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

Molecular Detection and Genotyping of Blastocystis in Farmed Minks and Raccoon Dogs in Northern China

Blastocystis is a common intestinal protozoan found in both humans and animals. However, research on Blastocystis infections in minks (Neovison vison) and raccoon dogs (Nyctereutes procyonoides) is limited. This study aimed to investigate the prevalence and subtypes of Blastocystis in these two species across northern provinces of China using small subunit rRNA gene sequence analysis. We examined 275 minks (89 from Hebei Province, 57 from Heilongjiang Province, 109 from Liaoning Province, and 20 from Shandong Province) and 235 raccoon dogs (114 from Hebei Province, 27 from Heilongjiang Province, 61 from Liaoning Province, and 33 from Jilin Province). The overall infection rate was 13.5% (69/510). Farmed minks had a prevalence of 1.5% (4/275), while raccoon dogs showed a significantly higher prevalence of 27.7% (65/235). We identified five distinct subtypes (ST1, ST2, ST3, ST5, and potentially novel subtype) across both species: ST1 (15 cases), ST2 (15 cases), ST3 (31 cases), ST5 (7 cases), and potentially novel subtype (1 case). This study is the first to report ST1 and ST3 in minks and ST1, ST2, ST5, and potentially novel subtype in raccoon dogs. As ST1, ST2, ST3, and ST5 subtypes are also found in humans, our findings suggest that minks and raccoon dogs may serve as potential reservoirs for human Blastocystis infections. Furthermore, the newly identified, potentially novel subtype might also be transmissible to humans or other animals. This research enhances our understanding of Blastocystis distribution among hosts in China and supports zoonotic disease prevention efforts related to farmed minks and raccoon dogs.

Epidemiology, molecular characterization, and risk factors of Acanthamoeba spp., Blastocystis spp., and Cyclospora spp. infections in snakes in China

Snakes are widely farmed in China for medicinal purposes and as pets worldwide. Acanthamoeba spp., Blastocystis spp., and Cyclospora spp. are significant zoonotic pathogens frequently discovered in various animals, causing diseases with global public health implications. However, their prevalence and zoonotic potential in snakes remain poorly understood. In this study, 812 snake faecal samples were collected across 28 China provinces. The partial small subunit (SSU) rRNA gene was amplified using polymerase chain reaction (PCR) to assess evolutionary relationships and genetic characterization. Detection rates for Acanthamoeba spp., Blastocystis spp., and Cyclospora spp. were 6.40 %, 3.33 %, and 2.71 %, respectively. Sequencing and phylogenetic analysis revealed that Cyclospora isolates were closely related to those found in humans and cattle. Subtyping for Blastocystis species identified two zoonotic subtypes (ST4, ST6) and four host-specific subtypes (ST10, ST15, ST21, ST42). Multiple Acanthamoeba genotypes were detected, including T4, T11, and T13. Furthermore, species, age, and living conditions are key risk factors. This study provides valuable insights into these infections in snakes and underscores the need for proper hygiene and One Health measures to reduce zoonotic transmission and environmental contamination.

Prevalence of Enterocytozoon bieneusi and Blastocystis sp. infection in foxes (Alopex lagopus) in northern China

To examine the prevalence of E. bieneusi and Blastocystis sp. in foxes in China, this study analyzed the prevalence and distribution of genotypes or subtypes. A total of 352 fresh fecal samples were collected from foxes across five provinces in northern China and analyzed using PCR. The overall prevalences of E. bieneusi and Blastocystis sp. were 48.3% and 2.0%, respectively; the highest prevalences were found in Shandong Province, with 87.1% and 5.4%, respectively. The prevalence rates were influenced by several factors; a breeding scale value <1,500 was related to higher prevalences. Multivariate analysis showed that the region and breeding scale were the main risk factors for E. bieneusi. Eleven genotypes of E. bieneusi were identified, all of which are classified within Group 1. This includes five previously characterized genotypes and six novel genotypes. Among these, CHN-F1 was the predominant genotype, accounting for 67.7% of cases. Blastocystis sp. was detected with only one subtype (ST3), which represents the first report of this genotype in foxes. The identification of E. bieneusi in foxes and the first detection of the ST3 subtypes of Blastocystis sp. contribute to a more comprehensive understanding of the epidemiology of these microeukaryotes. These findings suggest a potential pathway for the transmission of microeukaryotes from fox farms to human populations, underscoring the importance of monitoring the public health risks.

Molecular prevalence and subtype characteristics of Blastocystis among school children in Hainan, the tropical island province of China

Blastocystis is one of the most common zoonotic intestinal protozoa with global distribution and can cause gastrointestinal syndrome mainly characterized by diarrhea. School children are the main susceptible population. No epidemiological data on Blastocystis among school children in Hainan, the only tropical island province in China. Between March 2021 and June 2023, 1973 fecal samples were collected from school children across three regions in Hainan province. Blastocystis was examined by amplifying the small subunit ribosomal RNA (SSU rRNA) gene via polymerase chain reaction (PCR), and subtypes were identified through DNA sequencing and phylogenetic analysis. The overall prevalence of Blastocystis was 7.3 % (144/1973). The differences in infection rates across different regions, nationalities, and educational stages are statistically significant (P < 0.001). Five subtypes were identified, of which ST3 was the dominant subtype (60.4 %; 87/144), followed by ST1 (27.8 %; 40/144), ST7 (10.4 %; 15/144), ST6 (0.7 %; 1/144), and ST2 (0.7 %; 1/144). 42 known sequences and 15 novel sequences were identified including eight new variations of the ST1 (ST1-16∼ST1-23) with similarities ranging from 98.3 % to 99.78 % and seven new variations of the ST7 (ST7-7∼ST7-13) with similarities ranging from 97.7 % to 99.79 % by intra-subtype genetic polymorphisms analysis. The results evaluate the public health risks of Blastocystis among school children in Hainan and the sources of infection were discussed, providing important basic data for the effective prevention and control of intestinal parasitic diseases in Hainan.

Blastocystis hominis as a cause of chronic diarrhea in low-resource settings: A systematic review

BACKGROUND

Blastocystis hominis (B. hominis), an anaerobic unicellular protist parasite, is known for its diverse clinical manifestations upon infecting the human gastrointestinal tract. Although globally distributed, it is particularly prevalent in developing nations. Examining the symptoms and treatment outcomes of B. hominis infection in low-resource settings holds immense significance, providing healthcare practitioners with valuable insights to enhance patient care.

AIM

To synthesize existing evidence on the symptomatology and treatment outcomes of B. hominis infection in low-resource settings.

METHODS

Following the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines, a systematic review was conducted. The search spanned electronic databases including PubMed, Scopus, and Google Scholar. After a comprehensive screening process, a thorough examination of the papers, adhering to inclusion and exclusion criteria, and data extraction from eligible studies was conducted. The findings underwent summarization through simple descriptive analysis.

RESULTS

The search yielded 1200 papers, with 17 meeting inclusion criteria. Chronic diarrhea due to B. hominis infection was reported in only two studies, while abdominal pain, diarrhea, flatulence, constipation, and nausea/vomiting emerged as the most commonly documented symptoms. Recovery rates after one week of treatment ranged from 71.8% to 100%, and after two weeks, from 60% to 100%.

CONCLUSION

In low-resource settings, chronic diarrhea resulting from B. hominis infection is infrequent. Common symptoms include abdominal pain, diarrhea, flatulence, constipation, and nausea/vomiting. Post-treatment, clinical outcomes are notably favorable, supporting the recommendation for treatment. Metronidazole is advocated as the first-line agent, with consideration for switching to a second-line option in cases of treatment failure or poor response.

Molecular investigation of Blastocystis in children and calves in Bangladesh

BACKGROUND

Blastocystis, a widely distributed zoonotic protozoan infecting both humans and numerous animals, remains poorly understood with its potential medical and veterinary significance. This study examined the molecular occurrence and genetic variation of Blastocystis in children and calves in Bangladesh to explore cross-species transmission and disease burden.

METHODS

In total, 998 DNA samples were investigated, comprising 299 stool DNA from children and 699 fecal DNA from calves, using polymerase chain reaction and sequencing of the small subunit ribosomal RNA (SSU rRNA) gene.

