Epidemiological distribution of genotypes of Giardia duodenalis in humans in Spain

Prevalence and genotype analysis of Cryptosporidium and Giardia duodenalis from shelter dogs in South Korea

Cryptosporidium and Giardia duodenalis are common gastrointestinal protozoan parasites that cause diarrhea in humans and animals. Although dogs in animal shelters in South Korea can be reintroduced into human society as companions, no continuous investigations have been conducted on the prevalence and genetic characteristics of the protozoan parasites. In the present study, 345 fecal samples from dogs were obtained from animal shelters in six provinces between January and December 2022. The prevalence of Cryptosporidium and G. duodenalis were molecularly identified at the 18S rRNA gene. Cryptosporidium canis isolates were subtyped at the gp60 locus, and G. duodenalis assemblages were identified at the tpi, bg and gdh loci. Overall, 6.67% of the fecal samples tested positive for Cryptosporidium spp. and two species were identified: C. canis (5.51%) and Cryptosporidium parvum (1.16%). Significant regional differences in prevalence were identified for C. canis. Subtyping analysis of C. canis isolates revealed a predominance of the subtype families XXa and XXe over XXb, and XXc. G. duodenalis was detected in 17.68% of the samples, and significant regional differences were identified; its prevalence was also significantly highest in diarrhoeic animals. Molecular characterization of G. duodenalis reveal that most isolates belonged to the canine-specific assemblages C and D. The present results can contribute to further insights into the prevalence and genotypes of Cryptosporidium and G. duodenalis in shelter dogs in South Korea.

Prevalence and Genotyping of Water- and Food-Borne Parasitic Protozoans (Giardia duodenalis and Cryptosporidium spp.) in Hospitalized Patients from Northwestern Romania

Giardia duodenalis and Cryptosporidium spp. are important zoonotic protozoan pathogens that infect the gastro-intestinal tract of numerous vertebrates, including humans, and both parasites are responsible for water- or food-borne outbreaks of disease worldwide. Although, globally, both parasites are highly prevalent, particularly in developing countries, epidemiological data from Romania are scarce, and genotyping has rarely been performed. The aims of the present study were to investigate the occurrence and genetic diversity of G. duodenalis and Cryptosporidium spp. in patients hospitalized in Northwestern Romania in relation to clinical and paraclinical presentation and to identify the relative frequency of non-specific symptoms and potential risk factors. Between June 2022 and January 2024, 426 fecal samples were screened for gastro-intestinal parasites by rapid tests and microscopical examination, further confirmed by PCR and sequencing. Giardia duodenalis was detected and characterized in 12 samples (2.82%), while Cryptosporidium parvum was confirmed in four samples (0.94%). A majority of positive patients were symptomatic and reported nausea and vomiting with a significantly higher frequency compared to negative ones. This study provides new insights into the epidemiological status and clinical implications of gastro-intestinal parasite species and genospecies in Romania that are necessary for an in-depth understanding of the potential zoonotic transmission and improvement of patient care.

First report of prevalence and assemblage analysis of Giardia duodenalis in pigs from Guangxi Zhuang Autonomous Region, southern China

Giardia duodenalis is a common intestinal protozoan that can cause diarrhea and intestinal disease in animals and in humans. However, the prevalence and assemblages of G. duodenalis in pigs from Guangxi Zhuang Autonomous Region have not been reported. In this study, a total of 724 fecal samples (201 from nursery pigs, 183 from piglets, 175 from breeding pigs, and 165 from fattening pigs) were obtained in four areas of the region (Nanning, Yulin, Hezhou, and Guigang). The gene of the small subunit ribosomal RNA (SSU rRNA) of G. duodenalis was amplified by nested PCR. The results show that the prevalence of G. duodenalis in pigs was 3.59% (26/724), of which 14 samples belonged to assemblage A (53.85%) and 12 samples belonged to assemblage E (46.15%). The infection rates of G. duodenalis in Hezhou, Yulin, Nanning, and Guigang were 0%, 0.7%, 10.8% and 1.1%, respectively (χ2 = 45.616, p < 0.01); whereas 5.1% of breeding pigs, 6.0% of piglets, 2.4% of fattening pigs, and 1.0% of nursery pigs were infected with G. duodenalis (χ2 = 8.874, p < 0.05). The SSU rRNA-positive samples were amplified by PCR based on the β-giardin (bg), glutamate dehydrogenase (gdh), and triphosphate isomerase (tpi) genes. Ten, eight and seven positive samples were detected, respectively. Based on phylogenetic analysis of the three genetic loci sequences, a multilocus genotyping A1 was found. The findings of this study provide basic data for the development of prevention and control of G. duodenalis infections in pigs and humans in the Guangxi Zhuang Autonomous Region.

