis), start drawing the subtype of Blastocystis and increase the subtype related to its clinical symptoms.

Prevalence and Subtype Distribution of Blastocystis Infection in Patients with Diabetes Mellitus in Thailand

Diabetes mellitus (DM) is a major global public health problem with an increasing prevalence. DM increases the risk of infections caused by bacteria, fungi, viruses, and parasites. We examined the prevalence, subtypes, and risk factors of Blastocystis infection in patients with and without DM in central Thailand. Stool samples and questionnaires were obtained from 130 people in the DM group and 100 people in the non-DM group. Blastocystis infection was identified via a nested polymerase chain reaction and subtyped via sequencing of the partial small-subunit ribosomal RNA (SSU rRNA) gene. Analysis of potential risk factors was conducted via binary logistic regression. The overall prevalence of Blastocystis infection was 10.8%, including rates of 9% and 12.3% in the non-DM and DM groups, respectively. The most prevalent subtype was ST3, followed by ST1, and ST4. Factors that potentially increased the risk of Blastocystis infection include patients being >65 years old, the presence of DM, a DM duration of ≥10 years, a low level of education, and animal ownership. In conclusion, this is the first study of Blastocystis infection in DM, and a high prevalence was found among this population. Therefore, health education promoting sanitation and hygiene is necessary to reduce and prevent infection in the community.

Socio-Demographic Determinants Associated with Blastocystis Infection in Arequipa, Peru

Blastocystis is one of the most common protozoa in the human gut and a zoonotic organism related to unsanitary living conditions. This protozoon shows a broad distribution, unclear symptomatology, and undefined pathogenicity. In Peru, studies report the presence of Blastocystis in many regions, but the highest prevalence levels are reported in Arequipa. The aim of this study was to link Blastocystis infection with social determinants of health. We recruited and surveyed 232 infected and uninfected participants from houses with at least one Blastocystis-infected person. All samples were concentrated by spin concentration method in saline solution, examined by wet mount under light microscopy and confirmed with methylene-stained stool smear. We found a human Blastocystis prevalence of 51.3% in the study sample. We also found statistical associations between Blastocystis infection and peri-urban location in the city as well as the use of alternative non-domiciliary water supplies, suggesting these are risk factors for human Blastocystis infection.

Antiprotozoal potential of Salvadora persica against three virulent subtypes of Blastocystis sp

Blastocystis sp. is a group of anaerobic protozoa parasitizing the gastrointestinal tract of humans and a broad variety of animals. Evidences of Blastocystis parasites resistance development to antiprotozoal drugs urge the exploration of new therapeutics. Antiprotozoal potential of Salvadora persica, a medicinal plant traditionally used for oral hygiene, was evaluated in vitro against Blastocystis sp. human isolates. Until now, no study has described the effect of S. persica extracts on this parasitic protozoa. Blastocystis sp. positive stool samples collected from patients with gastrointestinal complaints and asymptomatic individuals diagnosed by microscopy were furthermore cultured in vitro and characterized by PCR and multiplex-PCR using sequence-tagged-site primers to determine their subtypes. Out of 21 Blastocystis sp. isolates, five were determined as ST1, 14 as ST3, and two as ST5 subtypes. Antiprotozoal activity of untreated and heat-treated S. persica roots aqueous extracts was evaluated in vitro by serial dilutions on three Blastocystis sp. subtypes; ST1, ST3, and ST5 isolated from symptomatic patients. A significant killing activity was observed with both, untreated and heat-treated aqueous extracts of S. persica at minimal concentration of 2.5 μl/ml compared to parasites' growth controls (P < 0.05). Maximal antiprotozoal effect was reached at a concentration of 20 µl/ml of S. persica aqueous extract. Means of growth inhibition effect obtained with untreated and heat-treated extracts at 40 µl/ml against the three subtypes of Blastocystis sp. were 80% (SD 2.3) and 82% (SD 1.1), respectively. No significant difference was observed in the inhibitory effect of S. persica extracts between the three Blastocystis sp. subtypes. Aqueous extract of S. persica roots contains therefore heat-stable components with significant antiprotozoal activity against Blastocystis sp. subtypes ST1, ST3, and ST5 in vitro. Further investigations are required to determine and characterize the active antiprotozoal components of S. persica roots and their evaluation in vivo.

First detection of Blastocystis sp. in pigs in Slovakia and in Europe

Blastocystis sp. is a single-cell microorganism occurring in the gastrointestinal tract of humans and various animals and is distributed worldwide. Blastocystis exhibits extensive genetic diversity of 28 subtypes (STs) based on the small subunit ribosomal RNA (SSU rRNA) gene. In this study, the genetic diversity and zoonotic potential of Blastocystis were evaluated using pig faecal samples from two farms in Slovakia. Blastocystis spp. were detected in pigs intended for distribution and consumption. ST 5 subtype was identified in all positive samples and age categories with a prevalence of 12%. However, the prevalence on one of the farms was up to 28.6%. This is the first study of Blastocystis in pigs carried out in Slovakia. Although a number of samples obtained was small, the identified subtype of ST5 Blastocystis sp. occurs in humans and animals. It may have zoonotic potential and therefore may be a risk factor due to the close contact between humans and pigs on the breeding farms.

