Association between Blastocystis sp. infection and immunocompromised patients: a systematic review and meta-analysis

Foodborne concerns of Blastocystis spp. in marine animals (fish, bivalves, and sponges): A systematic review and meta-analysis of global prevalence and subtypes distribution

Blastocystis spp. is a common intestinal parasite found in humans and various animals, including marine species like fish, bivalves, and sponges. While traditionally considered non-pathogenic, emerging evidence suggests potential foodborne concerns, especially for vulnerable populations. The present systematic review and meta-analysis reviewed four electronic databases (PubMed, Scopus, Google Scholar, and Web of Science) until June 13, 2024, for studies reporting the prevalence and subtypes (STs) distribution of Blastocystis spp. in marine animals, including fish, bivalves, and sponges, to assess foodborne concern and zoonotic importance. In the analysis of 11 studies involving 1329 marine animals from nine countries, five studies/datasets (742 samples) focused on fish, five studies/datasets (567 samples) on bivalves, and one (20 samples) on sponges. This review found that 12.4 % (95 % CI: 4.3-31 %) of marine animals globally were infected by Blastocystis spp., with bivalves showing the highest infection rate at 32 % (95 % CI: 13-59.7 %), exceeding sponges with a single study at 10 % (95 % CI: 2.5-32.4 %), and fish at 4.4 % (95 % CI: 2-9.3 %). Sensitivity analysis assessed changes in weighted prevalence after excluding certain studies. A subgroup analysis of Blastocystis spp. prevalence was conducted based on publication years, countries, continents, WHO regions, and sample sizes. The data collected indicated that marine animals serve as suitable reservoirs for various Blastocystis spp. STs (ST1-ST4, ST7, ST8, ST10, ST14, ST23, ST26, and ST44), with most (except for ST26 and ST44) having the potential for zoonotic transmission. Overall, the findings emphasize the potential for foodborne risk posed by Blastocystis spp. in marine animals and highlight the need for improved monitoring and control measures to ensure food safety.

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.

First molecular subtyping and zoonotic significance of Blastocystis sp. in Dromedary (C. dromedarius) and Bactrian (C. bactrianus) camels in Iran: A molecular epidemiology and review of available literature

BACKGROUND

Blastocystis sp. is a zoonotic protozoan parasite, and there is limited information about its molecular prevalence and subtypes (STs) distribution in camels globally, especially in Iran.

OBJECTIVES

This study aimed to examine the prevalence, STs distribution, and zoonotic potential of Blastocystis sp. in one-humped and two-humped camels in Ardabil province, northwestern Iran.

METHODS

A PCR-sequencing tool using the SSU rRNA gene was employed to examine the occurrence and genetic variation of Blastocystis sp. in 150 faecal samples from Bactrian (Camelus bactrianus, 50 samples) and Dromedary (Camelus dromedarius, 100 samples) camels in Ardabil province.

RESULTS

The overall prevalence of Blastocystis sp. in camels was determined to be 12% (18/150) through microscopy and PCR analyses. Phylogenetically, this study identified three distinct zoonotic STs: ST7, ST10, and ST14. ST10 was the most prevalent, comprising 50% (9/18) of the isolated STs from camels. ST14 closely followed with 38.9% (7/18), while ST7 made up 11.1% (2/18) of the total STs. In brief, ST10, ST14, and ST7 represented 50% (7/14), 35.7% (5/14), and 14.3% (2/14) of the Blastocystis-positive cases in one-humped camels, respectively. Further, each of the ST10 and ST14 accounted for 50% (2/4) of the Blastocystis-positive samples in two-humped camels. An analysis of the available data reveals that out of the 37-44 identified Blastocystis STs, 15 (ST1-ST7, ST10, ST14, ST15, ST21, ST24, ST25, ST26, and ST30) have been reported in camels. The predominant STs observed are ST10 and ST14. Furthermore, among the 15 zoonotic STs (ST1-ST10, ST12-ST14, ST16, and ST23) of Blastocystis reported thus far, nine zoonotic STs (ST1-ST7, ST10, and ST14) have been found in camels.

CONCLUSIONS

These findings indicate that camels serve as a proper reservoir for a diverse array of Blastocystis STs and thereby can play a significant role in the transmission of this protozoan infection to humans, animals, and water reservoirs.