The detection and phylogenetic characterization of Cryptosporidium, Cystoisospora, and Giardia duodenalis of cats in South Korea

Introduction

Cryptosporidium, Cystoisospora, and Giardia duodenalis are gastrointestinal protozoa parasites that cause diarrhea in various animals. However, information regarding the detection and phylogenetic characterization of gastrointestinal protozoa parasites in cats is limited throughout South Korea. Therefore, this study aimed to determine the detection and identify subspecies of gastrointestinal protozoa parasites in cats from South Korea.

Methods

A total of 290 fecal samples were collected from stray, companion, and shelter cats in six provinces. Cryptosporidium, Cystoisospora, and G. duodenalis were identified by PCR. All positive samples were subtyped by PCR and sequencing of gp60, ITS-1, tpi, bg, and gdh.

Results

The overall detection of gastrointestinal protozoan parasitic infection was 17.93%. G. duodenalis was the most prevalent, with 7.93%, followed by Cystoisospora spp. (7.24%) and Cryptosporidium spp. (4.48%). In addition, C. felis (n=10), C. parvum (n=2), C. ryanae (n=1), Cystoisospora felis (n=14), Cystoisospora suis (n=5), Cystoisospora ohioensis (n=1), Cystoisospora spp. were identified in subspecies analysis of positive samples. C. felis showed a significant association with diarrhea (7.81%) and living condition (6.04%), and Cystoisospora felis in diarreha (9.38%) according to detection. Through phylogenetic analysis of the tpi, bg, and gdh genes from 23 G. duodenalispositive samples, it was confirmed that the samples of present study belonged to assemblage A, B, C, and D.

Discussion

South Korean cats have a high rate of gastrointestinal protozoan parasites infection with cat-specific Cryptosporidium and Cystoisospora, which are associated with living conditions and diarrhea symptoms. Moreover, zoonotic and other animal-specific subtype of protozoan parasites have been detected in cat feces.

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.

Genotyping of G. duodenalis in the People Referred to Health Centers of Semnan City

Giardia duodenalis (G. duodenalis), is one of the major causes of gastrointestinal disorders worldwide, infecting the small intestine of humans and animals. Based on the genetic characteristics of the parasite, eight genotypes (A to H) have been identified in clinical samples. The main purpose of the present study was to find the genetic diversity of Giardia in people referred to health centers in Semnan, Iran, using PCR. Totally, 300 stool samples were collected from people referred to health centers in Semnan. The stool samples were first examined using the microscopic method (direct method and Lugol staining), and the samples were checked with trichrome staining. After DNA extraction, the GDH gene of positive samples was amplified by the semi-nested PCR method. The genotype of positive samples was determined by the sequencing method. Out of 300 samples, only 20 (6.66%) samples were found to be positive in the microscopic examination of the stool. In the PCR test, only 13 (4.33%) of the samples were positive. According to the multiple alignment results, it was found that the isolates belonged to AII, BIII, and BIV genotypes. Most of which are related to people without clinical symptoms of diarrhea. Identification of AII, BIV, and BIII genotypes indicates the anthroponotic and anthropozoonotic transmission cycle of Giardia infection in Semnan.