Current status of Blastocystis sp. in animals from Southeast Asia: a review

Blastocystis is the most frequently observed eukaryotic gastrointestinal symbiont in humans and animals. Its low host specificity and zoonotic potential suggest that animals might serve as possible reservoirs for transmission. The prevalence and subtype distributions of Blastocystis sp. in animal populations in Southeast Asia, a hotspot for zoonotic diseases, are reviewed. Recommendations for future research aimed at understanding the zoonotic role of Blastocystis are also included. Seven countries have, so far, reported Blastocystis infection in various animals, such as livestock, poultry, companion animals, and non-human primates. Pigs were the most studied animals, and there were records of 100% prevalence in pigs, cattle, and ostriches. Using polymerase chain reaction (PCR)-based approaches, twelve Blastocystis sp. subtypes (STs), namely ST1, ST2, ST3, ST4, ST5, ST6, ST7, ST8, ST9, ST10, ST12, and ST14 have been recognised infecting animals of Southeast Asia. ST1 and ST5 were the most frequently identified, and Malaysia observed the most diverse distribution of subtypes. Further investigations on Blastocystis sp. in various animal hosts, using adequate sample sizes and uniform detection methods, are essential for a better understanding of the distribution of this organism. Detailed genome studies, especially on STs shared by humans and animals, are also recommended.

Prevalence and Subtype Distribution of Blastocystis sp. in Senegalese School Children

Blastocystis sp. is an enteric protozoan that frequently colonizes humans and many animals. Despite impacting on human health, data on the prevalence and subtype (ST) distribution of Blastocystis sp. remain sparse in Africa. Accordingly, we performed the first multicenter and largest epidemiological survey ever conducted on Blastocystis sp. for this continent. A total of 731 stool samples collected from healthy school children living in 10 villages of the northwestern region of Senegal were tested for the presence of Blastocystis sp. by real-time polymerase chain reaction followed by subtyping of positive samples. Considerable variation in prevalence between villages (51.7 to 100%) was evident with the overall prevalence being 80.4%. Mixed infections were identified in 23% of positive individuals. Among 453 school children with a single infection, ST2 was predominant, followed by ST1, ST3, ST7, ST10, and ST14; this is the first report of ST10 and ST14 in humans. Genetic polymorphisms were evident at the intra-ST level with the identification of numerous ST1 to ST3 genotypes. ST1 showed the greatest intra-ST diversity followed by ST2 and ST3. The prevalence and distribution of STs and genotypes varied among target villages, pointing to several potential infection sources, including human-to-human, zoonotic, and waterborne transmission.

First Report on the Prevalence and Subtype Distribution of Blastocystis sp. in Edible Marine Fish and Marine Mammals: A Large Scale-Study Conducted in Atlantic Northeast and on the Coasts of Northern France

Blastocystis is frequently identified in humans and animal hosts and exhibits a large genetic diversity with the identification of 17 subtypes (STs). Despite its zoonotic potential, its prevalence and ST distribution in edible marine fish and marine mammals remain unknown. A large-scale survey was thus conducted by screening 345 fish caught in Atlantic Northeast and 29 marine mammals stranded on the coasts of northern France for the presence of the parasite using real-time Polymerase Chain Reaction PCR. The prevalence of the parasite was about 3.5% in marine fish. These animals were mostly colonized by poikilotherm-derived isolates not identified in humans and corresponding to potential new STs, indicating that fish are natural hosts of Blastocystis. Marine fishes are also carriers of human STs and represent a likely limited source of zoonotic transmission. 13.8% of the marine mammals tested were colonized and 6 different STs were identified including 3 potential new STs. The risk of zoonotic transmission through marine mammals is insignificant due to the lack of repeated contact with humans. The present survey represents the first data regarding the prevalence and ST distribution of Blastocystis in marine fish and marine mammals and provides new insights into its genetic diversity, host range and transmission.

Ancient Adaptive Lateral Gene Transfers in the Symbiotic Opalina–Blastocystis Stramenopile Lineage

Lateral gene transfer is a very common process in bacterial and archaeal evolution, playing an important role in the adaptation to new environments. In eukaryotes, its role and frequency remain highly debated, although recent research supports that gene transfer from bacteria to diverse eukaryotes may be much more common than previously appreciated. However, most of this research focused on animals and the true phylogenetic and functional impact of bacterial genes in less-studied microbial eukaryotic groups remains largely unknown. Here, we have analyzed transcriptome data from the deep-branching stramenopile Opalinidae, common members of frog gut microbiomes, and distantly related to the well-known genus Blastocystis. Phylogenetic analyses suggest the early acquisition of several bacterial genes in a common ancestor of both lineages. Those lateral gene transfers most likely facilitated the adaptation of the free-living ancestor of the Opalinidae–Blastocystis symbiotic group to new niches in the oxygen-depleted animal gut environment.