RESULTS

This study detected Blastocystis in 5.35% of the children and 14.74% of the calves. While slight variations in occurrence rates were observed across different study variables, none were statistically significant. The occurrence was highest among children under 5 years and calves aged 1-3 months. Regarding breed, the Holstein Friesian cross and the Jersey cross exhibited higher rates of infection. Conversely, occurrences were lower among children and calves in Gazipur district. The remaining parameters displayed nearly equivalent percentages of Blastocystis. The subtypes identified in children included ST1, ST3, and ST4, with ST1 comprising 50% of them. ST3 and ST4 were also found in calves, alongside ST10 (55.34%) being the most prevalent. Other subtypes found in calves were ST14, ST21, and ST24-ST26.

CONCLUSIONS

This study found that Blastocystis is more common in calves than in children in Bangladesh, with genetic diversity of nine subtypes. The common occurrence of identical variants of two subtypes in both populations suggests potential zoonotic transmission, highlighting the necessity for further molecular investigations and comprehensive measures within the One Health framework to mitigate public health risks.

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

Introduction

Globally, rodents and shrew populations constitute crucial elements of diverse environments and animal communities. It is imperative to study their population dynamics to mitigate any potential negative impact on humans, as they can be involved in the transmission of critical zoonotic agents, such as Blastocystis. Therefore, this study aimed to identify the prevalence and genetic composition of Blastocystis in wild rodents and shrews residing in the Zhejiang provinces of China.

Methods

A total of 652 wild rodents and and shrews were captured from three different regions in Zhejiang Province from April 1st to October 31, 2023. The DNA was isolated by collecting fresh feces from the intestines of each rodent or and shrew. Rodent and shrew species were examined by vertebrate cytochrome b (cytb) analysis and PCR amplification. Blastocystis was also found in all fecal samples using PCR analysis and sequencing of the partial small subunit of ribosomal RNA (SSU rRNA) gene.

Results

Among all the samples, 6.6% (43/652) showed a positive result for Blastocystis. In the results, 6 species of rodent and shrew were identified with Blastocystis, including Apodemus agrarius (n = 36) (2.8%), Niviventer confucianus (n = 75) (17.3%), Rattus losea (n = 18) (5.6%), R. norvegicus (n = 155) (2.6%), R. tanezumi (n = 86) (3.5%), and Suncus murinus (n = 282) (7.4%). The existence of 6 Blastocystis subtypes, ST4 (n = 33), ST1 (4), ST7 (n = 3), ST2 (n = 1), ST3 (n = 1), and ST5 (n = 1), were confirmed by sequence analysis.

Discussion

Based on the molecular data obtained, the wild rodents and shrews under investigation were found to be concurrently infected with zoonotic subtypes of Blastocystis, including ST1 to ST5 and ST7. This suggests that these animals could potentially pose a zoonotic threat to humans and other animals susceptible to Blastocystis infection.

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

Wild rodents are key carriers of various human pathogens, including Blastocystis spp. Our study aimed to assess the prevalence and genetic characteristics of Blastocystis among wild rodents in the Inner Mongolian Autonomous Region and Liaoning Province of China. From November 2023 to February 2024, 486 rodents were captured in these regions. Fresh feces were collected from the intestines of each rodent for the isolation of DNA and PCR amplification of the vertebrate cytochrome b (cytb) gene to identify rodent species. Subsequently, PCR analysis and sequencing of the partial small subunit of the ribosomal RNA (rRNA) gene were utilized to detect Blastocystis in all fecal samples. Of the total samples, 27.4% (133/486) were found to be Blastocystis positive. The results revealed the presence of four species of rodents infected with Blastocystis, 32.3% (63/195) in Rattus norvegicus, 15.1% (16/106) in Mus musculus, 20.2% (18/89) in Apodemus agrarius, and 37.5% (36/96) in Cricetulus barabensis. Sequence analysis confirmed the existence of five Blastocystis subtypes: ST1 (n = 4), ST2 (n = 2), the ST4 (n = 125, the dominant subtype), ST10 (n = 1), and a novel ST (n = 1). The identified zoonotic subtypes (ST1, ST2, ST4, and ST10) highlight the possible role played by wild rodents in the transmission of Blastocystis to humans, thereby elevating the chances of human infection. Meanwhile, the discovery of novel sequences also provides new insights into the genetic diversity of this parasite.

Recombinase polymerase amplification - lateral flow dipstick for rapid and visual detection of Blastocystis spp

Blastocystis spp. is a ubiquitous protozoon in the intestinal tract of human and many animals. Microscopic examination is the main method of clinical diagnosis for Blastocystis spp., which is prone to false negative. A simple and rapid diagnosis of Blastocystis spp. infection is an important step to prevent and control blastocystosis. Here, a recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) assay was developed for rapid visual detection of Blastocystis spp. DNA amplification could be performed within 18 min at 37°C. The minimum DNA detection limit was 1 pg/μL, and there was no cross-reactivity with 12 other non-target pathogens, which was consistent with the sensitivity of conventional PCR (cPCR). Furthermore, 56 fecal samples from the Third Affiliated Hospital of Xinxiang Medical University were tested using RPA and cPCR methods respectively, and the results were completely consistent. The results show that RPA-LFD method has high accuracy and visual results, which provides a new choice for the differential diagnosis and rapid field detection of Blastocystis spp.

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

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

Molecular Prevalence and Subtypes Distribution of Blastocystis spp. in Humans of Latin America: A Systematic Review

Blastocystis spp. are among the few enteric parasites with a prevalence that can reach up to approximately 80% in communities of developing countries. This systematic review updates and summarizes available literature on the molecular prevalence and subtype distribution of Blastocystis spp. in Latin American people. This work follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The literature revised covers from 1 January 2015 to 6 October 2023 in seven different scientific databases, and the material was selected through inclusion and exclusion criteria. According to data found in the 36 selected articles, the prevalence of Blastocystis spp. in Latin America ranged between 5.8% (Bolivian rural communities) and 94.0% (Colombian general public). Generally, genomic DNA was extracted from approximately 200 mg fecal sediments using commercial kits, such as the QIAamp Stool Mini Kit (QIAGEN, Hilden, Germany) or the Norgen Stool DNA Isolation Kit (Norgen Biotek Corporation, Thorold, ON, Canada). Subtype-specific primers (such as the couple of primers BhRDr-RD5) developed from unique sequences of the SSU rRNA gene were applied to Blastocystis subtyping. Ten specific subtypes (STs) were found as well as various mixed infections, and the most circulating Blastocystis STs were in the order ST3, ST1, ST2, and ST4. The most recent data about Blastocystis spp. molecular epidemiology and the STs in communities of Latin America are limited to studies from specific countries. Novel scientific data from the other countries are required to obtain a complete picture and truly understand the distribution and prevalence of Blastocystis spp. and the STs.

Systematic Review and Meta-Analysis: Epidemiology of Human Blastocystis spp. Infection in Malaysia

Blastocystis spp. is a unicellular enteric protozoan parasite in humans with a controversial role in disease etiology. It is common in developing countries among immunocompromised patients and people who have close contact with animals. In this study, we have systematically reviewed previous studies on the distribution and genotypes of human Blastocystis infection in Peninsular Malaysia. Studies examining the prevalence of Blastocystis in diverse demographics, including rural, urban, comorbid conditions, and high-risk populations, were taken into consideration. The infection has been reported in nine states; the total percentage of infection was 17.8% (1671/9397), with the most cases in Pahang (27.3%) and the least in Johor (3.4%). Molecular studies revealed the presence of six subtypes: ST1, ST2, ST3, ST4, ST5, and ST6. ST3 was reported as the predominant subtype in all the states, with a prevalence of 54.7% (338/618). The findings provide greater clarity on the epidemiology of Blastocystis in Malaysia, which will help in policy making towards planning and strategizing control measures against the parasite.

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.