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.

Assessment of the Health Status of Spanish Schoolchildren Based on Nutrimetry, Lifestyle and Intestinal Parasites

Malnutrition in Spanish schoolchildren, and its relationship with lifestyles, has been studied, but Nutrimetry (a nutritional status indicator), and data on intestinal parasitism and its risk factors, have never before been taken into account. A total of 206 children aged 3-11 years, from two schools in the Valencian Community, participated. Demographic characteristics, diet, lifestyles, behavioural habits and anthropometric (weight, height) and coproparasitological data were collected. Nutrimetry was used to analyse nutritional status. Statistical analyses were performed to ascertain associations between lifestyle, selected parasite species and nutritional status. Multivariate logistic regression analysis was used to assess the strength of the association of the suspected risk factors with the presence of intestinal parasitism. The prevalence of overweight was 32.6%. A total of 43.9% had a high adherence to the Mediterranean Diet, for which mean daily intake was 2428.7 kcal. Intestinal parasitism was identified in 49.5% of the children (Giardia duodenalis: 28.6%). The source of drinking water was found to be a risk factor for intestinal parasitism. No positive association between the variables analysed and nutritional status could be confirmed. Nutrimetry is a good indicator for a complete analysis of nutritional status. It highlights the prevalence of overweight. Intestinal parasitism was identified in almost half of the participants and is a variable that should not be underestimated.

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.

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.

Association Between Giardia Genotype and Oxidative Stress Biomarkers Among Giardia-Infected Children: A Case-Control Study

Purpose

Giardia duodenalis is the most common worldwide intestinal protozoal infection. The implication of free radicals in organ injury occurs through oxidative stress. Infections as Giardia may act as a triggering or promoting factor for oxidative stress, particularly in children with compromised immunity. Besides, the effect of Giardia genotype on oxidative stress status is yet to be explored. Therefore, we sought to compare the oxidative stress status between Giardia positive cases (case group) and Giardia negative cases (control group), and to explore the association between Giardia genotype and the level of oxidative stress markers in Giardia-infected children, especially those receiving immunosuppressive therapy.

Methods

Pediatric patients attending Mansoura University Children Hospital in the period from April 2015 to October 2016 were enrolled. Both case (n = 50) and control (n = 50) groups were further subdivided into immunosuppressive therapy recipients (ITR) and non-immunosuppressive therapy recipients (NITR). Genotyping of Giardia from positive stool samples by PCR was carried out, and oxidative stress markers were measured from venous blood samples.

Results

Giardia positive cases had higher levels of Malondialdehyde (MDA) and lower levels of total antioxidant capacity (TAC). MDA highest level was associated with mixed genotypes A and B, while the highest TAC level was associated with Giardia genotype A in both ITR and NITR cases.

Conclusion

Elevated oxidative stress biomarkers in pediatric patients infected with specific Giardia genotypes should receive considerable attention, because if prompt treatment is not conducted, oxidative damage may occur in patients with giardiasis, especially those receiving immunosuppressive therapy.

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.

A scoping review of risk factors and transmission routes associated with human giardiasis outbreaks in high-income settings

The flagellated pathogen Giardia duodenalis is one of the leading causes of parasitic gastrointestinal illness worldwide. In many higher income countries, such as the United Kingdom, the disease is often perceived as being travel-related, likely leading to the under-reporting of sporadic cases and outbreaks. A summary of the literature describing outbreaks and risk factors in higher income countries is necessary to improve our understanding of this pathogen and identify existing knowledge gaps. Initial literature searches were carried out in September 2016 and updated at regular intervals until November 2021, using appropriate search terms in Medline, Embase and PubMed databases. A total of 75 papers met the inclusion criteria, revealing that the consumption of contaminated water and contact with young children of diaper-wearing age were the most common transmission routes leading to outbreaks of giardiasis. Of the ten studies where food was primarily associated with outbreaks, food handlers accounted for eight of these. Another reported transmission route was direct contact with fecal material, which was reported in six studies as the primary transmission route. Travel-associated giardiasis was considered the sole transmission route in two studies, whereas multiple transmission routes contributed to giardiasis outbreaks in eleven studies. The evidence around zoonotic transmission was less clear and hampered by the lack of robust and regularly applied parasite molecular typing techniques. This literature review summarizes the findings of Giardia outbreak investigations and epidemiological studies in high-income countries. Transmission routes are identified and discussed to highlight the associated risk factors. These data also indicate gaps in our current knowledge that include the need for robust, in-depth molecular studies and have underscored the importance of water as a transmission route for Giardia cysts. These future molecular studies will improve our understanding of Giardia epidemiology and transmission pathways in higher income countries to prevent spread of this significantly under-reported pathogen.

