Enteric protozoa in the developed world: a public health perspective

The global prevalence of Cyclospora cayetanensis infection: A systematic review, meta-analysis, and meta-regression

Cyclospora cayetanensis (C. cayetanensis) is a significant pathogen that causes diarrheal illness and causes large foodborne diarrhea outbreaks in the USA and Canada. However, there is currently a lack of published meta-analysis on the prevalence of C. cayetanensis infection in the global population. A real estimation of a disease prevalence should always be done on the basis of studies designed for that purpose. We conducted a comprehensive search of various databases for articles pertaining to the prevalence of C. cayetanensis infection in humans, spanning from the inception of these databases to March 10, 2023. Utilizing a random effects model, we estimated the prevalence of C. cayetanensis infection in humans. Our analysis included a total of 150 datasets sourced from 42 different countries, which were ultimately selected for the final quantitative assessment. The prevalence of C. cayetanensis infection in humans worldwide was estimated to be 3.4 % (5636/166,611). Notably, Africa exhibited the highest prevalence rate at 5.9 % (606/11,068). Further subgroup analysis revealed a significantly higher infection rate in humans residing in low-income countries (7.6 %, 83/921) compared to those in lower-middle-income countries (4.8 %, 3280/48,852), upper-middle-income countries (2.9 %, 2194/99,419), and high-income countries (0.4 %, 79/17,419). The results indicate that the global prevalence of C. cayetanensis infection in humans is relatively low, despite its extensive geographical distribution and children were found to be more susceptible to C. cayetanensis infection compared to those adults. Sensitivity analysis revealed that one study significantly affects the prevalence of C. cayetanensis, which was adjusted to 2.9 % (4017/160,049; 95 % CI: 2.7-3.1 %) by excluding this study. The findings highlight the relatively high prevalence of C. cayetanensis infection in low-income countries and among humans with diarrhea, particularly in Africa. Consequently, routine surveillance for intestinal protozoa is crucial in these regions.

Selection of ssDNA aptamers and construction of aptameric electrochemical biosensor for the detection of Giardia intestinalis trophozoite protein

Giardia intestinalis is one of the most widespread intestinal parasites and is considered a major cause of epidemic or sporadic diarrhea worldwide. In this study, we aimed to develop a rapid aptameric diagnostic technique for G. intestinalis infection. First, the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) process generated DNA aptamers specific to a recombinant protein of the parasite's trophozoite. Ten selection rounds were performed; each round, the DNA library was incubated with the target protein conjugated to Sepharose beads. Then, the unbound sequences were removed by washing and the specific sequences were eluted and amplified by Polymerase Chain Reaction (PCR). Two aptamers were selected, and the dissociation constants (Kd), were determined as 2.45 and 16.95 nM, showed their high affinity for the G. intestinalis trophozoite protein. Subsequently, the aptamer sequence T1, which exhibited better affinity, was employed to develop a label-free electrochemical biosensor. A thiolated aptamer was covalently immobilized onto a gold screen-printed electrode (SPGE), and the binding of the targeted protein was monitored using square wave voltammetry (SWV). The developed aptasensor enabled accurate detection of the G. intestinalis recombinant protein within the range of 0.1 pg/mL to 100 ng/mL, with an excellent sensitivity (LOD of 0.35 pg/mL). Moreover, selectivity studies showed a negligible cross-reactivity toward other proteins such as bovine serum albumin, globulin, and G. intestinalis cyst protein.

Modified trichrome stain for faster and improved detection of intestinal protozoan parasites

Permanent stains such as trichrome have better sensitivity but are time-consuming and the fixative includes toxic mercuric chloride. Thus, a newer modification was tested and found to be a superior, faster and safer staining technique for intestinal parasitic detection. Our study lasted 9 months and a single stool sample was collected from each enrolled patient. We evaluated classical trichrome (T1 - using Schaudinn fixative) with newer modifications, which involved different fixatives with mordant combinations (T2 - acetic acid + hydrated aluminium sulphate, T3 - citric acid + copper sulphate hydrate). Conventional PCR targeting Entamoeba histolytica, Giardia lamblia and Cryptosporidium spp. was taken as the reference. Out of 175 stool samples, 25.1% protozoa were identified by wet mount, 24% by each T1 and T2, 25.7% by T3. Statistically, T3 and T2 had higher sensitivity as compared to T1 and wet mount when PCR was used as reference.

Profiling pathogenic protozoan and their functional pathways in wastewater using 18S rRNA and shotgun metagenomics

Despite extensive research, little is known about the composition of eukaryotic protists in environmental samples. This is due to low parasite concentrations, the complexity of parasite diversity, and a lack of suitable reference databases and standardized protocols. To bridge this knowledge gap, this study used 18S rRNA short amplicon and shotgun metagenomic sequencing approaches to profile protozoan microbial communities as well as their functional pathways in treated and untreated wastewater samples collected from different regions of South Africa. Results demonstrated that protozoan diversity (Shannon index P-value = 0.03) and taxonomic composition (PERMANOVA, P-value = 0.02) was mainly driven by the type of wastewater samples (treated & untreated) and geographic location. However, these WWTPs were also found to contain a core community of protozoan parasites. The untreated wastewater samples revealed a predominant presence of free-living, parasitic, and potentially pathogenic protists typically found in humans and animals, ranging from Alveolata (27 %) phylum (Apicomplexa and Ciliophora) to Excavata (3.88 %) (Discoba and Parasalia) and Amoebozoa (2.84 %) (Entamoeba and Acanthamoeba). Shotgun metagenomics analyses in a subset of the untreated wastewater samples confirmed the presence of public health-importance protozoa, including Cryptosporidium species (3.48 %), Entamoeba hystolitica (6.58 %), Blastocystis hominis (2.91 %), Naegleria gruberi (2.37 %), Toxoplasma gondii (1.98 %), Cyclospora cayetanensis (1.30 %), and Giardia intestinalis (0.31 %). Virulent gene families linked to pathogenic protozoa, such as serine/threonine protein phosphatase and mucin-desulfating sulfatase were identified. Additionally, enriched pathways included thiamine diphosphate biosynthesis III, heme biosynthesis, Methylerythritol 4-Phosphate Pathway, methyl erythritol phosphate (MEP), and pentose phosphate pathways. These findings suggest that protozoan pathogens may possess metabolic and growth potential within WWTPs, posing a severe risk of transmission to humans and animals if inadequately disinfected before release. This study provides a baseline for the future investigation of diverse protozoal communities in wastewater, which are of public health importance.

Irritable Bowel Syndrome Associated with Blastocystis hominis or Without Relationship to It? A Case-Control Study and Minireview

BACKGROUND

Blastocystis hominis (B. hominis) is a protozoan parasite that has a worldwide distribution. Some studies have suggested a link between B. hominis and the development of irritable bowel syndrome (IBS). The objective of this study was to determine the prevalence of B. hominis in patients with IBS compared to healthy individuals.

MATERIAL AND METHODS

A total of 65 stool samples from patients with IBS and 65 samples from healthy individuals in northern Iran were examined. The samples were tested using various methods including direct smear, formalin ether sedimentation and culture to detect the presence of B. hominis. Additionally, polymerase chain reaction (PCR) was performed on all culture-positive isolates to confirm the results and identify the genotype.

RESULTS

B. hominis was detected in 15.38% of IBS patients and 9.2% of the healthy group. The culture in RPMI1640 was found to be better than the formalin ether and direct smear methods. Positive samples were confirmed using the molecular method. No significant difference was observed in the order of B. hominis infection between the two groups.

CONCLUSIONS

The results of our study indicate that no significant difference was observed in the order of B. hominis infection between IBS patients and healthy groups. Therefore, further study is necessary to determine the potential pathogenic effects of this parasite and its role in causing IBS.