First description of Blastocystis sp. and Entamoeba sp. infecting zoo animals in the Qinghai-Tibetan plateau area, China

Protozoan parasites are a well-known threat to human health, particularly for people working at or visiting zoos, and potentially cause zoonotic diseases in humans. Captive wildlife may be potential reservoirs for human infection with protozoan parasites. Therefore, focusing on zoonotic protozoan infections in zoo animals is critical. However, there is no report on this topic in the Qinghai-Tibetan Plateau region. In this study, a total of 167 and 103 fecal samples were collected from 12 animal species from Qinghai-Tibet Plateau Wildlife Park in winter and summer, respectively, to detection the prevalence of infections and subtype distribution with Entamoeba sp., Cryptosporidium sp., Giardia duodenalis, Enteromicrosporidia bieneusi sp., Blastocystis sp. by PCR assay. The results showed that a total of 21 fecal samples collected in winter, including from 2 white-lipped deer, 8 Sika deer, 6 blue sheep, 2 wolves and 3 bears, were positive for Entamoeba, with a 12.6% (21/167) positive rate. However, 4.9% (5/103) of animals in summer were positive for Entamoeba, including 1 snow leopard, 1 tiger, 1 Tibetan argali and 2 mouflon. Moreover, 1 white-lipped deer and 1 bear were found to be positive for Blastocystis sp., one zoonotic STs (ST10) was identified and found in white-lipped deer. We found no effect on season on Blastocystis sp. and Entamoeba sp. colonization. To the best of our knowledge, this study is the first description of Blastocystis sp. and Entamoeba sp. infecting zoo animals in the plateau area. The findings provide the latest data on Entamoeba sp. and Blastocystis sp. in zoo animals in China.

Molecular identification and genotyping of Blastocystis sp. in sheep and goats from some areas in Inner Mongolia, Northern China

Blastocystis sp. is a kind of unicellular intestinal commensal which is widely distributed in humans and animals, and frequently found in the people who are in close contact with animals. To investigate the prevalence and evaluate the zoonotic potential of Blastocystis sp. in sheep and goats from Inner Mongolia, China, a total of 1037 samples were collected from them, and subjected to nested PCR amplification based on the small subunit ribosomal RNA (SSU rRNA) gene of Blastocystis sp. The sanger sequencing was used for Blastocystis sp. subtype identification. The results indicated that the average infection rate of Blastocystis sp. was 10.70% [95CI: 8.82%-12.58%] (111/1037), including 11.30% [95CI: 7.96%-14.64%] for sheep (39/345) and 10.40% [95CI: 8.13%-12.67%] for goats (72/692). Five Blastocystis subtypes (ST5, ST10, ST14, ST21 and ST26) were identified in the present study. Among them, ST10 was the most dominant subtype in sheep and goats, accounting for 70.27% (78/111) of the total identified positive samples. This is the first report regarding Blastocystis sp. subtypes ST21 and ST26 in goats in China. This study has provided a detail epidemiological data on the prevalence and subtypes distribution of Blastocystis sp. in sheep and goats in Inner Mongolia, China. Our results indicated that sheep and goats could be reservoir host for multiple Bastocystis subtypes, including the zoonotic subtypes. Further studies among humans, livestock and wild animals are needed to better understand their role in the spread of Blastocystis sp.

Extensive prevalence and significant genetic differentiation of Blastocystis in high- and low-altitude populations of wild rhesus macaques in China

BACKGROUND

Blastocystis is a common intestinal protist with a wide range of hosts. Thus far, 38 subtypes have been identified. In recent years, wild animals have been confronted with habitat fragmentation as well as an increasing risk of zoonotic disease transmission due to human disturbance. Only limited data are available on Blastocystis infection and subtype distribution in wild rhesus macaques in China. The aim of the present study was to investigate the prevalence and genetic diversity of Blastocystis in nine wild rhesus macaque populations in China.

METHODS

A total of 276 faecal samples were collected from five high-altitude populations (high-altitude group [HAG]; 2800-4100 m a.s.l.) and four low-altitude populations (low-altitude group [LAG]; 5-1000 m a.s.l) of rhesus macaques. PCR-based analysis, using a new primer pair for the amplification of a 1690-bp sequence of the small subunit ribosomal RNA (SSU rRNA) gene, was used for prevalence and genetic diversity analysis.

RESULT

Analysis of faecal samples revealed that Blastocystis infection was common in rhesus macaques, with an infection positivity rate of 80.1% (n = 221/276 samples). There was no significant difference (P = 0.121) in positivity rate between the LAG (84.3%) and HAG (76.8%). Overall, 33 haplotypes were obtained and classified into four subtypes (STs), of which three were potentially zoonotic subtypes (ST1, 29.7%; ST2, 16.7%; ST3, 31.9%) and one that was first identified in this study and named ST39 (12.0%). The STs were distributed differently among the rhesus macaque populations, except for ST3, which was found in all populations. Phylogenetic analyses revealed two major divergent clades of ST3 for the HAG and LAG. Genetic diversity analysis showed a high genetic diversity of ST3 (haplotype diversity: 0.846; nucleotide diversity: 0.014) in the rhesus macaques, but a high genetic differentiation (F_ST > 0.25) and a low gene flow (Nm = 0.09) between the HAG and LAG.

CONCLUSION

Our study, which is the first investigation on Blastocystis infection in multiple wild rhesus macaque populations in China, indicates a potential risk of zoonotic transmission of Blastocystis in the study areas. Blastocystis ST3 showed high genetic diversity in wild rhesus macaques and significant genetic differentiation between the HAG and LAG. Our results provide fundamental information on the genetic diversity and prevalence of Blastocystis in wild rhesus macaque populations.

Detection of Blastocystis sp. in ulcerative colitis, Crohn's and chronic diarrheal patients by microscopy, culture and real-time polymerase chain reaction

Blastocystis sp. is a zoonotic parasite that is common in humans and animals and settles in the large intestine. The parasite can cause various gastrointestinal system complaints such as indigestion, diarrhea, abdominal pain, bloating, nausea and vomiting. The aim of this study is to determine the distribution of Blastocystis in patients diagnosed with ulcerative colitis, Crohn's and diarrhea from the gastroenterology outpatient clinic and to compare the diagnostic value of the most preferred methods. A total of 100 patients, 47 men and 53 women, were included in the study. Of the cases, 61 had diarrhea, 35 had ulcerative colitis (UC) and four had Crohn's disease. Stool samples of the patients were analyzed by as direct microscopic examination (DM), culture and real-time polymerase chain reaction (qPCR). A total of 42% positivity was detected, 29% positivity in DM and trichrome staining, 28% in culture and 41% in qPCR. 40.4% (20/47) of men and 37.7% (22/53) of women were found to be infected. Blastocystis sp. was found in 75% of Crohn's, 42.6% of diarrheal and 37.1% of UC patients. Diarrhea cases are more common with UC and there is a close relationship between Crohn's and Blastocystis positivity. While DM and trichrome staining showed a sensitivity of 69%, PCR test was found to be the most sensitive diagnostic method with approximately 98%. Diarrhea and UC are often seen together. A close relationship was detected between Crohn's disease and Blastocystis. High prevalence of Blastocystis in cases with clinical symptoms reveals the importance of the parasite. There is a need for studies on the pathogenicity of Blastocystis sp. in various gastrointestinal cases, and it is thought that molecular techniques should be used since PCR is seen to be a much more sensitive.

First detection of Blastocystis sp. in migratory whooper swans (Cygnus cygnus) in China

Blastocystis is a usual intestinal protist that always found in humans and various animals. Currently, the prevalence of Blastocystis in the migratory whooper swan (Cygnus cygnus) is unknown. In our research, we aimed to determine the occurrence, prevalence, subtype distribution and dynamic transmission mechanisms of Blastocystis in the migratory whooper swan in China. We also assessed the zoonotic potential of Blastocystis isolates, as well as possible routes of transmission and impact of this organism on One Health perspective. Fecal samples (n = 770) were collected from whooper swans inhabiting the Sanmenxia Swan Lake National Urban Wetland Park, China. The overall prevalence of Blastocystis was 11.6% (89/770). We identified 9 subtypes of Blastocystis sp., including 5 zoonotic subtypes [ST1 (Cakir et al., 2019 (8)), ST4 (Selma and Karanis, 2011 (4)), ST5 (Stensvold et al., 2009 (1)), ST6 (Fare et al., 2019 (5)) and ST7(58)] and 3 host-specific subtypes [ST10 (Zhao et al., 2018 (7)), ST14 (Tan et al., 2010 (2)), ST23 (Wang et al., 2018 (3)), and ST25 (Stensvold et al., 2009 (1))]. Subtypes ST4, ST5, ST6, ST10, ST14, ST23, and ST25 were first identified in the whooper swan. Among these subtypes, ST23 and ST25 were identified in birds for the first time, indicating that these subtypes are expanding their host range. So far, this is the first research reporting on the prevalence and subtypes distribution of Blastocystis in the migratory whooper swan in China. The findings obtained in this study will provide new insights into the genetic diversity and transmission routes of Blastocystis, and the possible public health concerns posed by this organism.