Endoparasitism of Greek ostriches: First report of Entamoeba struthionis and Balantioides coli

Ostrich farming is a worldwide practice and an internationally developing industry. Among challenges in livestock production are the parasitic infections. The present study aimed to the investigation of the gastrointestinal parasites biota and prevalence in ostriches raised in different areas of Greece. A total of 141 clinically healthy ostriches originating from four different localities of Greece were coprologically examined for parasites of the gastrointestinal tract. Coprological examination revealed a considerably high rate of infection (65.9%) with protozoa; however, no helminths (trematodes, cestodes and nematodes) were detected. In detail, cysts of Entamoeba struthionis have been found in 57.4% of the examined birds. Moreover, 39.0% of sampled ostriches harboured cysts of Balantioides coli (syn. Balantidium coli), while oocysts of Cryptosporidium sp. were detected at a low percentage (2.1%). Partial sequences of the small subunit rRNA (16S rRNA) gene and the ITS region were amplified from pooled Entamoeba and Balantioides positive samples, respectively, confirming for the first time the presence of Entamoeba struthionis and Balantioides coli in ostriches in Greece. Some of these parasitoses require attention as they may affect productivity performance of the animals in commercial ostrich farming and possibly pose disease risk for livestock and humans.

Molecular epidemiology of Blastocystis sp. in dogs housed in Italian rescue shelters

Blastocystis is a ubiquitous protozoan with a wide range of hosts. In humans, its presence has been associated with gastrointestinal disorders, although its role as a pathogen still needs to be elucidated. Until now, 17 Blastocystis subtypes (STs) have been identified, with ST1-ST4 the most commonly found in humans. Among domestic animals, the same STs reported in humans have been detected in dogs. An epidemiological survey on dog kennels was carried out to evaluate the prevalence of Blastocystis and the STs involved. Overall, 99 faecal samples were collected from the rescue shelters. Blastocystis detection was performed through conventional barcoding PCR targeting the 1800-bp SSU-rDNA, followed by sequencing and phylogenetic analysis. Blastocystis DNA was found in 21 faecal samples (21.2%), and all samples were successfully sequenced and identified as ST3 in a unique monophyletic group. The presence of Blastocystis was reported for the first time in dogs from Italy, with the identification of ST3, the subtype most commonly found in humans.

Metagenomics for broad and improved parasite detection: a proof-of-concept study using swine faecal samples

Efficient and reliable identification of emerging pathogens is crucial for the design and implementation of timely and proportionate control strategies. This is difficult if the pathogen is so far unknown or only distantly related with known pathogens. Diagnostic metagenomics - an undirected, broad and sensitive method for the efficient identification of pathogens - was frequently used for virus and bacteria detection, but seldom applied to parasite identification. Here, metagenomics datasets prepared from swine faeces using an unbiased sample processing approach with RNA serving as starting material were re-analysed with respect to parasite detection. The taxonomic identification tool RIEMS, used for initial detection, provided basic hints on potential pathogens contained in the datasets. The suspected parasites/intestinal protists (Blastocystis, Entamoeba, Iodamoeba, Neobalantidium, Tetratrichomonas) were verified using subsequently applied reference mapping analyses on the base of rRNA sequences. Nearly full-length gene sequences could be extracted from the RNA-derived datasets. In the case of Blastocystis, subtyping was possible with subtype (ST)15 discovered for the first known time in swine faeces. Using RIEMS, some of the suspected candidates turned out to be false-positives caused by the poor status of sequences in publicly available databases. Altogether, 11 different species/STs of parasites/intestinal protists were detected in 34 out of 41 datasets extracted from metagenomics data. The approach operates without any primer bias that typically hampers the analysis of amplicon-based approaches, and allows the detection and taxonomic classification including subtyping of protist and metazoan endobionts (parasites, commensals or mutualists) based on an abundant biomarker, the 18S rRNA. The generic nature of the approach also allows evaluation of interdependencies that induce mutualistic or pathogenic effects that are often not clear for many intestinal protists and perhaps other parasites. Thus, metagenomics has the potential for generic pathogen identification beyond the characterisation of viruses and bacteria when starting from RNA instead of DNA.

Epidemiology of Blastocystis sp. infection in China: a systematic review

Blastocystis sp., a unicellular intestinal parasite in humans and animals worldwide, is frequently found in immunocompromized patients and people in close contact with animals. Here, we reviewed recent studies on the prevalence, subtypes, and distribution of Blastocystis infection in humans and animals in China. To date, more than 12 provinces have reported Blastocystis infection in humans, with identification of six different subtypes (ST1, ST2, ST3, ST4, ST5, and ST6). The overall infection rate reported was 3.37% (3625/107,695), with the lowest prevalence (0.80%) in Fujian province and the highest prevalence (100%) in Guangdong province. ST3 (62%, 186/300) was the most dominant subtype, identified in all tested provinces in China. A total of eight provinces have reported Blastocystis infection in various animals, with the overall prevalence being 24.66% (1202/4874). Molecular analysis revealed 14 subtypes that infected animals, including 10 known (ST1, ST2, ST3, ST4, ST5, ST6, ST7, ST10, ST13, ST14), and 4 novel (Novel1, Novel2, Novel3, Novel4) subtypes. ST5 was the dominant subtype infecting artiodactyls (44.1%, 460/1044), while ST1 commonly infected carnivores (45.5%, 5/11). These findings provide insights into the epidemiological behavior of Blastocystis sp. in China, and could help in developing effective control strategies against the parasite.