Evaluation of the Use of Singleplex and Duplex CerTest VIASURE Real-Time PCR Assays to Detect Common Intestinal Protist Parasites

Cryptosporidium spp., Giardia duodenalis and Entamoeba histolytica are species of protozoa- causing diarrhoea that are common worldwide, while Entamoeba dispar, Dientamoeba fragilis and Blastocystis sp. appear to be commensal parasites whose role in pathogenicity remains controversial. We conducted the clinical evaluation of five singleplex and one duplex CerTest VIASURE Real-Time PCR Assays against a large panel of positive DNA samples (n = 358), and specifically to Cryptosporidium spp. (n = 96), G. duodenalis (n = 115), E. histolytica (n = 25) E. dispar (n = 11), Blastocystis sp. (n = 42), D. fragilis (n = 37), and related parasitic phylum species such as Apicomplexa, Euglenozoa, Microsporidia and Nematoda. DNA samples were obtained from clinical stool specimens or cultured isolates in a national reference centre. Estimated diagnostic sensitivity and specificity values were 0.94-1 for Cryptosporidium spp., 0.96-0.99 for G. duodenalis, 0.96-1 for E. histolytica, 1-1 for E. dispar, and 1-0.99 for D. fragilis in the evaluated singleplex assays. In the duplex assay for the simultaneous detection of Blastocystis sp. and D. fragilis these values were 1-0.98 and 1-0.99, respectively. Measures of diagnostic precision for repeatability and reproducibility were found to be under acceptable ranges. The assays identified six Cryptosporidium species (C. hominis, C. parvum, C. canis, C. felis, C. scrofarum, and C. ryanae), four G. duodenalis assemblages (A, B, C, and F), and six Blastocystis subtypes (ST1-ST5, and ST8). The evaluated singleplex and duplex VIASURE Real-Time PCR assays provide sensitive, practical, and cost-effective choices to the molecular diagnosis of the main diarrhoea-causing intestinal protists in clinical microbiology and research laboratories.

A systematic review and meta-analysis of protozoan parasite infections among patients with mental health disorders: an overlooked phenomenon

BACKGROUND

Patients with mental disorders have a high risk of intestinal parasitic infection due to poor hygiene practices. Hence, to better clarify this overlooked phenomenon, the current study is conducted to determine the global prevalence of protozoan parasite infections in patients with mental disorders and investigate the associated risk factors.

METHODS

Several databases (PubMed, Scopus, Web of Science, ProQuest, and Google Scholar) were searched for papers published until December 2022. The fixed effect meta-analysis was used to estimate the overall odds ratio (OR) and pooled prevalence was estimated using a random-effects model with a 95% confidence interval (CI).

RESULTS

Totally, 131 articles (91 case-control and 40 cross-sectional studies) met the eligibility criteria. Patients with mental disorders were significantly at higher risk for protozoan parasites than healthy controls (OR: 2.059, 1.830-2.317). The highest pooled OR (2.485, 1.413-4.368) was related to patients with neurodevelopmental disorders, and the highest pooled prevalence was detected in patients with neurodevelopmental disorders (0.341, 0.244-0.446), followed by bipolar and related disorders (0.321, 0.000-0.995). Toxoplasma gondii was the most prevalent protozoan parasite (0.343, 0.228-0.467) in cross-sectional studies and the highest pooled OR was related to Cyclospora cayetanensis (4.719, 1.352-16.474) followed by Cryptosporidium parvum (4.618, 2.877-7.412).

CONCLUSION

Our findings demonstrated that individuals afflicted with mental disorders are significantly more susceptible to acquiring protozoan parasites in comparison to healthy individuals. Preventive interventions, regular screening, and treatment approaches for parasitic diseases should be considered for patients with mental disorders.

Monitoring potentially pathogenic protists in sewage sludge using Metataxonomics

Intestinal parasites continue to pose a significant threat to human health worldwide, particularly among children. Contaminated water and soil serve as major transmission vehicles for these parasites and intestinal protists are among the most prevalent parasites in both developed and developing nations. Traditionally, parasites have been studied using human or animal fecal samples, while studying them in environmental samples has been challenging due to technical limitations. However, advancements in Next-Generation Sequencing (NGS) and bioinformatic approaches now enable the detection of parasite DNA in environmental samples. In this study, we applied a metataxonomic and phylogenetic strategy to detect and classify DNA of protists present in sewage sludge from two major cities in Colombia: Medellin and Cali. We successfully detected several human pathogenic parasites including Giardia intestinalis, Entamoeba histolytica, and Blastocystis sp., among other protists, in all sludge samples examined. We also investigated the entry and exit of parasite DNA from the San Fernando wastewater treatment plant (WWTP). We observed a higher number of parasite DNA sequences in the plant's influent wastewater, but we also detected the discharge of DNA from pathogenic parasites in both effluent waters and biosolids.

Chemokines: A key driver for inflammation in protozoan infection

Chemokines belong to the group of small proteins within the cytokine family having strong chemo-attractant properties. In most cases, the strong immuno-modulatory role of chemokines is crucial for generating the immune response against pathogens in various protozoan diseases. In this review, we have given a brief update on the classification, characterization, homeostasis, transcellular migration, and immuno-modulatory role of chemokines. Here we will evaluate the potential role of chemokines and their regulation in various protozoan diseases. There is a significant direct relationship between parasitic infection and the recruitment of effector cells of the immune response. Chemokines play an indispensable role in mediating several defense mechanisms against infection, such as leukocyte recruitment and the generation of innate and cell-mediated immunity that aids in controlling/eliminating the pathogen. This process is controlled by the chemotactic movement of chemokines induced as a primary host immune response. We have also addressed that chemokine expressions during infection are time-dependent and orchestrated in a systematic pattern that ultimately assists in generating a protective immune response. Taken together, this review provides a systematic understanding of the complexity of chemokines profiles during protozoan disease conditions and the rationale of targeting chemokines for the development of therapeutic strategies.

Genotyping and epidemiological distribution of diarrhea-causing isolates of Giardia duodenalis in southeastern part of West Bengal, India

The prevalence and genetic diversity of the protozoan pathogen Giardia duodenalis have been extensively studied worldwide. There is currently a lack of data regarding the genetic variability of the organism in eastern India. Understanding the circulating genotypes and associated risk factors is crucial for effective planning and implementing control measures. Therefore, the objective of the study was to conduct an epidemiological study to determine the prevalence and identify the various genotypes present. This survey adds to our knowledge on the occurrence and distribution of Giardia genotypes in the studied region. The overall prevalence was found to be 6.8%. This parasitic infection was significantly associated with two age groups, i.e., >0-5 years and >5-12 years. Using a multilocus genotyping method, we genotyped 52 human Giardia isolates that were obtained from diarrheal patients. Two distinct assemblages were found in the population-30.8% belonged to assemblage A; 63.5% belonged to assemblage B, prevalent in the population; and 5.7% belonged to a combined assemblage A+B. Sub-assemblage AII was found in 17.3% of the cases, followed by sub-assemblage AI (13.5%). High levels of genetic diversity were found within the population of assemblage B undergoing balancing selection. Overall, the high prevalence of the parasite observed, particularly among children, raises a major concern and necessitates implementation of robust control measures. Furthermore, we report the presence of numerous unique genotypes, circulating in this limited geographical boundary, which can be useful dataset for future studies.

A Study on the Monitoring of Toxocara spp. in Various Children's Play Facilities in the Republic of Korea (2016-2021)

Toxocara spp. is a zoonotic soil-transmitted parasite that infects canids and felids, which causes toxocariasis in humans, migrating to organ systems, including the lungs, the ocular system, and the central nervous system. Since Toxocara spp. is usually transmitted through soil, children tend to be more susceptible to infection. In order to monitor contamination with Toxocara spp. in children's play facilities in the Republic of Korea, we investigated 11,429 samples of soil from daycare centers, kindergartens, elementary schools, and parks across the country from January 2016 to December 2021. Since the Environmental Health Act in the Republic of Korea was enacted in March 2008, there have been sporadic reports of contamination by Toxocara spp. in children's activity zones. In this study, soil from children's play facilities in regions across the Republic of Korea was monitored according to the Korean standardized procedure to use it as basic data for preventive management and public health promotion. The national average positive rate was 0.16% (18/11,429), and Seoul showed a higher rate of 0.63% (2/318) than any other regions while Incheon, Daegu, Ulsan, Kangwon-do, Jeollabuk-do, and Jeollanam-do were negative (p < 0.05). The positive rates were as follows: 0.37% (4/1089) in daycare centers, 0.13% (3/2365) in kindergartens, 0.2% (7/4193) in elementary schools, 0.09% (1/1143) in apartments, and 0.14% (3/2198) in parks. In addition, it was confirmed that 0.2% (1/498) of elementary schools and 1.17% (2/171) of parks were re-contaminated among play facilities managed with the establishment of a regular inspection cycle. Consequently, there is an essential need for continuous monitoring of Toxocara spp. contamination and regular education for preschool and school children in order to prevent soil-borne parasite infections.