Occurrence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis among captive mammals in the Bangladesh National Zoo

Cryptosporidium and Giardia are protozoan parasites capable of causing gastrointestinal illness in humans and animals. The purpose of this research was to determine the occurrence, genetic characteristics, and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in captive mammals at the Bangladesh National Zoo. A total of 200 fresh fecal samples from 32 mammalian species were collected and examined for Cryptosporidium spp. using nested polymerase chain reaction (PCR) targeting the small subunit (SSU) rRNA gene and G. duodenalis targeting the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. The overall infection rates of Cryptosporidium and G. duodenalis among captive mammals in the zoo were 3.5% (7/200) and 5.5% (11/200), respectively. Five species/genotypes of Cryptosporidium (C. hominis, C. andersoni, C. muris, C. felis, and Cryptosporidium deer genotype) were identified. C. hominis was subtyped as IbA12G3 by sequence analysis of the glycoprotein 60 (gp60) gene. Multilocus genotyping of G. duodenalis revealed assemblages A, B, and D. Mixed infections of assemblages B and D and A and B were found in an Asiatic jackal and a Nilgiri langur, respectively. To our knowledge, this is the first report on the occurrence and genetic identity of the two parasites among zoo animals in Bangladesh. The results suggest that zoonotic Cryptosporidium spp. and G. duodenalis are maintained in and transmitted between captive mammals. Therefore, washing, cleaning, and disinfection measures should be implemented to reduce the spread of Cryptosporidium and G. duodenalis infections.

Detection of Point Prevalence and Assemblages of Giardia spp. in Dairy Calves and Sika Deer, Northeast China

Giardia lamblia (syn Giardia duodenalis) is an important protozoan parasite that can cause enterocyte damage and loss of brush border of the epithelial cells in the intestine, resulting in shortening of microvilli and altered epithelial barrier function. Many animals have been detected as the hosts of the G. lamblia. However, the information on the epidemiology and molecular detection of G. lamblia in dairy calves and sika deer in northeastern China is limited. To investigate the prevalence and genotypes of dairy calves and sika deer in northeastern China, a total of 321 fecal samples from dairy calves in Heilongjiang Province and 818 fecal samples from sika deer in four provinces (Jilin Province, Heilongjiang Province, Liaoning Province, and Inner Mongolia Autonomous Region) in China were conducted by PCR methods, between September 2017 and April 2018. The overall prevalence of G. lamblia in dairy calves in Heilongjiang Province and sika deer in the four provinces was 4.98% (16/321) and 0.61% (5/818), respectively. In this study, the point prevalence of Giardia spp. in different factor groups was dissimilar. A total of 16 Giardia spp. positive samples in dairy calves were identified as assemblage E based on the triosephosphate isomerase (tpi), β-giardine (bg), and glutamate dehydrogenase (gdh) genes. Furthermore, two positive samples of assemblage A and three positive samples of assemblage E were identified with gdh and bg genes in the sika deer. Assemblage A was zoonotic genotype of G. lamblia, and assemblage E was identified as the predominant assemblage in dairy calves and sika deer. This study reported the prevalence and genotypes of G. lamblia in dairy calves in Heilongjiang Province and sika deer in four provinces in China. These results provided basic information to understand the epidemiology of G. lamblia in dairy calves and sika deer in China.