Identification and genetic characterization of Blastocystis subtypes in Père David's deer (Elaphurus davidianus) from Shishou, China

Blastocystis is a protozoan parasite frequently reported in the gastrointestinal tract of humans and animals, with a global distribution. No information on the infections of Blastocystis in Père David's deer (Elaphurus davidianus, PDD) is available. In this study, a total of 128 fecal samples collected in the National Nature Reserve of Shishou, Hubei Province of China, were used to determine the occurrence and subtypes of Blastocystis in PDD. Amplification of the SSU rDNA gene confirmed the common presence of Blastocystis infection, with an observed prevalence of 56.3% (72/128). Through nucleotide sequencing and phylogenetic analysis, five known subtypes, which consisted of one zoonotic subtype (ST10) and four ruminant-specifical subtypes (ST21, ST23, ST25, and ST26), were identified in this study. This represents a high degree genetic diversity of parasites within the host. Of the 72 PCR-positive samples, ruminant-specific subtypes were the most frequently observed, with ST21 being the most prevalent subtype (56.9.7%, 41/72). This is the first report characterizing the molecular subtypes of Blastocystis in PDD. The findings demonstrate a broad diversity and zoonotic potential of Blastocystis in PDD. Further study of the transmission potential between wildlife and humans or domestic animals in the region is required.

Molecular Epidemiology of Blastocystis in Confined Slow Lorises, Macaques, and Gibbons

Blastocystis sp. is a common intestinal anaerobic parasite infecting non-human primates and many other animals. This taxon threatens the health of NHPs due to its high genetic diversity, impeding efforts to improve confined management and subsequent conservation practices. This study collected 100 and 154 fecal samples from captive macaques, gibbons, and slow lorises in the summer and winter, respectively. The Blastocystis infection, its gene subtypes, and its zoonotic potential based on small subunit ribosomal RNA (SSU rRNA) were analyzed. The prevalence of Blastocystis in the three primate genera was 57.79% (89/154) in the summer (2021) and 29.00% (29/100) in the winter (2020). Four zoonotic subtypes-ST1, ST2, ST3, and ST4-were identified. ST2 was the most prevalent subtype, suggesting that these animals may serve as reservoirs for pathogens of human Blastocystis infections. The macaques showed a more significant variation in Blastocystis infection between seasons than gibbons and slow lorises. The slow lorises in small cages and enclosure areas were potentially more infected by Blastocystis in the summer, indicating that inappropriate captive management may have detrimental effects on their health.

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.

Molecular identification and subtype analysis of Blastocystis in captive Asiatic black bears (Ursus thibetanus) in China’s Heilongjiang and Fujian provinces

Blastocystis sp. is the most isolated enteric protozoan in parasitological surveys of humans. A substantial percentage of human infections is attributed to zoonotic transmissions. However, the contribution of each animal source to human infections with blastocystis is not yet fully understood. This study thus aimed to determine the infection rates and subtype distributions of Blastocystis sp. in captive Asiatic black bears (Ursus thibetanus) in China’s Heilongjiang and Fujian provinces. A total of 218 fresh fecal specimens were collected from captive Asiatic black bears in Heilongjiang (n = 36) and Fujian (n = 182) between May 2015 and December 2017. Genomic DNA was extracted from each sample and then examined for Blastocystis through SSU rRNA gene amplicon-based sequencing. A phylogenetic tree based on the Blastocystis positive sequences was reconstructed using the Mega X program. Eleven percent (24/218) of the animals had Blastocystis and six Blastocystis subtypes, including ST4 (n = 14), ST10 (n = 3), ST1 (n = 2), ST2 (n = 1), ST5 (n = 1), and ST12 (n = 1) were identified. A total of 14 representative sequences, including seven sequences that have been described previously and seven novel sequences comprising ST10 (n = 2), ST5 (n = 1), and ST4 (n = 4), were obtained from the six subtypes of Blastocystis. This study is the first to report the presence of Blastocystis in captive Asiatic black bears in Fujian, China. It provides baseline data for controlling and preventing Blastocystis infection in farm communities. Zoonotic infections in bears with ST1, ST2, ST4, ST5, ST10, and ST14 should be considered potential public health threats. The novel ST sequences of Blastocystis generated in this study provide novel insights into the genotypic variation within the Blastocystis sp.

Frequency, spatial distribution, and genetic diversity of Blastocystis among referred individuals to a clinical laboratory: First report of subtype 9 in Brazil

The enteric protist Blastocystis has a worldwide distribution, however its prevalence in the human population is still underestimated, especially in developing countries where proper diagnosis is not performed in the routine of clinical laboratories. In this study, we aimed to assess the frequency, genetic diversity, and spatial distribution of Blastocystis isolates detected in fecal samples referred to a clinical laboratory for routine examination in inner São Paulo State, Brazil. A total of 348 leftover stool samples available for disposal from female and male individuals with age ranging from 3 months to 88 years were analyzed by both microscopic examination and PCR/sequencing of the SSU rRNA gene. The overall frequency of Blastocystis sp. was 31% (108/348), including 20.1% (70/348) and 31% (108/348) by microscopic examination and PCR/sequencing, respectively. Significant association was found only between Blastocystis infection and age, since the highest rate of positive samples was detected among 5-9 years old individuals (p < 0.0001). In addition, spatial distribution revealed a wide distribution of the positive samples, however they were densely concentrated in more populated areas. Seven subtypes were identified, namely ST1 (40.7%), ST2 (9.2%), ST3 (45.3%), ST4 (0.9%), ST6 (1.8%), ST7 (0.9%) and ST9 (0.9%). The intra-subtype analysis revealed a total of 25 different alleles previously reported. Here, the findings lead us to highlight the following aspects: (1) the identification of a ST9 isolate is a relevant finding since it is considered a very rare subtype in human infections as well as this is the first report in Brazil; (2) the high frequency of Blastocystis in fecal samples submitted for examination in a clinical laboratory points to the need to consider its search in routine parasitological examinations, (3) the spatial distribution of Blastocystis infection was not homogeneous but concentrated in more populated areas where the access for population to diagnostic services in healthcare is likely to be easier and, (4) the genetic variability of Blastocystis isolates suggests exposure of inhabitants living in inner municipalities to different sources of contamination involving anthroponotic and zoonotic transmission pathways.

Are Blastocystis hominis and Cryptosporidium spp. playing a positive role in colorectal cancer risk? A systematic review and meta-analysis

Objective

Intestinal protozoa Blastocystis hominis and Cryptosporidium spp. are two influential factors in intestinal complications and malignancies. In present study, we estimated the pooled prevalence and odds ratio (OR) of the two parasites in colorectal cancer (CRC) patients and their possible association with the deadly disease.

Method

Our systematic search was conducted for published researches between January 1, 2000 and April 30, 2022 by using four international databases include Scopus, PubMed, and Web of Science as well as Google scholar search engine. The random- and fixed-effects models were used to estimate the pooled prevalence, OR, and 95% confidence interval (CI) by comprehensive meta-analysis (V2.2, Bio stat) software. Inclusion and exclusion criteria were applied.

Results

Thirteen papers (seven case–control and six cross-sectional studies) for B. hominis/CRC and six papers (two case–control and four cross-sectional studies) for Cryptosporidium spp./CRC were eligible to include in data synthesis. Pooled prevalence of B. hominis and Cryptosporidium spp. in CRC patients was calculated to be 26.8% (95% CI 19.4–35.7%) and 12.7% (95% CI 6.8–22.5%), respectively. Based on case–control studies, significant difference was found between case and controls in both protozoa (B. hominis OR 2.10; 95% CI 1.39–3.18% vs. Cryptosporidium spp. OR 5.06; 95% CI 1.8–13.6%). Considering the Blastocystis subtypes, ST1 (5/6; 83.33% studies) and ST3 (5/6; 83.33% studies) had the highest number of reports in CRC patients. Regarding the Cryptosporidium species, only C. parvum and C. hominis were reported.

Conclusion

Given the significant prevalence of both parasites in CRC patients and their statistically significant association, there is a need to pay more attention to these two intestinal parasites in under treatment patients.