First report on the prevalence and subtype distribution of Blastocystis sp. in dairy cattle in Lebanon and assessment of zoonotic transmission

Blastocystis sp. is frequently identified in a wide range of animal hosts, including bovids. Because of its burden and zoonotic potential, this parasite has been sought in domestic cattle from various countries, since this livestock may also represent a possible reservoir of human infection. However, epidemiological data regarding the prevalence and ST distribution of Blastocystis sp. in this animal group is lacking in Lebanon. Therefore, faecal samples were collected from a total of 254 dairy cattle raised on 55 farms located in the North Lebanon region and screened for the presence of the parasite by quantitative real-time PCR. The overall prevalence of Blastocystis sp. was shown to reach 63.4% in cattle livestock. Sequence analysis of positive samples indicated the presence of seven STs, with predominance of ST10 (44.0%) and ST14 (36.8%) and lower proportions of ST2 (8.0%), ST1 (7.2%), ST5 (2.4%), ST3 and ST7 (0.8% each). This survey was the first conducted worldwide reporting ST2 and ST7 in domestic cattle and confirmed that ST10 and ST14 represent cattle-adapted STs in view of their high prevalence. Faecal samples from in-contact dairy farmers and patients hospitalised in the same Lebanese governorate who reported no contact with cattle livestock were also analysed for the presence of Blastocystis sp. The same three STs were identified in both human cohorts, with predominance of ST3, followed either by ST1 or ST2 depending of the group. No other STs, including ST10 or ST14, have been reported. Moreover, even though ST1, ST2 and ST3 were found to be common to dairy cattle and farmers cohorts, only one ST3 isolate showed 100% sequence identity between both hosts. Consequently, the presence and low prevalence of ST1, ST2, ST3, ST5 and ST7 identified herein in domestic cattle, most of which exhibit low host specificity, could be derived from occasional direct exposure to faecal material from human and non-human hosts or by ingestion of contaminated drinking water or food in the enclosure of the farms. Together with the absence of ST10 and ST14 in the human population, these data suggest that cattle play a negligible role as zoonotic reservoirs of Blastocystis sp.

Molecular detection and epidemiological risk factors associated with Cryptosporidium infection among cattle in Peninsular Malaysia

Enteric protozoa infection among cattle may pose a threat to productivity and survival leading to negative impacts on the livestock industry. A number of these pathogens are also known to be zoonotic and are of public health concern. Despite the importance of these enteric protozoa to both animal and human health, there remains a paucity of published information on the epidemiological risk factors that may be associated with bovine cryptosporidiosis in Southeast Asia. The present study was undertaken to determine the molecular prevalence and associated risk factors for Cryptosporidium infection among beef and dairy cattle in Peninsular Malaysia. Faecal samples were collected from 824 cattle in 39 farms (526 beef and 298 dairy) situated in 33 locations throughout the country, and subjected to PCR detection for Cryptosporidium using primers targeting the 18S SSUrRNA gene. Epidemiological variables including host, environment and management factors were subjected to univariate and multivariate logistic regression analyses to determine the potential risk factors for infection. The prevalence of Cryptosporidium among the cattle was 12.5%, with significant difference in the infection rate among the various breeds. There was no significant effect of gender, and both the beef and dairy cattle were at similar odds for infection. The younger cattle had a significantly higher infection rate compared to the older animals. Multivariate analysis revealed that deworming practice, distance to human settlement, geographical location (zone) and farm management system were significant risk factors associated with Cryptosporidium infection. The cattle that were reared on farms located in the northeast of the country, closest (≤200 m) to human settlements, reared extensively, and dewormed every four months were at highest risk of infection. The present study constitutes the first attempt to analyze the multivariable epidemiological risk factors involved in bovine cryptosporidiosis in Malaysia and in Southeast Asia. It is envisaged that the data obtained will facilitate better control and prevention measures for Cryptosporidium infection among cattle in the region. Due to the potential zoonotic nature of the infection, serious steps should be instituted for animal treatment and biohazard waste management on local cattle farms.

Establishing a protocol for water sample processing for the detection of Blastocystis sp

This study was aimed at establishing a protocol for water sample processing for the detection of Blastocystis sp. using distilled water spiked with Blastocystis sp. cysts. The study established a protocol involving eight technical aspects, namely, storage temperature, storage duration, minimum water sample volume, optimum relative centrifugal force, centrifugation duration, minimum number of cyst for inoculation in Jones' medium and turn-around-time for the detection of vacuolar forms of Blastocystis sp. Results showed a minimum of 1.0 L water sample should be collected and processed on the same day. Otherwise, it should be stored at 4 °C and processed within 3 days. Water sample should be centrifuged at 1400×g for 10 min. For the isolation of Blastocystis sp. cysts, parasite pellet could be layered on top of Ficoll-Paque™ PLUS, centrifuged at 1400×g for 20 min and washed twice using 0.9% saline with centrifugation at 1400×g for 10 min. A minimum of 1 × 10⁵ cysts could then be inoculated in Jones' medium supplement with 10% horse serum, incubated at 37 °C and examined for any presence of vacuolar forms of Blastocystis sp. after 3 days of inoculation. A protocol for water sample processing for the detection of Blastocystis sp. has successfully been established. The protocol was validated using 106 various water samples. This protocol will be very useful in determining the extent of Blastocystis sp. contamination in water sources in order to identify the seriousness of contamination.