Genetic Diversity and Prevalence of Giardia duodenalis in Qatar

Background

Giardia duodenalis is a common human intestinal parasite worldwide, and the causative agent of diarrhea, with the severity of disease ranging from asymptomatic to intense and debilitating infection. G. duodenalis is known to consist of eight genetically distinct assemblages, named from A to H. No data available on the genotypes and genetic diversity of G. duodenalis circulating in Qatar.

Methods

We genotyped 54 human Giardia isolates, collected from asymptomatic immigrants in Qatar, using a multilocus genotyping (MLGs) tool. We also investigated relationships between the subjects’ genotypes and their demographic data.

Results

Genomic DNA from 54 isolates were tested by PCR and sequence analysis at three loci: glutamate dehydrogenase (gdh), β-giardin (bg) and triose phosphate (tpi)). Assemblage A was identified in nine (16.67%), assemblage B in thirty (55.55%), and a mixture of assemblages A+B in fifteen (27.78%) isolates. All assemblage A isolates, genotyped in different loci, were assigned to sub-assemblage AII, and six of them had MLGs AII-1 while one new MLG was identified in two isolates. Sequences of assemblage B isolates have high level of genetic diversity and high presence of heterogeneous peaks, especially within the gdh gene. No significant associations between genotypes and the immigrants’ demographic data were found due to the extensive number of new variants.

Conclusions

MLGs was used herein to genotype 54 immigrant Giardia isolates. The high level of genetic variability found in our isolates hampered MLGs determination, more investigations are now required to consolidate our findings, and to enable a comprehensive understanding of the diversity within G. duodenalis assemblage B isolates.

Detection of enteric parasites and molecular characterization of Giardia duodenalis and Blastocystis sp. in patients admitted to hospital in Ankara, Turkey

This epidemiological study assesses the occurrence of enteric parasites in 4303 patients attended at two public hospitals in Ankara (Turkey) during 2018-2019. Microscopy was used as a screening test. Giardia duodenalis was also identified using a commercial ELISA for the detection of parasite-specific coproantigens. Giardia-positive samples by microscopy/ELISA were confirmed by real-time PCR and characterized using a multilocus genotyping scheme. Blastocystis sp. was genotyped in a sample subset. Blastocystis sp. (11.1%, 95% CI 11.4‒14.8%) and G. duodenalis (1.56%, 95% CI 1.22‒1.96) were the most prevalent pathogens found. Cryptosporidium spp., Entamoeba histolytica and intestinal helminths were only sporadically (<0.5%) found. For G. duodenalis, sequence (n = 30) analyses revealed the presence of sub-assemblages AII (23.3%), discordant AII/AIII (23.3%) and mixed AII + AIII (6.7%) within assemblage A, and BIII (10.0%), BIV (3.3%) and discordant BIII/BIV (23.3%) within assemblage B. Two additional sequences (6.7%) were assigned to the latter assemblage but sub-assemblage information was unknown. No associations between G. duodenalis assemblages/sub-assemblages and sociodemographic and clinical variables could be demonstrated. For Blastocystis sp., sequence (n = 6) analyses identified subtypes ST1, ST2 and ST3 at equal proportions. This is the first molecular characterization of G. duodenalis based on MLG conducted in Turkey to date.