Tailored hybrid microbial water disinfection system using sequentially assembled microbial fuel cells and an ultraviolet C light-emitting diode

An integrated ultraviolet C light-emitting diode (UV-C LED) water disinfection system activated by microbial fuel cells (MFCs) was developed, and optimized via electric circuit and device voltage profiling. The intensity of the renewable energy operated, self-powered UV-C LED for E. coli inactivation was calculated by bio-dosimetry to be 2.4  × 10-2 μW cm-2 using fluence-based rate constant (k) of ∼1.03 (±0.11) cm2/mJ to obtain the reduction equivalent fluence kinetics value. Finally, the first-order rate constant for E. coli inactivation during the tailored hybrid disinfection system was found to be 0.53 (±0.1) cm2/mJ by multiplying intensity with 1.09 (±0.1) × 10-5 s-1 derived from the linear regression of E. coli inactivation as a function of time. Furthermore, selected model microbial consisting of two bacteria (Salmonella sp. and Listeria sp.) and three viruses (MS2 bacteriophage, influenza A virus, and murine norovirus-1) were treated with UV-C LED irradiation under controlled experimental conditions to validate the disinfection efficiency of the system. Consequently, the required to achieve significant removal (i.e., >3-log; 99.9%) UV fluence and dose time were calculated to be 4-7 cm2/mJ and 54-76 h and 33-53 cm2/mJ and 400-622 h for model bacterial and viral, respectively. This study expands the applicability of microbial electrochemical system (MES) for microbial disinfection and could be utilized in future MFCs implementation studies for predicting and measuring the kinetics of microbial elimination using a tailored hybrid water treatment system.

Waterborne transmission of protozoan parasites: a review of worldwide outbreaks - an update 2017-2022

The current study presents a comprehensive review of worldwide waterborne parasitic protozoan outbreaks reported between 2017 and 2022. In total, 416 outbreaks were attributed to the waterborne transmission of parasitic protozoa. Cryptosporidium accounted for 77.4% (322) of outbreaks, while Giardia was identified as the etiological agent in 17.1% (71). Toxoplasma gondii and Naegleria fowleri were the primary causes in 1.4% (6) and 1% (4) of outbreaks, respectively. Blastocystis hominis, Cyclospora cayetanensis, and Dientamoeba fragilis were independently identified in 0.72% (3) of outbreaks. Moreover, Acanthamoeba spp., Entamoeba histolytica, Vittaforma corneae, and Enterocytozoon bieneusi were independently the causal agents in 0.24% (1) of the total outbreaks. The majority of the outbreaks (195, 47%) were reported in North America. The suspected sources for 313 (75.2%) waterborne parasitic outbreaks were recreational water and/or swimming pools, accounting for 92% of the total Cryptosporidium outbreaks. Furthermore, 25.3% of the outbreaks caused by Giardia were associated with recreational water and/or swimming pools. Developing countries are most likely to be impacted by such outbreaks due to the lack of reliable monitoring strategies and water treatment processes. There is still a need for international surveillance and reporting systems concerning both waterborne diseases and water contamination with parasitic protozoa.

The Gut-Wrenching Effects of Cryptosporidiosis and Giardiasis in Children

Cryptosporidium species and Giardia duodenalis are infectious intestinal protozoan pathogens that cause alarming rates of morbidity and mortality worldwide. Children are more likely to have clinical symptoms due to their less developed immune systems and factors such as undernutrition, especially in low- and middle-income countries. The severity of the symptoms and clinical manifestations in children may vary from asymptomatic to life-threatening depending on the Cryptosporidium species/G. duodenalis strains and the resulting complex stepwise interactions between the parasite, the host nutritional and immunologic status, and the gut microbiome profile. Structural damages inflicted by both parasites to epithelial cells in the large and small intestines could severely impair children's gut health, including the ability to absorb nutrients, resulting in stunted growth, diminished neurocognitive development, and other long-term effects. Clinically approved cryptosporidiosis and giardiasis drugs have broad antimicrobial effects that have incomprehensible impacts on growing children's gut health.

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.

Epidemiological study on equine coccidiosis in North and Northeast of Iran

BACKGROUND

Eimeria is a genus of protozoan parasites that infect many animal species, including horses. We conducted a cross-sectional study of indigenous breeds of horses from the North and Northeast of Iran to establish the prevalence and distribution of Eimeria species.

MATERIAL AND METHODS

Using standard coprological techniques, 340 faecal samples from randomly selected horses (141 from North Iran and 199 from Northeast Iran) were examined for Eimeria oocyst.

RESULTS

Out of 340 samples, only three from north Iran were positive for coccidiosis. Infections occurred by Eimeria leuckarti. The mean intensity of oocyst output (3-38 o.p.g.) was very low. No clinical signs of gastrointestinal disorders were noticed in horses during this study.

CONCLUSION

In conclusion, the results of this study suggest that the prevalence of Eimeria species causing coccidiosis in indigenous breeds of horses from the North and Northeast of Iran is relatively low. These findings provide valuable insights into the health status of indigenous horses in Iran and may help guide future efforts to promote their welfare and productivity.

Waterborne Infectious Diseases Associated with Exposure to Tropical Cyclonic Storms, United States, 1996-2018

In the United States, tropical cyclones cause destructive flooding that can lead to adverse health outcomes. Storm-driven flooding contaminates environmental, recreational, and drinking water sources, but few studies have examined effects on specific infections over time. We used 23 years of exposure and case data to assess the effects of tropical cyclones on 6 waterborne diseases in a conditional quasi-Poisson model. We separately defined storm exposure for windspeed, rainfall, and proximity to the storm track. Exposure to storm-related rainfall was associated with a 48% (95% CI 27%-69%) increase in Shiga toxin-producing Escherichia coli infections 1 week after storms and a 42% (95% CI 22%-62%) in increase Legionnaires' disease 2 weeks after storms. Cryptosporidiosis cases increased 52% (95% CI 42%-62%) during storm weeks but declined over ensuing weeks. Cyclones are a risk to public health that will likely become more serious with climate change and aging water infrastructure systems.

Treatment of Urticaria caused by severe cryptosporidiosis in a 17-month-old child - a case report

BACKGROUND

Cryptosporidium is an intracellular protozoan that causes gastrointestinal symptoms in humans and animals. In immunocompromised patients and children under 5 years of age, the infection is severe and can be life-threatening due to severe diarrhea.

CASE PRESENTATION

We report a case of urticaria associated with Cryptosporidium in a 17-month-old female Iranian child. The patient had moderate diarrhea (> 3 loose, watery stools but not more than 10 diarrhea stools in a day), weight loss, and acute urticarial (rash clears completely within 6 weeks). Since the child's father worked in livestock farming, the parasite may have been transferred from the cow or calve to the house and the child. Several Cryptosporidium oocysts were detected in the modified acid-fast staining of the child's stool sample. The patient was successfully treated with nitazoxanide (100 mg twice daily) and became negative for parasites three days after treatment and one week after discharge from the hospital. The child was observed to produce < 3 loose stools in the previous 24 h after 1-week post-treatment and after 6 months of follow-up.

CONCLUSION

A number of parasites are associated with urticaria, but to our knowledge, there is no information on Cryptosporidium-induced urticaria. Therefore, our result may be evidence for the role of this parasite in the development of urticaria if other causes such as food allergies, autoimmune diseases and etc. don't role in urticaria.

Molecular detection and characterization of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi infections in dromedary camels (Camelus dromedaries) in Egypt

Introduction

Few studies have investigated the occurrence of microeukaryotic gut parasites in dromedary camels in Egypt, and the majority of these investigations are based on microscopic analysis of fecal material.

Methods

Herein, we assessed the occurrence, molecular diversity, and zoonotic potential of protozoan (Cryptosporidium spp. and Giardia duodenalis) and microsporidian (Enterocytozoon bieneusi) pathogens in individual fecal samples (n = 102) of dromedary camels with (n = 26) and without (n = 76) diarrhea from Aswan Governorate, Upper Egypt. Other factors possibly associated with an increased risk of infection (geographical origin, sex, age, and physical condition) were also analyzed. The SSU rRNA or ITS genes were targeted by molecular (PCR and Sanger sequencing) techniques for pathogen detection and species identification.