First molecular characterization of Blastocystis subtypes from domestic animals (sheep and cattle) and their animal-keepers in Ilam, western Iran: A zoonotic concern

A total of 360 fecal samples were randomly collected from 150 cattle, 150 sheep, and 60 humans (30 people with close animal contact and 30 individuals without close animal contact) at 10 farms in Ilam, western Iran from June 2022 to August 2023. All samples were directly examined for Blastocystis by zinc sulfate flotation, followed by microscopic observation. Positive samples were further subtyped using conventional PCR and sequencing methods. A mean prevalence of 5.3% (16/300) was estimated for Blastocystis infection among examined animals, with 6% and 4.7% for cattle and sheep, respectively. Among the people who had close and non-close animal contact, 16.7% (5/30) and 3.3% (1/30) were infected with Blastocystis, respectively (p < 0.05). All 22 positive samples were successfully sequenced at the SSU rRNA locus. Accordingly, Blastocystis isolates infecting domestic animals in Ilam belonged to the four STs (ST1-ST3, and ST10). Of the 16 animal isolates, nine sequences (four ST10, three ST3, and two ST1) were related to cattle, and seven sequences (three ST10, two ST3, and two ST2) were isolated from sheep. Among the six human isolates, ST3 was the most predominant ST, followed by STs 1, 2, 6, and 7 (one case each). Of note, ST1-ST3 were isolated in various farms both from animals and their breeders, which indicates the possible circulation of these STs between animal and human populations.

First Molecular Identification and Subtyping of Blastocystis sp. in the Most Consumed Edible Marine Fish of Iran: A Foodborne Concern

PURPOSE

The presence of Blastocystis sp. is commonly observed in humans and different animals, displaying a wide range of genetic variations with the discovery of multiple subtypes (STs). However, the prevalence and distribution of these STs in edible marine fish and marine mammals remain uncertain. This study marks the first survey conducted in Iran and the second global molecular investigation to examine the occurrence and STs distribution of Blastocystis in various species of edible marine fish.

METHODS

This study screened 200 fresh intestinal contents from 10 well-known fish species (Narrow-barred mackerel, Indo-pacific king mackerel, Tigertooth croaker, Silver pomfret, Black pomfret, Longtail tuna, John's snapper, Blackspotted croaker, Four-finger threadfin, and Javelin grunter) in southern Iran, caught in the Persian Gulf. All collected samples were evaluated by microscopy and SSU-PCR methods.

RESULTS

Based on both microscopy and PCR, the overall prevalence of Blastocystis sp. in evaluated fish species was 2% (4/200). In brief, Blastocystis sp. was reported from Narrow-barred mackerel [10% (2/20)], Silver pomfret [5% (1/20)], and Tigertooth croaker [5% (1/20)]. Interestingly, among infected fish species three zoonotic STs (ST1, ST2, and ST7) were identified. ST2 was the most predominant ST [50% (2/4)], followed by ST1 and ST7, one sample each [5% (1/20)].

CONCLUSION

Overall, the prevalence and STs distribution of Blastocystis in edible marine fish along with the possibility of its zoonotic transmission are still open to question and require extensive and more detailed studies.

Identification of Blastocystis spp. in Urban Rodents of Different Districts in Southwestern Iran: Subtype Distribution and Possible Zoonotic Potential

PURPOSE

Rodents are one of the most abundant and diverse species of mammals and have recently been identified as carriers of numerous human pathogens. The current study was conducted to assess the prevalence, subtype (STs) distribution, and zoonotic potential of Blastocystis spp. in various species of rodents in Shiraz, southwestern Iran.

METHODS

For this aim, a total of 120 fresh fecal samples were collected from Mus musculus (n = 40), Rattus norvegicus (n = 40), and Rattus rattus (n = 40) in various municipality districts of Shiraz (6 out of 10 districts) between February and November 2020. Upon detecting parasites using light microscopy, a DNA fragment of the Blastocystis SSU rDNA gene was amplified using conventional PCR.

RESULTS

By employing direct wet mount examination, 8 out of 120 fecal samples (6.7%; 2 from house mice, 3 from black rats, and 3 from brown rats) tested positive. Similarly, 5% (2/40) of house mice, 7.5% (3/40) of black rats, and 7.5% (3/40) of brown rats tested positive using the molecular method. Phylogenetic analysis revealed that the Blastocystis infecting different rodent species in Shiraz belonged to two potentially zoonotic STs (ST1 and ST4). Accordingly, rodents should not be overlooked as potential reservoirs of zoonotic Blastocystis infections. Different sampled urban districts and their statistical association with reported prevalence rates were analyzed separately.