One Health Approach to Zoonotic Parasites: Molecular Detection of Intestinal Protozoans in an Urban Population of Norway Rats, Rattus norvegicus, in Barcelona, Spain

Rattus norvegicus, the brown or Norway rat, is the most abundant mammal after humans in urban areas, where they live in close proximity to people. Among rodent-borne diseases, the reservoir role of Norway rats of zoonotic parasites in cities has practically been ignored. Considering the parasitic diseases in the One Health approach, we intended to identify and quantify the zoonotic intestinal protozoans (ZIP) in an urban population of R. norvegicus in the city of Barcelona, Spain. We studied the presence of ZIP in 100 rats trapped in parks (n = 15) as well as in the city’s sewage system (n = 85) in the winter of 2016/17. The protozoans were molecularly identified by means of a multiplex PCR (Allplex^TM Gastrointestinal Panel-Parasite Assay). We also investigated the presence of co-infections among the species found. Four ZIP were identified, presenting significant prevalences in sewers, specifically Blastocystis (83.5%), Giardia duodenalis (37.7%), Cryptosporidium spp. (34.1%), and Dientamoeba fragilis (14.1%). Several co-infections among the detected ZIP were also detected. The reservoir role of ZIP that Norway rats play in cities as well as the role rats may play as sentinels of zoonotic parasites affecting humans in urban areas are strongly backed up by our findings. The increasing worldwide urbanization, climate change, and the COVID-19 pandemic are factors that are producing an increase in human–rat interactions. Our results should be considered a warning to the authorities to intensify rat control and surveillance in public health interventions.

Multilocus Genotyping of Giardia duodenalis in Mostly Asymptomatic Indigenous People from the Tapirapé Tribe, Brazilian Amazon

Little information is available on the occurrence and genetic variability of the diarrhoea-causing enteric protozoan parasite Giardia duodenalis in indigenous communities in Brazil. This cross-sectional epidemiological survey describes the frequency, genotypes, and risk associations for this pathogen in Tapirapé people (Brazilian Amazon) at four sampling campaigns during 2008–2009. Microscopy was used as a screening test, and molecular (PCR and Sanger sequencing) assays targeting the small subunit ribosomal RNA, the glutamate dehydrogenase, the beta-giardin, and the triosephosphate isomerase genes as confirmatory/genotyping methods. Associations between G. duodenalis and sociodemographic and clinical variables were investigated using Chi-squared test and univariable/multivariable logistic regression models. Overall, 574 individuals belonging to six tribes participated in the study, with G. duodenalis prevalence rates varying from 13.5–21.7%. The infection was positively linked to younger age and tribe. Infected children <15 years old reported more frequent gastrointestinal symptoms compared to adults. Assemblage B accounted for three out of four G. duodenalis infections and showed a high genetic diversity. No association between assemblage and age or occurrence of diarrhoea was demonstrated. These data indicate that the most likely source of infection was anthropic and that different pathways (e.g., drinking water) may be involved in the transmission of the parasite.

Molecular diversity of Giardia duodenalis in children under 5 years from the Manhiça district, Southern Mozambique enrolled in a matched case-control study on the aetiology of diarrhoea