Results and discussion

The most abundant species detected was G. duodenalis (3.9%, 4/102; 95% CI: 1.1-9.7), followed by Cryptosporidium spp. (2.9%, 3/102; 95% CI: 0.6-8.4). All samples tested negative for the presence of E. bieneusi. Sequence analysis data confirmed the presence of zoonotic C. parvum (66.7%, 2/3) and cattle-adapted C. bovis (33.3%, 1/3). These Cryptosporidium isolates, as well as the four Giardia-positive isolates, were unable to be amplified at adequate genotyping markers (Cryptosporidium: gp60; Giardia: gdh, bg, and tpi). Camels younger than 2 years old were significantly more likely to harbor Cryptosporidium infections. This connection was not statistically significant, although two of the three cryptosporidiosis cases were detected in camels with diarrhea. The spread of G. duodenalis infections was unaffected by any risk variables studied. This is the first report of C. parvum and C. bovis in Egyptian camels. The finding of zoonotic C. parvum has public health implications since camels may function as sources of oocyst pollution in the environment and potentially infect livestock and humans. Although preliminary, this study provides useful baseline data on the epidemiology of diarrhea-causing microeukaryotic parasites in Egypt. Further research is required to confirm and expand our findings in other animal populations and geographical regions of the country.

Development of a new multiplex PCR to detect fecal coccidian parasite

BACKGROUND

Cryptosporidium spp., Cystoisospora belli and Cyclospora cayetanensis are common intestinal coccidian parasites causing gastroenteritis. The clinical presentation caused by each parasite is indistinguishable from each other. Uniplex polymerase chain reaction (PCR) for these three groups of intestinal coccidian parasites was developed by us in our laboratory. Thereafter, we planned to develop a single-run multiplex polymerase chain reaction (mPCR) assay to detect Cryptosporidium spp., C. belli and C. cayetanensis simultaneously from a stool sample and described it here as coccidian mPCR.

METHODS

New primers for C. belli and C. cayetanensis were designed and uniplex PCRs were standardized. The coccidian mPCR was standardized with known positive DNA control isolates. It was validated with 58 known positive and 58 known negative stool samples, which were previously identified by uniplex PCR.

RESULTS

The coccidian mPCR was standardized with earlier primers designed by us for Cryptosporidium spp. and C. cayetanensis, and a newly designed primer for the internal transcribed spacer-1 (ITS-1) gene for C. belli. The coccidian mPCR was 92.1% sensitive for Cryptosporidium spp., and 100% sensitive for C. belli and C. cayetanensis each, when tested on 116 known samples. It was 100% specific for all intestinal coccidian parasites. Two representative PCR products of the newly designed ITS-1 primer for C. belli were sequenced and submitted to the GenBank, which best match with the sequences of C. belli.

CONCLUSION

A highly sensitive, specific, cost-effective, indigenous, single-run coccidian mPCR has been developed, which can simultaneously detect Cryptosporidium spp., C. belli and C. cayetanensis.

Migrating Anatidae as Sources of Environmental Contamination with Zoonotic Giardia, Cryptosporidium, Cyclospora and Microsporidia

Giardia, Cryptosporidium, Cyclospora, and microsporidia are gastrointestinal pathogens that can cause various disease symptoms in both animals and humans. Numerous studies worldwide have confirmed the presence of these eukaryotic pathogens in nesting and migrating wild geese, ducks, and swans. Migration spreads these zoonotic enteric pathogens to distant locations, which could have public health implications. Soils and water bodies (lakes, ponds, rivers and wetlands) in urban and suburban areas have been shown to be vulnerable to contamination by waterfowl droppings. This review addresses the epidemiology of these enteric pathogens in wild migratory bird species (Anatidae) and some consequences of their spread in the environment. To date, both zoonotic pathogens and genotypes restricted to avian hosts have been found in faecal samples from 21 anatid species worldwide. One of the routes of infection for these zoonotic gastrointestinal micropathogens is the indirect route. For example, shared water bodies (e.g., for drinking or recreational purposes) previously contaminated by birds during the migratory season may facilitate infections of humans through water. However, it is unclear how much wild waterfowl contribute to the transmission of giardiasis, cryptosporidiosis, cyclosporosis, and microsporidiosis in many regions through contaminated environmental sources. Comprehensive epidemiological surveillance based on molecular data on gastrointestinal pathogens is crucial to take measures to control infections in the future.

Zoonotic Parasites in Playgrounds in Southern Spain: A One Health Approach

Zoonotic parasitic diseases are considered a global threat to public health. In this sense, canines and felines may be infected by different cosmopolitan parasites, with playgrounds serving as an important focus of infection for humans, as well as domestic or wild animals. Knowledge of the epidemiological situation of parasites in animal reservoirs integrated into the environment, identifying the spread pathways, is a key element for an effective response to this threat. Thus, the aim of this study was to assess the frequency of intestinal parasites with zoonotic potential in 120 playgrounds in the Malaga province (Spain). Samples were processed and analysed following standard parasitological procedures. Some 36.7% of playgrounds were parasite-positive with one or more zoonotic parasites. The most common parasites recovered were nematodes (60.0%), followed by protozoan species (33.3%) and cestodes (6.7%). In the parasite-positive playgrounds, Toxocara spp. (17.0 ± 3.5%) and Giardia duodenalis (17.0 ± 3.4%) were the most predominant parasites. In addition, 34.1% of playgrounds were infected with multiple parasites. Our results show a high presence of parasitic forms with zoonotic potential in playgrounds in Malaga, Spain. Due to the close contact between pets and humans in playgrounds, the potential zoonotic risk may increase if prevention and control measures are not designed.

Prevalence and temporal dynamics of Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. among toddlers attending day-care centres in Spain. A prospective molecular-based longitudinal study

Giardia duodenalis, Cryptosporidium spp., and Blastocystis sp. are common intestinal eukaryotic parasites affecting children in developed and resource-limited countries. Lack of information on the epidemiology and long-term stability in asymptomatic children complicates interpretation of transmission and pathogenesis. To assess the occurrence, genetic diversity, and temporal dynamics of intestinal eukaryotic parasites in young children, 679 stool samples from 125 toddlers attending six public day-care centres in Central Spain were collected bimonthly within a 1-year period. Detection and identification of species/genotypes were based on PCR and Sanger sequencing methods. Four eukaryotic species were identified: G. duodenalis (2.5‒31.6%), Cryptosporidium spp. (0.0‒2.4%), Blastocystis sp. (2.5‒6.4%), and Entamoeba dispar (0.0‒0.9%). Entamoeba histolytica and Enterocytozoon bieneusi were undetected. Sequence analyses identified assemblage A (63.6%) and B (36.4%) within G. duodenalis (n = 11), C. hominis (40%), C. parvum (40%), and C. wrairi (20%) within Cryptosporidium spp. (n = 5), and ST1 (3.8%), ST2 (46.2%), ST3 (15.4%), and ST4 (34.6%) within Blastocystis sp. (n = 26). Giardia duodenalis sub-assemblage AII/AIII was detected in a toddler for 10 consecutive months. Stable carriage of Blastocystis ST2 allele 9, ST3 allele 34, and ST4 allele 42 was demonstrated in five toddlers for up to 1 year.   Conclusions: Giardia duodenalis and Blastocystis sp. were common in toddlers attending day-care centres in Central Spain. Long-term infection/colonization periods by the same genetic variant were observed for G. duodenalis (up to 10 months) and Blastocystis sp. (up to 12 months). What is Known: • Asymptomatic carriage of G. duodenalis and Blastocystis sp. is frequent in toddlers. • The epidemiology and long-term stability of these eukaryotes in asymptomatic young children is poorly understood. What is New: • Long-term colonization/infection periods by the same genetic variant were described for Blastocystis sp. (up to 12 months) and G. duodenalis (up to 10 months).

Neglected gut microbiome: interactions of the non-bacterial gut microbiota with enteric pathogens

A diverse array of commensal microorganisms inhabits the human intestinal tract. The most abundant and most studied members of this microbial community are undoubtedly bacteria. Their important role in gut physiology, defense against pathogens, and immune system education has been well documented over the last decades. However, the gut microbiome is not restricted to bacteria. It encompasses the entire breadth of microbial life: viruses, archaea, fungi, protists, and parasitic worms can also be found in the gut. While less studied than bacteria, their divergent but important roles during health and disease have become increasingly more appreciated. This review focuses on these understudied members of the gut microbiome. We will detail the composition and development of these microbial communities and will specifically highlight their functional interactions with enteric pathogens, such as species of the family Enterobacteriaceae. The interactions can be direct through physical interactions, or indirect through secreted metabolites or modulation of the immune response. We will present general concepts and specific examples of how non-bacterial gut communities modulate bacterial pathogenesis and present an outlook for future gut microbiome research that includes these communities.

[Microscopy vs. molecular biology in the diagnosis of intestinal protozoal infections, is it time for a change?]

OBJECTIVE

Microscopic examination of the intestinal parasites, from the patient's concentrated feces, has a lower sensitivity when compared to molecular diagnostic techniques. Therefore, the objective of this study has been to compare both techniques, as well as to evaluate whether there is a correlation between the microscopic examination and the threshold cycles (Ct) obtained for Blastocystis hominis.