CONCLUSION

 Overall, the issue of the frequency and ST distribution of Blastocystis in urban rodents of Iran is still open to question and for a proper understanding, wider and more comprehensive studies are needed.

Comparative molecular epidemiology, subtype distribution, and zoonotic potential of Blastocystis sp. in Equus animals (horses, donkeys, and mules) in northwestern Iran

A total of 500 fecal samples were collected from Equus animals in six different cities (Ardabil, Namin, Nir, Meshginshahr, Germi, and Khalkhal) of Ardabil Province, northwestern Iran, with 200 samples from horses, 200 from donkeys, and 100 from mules. Of the horse samples, 100 were from racing horses under special monitoring and care, while the remaining 100 were from non-racing horses, including those used for herding or in rural areas. All fecal samples were examined for the presence of Blastocystis sp. using PCR amplification of the SSU rRNA gene's barcode region after DNA extraction. The molecular prevalence of Blastocystis infection in Equus animals was 7.6% (38/500). Blastocystis was more common in horses [11.5% (23/200)] than in donkeys [5.5% (11/200)] and mules [4% (4/100)] (P > 0.05). Compared to racing horses [3% (3/100)], non-racing/rural horses [20% (20/100)] exhibited a substantially higher prevalence of Blastocystis (P < 0.05). The prevalence of Blastocystis in diarrheal samples and younger animals was remarkably higher than in formed samples and older animals, respectively (P < 0.05). No significant difference in Blastocystis infection prevalence was found between the genders of examined animals (P > 0.05). In Equus animals, 38 Blastocystis isolates included eight STs: ST10 [31.6% (12/38)], ST1 [21.1% (8/38)], ST2 [15.8% (6/38)], ST3 [10.5% (4/38)], ST4 [7.9% (3/38)], ST7 [5.2% (2/38)], ST14 [5.2% (2/38)], and ST6 [2.6% (1/38)]. These results suggest that Equus animals act as a proper reservoir for numerous Blastocystis STs, consequently playing a crucial part in the spread of this protozoan infection to humans, animals, and water reservoirs.

Prevalence of Blastocystis and Dientamoeba fragilis in diarrheal patients in Corum, Türkiye

To investigate the prevalence of Blastocystis and Dientamoeba fragilis in diarrhea patients and healthy individuals in Corum, Türkiye, fecal samples from 92 diarrhea patients and 50 healthy individuals were collected and evaluated using direct microscopy and molecular methods to screen for bacteria, protozoa, and viruses. The prevalence of Blastocystis was 24.6% in total and more frequent in the healthy group (30.0%). The commonly detected STs (subtypes) were ST3 (40.0%) and ST2 (34.2%). The distribution of Blastocystis STs in the healthy and diarrheal groups did not show any difference in sex and age, but ST3 was detected more frequently in patients aged from 40 to 59 years (p < 0.05). Alleles 4 (8/12) and 2 (4/12) were present in ST1; 9 (3/5) and 12 (2/5) in ST2; 34 (9/14), 36 (3/14), and 38 (2/14) in ST3; and only allele 42 (2/2) in ST4. D. fragilis was present in 8.4% of the population. However, there was no statistically significant difference between the healthy and diarrheic groups (12.0% and 6.5%, respectively), neither with respect to age nor sex. Co-infection was 58.3% and was more frequent in healthy individuals (33.3%) than in diarrhea patients (25.0%). Blastocystis ST3 was the most common subtype detected, with D. fragilis at 33.3%. Salmonella, Shigella, or helminth eggs were not observed in all groups, but Entamoeba histolytica, Giardia intestinalis, Cryptosporidium, Rotavirus, Adenovirus, and Clostridium difficile toxin were found only in diarrhea patients. These findings support the hypothesis that Blastocystis and D. fragilis may be part of the healthy human gut microbiome.