An Association Between Blastocystis Subtypes and Colorectal Cancer Patients: A Significant Different Profile from Non-cancer Individuals

PURPOSE

Blastocystis is a common enteric human parasite of non-conclusive pathogenicity which may be determined by subtype (ST) variation. Colorectal cancer (CRC) is considered one of the primary causes of cancer mortality. Blastocystis ST7 has been shown to reduce beneficial intestinal microbiota and may exacerbate CRC. This study assessed the possible association between Blastocystis STs and CRC in comparison to non-cancer patients.

MATERIAL AND METHODS

A total of 200 fecal samples were obtained from CRC (100) and non-CRC (100) individuals attending Beni-Suef University Hospital, Egypt. Blastocystis was searched for in all samples using microscopy and culturing. Positive subculture samples were genetically sequenced and subtyped using conventional polymerase chain reaction (PCR). Blastocystis STs were determined by sequencing and a phylogenetic tree was created. Related patient characteristics and tumor stages were analyzed for association with presence of Blastocystis.

RESULTS

Blastocystis was identified in 52% and 42% of CRC and non-cancer individuals, respectively. ST1, 2, and 3 were isolated from both cancer and non-cancer individuals; however, for the first time, ST7 was only isolated from CRC stool samples with significant association. Associated patient characteristics were evaluated as predictors.

CONCLUSION

Blastocystosis is highly prevalent in CRC patients, predominantly in the latest CRC grades and stages. To the best of our knowledge, this is the first study to report the identification of Blastocystis ST7 in CRC patients. To determine whether certain STs of Blastocystis are associated with CRC would require further research, including the role played by gut microbiota.

Subtype distribution of Blastocystis sp. isolated from humans in Iran: a systematic review and meta-analysis

Aim

This systematic review and meta-analysis evaluated the subtyped Blastocystis sp. isolated from humans in Iran.

Background

Blastocystis sp. is an anaerobic intestinal protozoan that infects humans as well as domestic and wild animals, i.e. mammals, amphibians, reptiles, and arthropods.

Methods

A comprehensive search for papers published before April 2022 was undertaken utilizing English and Persian databases. The following MeSH keywords were used in the electronic search: (Blastocystis sp.) AND (molecular OR subtype) AND (prevalence OR epidemiology) AND Iran. The quality of the included studies was evaluated. Thereafter, a random-effects meta-analysis was conducted to estimate the pooled prevalence and odds ratios regarding the included studies.

Results

A total of 32 studies comprised of five case-control studies and 27 cross-sectional studies met the eligibility criteria. The overall pooled prevalence of subtyped Blastocystis sp. in Iran was estimated to be 10% (95% confidence interval: 6 to 15%). Eight subtypes of Blastocystis sp. (ST1- ST7 and ST9) were identified in our study, of which ST3 was the most common subtype (0.04); 0.02-0.07). The difference in subtypes between two case and control groups in reported studies was not significant, but the odds ratio of infection by ST3 (0.98; 95% CI, 0.30 to 3.20) was higher in cases.

Conclusion

The current systematic review showed that with the exception of ST8 and ST12, all human Blastocystis sp. subtypes reported in the world are found in different parts of Iran.

Blastocystis One Health Approach in a Rural Community of Northern Thailand: Prevalence, Subtypes and Novel Transmission Routes

Blastocystis is the most commonly found eukaryote in the gut of humans and other animals. This protist is extremely heterogeneous genetically and is classified into 28 subtypes (STs) based on the small subunit ribosomal RNA (SSU rRNA) gene. Numerous studies exist on prevalence of the organism, which usually focus on either humans or animals or the environment, while only a handful investigates all three sources simultaneously. Consequently, understanding of Blastocystis transmission dynamics remains inadequate. Our aim was to explore Blastocystis under the One Health perspective using a rural community in northern Thailand as our study area. We surveyed human, other animal and environmental samples using both morphological and molecular approaches. Prevalence rates of Blastocystis were 73% in human hosts (n = 45), 100% in non-human hosts (n = 44) and 91% in environmental samples (n = 35). Overall, ten subtypes were identified (ST1, ST2, ST3, ST4 ST5, ST6, ST7, ST10, ST23, and ST26), eight of which were detected in humans (ST1, ST2, ST3, ST4, ST5, ST7, ST10, and ST23), three in other animals (ST6, ST7, and ST23), while seven (ST1, ST3, ST6, ST7, ST10, ST23, and ST26) were found in the environment. In our investigation of transmission dynamics, we assessed various groupings both at the household and community level. Given the overall high prevalence rate, transmission amongst humans and between animals and humans are not as frequent as expected with only two subtypes being shared. This raises questions on the role of the environment on transmission of Blastocystis. Water and soil comprise the main reservoirs of the various subtypes in this community. Five subtypes are shared between humans and the environment, while three overlap between the latter and animal hosts. We propose soil as a novel route of transmission, which should be considered in future investigations. This study provides a thorough One Health perspective on Blastocystis. Using this type of approach advances our understanding on occurrence, diversity, ecology and transmission dynamics of this poorly understood, yet frequent gut resident.

Molecular characterization of Blastocystis sp. in Chinese bamboo rats (Rhizomys sinensis)

Blastocystis sp., a parasitic eukaryote, widely colonizes the intestines of humans and a large number of animals, including rodents and lagomorphs. More than 30 million bamboo rats (Rhizomys sinensis) are farmed in China as a source of meat for human consumption. However, there have been no published articles on Blastocystis infection in Chinese bamboo rats prior to the present study. Herein, 480 fresh faecal samples were collected from R. sinensis on six farms located in four cities (Wugang, Chenzhou, Huaihua and Jishou) in Hunan Province, south-central China, and were examined for Blastocystis infection using polymerase chain reaction (PCR) targeting the small subunit ribosomal RNA (SSU rRNA) gene. The total prevalence of Blastocystis in R. sinensis was 4.58% (22/480), and significant differences in prevalence were detected among four age groups (<6 months, 6–12 months, 12–24 months and >24 months), with the highest prevalence (7.81%) in rats aged 6–12 months but with no positive samples in rats over 24 months. All farms, except for one in Jishou, were positive for Blastocystis infection, with the prevalence ranging from 1.80% to 7.27%. Sequence and phylogenetic analyses revealed two potentially zoonotic subtypes (namely ST4 and ST5) in these rodents, with ST4 predominant in all except one farm in Huaihua. Seven and five sequence types were identified within ST4 and ST5, respectively. This is the first report of Blastocystis infection in Chinese bamboo rats and the findings suggest the potential of R. sinensis to transmit Blastocystis to humans.

Prevalence of Blastocystis infection in free-range Tibetan sheep and Tibetan goats in the Qinghai-Tibetan Plateau in China

Blastocystis is one of the most common enteric parasites in humans and domestic animals. For Tibetan sheep and Tibetan goats, the traditional grazing methods still occupy a dominant position, and the close contact between humans and domestic animals increases the risk of infection by Blastocystis between herdsmen and livestock. However, less pertinent information is available for Tibetan sheep or Tibetan goats. In this study, 880 fecal specimens from Tibetan sheep and Tibetan goats were collected from 6 sampling sites in Tibet to test for Blastocystis using the polymerase chain reaction and sequencing analysis of the partial SSU rRNA gene. The infection rate of Blastocystis was 8.55% for Tibetan sheep (53/620) and 8.46% for Tibetan goats (22/260). The genetic analysis of 53 positive samples from Tibetan sheep identified 4 known subtypes (ST4, ST5, ST10, and ST14). Four known subtypes (ST1, ST5, ST6, and ST10) were identified in Tibetan goats. ST10 was the dominant subtype in Tibetan sheep and Tibetan goats, accounting for 65.33% (49/75) of total subtypes. ST1, ST4, ST5, and ST6 were recognized as belonging to zoonotic subtypes. This report provides a detailed data on the prevalence and subtype distribution of Blastocystis in Tibetan sheep and Tibetan goats in Tibet, which enriches the epidemiological data of Blastocystis infection in Tibetan sheep and Tibetan goats in China. Our results indicated that Tibetan sheep and Tibetan goats can be infected with multiple Blastocystis subtypes, including zoonotic subtypes. More research is needed among humans, livestock and wild animals in Tibet to better understand their role in the spread of Blastocystis. And, One Health measures need to be taken to control and prevent its zoonotic transmission.