METHODS

Retrospective study of the samples received in the Microbiology laboratory during September 2021. The MiniParasep SF® concentration test was performed for microscopic visualization and then PCR was performed with the Seegene AllplexTM Parasite Assay panel.

RESULTS

A 27% (n=74) of the samples were positive by molecular diagnosis, with a total of 87 parasites detected. 53% (n=39) were women with a mean age of 47 ± 24 years. In 76% (n=56) of the cases the service of origin was Primary Care. The most frequently found parasite was B. hominis, 85% (n=64), followed by Dientamoeba fragilis 20% (n=15) and Giardia lamblia 11% (n=8). Co-infection by two parasites was detected in 13 cases (B. hominis + D. fragilis in 6 cases, and B. hominis + G. lamblia in 7 cases). In the microscopic diagnosis, 9.5% (n=26) positivity was obtained. The most frequently found parasite was B. hominis, 84% (n=23), followed by G. lamblia, which was seen in three cases by microscopy. D. fragilis was not seen in any case. Coinfection of B. hominis + G. lamblia was observed in one sample.

CONCLUSIONS

Techniques for molecular diagnosis of intestinal parasites are fast, reliable and more sensitive than microscopic techniques, improving microbiological diagnosis and quality of care.

First report on occurrence and genotypes of Enterocytozoon bieneusi, Cryptosporidium spp. and Cyclospora cayetanensis from diarrheal outpatients in Ningbo, Southeast China

Enterocytozoon bieneusi, Cryptosporidium spp. and Cyclospora cayetanensis are three important zoonotic pathogens which were a major cause of foodborne or waterborne intestinal diseases in humans and animals. However, very little data about occurrence and genotypes of the three parasites in Ningbo in the south wing of the Yangtze River Delta, China, which is important for a tourist city. In the present study, molecular characterization of E. bieneusi, C. cayetanensis and Cryptosporidium spp. in fecal samples from 489 diarrheal outpatients were carried out. As a result, a total of 35 (7.16%, 35/489) and three (0.61%, 3/489) samples were positive for E. bieneusi and C. cayetanensis respectively. No Cryptosporidium-positive sample or mixed-infections were detected. Four known E. bieneusi genotypes (Type IV, D, I and CHN4) and 8 novel genotypes (NBH1-NBH8) were identified with type IV was the dominant genotype (n = 14), followed by genotypes D (n = 5), NBH8 (n = 5) and NBH7 (n = 3). The remaining genotypes were found in one sample each, and these genotypes were belonged to the previously described high-potential zoonotic group 1. One novel sequence named NBC315, and the other two sequences (NBC30 and NBC370) identical with the reported sequence were detected. Therefore, the existence and importance of zoonotic potential of E. bieneusi and C. cayetanensis in diarrheal outpatients in Ningbo indicates the public health threats, and more investigations should be carried out in human populations, animals and other environmental sources from the One Health perspective.

Asymptomatic Cryptosporidiosis in Children Living with HIV

Children living with human immunodeficiency virus (HIV) have an increased risk of opportunistic Cryptosporidium infection. Cryptosporidium usually causes chronic diarrhea that may lead to impaired growth and cognitive function in children. This study aimed to estimate the prevalence of cryptosporidiosis in children, describe its clinical characteristics, and the risk factors. A cross-sectional study involving children aged 6 months to 18 years old with confirmed HIV infection was carried out in Sardjito General Hospital, Yogyakarta. Diagnosis of cryptosporidiosis was made by PCR of 18S rRNA after being screened by microscopic examination. The clinical characteristics and risk factors were obtained from medical records and structured questionnaires. A total of 52 participants were included in the final analysis. The prevalence of cryptosporidiosis was 42.3%. Approximately 68% of the HIV children with cryptosporidiosis were asymptomatic, while those who reported symptoms showed weight loss and diarrhea. Independent risk factors of cryptosporidiosis were diarrhea (AOR 6.5; 95% CI 1.16–36.67), well water as drinking water source (AOR 6.7; 95% CI 1.83–24.93), and drink untreated water (AOR 5.8; 95% CI 1.04–32.64). A high prevalence of asymptomatic cryptosporidiosis was observed among children with HIV infection and PCR screening of Cryptosporidium in high-risk children is advisable.

Assessment of intestinal and blood protozoan infections among pregnant women visiting ante-natal care at Tafo Hospital, Ghana

Introduction

Intestinal and blood protozoans cause morbidity and mortality in both pregnant women and developing foetuses worldwide. It constitutes a major health problem in many tropical areas in Africa. This study assessed the prevalence of intestinal and blood protozoans’ parasitic load and their risk factors among pregnant women visiting antenatal care at Tafo Hospital, Ghana from November 2016 to January 2017.

Method

A pilot cross-sectional study was conducted among consented pregnant women who visited antenatal care at Tafo Government Hospital, Kumasi Ghana. Structured questionnaires were administered to obtain socio-demographic data, knowledge on protozoan infections, and their risk factors among study participants. A stool sample was obtained from each participant for the microscopic examination of the intestinal protozoa. Venous blood was taken from participants for the detection of Plasmodium and Toxoplasma gondii infections. Wet mount and the faecal protozoan concentrated method were done for the identification of intestinal parasites. Blood films and serological examination for malaria rapid diagnostic tests (RDT) were done for identification of Plasmodium parasites while an Enzyme-linked immunosorbent assay (ELISA) was used for detecting the antibodies of T. gondii among participants. Data were analyzed using statistical packages for the social sciences (SPSS).

Results

The mean age of the study participants was 27.83, and ranges from 18 to 40 years. The majority of the participants (82.2%) had never experienced stillbirth nor spontaneous abortion. Intestinal parasites were found in 36.7% of participants. Giardia lamblia (28.1%), Cryptosporidium parvum (5.3%), and Entamoeba histolytica/dispar (3.3%) were among the intestinal protozoans detected. T. gondii antibodies were detected by high levels of immunoglobulins, resulting in IgG (48.0%) and IgM (11.3%) being found among participants, with 7.3% testing positive for both IgM and IgG. The prevalence of malaria infection among the study participants was 2.7%. The consumption of raw or cooked vegetables had significant influence on their intestinal and blood protozoan infections status (p = 0.004) (OR = 0.32, CI = 0.12–0.86). There was a significant association between Hb levels and malaria (p = 0.014) and that of intestinal protozoans (p = 0.035).

Conclusion

The prevalence of intestinal protozoans and blood protozoans such as T. gondii were high and therefore effective measures should be put in place to reduce the infectivity. Environmental hygiene should be improved and education by relevant agencies should be intensified on the possible transmission of intestinal and blood parasite infections given the possible role of these infections in adverse pregnancy outcomes.

Assessing the prevalence and risk factors associated with Entamoeba complex infection among the Orang Asli school children in Perak, Malaysia through molecular approach

This study performed a cross-sectional investigation on the prevalence of Entamoeba complex infection comprising Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii and their associated risk factors among the Orang Asli school children in three districts in Perak, Malaysia. Stool samples collected from 544 school children aged between 7 and 12 years old were examined through the nested multiplex PCR assay. The univariate and multivariate regression analyses were then carried out to determine the risk factor associated with Entamoeba complex infection. The overall prevalence of Entamoeba complex infections (E. histolytica, E. dispar and E. moshkovskii) was 21.3% (116/544). Most positive school children were infected with E. moshkovskii (10.7%; 58/544), followed by E. dispar (9.0%; 49/544) and E. histolytica (5.0%; 27/544). Not washing their hands after using the toilet was identified as the only significant risk factor for E. histolytica. The significant risk factors associated with E. moshkovskii infection included children within the age of 10-12 years old, with high BMI, living with working and non-educated mothers, no toilet in the house, not washing their hands after using the toilet, and fever. On the other hand, drinking water from the river, well, and rain was associated with a decreased risk of E. dispar infection. In conclusion, this study showed a high prevalence of Entamoeba spp. infections among the Orang Asli school children in Perak, Malaysia. Addressing the identified risk factors coupled with a holistic approach in breaking the transmission of Entamoeba complex can help improve their quality of life.