Prevalence and distribution of subtypes of Blastocystis in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) farmed in Hainan, China

Blastocystis sp. is an important gastrointestinal parasite with global distribution, prevalent in humans, farmed animals, and wildlife. Therefore, this study aimed to investigate the prevalence and genetic diversity of Blastocystis sp. in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) in Hainan Province, China. A total of 900 fecal samples were collected from three farmed animal species including 257 porcupines, 360 rats, and 283 civets. Genomic DNA was extracted from each fecal sample and Blastocystis sp. was detected by PCR at the small subunit ribosomal RNA (SSU rRNA) gene. A phylogenetic tree was constructed using the maximum likelihood method. Blastocystis sp. was detected in 47 (5.2%) fecal samples: 12 (4.7%) Asiatic brush-tailed porcupines, 8 (2.2%) bamboo rats, and 27 (9.5%) masked palm civets. Three known Blastocystis sp. subtypes, including ST1, ST4, ST5, and one unnamed subtype (unST), were found in one, 19, 26, and one animal, respectively. Subtypes ST4 and unST were detected in porcupines, ST4 in rats, and ST1 and ST5 in civets. Our results suggest that the three farmed animal species reported in this study could serve as reservoirs for potentially zoonotic Blastocystis sp. subtypes and transmit this parasite to humans, other farmed animals, and wildlife.

Prevalence and Genetic Characterization of Blastocystis in Sheep and Pigs in Shanxi Province, North China: From a Public Health Perspective

Blastocystis is a common zoonotic intestinal protozoan and causes a series of gastrointestinal symptoms in humans and animals via the fecal-oral route, causing economic losses and posing public health problems. At present, the prevalence and genetic structure of Blastocystis in sheep and pigs in Shanxi province remains unknown. Thus, the present study collected 492 sheep fecal samples and 362 pig fecal samples from three representative counties in northern, central and southern Shanxi province for the detection of Blastocystis based on its SSU rRNA gene. The results showed that the overall prevalence of Blastocystis in the examined sheep and pigs were 16.26% and 14.09%, respectively. Sequences analyses showed that four known subtypes (ST5, ST10, ST14 and ST30) in sheep and two subtypes (ST1 and ST5) in pigs were detected in this study, with ST5 being the predominate subtype among the study areas. Phylogenetic analysis showed that the same subtypes were clustered into the same branch. This study reveals that sheep and pigs in Shanxi province are hosts for multiple Blastocystis subtypes, including the zoonotic subtypes (ST1 and ST5), posing a risk to public health. Baseline epidemiological data are provided that help in improving our understanding of the role of zoonotic subtypes in Blastocystis transmission.

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.

Global molecular prevalence of Giardia duodenalis in pigs (Sus domesticus): A systematic review and meta-analysis

Giardia duodenalis is one of the common intestinal parasites causing diarrhea in humans and livestock, including pigs. Thus, a healthy livestock would result in a clean environment, which benefits humans. In the present study, the global molecular prevalence of G. duodenalis infection was determined in pig populations, through systematic exploration of 4 international databases (MEDLINE/PubMed, Scopus, Web of Science, and Google Scholar) until March 4th, 2022. A random-effects meta-analysis model was used to estimate the overall and subgroup-based pooled prevalence of G. duodenalis, and I ² index was used for the evaluation of the heterogeneity. Altogether, 42 datasets from 18 papers examined 7272 pigs across 12 nations, showing a 9.1% (95% CI: 5.6-14.3%) pooled molecular prevalence. Sensitivity analysis demonstrated no remarkable variation in the reported total prevalence upon removing individual studies. It was found that 6 Giardia assemblages (A-F) are capable to infect pigs around the world, including assemblage E [16 datasets, 41.1% (95% CI: 24.8-59.6%)], B [8 datasets, 28.2% (95% CI: 12.2-52.6%)], D [3 datasets, 16.2% (95% CI: 10.6-24.1%)], C [3 datasets, 11.6% (95% CI: 7.3-17.9%)], and A [11 datasets, 9.9% (95% CI: 5.6-16.9%)]. Of note, assemblage F was only reported in one study. Meta-regression analysis showed that publication year was not significantly associated with the Giardia prevalence in swine population, in contrast to the sample size. Substantially, animals in weaner and fattener stages were more prone to giardiasis. Assemblages A and B are of utmost zoonotic significance for humans, while assemblages C, D and F have, also, been found in dogs and cats. Still, little is known on the prevalence and distribution of Giardia assemblages in pigs and requires more extensive and detailed studies.

Blastocystis sp. in Small Ruminants: A Universal Systematic Review and Meta-analysis

PURPOSE

The present review was done to evaluate the prevalence and subtype distribution of Blastocystis infection among small ruminants, at a global perspective.