Molecular epidemiology of Blastocystis isolated from animals in the state of Rio de Janeiro, Brazil

The enteric protist Blastocystis is one of the most frequently reported parasites infecting both humans and many other animal hosts worldwide. A remarkable genetic diversity has been observed in the species, with 17 different subtypes (STs) on a molecular phylogeny based on small subunit RNA genes (SSU rDNA). Nonetheless, information regarding its distribution, diversity and zoonotic potential remains still scarce, especially in groups other than primates. In Brazil, only a few surveys limited to human isolates have so far been conducted on Blastocystis STs. The aim of this study is to determine the occurrence of Blastocystis subtypes in non-human vertebrate and invertebrate animal groups in different areas of the state of Rio de Janeiro, Brazil. A total of 334 stool samples were collected from animals representing 28 different genera. Blastocystis cultivated samples were subtyped using nuclear small subunit ribosomal DNA (SSU rDNA) sequencing. Phylogenetic analyses and BLAST searches revealed six subtypes: ST5 (28.8%), ST2 (21.1%), ST1 and ST8 (19.2%), ST3 (7.7%) and ST4 (3.8%). Our findings indicate a considerable overlap between STs in humans and other animals. This highlights the importance of investigating a range of hosts for Blastocystis to understand the eco-epidemiological aspects of the parasite and its host specificity.

First molecular identification and subtype distribution of Blastocystis sp. isolated from hooded crows (Corvus cornix) and pigeons (Columba livia) in Tehran Province, Iran

Blastocystis is a common intestinal parasite among humans and animals such as non-human primates, pigs, cattle, birds, amphibians, and less frequently, rats, reptiles and insects. Since Blastocystis is a widely transmissible parasite between humans and mammals or birds, it is prominent to determine whether newly secluded non-human isolates are zoonotic. There are no comprehensive studies in Iran assessing the prevalence and molecular identification of Blastocystis infection in birds, especially in pigeons and crows. So, the aim of this study was to identify Blastocystis subtypes (STs) in crows and pigeons in Tehran province, Iran, using Nested PCR-RFLP and sequencing. Overall, 300 Blastocystis isolates from birds (156 pigeons and 144 crows) were subtyped by PCR, and the homology among isolates was then confirmed by RFLP analysis of the 18S rRNA gene. The prevalence of Blastocystis infection was detected 42.9% in pigeons and 44.4% in crows. All positive pigeons were owned by ST13 (100%). Among crows, 46 samples (71.8%) like pigeons were ST13, and 13 samples (20.3%) were ST14. Five samples (7.9%) remained unknown. This study was the first report of ST13 and ST14 of Blastocystis from birds. In the present study, our data revealed a high prevalence of Blastocystis sp. in pigeon's and crow's samples and the isolates from these birds were classified into two genetically distinct STs. Therefore, birds appear to be infected with various STs. It is important to determine the phylogenetic relationships between unknown STs from these birds and the multiple STs of Blastocystis.

Prevalence of intestinal parasites among food handlers in Kashan, central Iran, 2017-2018

The most important transmission path of intestinal parasites is the consumption of contaminated water and food. This survey was conducted to determine the prevalence of intestinal parasites among food handlers in Kashan, central Iran. This cross-sectional study was carried on 1018 food handlers who referred to the health centers in order to receive health certificate in 2017-2018. Stool samples of food handlers were collected and examined using direct and formalin-ethyl acetate methods. Results were recorded in information form along with some demographic data such as sex, age. The data were analyzed based on the tests of descriptive statistics by SPSS 16. Of the 1018 individuals examined 851 (83.6%) were men and 167 (16.4%) were female. Infection rate was 10.2% among the population and 9 types of parasites were diagnosed totally. Rate of infection to protozoan intestinal parasites were: Blastocystis sp. 7.17%, Giardia duodenalis 1.2%, Entamoeba coli 1.27%, Endolimax nana 1.08%, Dientamoeba fragilis 0.3%, Iodamoeba butschlii 0.3%, Entamoeba histolytica/E. dispar 0.2%, Chilomastix mesnili 0.1%. Hymenolepis nana (0.1%) was the only intestinal worm that observed. In this investigation, 8.9% of the individual were infected by one parasite, 1.08% by two and 0.2% by 3 or more parasites. This study showed that infection to intestinal helminthic is rare among food handlers in Kashan but the prevalence of protozoan intestinal parasites is high that similar to other regions of Iran. To reduce the rate of parasitic infections and inhibition of their transmission, continuing the process of promoting the health level is recommended.