First report of rodent-adapted Cryptosporidium wrairi in an immunocompetent child, Spain

Cryptosporidiosis is a leading cause of childhood diarrhoea. Two species, Cryptosporidium hominis and Cryptosporidium parvum, are responsible for most confirmed cases globally. Close contact with pet animals can be an unnoticed source of children infections. We describe a case of infection by rodent-adapted Cryptosporidium wrairi in a 22-month-old immunocompetent toddler with no clinical manifestations in close contact with a pet guinea pig and poor personal hygiene practices in Majadahonda (Madrid, Spain). Attempts to determine the C. wrairi genotype family at the 60-kDa glycoprotein marker failed repeatedly. This is the first description of C. wrairi in a human host. Although a spurious infection cannot be completely ruled out, data presented here suggest that C. wrairi can be transmitted zoonotically.

Survey of the occurrence of Giardia duodenalis cysts and Cryptosporidium spp. oocysts in green leafy vegetables marketed in the city of Valencia (Spain)

The role of vegetables usually consumed without prior culinary treatment is known to contribute to the prevalence of foodborne diseases. Cysts and oocysts can contaminate food, which can then be the source of infection in humans. The aim of the study was to assess the occurrence of Giardia duodenalis and Cryptosporidium spp. (oo)cysts in green leafy vegetables marketed in the city of Valencia (Spain) combining parasitological methods, two real-time qPCRs and light microscopy. An experimental field study was conducted on 129 vegetable samples, 64 from conventional farms and 65 from ecological (organic) farms. The samples were washed with water, and the resulting solution after removing the vegetables, was subjected to 24-hour sedimentation. The concentrated sediment was used for the search for protozoa. A positive result by both real-time PCRs, or a positive result by one qPCR and confirmation by microscopy was established as a positivity criterion. Giardia duodenalis was detected in 23.0 % of the samples, and Cryptosporidium spp. in 7.8 %. G. duodenalis (41.5 %) and Cryptosporidium spp. (20.0 %) were more frequent in ecological crops. The high level of contamination detected in organic vegetables may be due to the type of fertilizers and the quality of the water used for their irrigation and reinforces the need to take extreme hygiene measures in vegetables that are consumed raw.

Molecular Epidemiology of Cryptosporidium parvum and Giardia lamblia in Different Water Bodies, Soil, and Vegetables in Pakistan

There is a dearth of knowledge regarding transmission of Cryptosporidium (C) and Giardia (G) species through water and water-related sources in Pakistan. To this end, we conducted a study to evaluate the prevalence of these parasites in different water bodies, soil, and mixed raw vegetables in Pakistan. Researchers collected 200 samples from each reservoir including municipal water, sewage water, canal water, raw vegetables, soil of public parks, and soil of grazing areas. Researchers amplified the 18S ribosomal RNA gene of parasites using newly designed genus-specific primers through polymerase chain reaction testing. The sequencing analysis revealed that the obtained sequences belonged to C parvum and G lamblia. Phylogenetic clustering and sequence analysis of C parvum showed that the C parvum Pak1 (OM540369) and C parvum Pak2 (OM540370) as well as C parvum Pak3 (OM510450) and C parvum Pak6 (OM510445) were closely similar to each other. In the case of G lamblia, all the sequences appeared in the same clade. The epidemiological data showed lower prevalence of C parvum (11.5%) in all reservoirs, compared with G lamblia (20.5%). Among different reservoirs, prevalence of Cryptosporidium and Giardia was observed in sewage water (C = 13%, G = 26.5%), municipal water (C = 10%, G = 35%), canal water (C = 9.5%, G = 18.5%), raw vegetables (C = 5.5%, G = 8%), soil of public parks (C = 13%, G = 14%), and soil of grazing areas (C = 18.5%, G = 21.5%). Among targeted risk factors, poor hygienic conditions significantly affected the prevalence of parasites in sewage water (C = 20%, G = 41.2%), municipal water (C = 14.7%, G = 48.8.5%), raw vegetables (C = 11.3%, G = 15.1%), and soil of public parks (C = 19.5%, G = 21.9%). Similarly, contamination with sewage waste significantly affected (P < .05) the prevalence of these parasites in municipal water (C = 13.6%, G = 41.1%), canal water (C = 13.3%, G = 25%), raw vegetables (C = 12.1%, G = 15.1%), and soil of public parks (C = 23.3%, G = 15%). Results of this study illustrated a high risk of parasitic zoonosis through water bodies, soil, and vegetables.

Simultaneous detection of less frequent waterborne parasitic protozoa in reused wastewater using amplicon sequencing and qPCR techniques

Waterborne parasitic protozoa (WPP) infections have a worldwide distribution and are a source for epidemic and endemic human diseases. Although a variety of protozoa are commonly detected in wastewater and cited as causative agents of outbreaks, effluents from wastewater treatment plants (WWTPs) used for irrigation can contain other pathogenic protozoa that are not currently being controlled. The lack of control on a routine basis using rapid and sensitive methods to detect these parasites in water may keep them under-recognized. This study focused on using molecular tools, 18 S rRNA amplicon-based sequencing and qPCR, to characterize WPP distribution in wastewater samples from urban WWTPs used for irrigation. A total of eight wastewater samples (from secondary and tertiary disinfection treatment effluents) were collected. Potentially pathogenic protozoa identified by 18 S rRNA sequencing and/or qPCR in the analyzed samples included Acanthamoeba spp., Blastocystis sp., Entamoeba coli, Entamoeba dispar, Entamoeba hartmanni, Giardia intestinalis assemblage A and Toxoplasma gondii Positive results by qPCR were in non-quantifiable levels. Blastocystis sp. was the most represented protozoa among the sequences retrieved from the amplicon sequencing. Blastocystis ST1 and ST2 were the most abundant subtypes among the obtained OTUs. Moreover, Blastocystis sp. ST3, ST4, ST6 and ST8 were also detected, although in lower abundances. Results of this study showed that WWTP effluents used for irrigation can provide a source of WPP.

Evaluation of a Novel Commercial Real-Time PCR Assay for the Simultaneous Detection of Cryptosporidium spp., Giardia duodenalis, and Entamoeba histolytica

Cryptosporidium spp., Giardia duodenalis, and Entamoeba histolytica are the most common diarrhea-causing protozoan species globally. Misdiagnosis is a concern for asymptomatic and chronic infections. Multiplexing, i.e., the detection of more than one parasite in a single test by real-time PCR, allows high diagnostic performance with favorable cost-effectiveness. We conducted a clinical evaluation of the VIASURE Cryptosporidium, Giardia, & E. histolytica real-time PCR assay (CerTest Biotec, San Mateo de Gállego, Spain) against a large panel (n = 358) of well-characterized DNA samples positive for Cryptosporidium spp. (n = 96), G. duodenalis (n = 115), E. histolytica (n = 25), and other parasitic species of the phyla Amoebozoa (n = 11), Apicomplexa (n = 14), Euglenozoa (n = 8), Heterokonta (n = 42), Metamonada (n = 37), Microsporidia (n = 4), and Nematoda (n = 6). DNA samples were obtained from clinical stool specimens or cultured isolates in a national reference center. Estimated sensitivity and specificity were 0.96 and 0.99 for Cryptosporidium spp., 0.94 and 1 for G. duodenalis, and 0.96 and 1 for E. histolytica, respectively. Positive and negative predictive values were calculated as 1 and 0.98 for Cryptosporidium spp., 0.99 and 0.98 for G. duodenalis, and 1 and 0.99 for E. histolytica, respectively. The assay identified six Cryptosporidium species (Cryptosporidium hominis, Cryptosporidium parvum, Cryptosporidium canis, Cryptosporidium felis, Cryptosporidium scrofarum, and Cryptosporidium ryanae) and four G. duodenalis assemblages (A, B, C, and F). The VIASURE assay provides rapid and accurate simultaneous detection and identification of the most commonly occurring species and genetic variants of diarrhea-causing parasitic protozoa in humans. IMPORTANCE Thorough independent assessment of the diagnostic performance of novel diagnostic assays is essential to ascertain their true usefulness and applicability in routine clinical practice. This is particularly true for commercially available kits based on multiplex real-time PCR aimed to detect and differentiate multiple pathogens in a single biological sample. In this study, we conducted a clinical evaluation of the VIASURE Cryptosporidium, Giardia, & E. histolytica real-time PCR assay (CerTest Biotec) for the detection and identification of the diarrhea-causing enteric protozoan parasites Cryptosporidium spp., G. duodenalis, and E. histolytica. A large panel of well-characterized DNA samples from clinical stool specimens or cultured isolates from a reference center was used for this purpose. The VIASURE assay demonstrated good performance for the routine testing of these pathogens in clinical microbiological laboratories.