METHODS

Systematic search was performed in PubMed, Scopus, Google Scholar, and Web of Science until 30th January 2022 and total estimates along with 95% confidence intervals (CIs) were computed using a random-effects model.

RESULTS

Ultimately, the required data were extracted from 25 papers including 19 datasets for each animal. Among 3125 sheep, the Blastocystis prevalence was 25.3% (95% CI 16.1-37.4%) (10 countries), being lower in comparison to that in 2869 examined goats [20.5% (95% CI 11-35.1%)] (12 countries). Regarding STs distribution, fourteen genetically diverse STs of Blastocystis (ST1-ST5, ST7, ST10, ST12, ST14, ST15, ST21, ST23, ST24, ST26) have been reported in sheep, and the highest pooled prevalence was related to ST10 [11 datasets, 57.8% (95% CI 43.7-70.8%)], followed by ST14 [8 datasets, 28.4% (95% CI 20.2-38.4%)], and ST7 [2 datasets, 21.1% (95% CI 4.5-60.3%)]. Compared to sheep, more STs (ST1, ST3-ST7, ST10, ST12, ST14, ST21, ST23-ST26, and ST32) were reported from goats, and the highest weighted frequency was related to ST10 [6 datasets, 45.1% (95% CI: 25.6-66.2%)], followed by ST7 [2 datasets, 40.4% (95% CI 30-51.7%)], and ST14 [4 datasets, 29% (95% CI 15.5-47.7%)]. Out of ten known zoonotic STs reported for Blastocystis (ST1-ST9, and ST12), 7 were isolated from sheep (ST1-ST5, ST7, and ST12) and 7 were reported from goats (ST1, ST3-ST7, ST12).

CONCLUSIONS

Overall, Blastocystis epidemiology in sheep and goats is yet to be elucidated and demands more comprehensive studies.

Current global status, subtype distribution and zoonotic significance of Blastocystis in dogs and cats: a systematic review and meta-analysis

Background

Blastocystis is a common intestinal protozoa found in animal and human fecal samples, with over 1 billion individuals infected worldwide. Since domestication, dogs and cats have had a close bond with humans. However, their close proximity poses a potential health risk since they may harbor several zoonotic agents. A global estimate of Blastocystis infection and subtype (ST) distribution in dogs and cats would therefore be of great health importance to humans.

Methods

We performed a comprehensive systematic search of four English-language databases (PubMed, Scopus, Google Scholar, Web of Science) for relevant articles up to 8 November 2021. The random-effects model was used to make pooled estimates with confidence intervals (CIs).

Results

In total, we identified 49 publications that met our inclusion criteria and subsequently analyzed the 65 datasets in these articles, of which 23 and 42 datasets were on cats and dogs, respectively. Among the 2934 cats included in the 23 datasets, which involved 16 countries, the prevalence rate of Blastocystis infection was 9.3% (95% CI 5.3–15.9%). The prevalence of Blastocystis infection was slightly lower [7%, 95% CI 4.7–10.4%) among the 7946 dogs included in the 42 datasets, involving 23 countries. The sensitivity analysis showed that no remarkable variation in the estimates upon the stepwise removal of each dataset. Higher ST diversity was found among the examined dogs (ST1-8, ST10, ST23, ST24) than among cats (ST1-4, ST10, ST14). Among dogs, ST3 was the most frequent ST (41.3%), followed by ST2 (39.3%), ST1 (30.9%), ST4 (13.4%), ST8 (12.7%), ST10 (11%) and ST5 (8.1%). Also among dogs, each of ST6, ST7, ST23 and ST24 was observed in only one study. Of the ST found in the cats examined, ST4 (29.5%), followed by ST10 (22.5%), ST1 (19.8%) and ST3 (17.6%) were the most common. A single study also reported the presence of both ST2 and ST14 in cats. With respect to zoonotic Blastocystis STs (ST1–ST9 and ST12), eight were reported from dogs (ST1-ST8) and four were isolated from cats (ST1–ST4), showing the implication of dog and cats in zoonotic transmission.

Conclusions

Taken together, our results show that elucidation of the true epidemiology and ST distribution of Blastocystis in dogs and cats demands more comprehensive studies, particularly in the negelected regions of the world.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05351-2.