Giardia duodenalis is an enteric parasite commonly detected in children. Exposure to this organism may lead to asymptomatic or symptomatic infection. Additionally, early-life infections by this protozoan have been associated with impaired growth and cognitive function in poor resource settings. The Global Enteric Multicenter Study (GEMS) in Mozambique demonstrated that G. duodenalis was more frequent among controls than in diarrhoeal cases (≥3 loosing stools in the previous 24 hours). However, no molecular investigation was conducted to ascertain the molecular variability of the parasite. Therefore, we describe here the frequency and genetic diversity of G. duodenalis infections in children younger than five years of age with and without diarrhoea from the Manhiça district in southern Mozambique enrolled in the context of GEMS. Genomic DNA from 757 G. duodenalis-positive stool samples by immunoassay collected between 2007-2012, were reanalysed by multiplex PCR targeting the E1-HP and C1-P21 genes for the differentiation of assemblages A and B. Overall, 47% (353) of the samples were successfully amplified in at least one locus. Assemblage B accounted for 90% (319/353) of all positives, followed by assemblage A (8%, 29/353) and mixed A+B infections (1%, 5/353). No association between the presence of a given assemblage and the occurrence of diarrhoea could be demonstrated. A total of 351 samples were further analysed by a multi-locus sequence genotyping (MLSG) approach at the glutamate dehydrogenase (gdh), ß-giardin (bg) and triose phosphate isomerase (tpi) genes. Overall, 63% (222/351) of samples were genotyped and/or sub-genotyped in at least one of the three markers. Sequence analysis revealed the presence of assemblages A (10%; 23/222) and B (90%; 199/222) with high molecular diversity at the nucleotide level within the latter; no mixed infections were identified under the MLSG scheme. Assemblage A sequences were assigned to sub-assemblages AI (0.5%, 1/222), AII (7%, 15/222) or ambiguous AII/AIII (3%, 7/222). Within assemblage B, sequences were assigned to sub-assemblages BIII (13%, 28/222), BIV (14%, 31/222) and ambiguous BIII/BIV (59%, 132/222). BIII/BIV sequences accumulated the majority of the single nucleotide polymorphisms detected, particularly in the form of double peaks at chromatogram inspection. This study demonstrated that the occurrence of gastrointestinal illness (diarrhoea) was not associated to a given genotype of G. duodenalis in Mozambican children younger than five years of age. The assemblage B of the parasite was responsible for nine out of ten infections detected in this paediatric population. The extremely high genetic diversity observed within assemblage B isolates was compatible with an hyperendemic epidemiological scenario where infections and reinfections were common. The obtained molecular data may be indicative of high coinfection rates by different G. duodenalis assemblages/sub-assemblages and/or genetic recombination events, although the exact contribution of both mechanisms to the genetic diversity of the parasite remains unknown.

Identification of Uncommon Cryptosporidium viatorum (a Novel Subtype XVcA2G1c) and Cryptosporidium andersoni as Well as Common Giardia duodenalis Assemblages A and B in Humans in Myanmar

Cryptosporidium and Giardia are two important zoonotic intestinal protozoa responsible for diarrheal diseases in humans and animals worldwide. Feces from infected hosts, water and food contaminated by Cryptosporidium oocysts and Giardia cysts as well as predictors such as poverty have been involved in their transmission. Myanmar is one of the world’s most impoverished countries. To date, there are few epidemiological studies of Cryptosporidium and Giardia in humans. To understand the prevalence and genetic characterization of Cryptosporidium spp. and Giardia duodenalis in humans in Myanmar, a molecular epidemiological investigation of the two protozoa was conducted in four villages of Shan State. 172 fecal specimens were collected from Wa people (one each) and identified for the presence of Cryptosporidium spp. and G. duodenalis by sequence analysis of their respective small subunit ribosomal RNA genes. 1.74% of investigated people were infected with Cryptosporidium spp.—C. andersoni (n = 2) and C. viatorum (n = 1) while 11.05% infected with G. duodenalis—assemblages A (n = 6) and B (n = 13). By sequence analysis of 60-kDa glycoprotein gene, the C. viatorum isolate belonged to a novel subtype XVcA2G1c. DNA preparations positive for G. duodenalis were further subtyped. Five of them were amplified and sequenced successfully: different assemblage B sequences (n = 2) at the triosephosphate isomerase (tpi) locus; sub-assemblage AII sequence (n = 1) and identical assemblage B sequences (n = 2) at the β-giardin (bg) locus. This is the first molecular epidemiological study of Cryptosporidium spp. and G. duodenalis in humans in Myanmar at both genotype and subtype levels. Due to unclear transmission patterns and dynamics of Cryptosporidium spp. and G. duodenalis, future research effort should focus on molecular epidemiological investigations of the two parasites in humans and animals living in close contact in the investigated areas, even in whole Myanmar. These data will aid in making efficient control strategies to intervene with and prevent occurrence of both diseases.

[Giardiasis in a paediatric population of the province of castellon. Clinical details and impact]

INTRODUCTION

Giardiasis is a gastrointestinal parasitosis that has a great public health impact.

PATIENTS AND METHODS

Observational case study - in children under 15 years old in the Health Department 3 of the Province of Castellon (Spain), during the period 2012-2019.