Extra-enteric Blastocystis infection in a duck

Cell structures morphologically consistent with Blastocystis were aspirated from a subcutaneous facial swelling in a 13-mo-old pet duck. On PCR analysis and sequencing, the organism was confirmed as Blastocystis sp. subtype 7. Blastocystis is a single-celled protist that is found in the intestinal tract of many species, including mammals, birds, reptiles, amphibians, and insects. A complete understanding of the lifecycle and pathogenesis of the parasite remains elusive. Blastocystis has been implicated in human and animal disease; however, its role is controversial given that it is commonly found among healthy gut microbiota. Infection with Blastocystis outside the intestinal tract has been reported only rarely in humans. Our case of subcutaneous Blastocystis infection in a duck is a novel presentation of a ubiquitous, generally asymptomatic, parasite or commensal of the intestinal tract.

Prevalence and subtype distribution of Blastocystis sp. isolates from poultry in Lebanon and evidence of zoonotic potential

BACKGROUND

Blastocystis sp. is a common protozoan parasite frequently identified in the digestive tract of humans and a large variety of animal hosts worldwide, including birds. It exhibits a large genetic diversity with the identification of 17 subtypes (STs), most of them with low host specificity. ST6 and ST7 were identified in birds and suggested to represent avian STs only in the context of scarce small-scale epidemiological surveys. Moreover, these two STs also account for a significant proportion of human infections whose zoonotic origin has never been clearly confirmed. Therefore, molecular screening of Blastocystis sp. was conducted by quantitative real-time PCR for fecal samples from poultry farms and their in-contact humans from slaughterhouses in Lebanon. In parallel, a control group consisting of patients hospitalized in the same geographical area and reporting no contact with poultry was also screened for the presence of the parasite.

RESULTS

The overall prevalence of Blastocystis sp. was shown to reach around 32% in chicken samples and 65% in the farms screened. All the avian isolates were subtyped and belonged to either ST6 or ST7, with a large predominance of ST6. Fifty-four percent of slaughterhouse staff members were positive for Blastocystis sp. compared with a similar prevalence of 56% in hospitalized patients. ST3 was predominant in both human cohorts followed by either ST1 then ST2 among slaughterhouse staff or by ST2 then ST1 among hospitalized patients. ST6 was also identified in two slaughterhouse workers and not in the group of hospitalized patients. Gene sequence identity was observed between chicken and human ST6 isolates from the same slaughterhouse.

CONCLUSIONS

Our data revealed a high prevalence of Blastocystis sp. in chicken samples and confirmed that ST6 and ST7 represented avian-adapted STs. Among both human cohorts, Blastocystis sp. infection was shown to exceed 50% with a predominance of ST3. The identification of ST6 in slaughterhouse staff members confirmed the zoonotic transmission of this ST through repeated and direct contact between chickens and their handlers.

Prevalence of Cryptosporidium, Blastocystis, and other opportunistic infections in patients with primary and acquired immunodeficiency

Intestinal opportunistic infections are often caused by unicellular parasites. Individuals with decreased immunity are particularly susceptible to infection by said microorganisms, and when they are infected, diarrhea can be the main clinical manifestation. However, intestinal parasites have rarely been taken into account in intestinal disorders. In our study, an investigation was conducted to determine the prevalence of intestinal micro-pathogens, such as Cryptosporidium, Giardia, Blastocystis, and microsporidia, in hospitalized patients with different immunological statuses. The study at hand indicates that protozoan parasitic infections are rare among immunodeficient patients in Poland. The overall prevalence of micro-pathogens among participants was 4.6%; it was three times higher in adults (12.5%) than in children (2.3%). Cryptosporidium and Cyclospora species (Apicomplexa) were diagnosed as the main cause of heavy diarrhea. Accordingly, adult patients were positive mainly for Blastocystis and microsporidia, while children were more often infected with the Cryptosporidium species.

Parasitic profiling of Japanese quails (Coturnix japonica) on two farms with conventional production system in the Amazon region

ABSTRACT: The health monitoring and management systems of coturniculture can be deemed to be in a developmental phase when compared to the poultry industry. Studies regarding taxonomy and parasitic biology in quails (Coturnix japonica) has not been well conducted in Brazil. Most of the information is available from the autopsy case reports, in many ways the parasitic fauna of quails is still unknown. The aim of this study was to conduct a parasitological research in quails in order to contribute to ameliorate this situation. 31 quails, which were 12 months old, were used for the study. Their carcasses and viscera were sent to the Laboratory of Entomology and Tropical Diseases, INPA, Manaus/AM. The circulatory, nervous, respiratory, digestive and reproductive systems of these were studied separately. No blood parasites were found, however, nine species of endoparasites were registered which were distributed among the classes Cestoda, Nematoda and Protozoa. The helminths were distributed in the duodenum, jejunum, ileum, cecum and oviduct. The cecum was found to be the most parasitized organ and contained a wide range of parasites having three species of protozoa and three species of nematodes. Six morphotypes of Eutrichomastix globosus were recorded, and some morphotypes were hyperparasitized with sporangia Sphaerita sp. in the cytoplasm. A large number of parasites were recorded in this study, as well as the protozoan Blastocystis hominis was first being observed for quail.