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Tibetan sheep and Tibetan goats were examined the Blastocystis for the first time.

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Subtypes ST4, ST5, ST10, ST14 in Tibetan sheep and subtypes ST1, ST5, ST6, ST10 in Tibetan goats were identified separately.

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Four potential zoonotic subtypes (ST1, ST4, ST5, ST6) were detected in this article.

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

Blastocystis sp., the most common intestinal protozoa, remains a public health problem among people in many countries, particularly in rural areas of developing countries. The infection usually reflects poor sanitation in communities by waterborne, zoonotic, and person-to-person transmission. Interestingly, at least 17 subtypes (STs) have been reported and are associated with a broad range of animal hosts, including humans. In this study, we reported potential evidence of zoonotic transmission of Blastocystis ST1 in rural communities of eastern Thailand where the overall prevalence of Blastocystis infection was 15.7%. Two major and three minor subtypes were found to be distributed unequally in this region. Of 5 STs, only ST1 was found to be associated with pig feces in an open farm system that produced organic fertilizer for agriculture uses in the community. This finding suggests that properly protective contact and standard production of organic fertilizer from pig feces by-products could be key factors for reducing the prevalence of Blastocystis infection and prevent Blastocystis reinfection among people in the community.

IMPORTANCEBlastocystis 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. In this study, we reported potential evidence of zoonotic transmission of Blastocystis subtype 1 (ST1) in rural communities of eastern Thailand. Two major and three minor subtypes were found to be unequally distributed in this region. Interestingly, only ST1 was found to be associated with pig feces in an open farm system that produced organic fertilizer for agriculture uses in the community. The finding makes significant contributions to genetic and molecular investigations of microbial topics of practical value and suggest that properly protective contact and standard production of organic fertilizer from pig feces by-products could be key factors for reducing the prevalence of Blastocystis infection and prevent Blastocystis reinfection among people in the community.

Genetic characterization and zoonotic potential of Blastocystis from wild animals in Sichuan Wolong National Natural Reserve, Southwest China

Blastocystis is a prevalent eukaryotic parasite that has been identified in a wide range of hosts. Several species are considered potential sources of Blastocystis infection in humans, but little is known about the prevalence of Blastocystis in wild animals. In this study, the prevalence and subtypes of Blastocystis were investigated to assess the zoonotic potential of wild animals in Sichuan Wolong National Natural Reserve. A total of 300 fecal samples were collected from 27 wildlife species in three areas of the Reserve. The subtype (ST), genetic characteristics, and prevalence of Blastocystis were determined by PCR amplification of part (~600 bp) of the SSU rRNA gene. Thirty fecal samples (10.0%) were Blastocystis-positive. The highest prevalence of Blastocystis was found in Yinchanggou (18.3%), with significantly less found in Niutoushan (7.5%) and Genda (5.5%) (p < 0.05). No significant differences were associated with different orders of animals in prevalence, which may be because of the small number of positive samples obtained. Sequence analysis showed five subtypes (ST1, ST3, ST5, ST13, and ST14), with ST13 and ST14 being predominant (33% each), followed by ST1 (20%). This is the first molecular investigation of Blastocystis infection in the wild animals of southwestern China. Subtypes ST1, ST3, ST5, and ST14 have previously been identified in humans, suggesting that wild animals may be potential reservoirs of Blastocystis for humans.

Molecular Characterization of Blastocystis sp. in Camelus bactrianus in Northwestern China

Simple Summary

Knowledge for the distribution and genetic diversity of Blastocystis sp. can provide novel insights for the prevention and control of this parasite. The present study first reported the occurrence of Blastocystis infection in Camelus bactrianus, an important economic animal in northwestern China. We found the existence of eight Blastocystis subtypes in C. bactrianus, indicating potential risks and transmission of Blastocystis sp. for C. bactrianus.

Abstract

Blastocystis sp. is an important zoonotic protist in humans and various animals with worldwide distribution. However, there have been no data on the occurrence of Blastocystis sp. in C. bactrianus, an important economic animal in northwestern China. In the present study, a PCR-sequencing tool based on the SSU rRNA gene was applied to investigate the prevalence and genetic diversity of Blastocystis sp. in 638 faecal samples from C. bactrianus in 21 sampling sites within three main breeding areas (Gansu, Inner Mongolia and Xinjiang) in northwestern China. The total prevalence of Blastocystis sp. was 21.8% (139/638) in C. bactrianus, with the infection rates of 29.5% (18/61), 50.0% (14/28) and 19.5% (107/549) for animals aged <2 years, 2–6 years and >6 years, respectively. Significant differences in prevalence were detected among C. bactrianus from three geographic areas (χ² = 19.972, df = 2, p < 0.001) and all sampling sites (χ² = 104.154, df = 20, p < 0.001). A total of 16 of 21 sampling sites were positive for Blastocystis sp., with the prevalence ranging from 7.7% to 70.6%. Sequence analysis of the SSU rRNA gene identified eight subtypes in C. bactrianus in the present study, including seven animal adapted subtypes (ST10, ST14, ST21, ST24, ST25, ST26 and ST30) and one potentially novel subtype, with ST10 being the dominant one. To the best of our knowledge, this study provides the first insight for the occurrence and genetic make-up of Blastocystis sp. in C. bactrianus and contributes to the understanding of the transmission of Blastocystis infection in C. bactrianus in China.

Association of Blastocystis ST6 with higher protease activity among symptomatic subjects

BACKGROUND

Blastocystis sp. is an anaerobic intestinal protozoan parasite of humans and a wide range of animals worldwide. In the current study the correlation between the cysteine protease activity of clinical samples of Blastocystis sp. ST1-3 and 6 with the levels of pro-inflammatory cytokines was evaluated.

METHODS

Stool samples were collected from subjects with or without clinical symptoms. All samples were cultivated in DMEM medium. The bacteria were eliminated or reduced in Blastocystis sp. positive samples subtypes 1-3 and 6 by a variety of antibiotics and consecutive sub-cultures. To prepare parasite lysate, 1 × 105 Blastocystis sp. from each isolate were harvested and lysed using freeze-thaw. Protease activity of each isolate was measured and the gene expression of pro-inflammatory biomarkers in HT-29 cell line sensed by isolates was investigated using quantitative Real-time PCR.

RESULTS

Protease activity assay showed inter- and intra-subtype variations among subtypes regarding the presence of symptoms, while the protease activity of symptomatic isolates was higher than asymptomatic isolates. The highest and lowest levels of protease activity were seen in ST6 and ST2, respectively. However, patterns of the expression of pro-inflammatory biomarkers in HT-29 cell line was different regarding the presence of symptoms and time points. There was no significant correlation between protease activity of different subtypes with the expression levels of pro-inflammatory biomarkers.

CONCLUSIONS

Our study indicated a higher protease activity among isolates from symptomatic compared to asymptomatic subjects, suggesting functional role for proteases in clinical symptoms due to Blastocystis sp. The lack of correlation between the levels of expression of pro-inflammatory biomarkers with subtypes regarding the presence of clinical symptoms proposes the importance of host-related factors in presentation of clinical symptoms.

The Presence of Blastocystis in Tibetan Antelope (Pantholops hodgsonii)

Blastocystis is a protozoan that parasitizes the intestines. A number of hosts of Blastocystis have been found, including human and animals. However, there has been no research on the prevalence of Blastocystis in Tibetan antelope. Here, a molecular test was performed using 627 Tibetan antelope fecal samples collected on Tibet in China from 2019 to 2020. The result showed that 30 (4.8%) samples were Blastocystis positive. The highest prevalence of Blastocystis was in Shuanghu County (25/209, 12.0%), followed by Shenza County (2/103, 1.9%), Nyima County (3/182, 1.6%), and Baigoin County (0/133, 0.0%). In addition, logistic regression analysis showed that the gender, sampling year, and area of Tibetan antelope were risk factors for Blastocystis prevalence. Three subtypes (ST10, ST13, and ST14) of Blastocystis were found in Tibetan antelope through a subtype sequence analysis, and ST13 was identified to be the dominant subtype. This is the first investigation for the infection of Blastocystis in Tibetan antelope. Collectively, the data in this study have expanded the host range of Blastocystis and provided basic information for the distribution of Blastocystis subtypes, which could support the prevention of Blastocystis infection in wild animals.