Cryptosporidium and colorectal cancer: a review of epidemiology and possible association

Cryptosporidiosis is an important protozoan disease with serious public health implications. The contribution of Cryptosporidium to colorectal cancer is still vaguely studied, but little evidence from experimental and epidemiological studies has suggested a possible association. This review discusses the epidemiology of cryptosporidiosis and colorectal cancer and attempts to unravel the possible link between the two diseases using epidemiological, pathological, molecular, and immunological evidence. The review stressed the need to undertake more studies in this relatively neglected field.

High intestinal parasite infection detected in children from Región Autónoma Atlántico Norte (R.A.A.N.) of Nicaragua

There is a lack of epidemiological information concerning intestinal parasitic infections, and especially in soil-transmitted helminths, occurring in some departments of Nicaragua. Up to now, this is the first study involving two nearby areas (Puerto Cabezas and Siuna municipalities) of the Región Autónoma Atlántico Norte (R.A.A.N.). One stool sample was analyzed by Kato-Katz, formaldehyde-ethyl acetate concentration method and modified Ziehl-Neelsen technique, and a simple questionnaire concerning demographic, sanitary and behavioral data was distributed among 735 children and evaluated. Overall prevalence of infection reached 97.0%, being the highest prevalences detected in all Nicaragua. The higher protozoan prevalence appears in Siuna (94.5%), a rural interior municipality, with a typical tropical monsoon climate, while the higher helminths rates were reached in Puerto Cabezas (92.8%), the urbanized coastal capital, with a typical tropical rainforest climate. No statistical differences were found with regard to sex. However, the 6-11-year age-group children presented the highest prevalences. Most T. trichiura infections (59.4%) were of light intensity, while 51.7% of Ascaris lumbricoides were of moderate intensity. Multivariable logistic regression analysis indicated that those who drink rainwater and walk barefoot were 2.9 and 2.5 times more likely to have helminth infections, respectively. Results from one geographical setting might not be applied to other nearby with different climatic conditions. The use of anthelmintic drugs only will not be sufficient to bring prevalence to low levels. It is necessary to design geographically more specific intervention, with communication and interaction between different disciplines (e.g. parasitology, biochemistry, molecular biology, epidemiology, public health, etc.) being imperative to reduce STH infection.

NLRP1B and NLRP3 Control the Host Response following Colonization with the Commensal Protist Tritrichomonas musculis

Commensal intestinal protozoa, unlike their pathogenic relatives, are neglected members of the mammalian microbiome. These microbes have a significant impact on the host's intestinal immune homeostasis, typically by elevating anti-microbial host defense. Tritrichomonas musculis, a protozoan gut commensal, strengthens the intestinal host defense against enteric Salmonella infections through Asc- and Il1r1-dependent Th1 and Th17 cell activation. However, the underlying inflammasomes mediating this effect remain unknown. In this study, we report that colonization with T. musculis results in an increase in luminal extracellular ATP that is followed by increased caspase activity, higher cell death, elevated levels of IL-1β, and increased numbers of IL-18 receptor-expressing Th1 and Th17 cells in the colon. Mice deficient in either Nlrp1b or Nlrp3 failed to display these protozoan-driven immune changes and lost resistance to enteric Salmonella infections even in the presence of T. musculis These findings demonstrate that T. musculis-mediated host protection requires sensors of extracellular and intracellular ATP to confer resistance to enteric Salmonella infections.

Balantidium coli; Rare and Accidental Finding in the Urine of Pregnant Woman: Case Report

Background

Balantidium coli is a ciliated protozoan parasite, which causes intestinal and extraintestinal infections in humans. It is transmitted feco-orally by ingesting infective cysts with food and water. Urinary balantidiasis may occur through contamination (direct spread from the anal area), secondarily to rectovaginal fistula and following immune suppression. Data about cases of urinary balantidiasis are rare in the world. Currently, there are no documented reports of urinary balantidiasis in Ethiopia. As our understanding, there are only eleven documented reports of urinary balantidiasis globally. However, cases of urinary balantidiasis among pregnant women have not been documented yet. The aim of this report is to alarm health professionals for considering the occurrence of such rare cases and conduct diagnosis.

Case Presentation

A 24-year old pregnant woman was admitted due to severe preeclampsia and preterm delivery at Debre Tabor Comprehensive Specialized Hospital, gynecology ward. Her urine was presented to inpatient laboratory for routine urinalysis. We detected unusual and ciliated parasite from her urine sediment characterized by its active and rotary motility through its cilia and possessing macro- and micro-nuclei, several food vacuoles and ingested red blood cells inside the cytoplasm. Hematuria, many white blood cells and epithelial cells were also detected from the urine sediment, which suggests genito-urinary tract infection due to this parasite. This rare parasite finding was confirmed to be B. coli.

Conclusion

The route of transmission and extraintestinal existence from this woman’s urine was unclear. It might be due to feco-oral transmission and spread to the genitourinary tract through direct anal contact. Moreover, it might be associated with immune suppression as she is pregnant woman.

The controversies surrounding Giardia intestinalis assemblages A and B

Giardia intestinalis continues to be one of the most encountered parasitic diseases around the world. Although more frequently detected in developing countries, Giardia infections nonetheless pose significant public health problems in developed countries as well. Molecular characterisation of Giardia isolates from humans and animals reveals that there are two genetically different assemblages (known as assemblage A and B) that cause human infections. However, the current molecular assays used to genotype G. intestinalis isolates are quite controversial. This is in part due to a complex phenomenon where assemblages are incorrectly typed and underreported depending on which targeted locus is sequenced. In this review, we outline current knowledge based on molecular epidemiological studies and raise questions as to the reliability of current genotyping assays and a lack of a globally accepted method. Additionally, we discuss the clinical symptoms caused by G. intestinalis infection and how these symptoms vary depending on the assemblage infecting an individual. We also introduce the host-parasite factors that play a role in the subsequent clinical presentation of an infected person, and explore which assemblages are most seen globally.

Prevalence and Distribution of Cryptosporidium spp. and Giardia lamblia in Rural and Urban Communities of South Africa

OBJECTIVE

Enteric diseases remain a serious health problem globally. High prevalence is evident in regions with poor socioeconomic conditions, poor sanitation, and inadequate clean water supply, such as South Africa. Designing an effective strategy, however, requires local knowledge, which can be particularly challenging to acquire in low-and middle-income countries. As the first step in this process, we investigated the prevalence and distribution of protozoan parasites Cryptosporidium and Giardia in the rural and urban gastrointestinal clinics of South Africa.

METHODS

A cross-sectional study was conducted to assess the prevalence of enteric parasites Cryptosporidium and G. lamblia in rural and urban communities of South Africa. Stool samples were collected from November 2013 to June 2015 from patients with diarrhea (n=227) and without diarrhea (n=257). DNA was extracted and a diagnostic Taqman qPCR assay was performed to detect these protozoan parasites, which was further confirmed by the Sanger sequencing of a few samples.

RESULTS

Of the 484 stool specimens collected, 34% (166/484) were positive for either Cryptosporidium spp. or Giardia lamblia parasites, with only 5% containing both parasites (22/484). In both study populations, Cryptosporidium was the most prevalent parasite (overall 25%) followed by Giardia (19%).

CONCLUSION

This study discovered that both Giardia and Cryptosporidium parasites might contribute to diarrheal disease in South Africa and are more prevalent in rural communities. Future studies are needed to identify the source of the infection and design appropriate interventions to reduce the burden of the disease.

AMAÇ

Enterik hastalıklar küresel olarak ciddi bir sağlık sorunu olmaya devam etmektedir. Güney Afrika gibi düşük sosyo-ekonomik koşulların, kötü sanitasyonun ve yetersiz temiz su kaynaklarının olduğu bölgelerde yüksek prevalans görülmektedir. Ancak etkili bir strateji tasarlamak için, düşük ve orta gelirli ülkelerde edinilmesi özellikle zor olabilecek yerel bir bilgi gerektirmektedir. Bu süreçte biz ilk adım olarak, Güney Afrika’nın kırsal ve kentsel gastrointestinal kliniklerinde protozoan parazitler Cryptosporidium ve Giardia’nın prevalansını ve dağılımını araştırdık.

YÖNTEMLER

Güney Afrika’nın kırsal ve kentsel topluluklarında Cryptosporidium ve G. lamblia enterik parazitlerinin sıklığını araştırmak için kesitsel bir çalışma yapıldı. İshali olan (n=227) ve olmayan (n=257) hastaların Kasım 2013-Haziran 2015 tarihleri arasında dışkı örnekleri toplandı. DNA ekstrakte edildi ve bu protozoan parazitleri saptamak için tanısal bir Taqman qPCR tahlili kullanılarak, birkaç örnek Sanger dizilimi ile daha da doğrulandı.