Molecular characterization of Blastocystis from pigs in Shaanxi province of China

Blastocystis is an enteric eukaryote of mystery for its ubiquitous presence in animals and humans worldwide and a broad diversity genetically. The animals have been suggested to be an important reservoir to transmit Blastocystis to humans because of high colonization frequency and the presence of zoonotic subtypes. In the present study, the prevalence and subtypes of Blastocystis in pigs in Shaanxi province of China were determined using the molecular technique based on the small subunit rRNA (SSU rRNA) gene fragment. Of 560 pig faecal samples collected from different geographical origins, 419 (74.8%) were positive for Blastocystis colonization. The prevalence was significant affected by the age and the geographical origin. Four subtypes, including three zoonotic (ST1, ST3 and ST5) and one animal specific (ST10) subtypes, were identified. To our knowledge, this study provides the first run-through information for colonization of Blastocystis in pigs in China.

Molecular characterization of Blastocystis sp. in captive wild animals in Qinling Mountains

Blastocystis is one common protist inhabiting in gastrointestinal tracts of animals and humans. Examining the subtypes has important implications for assessing the zoonotic potential of Blastocystis and intestinal health of hosts. In the present study, a total of 497 fecal samples collected from 37 wild animal species in Qinling Mountains were investigated for the presence and subtypes of Blastocystis. Of them, 200 (40.2%) were positive for Blastocystis and 13 subtypes were found, including eight known subtypes (STs1-3, 5, 10, 12-14) and five possible novel subtypes (temporarily named as STs18-22), with ST10 as the predominate subtype and the subtype ST5 was detected in an ostrich for the first time. These findings indicated the wide distribution and specific subtype characteristics of Blastocystis in wild animals of Qinling Mountains.

Predominance and association risk of Blastocystis hominis subtype I in colorectal cancer: a case control study

Background

Blastocystis, a genetically diverse intestinal parasite with controversial pathogenic potential, has increasingly been incriminated for diarrheal illness in immunocompromised individuals including colorectal cancer (CRC) patients. The aim of the current study was to assess the possible association between Blastocystis infection and CRC condition in Makkah, Saudi Arabia (KSA).

Methods

Stool samples were collected from 80 non-cancer (NC) and 138 cancer subjects including 74 CRC patients and 64 patients with other cancers outside gastrointestinal tract (COGT). Molecularly confirmed Blastocystis isolates were genetically grouped and subtyped using multiplex polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) and sequence-tagged site primers-based PCR (PCR-STS), respectively.

Results

Blastocystis hominis were confirmed in 29.7, 25 and 15% among CRC, COGT and NC patients, respectively. Obtained Blastocystis isolates were initially categorized into 2 groups (A and C), which were subsequently subtyped into 3 different subtypes; subtype-I (38%), subtype-II (44%) and subtype-V (22%). Interestingly, subtype-I was the most predominantly detected subtype (54.5%) among CRC patients with a significant association risk (COR 7.548; 95% CI: 1.629–34.987; P = 0.004).

Conclusion

To the best of our knowledge, the current study is the first to provide genetic insights on the prevalence of Blastocystis hominis among CRC patients in Makkah, KSA. Moreover, the study suggests for a possible association between subtype-I of Blastocystis hominis and CRC, which could indicate a potential influence of Blastocystis on CRC condition. Further studies are required to confirm this association risk and to investigate the possible underlying mechanism of postulated carcinogenic influence of Blastocystis hominis subtype-I.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-017-0131-z) contains supplementary material, which is available to authorized users.

Inter- and intra-subtype variation of Blastocystis subtypes isolated from diarrheic and non-diarrheic patients in Iran

Blastocystis is a common intestinal parasitic protist infecting birds and mammals. Blastocystis comprises at least 17 subtypes (ST), of which ST1-ST9 have been detected in humans. Significant correlation between certain subtypes and pathogenicity remains to be established. Nevertheless, some studies suggest a potential linkage between subtypes (inter- and intra-subtype variation) and clinical manifestations. The aim of this study was to identify intra-subtype genetic variation of subtypes of Blastocystis in stools samples submitted by diarrheic and non-diarrheic patients. A 550-bp fragment of the nuclear small subunit ribosomal rRNA gene was amplified from 58 culture-positive samples isolated from diarrheic and non-diarrheic Iranian patients. PCR products were sequenced and sequences subjected to phylogenetic analysis. Intra-and inter-subtype variation was calculated. Based on comparison with reference sequences in GenBank, ST1, ST2 and ST3 were found in 18 (31.03%), 21 (36.22%), and 19 (32.75%) of the samples, respectively. Diarrheic stools were observed in eight (44.44%), 10 (47.61%), and nine (47.36%) patients with ST1, ST2, and ST3, respectively. No statistically significant correlation was found between subtypes and diarrhea (P=1.000). Multiple sequence alignment exhibited a within-subtype similarity of 98.76%, 97.17%, and 99.78% in ST1, ST2, and ST3, respectively. Highest similarity was seen among ST3 isolates, while lowest similarity was seen among ST2 isolates. Phylogenetic analysis did not suggest any correlation between diarrhea and intra-subtype variation. Inter- and intra-subtype variation in SSU rRNA gene appears not to reflect differences in the clinical outcome of Blastocystis carriage.