Alteration of gut bacteria composition among individuals with asymptomatic Blastocystis infection: A case-control study

The gut microbiota consists a diverse and complex ecosystem that is involved in beneficial functions as well as potentially harmful conditions for human. Blastocystis sp. is a common parasite of the digestive tract of animals and humans; however, limited data is available concerning the association of asymptomatic Blastocystis infection and gut bacteria composition. Hence, in this cross-sectional study, the gut bacteria composition of twenty asymptomatic Blastocystis sp. positive and twenty Blastocystis sp. negative individuals was assessed with real time PCR. The case and control groups were matched for age and sex. Both groups were negative for other gastrointestinal infections and did not have any gastrointestinal symptoms. The subtype of ten Blastocystis sp. isolates was assessed based on sequencing. Sequencing of ten Blastocystis sp. isolates revealed the ST1, ST2, and ST3 subtypes in 40%, 30%, and 30% of the isolates. The relative expression of each bacteria in the case than control group revealed that the expression level of Bifidobacterium group (P < 0.033), Peptostreptococcus productus (P < 0.014), Lactobacillus/Enterococcus group (P < 0.001), and Escherichia coli (P < 0.001) were significantly upregulate in the Blastocystis sp. carriers than the control group, while the relative amounts of Bacteroides fragilis (P < 0.001) and Enterococcus sp. (P < 0.001) were significantly downregulated in the case than the control group. Taken together, the results of this study have shown that asymptomatic Blastocystis infection could alter the composition of gut bacteria in healthy individuals.

Rare Occurrence of Blastocystis in Pet Animals and Their Owners in the Pomeranian Voivodeship in Poland in the Light of Literature Data

Blastocystis is an intestinal microeukaryote with ambiguous pathogenicity, commonly detected in human feces worldwide. It comprises at least 28 genetically diverse subtypes (STs), 12 of which also occur in a wide range of animal species, giving rise to suspicion of zoonotic transmission. To investigate this, we conducted a molecular study of 145 stool samples of pet animals, and 67 of their owners, living in an urban area in Poland. Blastocystis was detected in only three (2.1%) animal samples (of two bearded agamas and a leopard gecko), while all dogs, cats, and pet rodents were Blastocystis-negative. Blastocystis was also present in three (4.5%) owners of animals, but they were cat owners, not reptile owners, and the subtypes identified in them differed significantly from those of reptiles. Additionally, the frequency of Blastocystis in different groups of dogs (depending on how they were kept) was analyzed. This work is the first to find Blastocystis in pet reptiles, and we encourage further investigation of Blastocystis in this poorly examined group of animals, as well as continued study on the transmission of this microorganism between humans and animals.

Molecular Epidemiology, Species Distribution, and Zoonotic Importance of the Neglected Meat-Borne Pathogen Sarcocystis spp. in Cattle (Bos taurus): A Global Systematic Review and Meta-analysis

BACKGROUND

Sarcocystis species are diverse apicomplexan parasites, though only two zoonotic species (S. hominis and S. heydorni) circulate between cattle and humans. Due to the importance of cattle in the human food chain and to prevent the consequences of parasitosis in humans, the first global systematic review and meta-analysis on molecular epidemiology, species distribution, and zoonotic significance of Sarcocystis infection in cattle was performed.

METHODS

For this aim, four international English databases (PubMed, Scopus, Google Scholar, and Web of Science) were systematically searched till 20th September 2021, and random-effect models were drawn to calculate total estimates and their 95% confidence intervals (CIs).

RESULTS

Finally, 44 papers from 21 countries were qualified for this review which examined 8526 cattle regarding Sarcocystis infection, rendering a total prevalence of 62.7% (95% CI 53-71.5%). Globally, 12 Sarcocystis spp. have been reported from cattle, including S. cruzi, S. hominis, S. hirsuta, S. rommeli, S. heydorni, S. bovifelis, S. bovini, S. sinensis, S. gigantea, S. fusiformis, S. hjorti and S. tenella. Among them, S. cruzi (37 studies), S. hominis (22 studies) and S. hirsuta (19 studies) were the 3 most common species, with 76.4% (95% CI 64.8-85%), 30.2% (95% CI 19.3-44%) and 8.7% (95% CI 3.8-18.6%), respectively. However, molecular identification was not performed in 48.4% (95% CI 27.3-70.1%) of the positive samples.

CONCLUSION

Despite the zoonotic significance of Sarcocystis spp., particularly S. hominis, the epidemiology and distribution of Sarcocystis infection in cattle remains unclear and demands more extensive researches around the world.