RESULTS

A total of 190 cases of giardiasis were recorded in children under 15 years old. The number of cases varied significantly according to age group and month of the year. There were 115 males. The most frequent symptoms were diarrhea and abdominal pain. The most commonly used treatment was standard metronidazole (80% of patients). Co-infection occurred in 13% of cases, and comorbidities in 36%, especially atopic dermatitis and lactose/fructose intolerance. Relapses and/or re-infections were recorded in 8%. All cases were diagnosed by conventional parasitological stool tests and complementary immunochromatography (63 cases). Thirty-five samples were positive for Giardia duodenalis by qPCR. The direct health cost per patient was 117€. A disease notification bias was detected between 2012-2016 at a national scale.

CONCLUSIONS

Giardiasis is a current disease in Castellon, and should be considered as a probable diagnosis of gastrointestinal disease in a child under 4 years-old with diarrhea and abdominal pain. Its correct clinical and therapeutic management could reduce the possibility of worsening of the patient's condition and, additionally, would reduce the economic impact of the disease in terms of direct health costs.

First multilocus sequence typing (MLST) of Giardia duodenalis isolates from humans in Romania

Background

Giardia duodenalis is one of the most prevalent and highly diverse human parasites, encompassing a complex of eight genetically distinct assemblages, each further divided into sub-assemblages. While in recent years, G. duodenalis genotype distribution patterns in humans have been intensely studied, there is still very little information available on the diversity of Giardia genotypes and sub-assemblages infecting people in Romania. In the present study, we investigated the genetic diversity of Giardia duodenalis in asymptomatic patients from Romania.

Methods

Over an 11-month period, human feces from 7805 healthy adults were screened by microscopic analysis for G. duodenalis cysts during their obligatory periodic check-ups. DNA extraction was performed from microscopic-positive fecal samples, followed by multilocus sequence typing of four genetic loci of the ITS region, gdh, tpi and bg genes, followed by DNA sequencing and phylogenetic analysis. Statistical analysis was performed using EpiInfo 2000 software.

Results

The prevalence of giardiasis in the present study was 0.42% (33/7805). Twenty-three samples (76.67%) were successfully genotyped at each locus. The bg and tpi genes had the highest typing success rate (100%). The identified assemblages were assemblage A in 27 cases (subtypes A2 and A3), and B in 3 cases.

Conclusions

To our knowledge, the present study is the first report of multilocus sequence typing of G. duodenalis isolated from humans in Romania. The present results may shed light on G. duodenalis infection in humans at a regional and national level, thus increasing awareness against this parasitic infection.

Molecular Diversity of Giardia duodenalis, Cryptosporidium spp. and Blastocystis sp. in Asymptomatic School Children in Leganés, Madrid (Spain)

Enteric parasites including Giardia duodenalis, Cryptosporidium spp., and to a lesser extent, Blastocystis sp. and Enterocytozoon bieneusi, are major worldwide contributors to diarrhoeal disease. Assessing their molecular frequency and diversity is important to ascertain the sources of infection, transmission dynamics, and zoonotic potential. Little molecular information is available on the genotypes of these pathogens circulating in apparently healthy children. Here, we show that asymptomatic carriage of G. duodenalis (17.4%, 95% CI: 15.5‒19.4%), Blastocystis sp. (13.0%, 95% CI: 11.4‒14.8%), and Cryptosporidium spp. (0.9%, 95% CI: 0.5‒1.5%) is common in children (1‒16 years; n = 1512) from Madrid, Spain. Our genotyping data indicate that; (i) the observed frequency and diversity of parasite genetic variants are very similar to those previously identified in Spanish clinical samples, so that the genotype alone does not predict the clinical outcome of the infection, (ii) anthroponotic transmission accounts for a large proportion of the detected cases, highlighting that good personal hygiene practices are important to minimizing the risk of infection, (iii) Blastocystis ST4 may represent a subtype of the parasite with higher pathogenic potential, and (iv) Enterocytozoon bieneusi does not represent a public health concern in healthy children.