[Concordance between the zinc sulphate flotation and centrifugal sedimentation methods for the diagnosis of intestinal parasites]

INTRODUCTION

The diagnosis of intestinal parasitic infections depends on the parasite load, the specific gravity density of the parasite eggs, oocysts or cysts, and the density and viscosity of flotation or sedimentation medium where faeces are processed.

OBJECTIVE

To evaluate the concordance between zinc sulphate flotation and centrifugal sedimentation in the recovery of parasites in faecal samples of children.

MATERIALS AND METHODS

Faecal samples of 330 children from day care centers were evaluated by zinc sulphate flotation and centrifugal sedimentation techniques. The frequencies of detection of parasites by each method were determined and the agreement between the diagnostic techniques was evaluated using the kappa index, with 95% confidence intervals.

RESULTS

The faecal flotation in zinc sulphate diagnosed significantly more cases of Trichuris trichiura infection when compared to centrifugal sedimentation (39/330; 11.8% vs. 13/330; 3.9%, p<0.001), with low diagnostic concordance between methods (kappa=0.264; 95% CI: 0.102-0.427). Moreover, all positive samples for Enterobius vermicularis eggs (n=5) and Strongyloides stercoralis larvae (n=3) were diagnosed only by zinc sulphate. No statistical differences were observed between methods for protozoa identification.

CONCLUSIONS

The results showed that centrifugal flotation in zinc sulphate solution was significantly more likely to detect light helminths eggs such as those of T. trichiura and E. vermicularis in faeces than the centrifugal sedimentation process.

Evaluation of the NanoCHIP® Gastrointestinal Panel (GIP) Test for Simultaneous Detection of Parasitic and Bacterial Enteric Pathogens in Fecal Specimens

Infectious gastroenteritis is a global health problem associated with high morbidity and mortality rates. Rapid and accurate diagnosis is crucial to allow appropriate and timely treatment. Current laboratory stool testing has a long turnaround time (TAT) and demands highly qualified personnel and multiple techniques. The need for high throughput and the number of possible enteric pathogens compels the implementation of a molecular approach which uses multiplex technology, without compromising performance requirements. In this work we evaluated the feasibility of the NanoCHIP® Gastrointestinal Panel (GIP) (Savyon Diagnostics, Ashdod, IL), a molecular microarray-based screening test, to be used in the routine workflow of our laboratory, a big outpatient microbiology laboratory. The NanoCHIP® GIP test provides simultaneous detection of nine major enteric bacteria and parasites: Campylobacter spp., Salmonella spp., Shigella spp., Giardia sp., Cryptosporidium spp., Entamoeba histolytica, Entamoeba dispar, Dientamoeba fragilis, and Blastocystis spp. The required high-throughput was obtained by the NanoCHIP® detection system together with the MagNA Pure 96 DNA purification system (Roche Diagnostics Ltd., Switzerland). This combined system has demonstrated a higher sensitivity and detection yield compared to the conventional methods in both, retrospective and prospective samples. The identification of multiple parasites and bacteria in a single test also enabled increased efficiency of detecting mixed infections, as well as reduced hands-on time and work load. In conclusion, the combination of these two automated systems is a proper response to the laboratory needs in terms of improving laboratory workflow, turn-around-time, minimizing human errors and can be efficiently integrated in the routine work of the laboratory.

Immunopathological assessments of human Blastocystis spp. in experimentally infected immunocompetent and immunosuppresed mice

Blastocystis spp., one of the most common parasites colonizing the human intestine, is an extracellular, luminal protozoan with controversial pathogenesis. The host's immune response against Blastocystis spp. infection has also not been defined yet. Therefore, this research aimed to assess the potential pathogenicity of this parasite and its ability to modulate the immune response in experimental infected immunocompetent and immunosuppresed mice. These results demonstrated that the infected immunosuppressed mice were more affected than infected immunocompetent mice. Histopathological examination of the small intestine in the infected immunosuppressed mice showed that Blastocystis spp. infiltrated all the layers. Moreover, the epithelia showed exfoliation and inflammatory cell infiltration in submucosa compared to that of the infected immunocompetent mice. As well, examination of the large intestine of the infected immunosuppressed group showed severe goblet cell hyperplasia. Blastocystis spp. infiltrated all the large intestine layers compared to that of the infected immunocompetent group. Furthermore, there was a significant upregulation of the expression of proinflammatory cytokines: interleukin 12 (IL-12) and tumor necrosis factor alpha (TNF-α) in the infected immunosuppressed mice compared to that of the infected immunocompetent ones (p ≤ 0.004 and p ≤ 0.002, respectively). However, the expression of anti-inflammatory cytokines (IL-4 and IL-10) was significantly downregulated in the infected immunosuppressed group compared to that of the infected immunocompetent group one at 10 days postinfection (p ≤ 0.002 and p ≤ 0.001, respectively). The results of this study revealed that Blastocystis spp. affected the production of pro- and anti-inflammatory cytokines in both groups of mice compared to healthy normal (naive) group. Additionally, these data showed that there was a significant upregulation (p ≤ 0.005) of the locally synthesized antibody: secretary IgA (sIgA) in the gut of the infected immunocompetent mice when compared to that of the infected immunosuppressed ones.