Occurrence and molecular characterization of Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. in captive wild animals in zoos in Henan, China

BACKGROUND

Captive wild animals in zoos infected with Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. can be sources of zoonotic infections and diseases. Therefore, to investigate the distribution of these pathogens in captive wild animals of zoos in Henan, China, a total of 429 fresh fecal samples were collected from six zoos in Henan, China. The infection rates of Cryptosporidium spp., G. duodenalis, E. bieneusi, and Blastocystis sp. were determined by PCR analysis of corresponding loci. Positive results for Cryptosporidium (C. parvum and C. hominis) were subtyped based on the (gp60) gene.

RESULTS

The overall prevalence was 43.1% (185/429), and the prevalence of Cryptosporidium, Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. were 2.8% (12/429), 0.5% (2/429), 20.8% (89/429), and 19.1% (82/429), respectively. Five Cryptosporidium species, namely, C. hominis, C. parvum, C. muris, C. andersoni, and C. macropodum, were identified in this study. Cryptosporidium parvum was further subtyped as IIdA19G1. Two Giardia duodenalis assemblages (A and E) were also identified. A total of 20 Enterocytozoon bieneusi genotypes were detected, including 18 known (BEB6, D, HND-1, CD7, SDD1, Henan-IV, KIN-1, CHK1, Peru8, Henan-V, CHG11, CHG-1, CHS9, CHG21, Type-IV, CHC9, CM5, and CHB1) and 2 novel genotypes (CHWD1 and CHPM1). A total of nine subtypes of Blastocystis sp. (ST1, ST2, ST3, ST5, ST6, ST7, ST10, ST13, and ST14) were identified in captive wild animals in zoos in the present study. Cryptosporidium andersoni, nine Enterocytozoon bieneusi genotypes, and five Blastocystis subtypes were here first identified in new hosts.

CONCLUSIONS

Our study has expanded the host ranges of these four pathogens. The data indicate that animals in zoos can commonly be infected with these four zoonotic pathogens, and animals in zoos are potential sources of zoonotic infections in humans.

Molecular prevalence and subtype distribution of Blastocystis sp. in Asia and in Australia

Blastocystis is a prevalent protozoan parasite reported in humans, animals, and environmental samples. Over the past decade, numerous studies have investigated the prevalence and subtype distribution of Blastocystis sp. alongside with its genetic and biochemical features. However, studies on subtype distribution of this protozoan in humans, animals, and environmental samples represent the potential transmission routes. In this review, we evaluated studies performed in Asian countries and in Australia to provide an overview of environmental factors on the prevalence and subtype distribution of Blastocystis sp. among humans, animals, and the environment.

Prevalence and Subtype Distribution of Blastocystis sp. in Diarrheic Pigs in Southern China

Blastocystis sp. is a common pathogen that infects the intestines of humans and animals, causing a threat to public health. However, little information on the prevalence and subtypes of Blastocystis sp. in diarrheic pigs in China is available. Herein, 1254 fecal samples were collected from diarrheic pigs in 37 intensive pig farms in Hunan, Jiangxi, and Fujian provinces in southern China, and the prevalence and subtypes of Blastocystis sp. were investigated. Blastocystis sp. was detected by PCR assay, which amplified the small subunit rRNA (SSU rRNA) gene. Overall prevalence of Blastocystis sp. was 31.4% (394/1254), including 21.5% (66/307), 33.1% (99/299), 58.9% (56/95), and 31.3% (173/553) in suckling piglets, weaned piglets, fattening pigs, and sows, respectively. Moreover, age and region factors were significantly related to prevalence of Blastocystis sp. (p < 0.05). Four Blastocystis sp. subtypes were identified, including ST1, ST3, ST5, and ST14. The preponderant subtype was ST5 (76.9%, 303/394). To our knowledge, ST14 was firstly found in pigs in China. The human-pathogenic subtypes (ST1, ST3, ST5, and ST14) that were observed in this study indicate a potential threat to public health. These findings provided a new sight for studying the genetic structure of Blastocystis sp.

PREVALENCE AND MOLECULAR CHARACTERISTICS OF BLASTOCYSTIS SP. FROM PEAFOWL (PAVO CRISTATUS) IN CHINA

This study is the first description of Blastocystis infection in peafowls in China. In total, 143 fecal specimens collected from a peafowl breeding farm in Henan Province were tested for Blastocystis infection by PCR assay targeting the small subunit ribosomal RNA (SSU rRNA) gene, and a total of 50 specimens (35.0%) were positive. Based on sequences and phylogenetic analysis, 2 genetically distinct subtypes (STs) were determined: ST9 and ST7. ST9 was the predominant subtype, accounting for 82% (41/50). The rare zoonotic subtype ST7 was also identified in peafowls, with the infection rate of 18% (9/50). Altogether, the present study is the first report of the prevalence and molecular characteristics of Blastocystis in peafowls in central China. The presence of zoonotic subtypes in peafowls suggests the potential risk of zoonotic transmission of Blastocystis to workers at peafowl farms.

Molecular epidemiology and genotype/subtype distribution of Blastocystis sp., Enterocytozoon bieneusi, and Encephalitozoon spp. in livestock: concern for emerging zoonotic infections

Intestinal parasitic infections have high prevalence rate in many regions especially in developing countries. The aim of this study was to determine the presence and genotype/subtype of some intestinal protozoa in livestock in Iran. Stool samples were collected from cattle, sheep, chickens, and horses. The presence of targeted parasites was evaluated using real-time PCR. Genotyping/subtyping of positive samples was characterized using sequencing of the ITS and barcoding region, respectively. Blastocystis sp., 27.7% (48/173) and Enterocytozoon bieneusi 26.0% (45/173) were the most frequent protozoa followed by Encephalitozoon spp., 0.57% (1/173). Cryptosporidium spp. were not detected among samples. Encephalitozoon spp., was detected only in chickens 2.2% (1/45). A statistically correlation was seen between animals and the prevalence of targeted protozoa. E. bieneusi genotypes I (9/38; 23.68%), BEB6 (22/38; 57.89%), D (6/38; 15.79%), and horse1 (1/38; 2.63%) were detected among samples. A statistically significant correlation was seen between the genotypes and animals (P ≤ 0.05). Blastocystis sp., ST1 (1/45; 2.22%), ST5 3/45; 6.66%), ST7 (1/45; 2.22%), ST10 (24/45; 53.33%), and ST14 (16/45; 35.55%) were characterized among samples. There was no significant correlation between certain subtypes and animals (P = 0.173). The presence of zoonotic potential genotypes of E. bieneusi in animals and zoonotic potential subtypes ST1 and ST7 among our samples provide a clue about the transmission dynamic of E. bieneusi and Blastocystis sp. between animals–animals and humans–animals.

Genotypes of Blastocystis sp. among elderly health checkup people in South Korea with a questionnaire on risk factors

Blastocystis sp. is a common zoonotic intestinal parasite of humans and animals, and has been classified into at least 17 distinct subtypes. Despite its potential impact on public health, the prevalence and subtype distribution of Blastocystis sp. have seldom been the study subject in South Korea. To determine the prevalence and subtype distribution of Blastocystis sp. and to obtain information on risk factors, we performed a cross-sectional study targeting elderly health checkup people, who visited Seoul Western Branch of the Korea Association of Health Promotion (KAHP) in October 2019. Stool samples were collected from 293 participants consisting of 128 males and 165 females with a mean age of 64.7 years (from 50 to 88 years) with a questionnaire on potential risk factors. All the samples were tested by PCR targeting the SSU rRNA gene of Blastocystis sp., and nucleotide sequences of positive samples were used to identify the subtypes. The overall prevalence of Blastocystis sp. was 9.2% (27/293). Among the positive samples, subtype 3 was predominant (59%; 16/27), followed by subtype 1 (41%; 11/27). No other subtypes were detected. In the univariable analysis, the age, sex, presence of digestive symptoms, source of drinking water, and history of drug intake were not significantly associated with Blastocystis sp. infection. Two parameters, including the Enterococcus hirae bacterial infection and the frequency of intake of cooked or boiled vegetables less than twice a week, showed statistical significance. However, the multivariable regression analysis revealed that only the latter parameter was statistically significant. The results suggested that subtypes 3 and 1 are the 2 major genotypes of Blastocystis sp. among elderly people in South Korea, and low frequency of consuming cooked or boiled vegetables is a potential risk factor.