BULGULAR

Toplanan 484 dışkı örneğinin %34’ü (166/484) Cryptosporidium spp. veya Giardia lamblia parazitleri için pozitifti ve örneklerin sadece %5’i her iki paraziti de içeriyordu (22/484). Her iki çalışma popülasyonunda da Cryptosporidium en yaygın parazitti (toplam %25) ve bunu Giardia (%19) izledi.

SONUÇ

Bu çalışma, hem Giardia hem de Cryptosporidium parazitlerinin Güney Afrika’daki ishal hastalığına katkıda bulunabileceğini ve kırsal topluluklarda daha yaygın olduğunu göstermiştir. Hem enfeksiyonun kaynağını belirlemek hem de hastalığın yükünü azaltmak için uygun müdahaleleri tasarlamak için gelecekteki çalışmalara ihtiyaç vardır.

Selecting a multiplex PCR panel for accurate molecular diagnosis of intestinal protists: a comparative study of Allplex® (Seegene®), G-DiaParaTrio (Diagenode®), and RIDA®GENE (R-Biopharm®) assays and microscopic examination

Commercial multiplex PCR assay panels were developed to overcome the limitations of microscopic examination for parasitological diagnosis on stool samples. However, given the increased supply of this diagnostic approach, these assays must be evaluated to position them in a diagnostic algorithm. Analytical performances of the multiplex PCR assay G-DiaParaTrio, Allplex^® GI parasite and RIDA^®GENE parasitic stool panel for detecting Blastocystis sp., Entamoeba histolytica, Giardia duodenalis, Cryptosporidium spp., Dientamoeba fragilis, and Cyclospora cayetanensis, were assessed through a retrospective comparative study on 184 stool samples initially sent for parasitological investigation. The composite reference method for parasitological diagnosis was microscopic observation and Entamoeba histolytica-specific adhesion detection when necessary. Multiplex PCR assays were performed on extracted DNA from each stool, following the manufacturer's recommendations. Discrepant results with the composite reference method were investigated with species-specific PCR to approach a final parasitological diagnosis. Overall sensitivity/specificity for the multiplex PCR assays was 93.2%/100% for G-DiaParaTrio, 96.5%/98.3% for Allplex^® GI parasite and 89.6%/98.3% for RIDA^®GENE, whereas the composite reference method presented an overall sensitivity/specificity of 59.6%/99.8%. These results confirmed the added diagnostic value of the multiplex PCR approach for gastrointestinal protists. Nevertheless, the PCR procedure and the analytical performance for each protist of interest, variable depending on the multiplex PCR assay, must be considered when implementing a PCR-based diagnostic approach.

Treatment strategies for nitroimidazole-refractory giardiasis: a systematic review

RATIONALE FOR REVIEW

Giardiasis is one of the most common human protozoal infections worldwide. First-line therapy of giardiasis includes nitroimidazole antibiotics. However, treatment failure with nitroimidazoles is increasingly reported, with up to 45% of patients not responding to initial treatment. There is no clear consensus on the approach to the management of nitroimidazole-refractory giardiasis. This systematic review aims to summarize the literature on pharmacotherapy for nitroimidazole-refractory giardiasis.

METHODS

We conducted a systematic review of the literature to determine the optimal management strategies for nitroimidazole-refractory giardiasis. We searched Pubmed/MEDLINE, Embase and Cochrane library using the following search terms 'Giardia' AND 'treatment failure' OR 'refractory giardia' OR 'resistant giardia' with date limits of 1 January 1970 to 30 June 2021. We included all reports on humans, which described clinical outcomes of individuals with treatment refractory giardiasis, including case series and case reports. A descriptive synthesis of the data was conducted with pooling of data for interventions.

KEY FINDINGS

Included in this review were five prospective studies, three retrospective studies, seven case series and nine case reports. Across these reports, a wide heterogeneity of treatment regimens was employed, including retreatment with an alternative nitroimidazole, combination therapy with a nitroimidazole and another agent and monotherapy with non-nitroimidazole regimens, including quinacrine, paromomycin and nitazoxanide. Retreatment with a nitroimidazole was not an effective therapy for refractory giardiasis. However, treatment with a nitroimidazole in combination with albendazole had a cure rate of 66.9%. In the included studies, quinacrine monotherapy was administered to a total of 179 patients, with a clinical cure rate of 88.8%. Overall, quinacrine was fairly well tolerated.

CONCLUSIONS

Reports on the treatment of nitroimidazole-refractory giardiasis demonstrate a heterogeneous approach to treatment. Of these, quinacrine appeared to be highly effective, though more data on its safety are needed.

Intestinal Parasite Infections and Associated Risk Factors among Pre-School Aged Children in Kibera Informal Settlement, Nairobi, Kenya

BACKGROUND

Infections with intestinal parasites are a major public health problem in children in developing countries like Kenya. School going children are considered at most risk and are included in school-based de-worming program. Less focus is given to pre-school children and information is scarce about intestinal parasitosis among this age group. In this study, we determined the prevalence and intensity of protozoa and helminth infections, and associated risk factors in an informal settlement.

METHODS

A community based cross-sectional study was conducted from October 2016 to January 2017 among 406 children aged 2-5 years in Kibera informal settlements in Nairobi County, Kenya. Structured interviewer-administered questionnaire was used to collect sociodemographic information and data on associated factors. Stool samples were examined microscopically using formal ether concentration, iodine wet mounting, modified Ziehl-Neelsen staining, and Kato-Katz methods. Multivariable logistic regression analysis was used to identify risk factors associated with intestinal parasites.

RESULTS

The overall prevalence of any helminth and protozoa infections was 13.1% 53/406) and 22.4% (91/406) respectively. The predominant parasites were Giardia lamblia (13.8%), Ascaris lumbricoides (11.3%), Entamoeba histolytica/dispar (9.4%), Trichuris trichiura (3.9%), Entamoeba coli (1.5%) and hookworm (0.2%). Prevalence of co-infection with any helminths or protozoan was 2.7%. About 10.8% (44/406) and 20.7% (84/406) children were infected with single species of helminth and protozoan parasites. All helminth infections were light, with a mean intensity of 592 egg per gram. Intensity of any protozoan infections was heavy 62.6% (57/406). Dirt floors in the household (aOR = 2.22, p = .046), dirty toilets (aOR = 2.33, p=.014), water from communal taps (aOR = 0.27, p=.019), parent's education level (aOR=0.27, p=.032) and parent's earning (aOR =3.34, p=.007) were factors significantly associated with intestinal parasites.

CONCLUSION

The study found both helminth and protozoan parasites to be prevalent among pre-school aged children in Kibera. Intervention measures including education on the improvement of hygiene and health, socio-economic conditions, sanitation, and provision of safe drinking water could reduce the prevalence of these infections.

Giardia duodenalis and Its Secreted PPIB Trigger Inflammasome Activation and Pyroptosis in Macrophages through TLR4-Induced ROS Signaling and A20-Mediated NLRP3 Deubiquitination

The extracellular protozoan parasite Giardia duodenalis is a well-known and important causative agent of diarrhea on a global scale. Macrophage pyroptosis has been recognized as an important innate immune effector mechanism against intracellular pathogens. Yet, the effects of noninvasive Giardia infection on macrophage pyroptosis and the associated molecular triggers and regulators remain poorly defined. Here we initially observed that NLRP3 inflammasome-mediated pyroptosis was activated in Giardia-treated macrophages, and inhibition of ROS, NLRP3, or caspase-1 could block GSDMD cleavage, IL-1β, IL-18 and LDH release, and the cell viability reduction. We also confirmed that Giardia-induced NLRP3 inflammasome activation was involved in its K63 deubiquitination. Thus, six candidate deubiquitinases were screened, among which A20 was identified as an effective regulator. We then screened TLRs on macrophage membranes and found that upon stimulation TLR4 was tightly correlated to ROS enhancement, A20-mediated NLRP3 deubiquitination, and pyroptotic signaling. In addition, several Giardia-secreted proteins were predicted as trigger factors via secretome analysis, of which peptidyl-prolyl cis-trans isomerase B (PPIB) independently induced macrophage pyroptosis. This was similar to the findings from the trophozoite treatment, and also led to the TLR4-mediated activation of NLRP3 through K63 deubiquitination by A20. Collectively, the results of this study have significant implications for expanding our understanding of host defense mechanisms after infection with G. duodenalis.