Molecular identification and subtyping of Blastocystis sp. in hospital patients in Central China

Blastocystis is a common enteric protist that inhabits the gastrointestinal tract of approximately 1 billion people worldwide. In this study, a total of 1,070 patients from two hospitals in Zhengzhou, Central China were enrolled to know molecular characteristics of Blastocystis sp. The microorganism was identified and subtyped with a PCR amplification and sequencing of the small subunit ribosomal deoxyribonucleic acid (SSU-rDNA). The overall minimum prevalence of Blastocystis sp. in participants was 3.1% (33/1070). Although there were no significant differences on Blastocystis sp. infections among study sites, age groups, and gender, the higher infection was observed in the patients with gastrointestinal diseases (8.8%, 15/170). Sequence analysis of the 33 isolates revealed three known subtypes, such as ST1 (n = 7), ST3 (n = 23), and ST7 (n = 3). Among them, ST3 was the dominant subtype being detected in 23 isolates (69.7%), followed by ST1 (21.2%, 7/33) and ST7 (9.1%, 3/33). The phylogenetic analysis demonstrated that three subtypes (ST1, ST3 and ST7) were clustered with their reference sequences with good bootstrap support. The subtype determination of Blastocystis sp. isolates by the phylogenetic analysis was well supported by online platform. The present study provides the first molecular report of Blastocystis sp. infections in hospital patients in Central China.

New insights into the interactions between Blastocystis, the gut microbiota, and host immunity

The human gut microbiota is a diverse and complex ecosystem that is involved in beneficial physiological functions as well as disease pathogenesis. Blastocystis is a common protistan parasite and is increasingly recognized as an important component of the gut microbiota. The correlations between Blastocystis and other communities of intestinal microbiota have been investigated, and, to a lesser extent, the role of this parasite in maintaining the host immunological homeostasis. Despite recent studies suggesting that Blastocystis decreases the abundance of beneficial bacteria, most reports indicate that Blastocystis is a common component of the healthy gut microbiome. This review covers recent finding on the potential interactions between Blastocystis and the gut microbiota communities and its roles in regulating host immune responses.

First identification and molecular subtyping of Blastocystis sp. in zoo animals in southwestern China

BACKGROUND

Blastocystis sp. is an anaerobic protozoan that parasitizes many animal hosts and the human gastrointestinal tract, and its pathogenicity is controversial. Captive wildlife may be potential reservoirs for human infection with Blastocystis sp. The present study was performed to investigate the prevalence and subtype distribution of Blastocystis sp. in zoo animals in Sichuan Province, southwestern China.

METHODS

A total of 420 fresh fecal samples were collected from 54 captive wildlife species in four zoos in southwestern China between June 2017 and September 2019. The prevalence and subtype (ST) genetic characteristics of Blastocystis sp. were determined by PCR amplification of the barcode region of the SSU rRNA gene and phylogenetic analysis.

RESULTS

Overall, 15.7% (66/420) of the animal samples and 20.7% (14/54) of the species tested were shown to be infected with Blastocystis sp. The highest prevalence of Blastocystis sp. was found in Panzhihua Zoo (24.3%), which was significantly higher than that in Chengdu Zoo (6.9%), and Xichang Zoo (2.9%) (P < 0.05). There are also significant differences in the prevalence of Blastocystis sp. among different species (P < 0.05), and the highest of Blastocystis sp. prevalence was observed in white-cheeked gibbon, black great squirrel, and red giant flying squirrel (100%). Subtype analysis of Blastocystis sp. revealed nine subtypes, including six zoonotic STs (ST1-5, and ST8) and three animal-specific STs (ST10, ST14, and ST17), with ST17 as the predominant subtype (26/66) in Blastocystis sp.-positive isolates.

CONCLUSIONS

To our knowledge, this is the first report on the prevalence and subtype distribution of Blastocystis sp. among captive wildlife in zoos in southwestern China. This study highlights that these animals may serve as reservoirs for human Blastocystis sp. infections.

Blastocystis infection and subtype distribution in domestic animals in the Qinghai-Tibetan Plateau Area (QTPA) in China: A preliminary study

Blastocystis is a common intestinal protozoan parasite of humans and a variety of animal species. To date, the prevalence of Blastocystis and major subtypes distribution in the domestic animals inhabiting in the Qinghai-Tibetan Plateau Area (QTPA) of China is yet poorly studied. In this study, we investigated the distribution and genetic diversity of Blastocystis in seven animal species in QTPA in China. Four hundred and five fresh fecal samples were collected from domestic animals in Qinghai, Yunnan, and Tibet of China and analyzed using nested PCR and SSU rRNA gene sequencing. It was found that the overall prevalence of Blastocystis infection was 40.2% (163/405) in the animals studied. The most predominant subtype of Blastocystis was ST10 (57.7%) followed by ST14 (28.8%) and ST2 (13.5%). These results reveal the epidemiological features of Blastocytis infection in animals in the high altitude plateau area. The finding of presence of ST2 in a number of animal species suggests a zoonotic nature of Blastocystis and might be of importance of public health.

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.

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.

Cockroach as a Vector of Blastocystis sp. is Risk for Golden Monkeys in Zoo

Blastocystis sp. is a kind of protozoa living in the intestinal tract of human and animals, which will cause intestinal diseases such as diarrhea, abdominal distension and vomiting. This paper was aimed to understand the infection of Blastocystis sp. In golden monkeys and the transmission path in North China. Thirty-seven feces samples from golden monkeys and 116 cockroach samples from Shijiazhuang Zoo were collected from July to October 2019 for PCR analysis of Blastocystis sp. Genetic diversity analysis was further conducted on the samples with positive PCR results. The results showed that the infection rate was 48.7% (18/37) in golden monkeys and 82.8% (96/116) in cockroaches, respectively. The genetic evolution analysis based on small subunit ribosomal RNA demonstrated that three subtypes (ST) of Blastocystis sp. including ST1, ST2, and ST3 existed in the intestinal tract of golden monkeys, while only ST2 was detected in the intestinal tract of cockroaches. This paper may provide supports for the quarantine and control of Blastocystis sp. for the zoo in Northern China.

Molecular Epidemiology and Risk Factors of Blastocystis sp. Infections Among General Populations in Yunnan Province, Southwestern China

BACKGROUND

Blastocystis is a common enteric parasite of controversial pathogenic roles in human diseases. Although the prevalence of Blastocystis infections has been investigated in a diverse range of populations, there is little knowledge on the molecular epidemiology and risk factors of Blastocystis infections among general populations in southeastern China.

MATERIALS AND METHODS

A total of 507 individuals were randomly selected in Yunnan province, China from July 2016 to March 2017. Stool specimens were sampled for detection of Blastocystis sp. using PCR assay, and the risk factors of Blastocystis infections were identified. Blastocystis isolates were subtyped, and the associations of Blastocystis infections and subtypes with clinical manifestations were examined.

RESULTS

The overall detection rate of Blastocystis sp. was 9.47% (95% CI: 7.13-12.44%). Toilet type (OR = 3.248, 95% CI: 1.245-8.473), anemia (OR = 2.601, 95% CI: 1.245-8.473) and type of daily drinking water (OR = 3.11, 95% CI: 1.557-6.213) were identified as risk factors of Blastocystis infections; however, Blastocystis infections showed no associations with clinical symptoms. Four subtypes (ST1 to ST4) were characterized in Blastocystis isolates, in which ST3 was predominant (4.73%, 95% CI: 3.2-6.94%), followed by ST1 (3.16%, 95% CI: 1.95-5.07%), ST4 (1.38%, 95% CI: 0.07-2.82%) and ST2 (0.2%, 95% CI: 0-1.11%). In addition, ST1 subtype infection was found to correlate with anemia (OR = 4.66, 95% CI: 1.631-14.314).

CONCLUSIONS

There is a high prevalence of Blastocystis infections among general populations in Yunnan province, southwestern China, and toilet type, anemia and type of daily drinking water are risk factors of Blastocystis infections. ST3 is the dominant subtype of Blastocystis sp. characterized, and ST1 correlates with anemia. Improving hygiene conditions, developing healthy lifestyles and intensifying health education programs are strongly recommended to reduce the prevalence and transmission potential of Blastocystis infections.