Determination of Giardia duodenalis assemblages and multi-locus genotypes in patients with sporadic giardiasis from England

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.

Genomic survey maps differences in the molecular complement of vesicle formation machinery between Giardia intestinalis assemblages

Giardia intestinalis is a globally important microbial pathogen with considerable public health, agricultural, and economic burden. Genome sequencing and comparative analyses have elucidated G. intestinalis to be a taxonomically diverse species consisting of at least eight different sub-types (assemblages A-H) that can infect a great variety of animal hosts, including humans. The best studied of these are assemblages A and B which have a broad host range and have zoonotic transmissibility towards humans where clinical Giardiasis can range from asymptomatic to diarrheal disease. Epidemiological surveys as well as previous molecular investigations have pointed towards critical genomic level differences within numerous molecular pathways and families of parasite virulence factors within assemblage A and B isolates. In this study, we explored the necessary machinery for the formation of vesicles and cargo transport in 89 Canadian isolates of assemblage A and B G. intestinalis. Considerable variability within the molecular complement of the endolysosomal ESCRT protein machinery, adaptor coat protein complexes, and ARF regulatory system have previously been reported. Here, we confirm inter-assemblage, but find no intra-assemblage variation within the trafficking systems examined. This variation includes losses of subunits belonging to the ESCRTIII as well as novel lineage specific duplications in components of the COPII machinery, ARF1, and ARFGEF families (BIG and CYTH). Since differences in disease manifestation between assemblages A and B have been controversially reported, our findings may well have clinical implications and even taxonomic, as the membrane trafficking system underpin parasite survival, pathogenesis, and propagation.

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.

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.

Gastrointestinal parasites in captive olive baboons in a UK safari park

From the safety inside vehicles, Knowsley Safari offers visitors a close-up encounter with captive olive baboons. As exiting vehicles may be contaminated with baboon stool, a comprehensive coprological inspection was conducted to address public health concerns. Baboon stools were obtained from vehicles, and sleeping areas, inclusive of video analysis of baboon–vehicle interactions. A purposely selected 4-day sampling period enabled comparative inspections of 2662 vehicles, with a total of 669 baboon stools examined (371 from vehicles and 298 from sleeping areas). As informed by our pilot study, front-line diagnostic methods were: QUIK-CHEK rapid diagnostic test (RDT) (Giardia and Cryptosporidium), Kato–Katz coproscopy (Trichuris) and charcoal culture (Strongyloides). Some 13.9% of vehicles were contaminated with baboon stool. Prevalence of giardiasis was 37.4% while cryptosporidiosis was <0.01%, however, an absence of faecal cysts by quality control coproscopy, alongside lower than the expected levels of Giardia-specific DNA, judged RDT results as misleading, grossly overestimating prevalence. Prevalence of trichuriasis was 48.0% and strongyloidiasis was 13.7%, a first report of Strongyloides fuelleborni in UK. We advise regular blanket administration(s) of anthelminthics to the colony, exploring pour-on formulations, thereafter, smaller-scale indicator surveys would be adequate.

A shotgun metagenomic analysis of the fecal microbiome in humans infected with Giardia duodenalis

BACKGROUND

The mechanisms underlying the clinical outcome disparity during human infection with Giardia duodenalis are still unclear. In recent years, evidence has pointed to the roles of host factors as well as parasite's genetic heterogeneity as major contributing factors in the development of symptomatic human giardiasis. However, it remains contested as to how only a small fraction of individuals infected with G. duodenalis develop clinical gastrointestinal manifestations, whereas the majority of infected individuals remain asymptomatic. Here, we demonstrate that diversity in the fecal microbiome correlates with the clinical outcome of human giardiasis.

METHODS

The genetic heterogeneity of G. duodenalis clinical isolates from human subjects with asymptomatic and symptomatic giardiasis was determined using a multilocus analysis approach. We also assessed the genetic proximity of G. duodenalis isolates by constructing phylogenetic trees using the maximum likelihood. Total genomic DNA (gDNA) from fecal specimens was utilized to construct DNA libraries, followed by performing paired-end sequencing using the HiSeq X platform. The Kraken2-generated, filtered FASTQ files were assigned to microbial metabolic pathways and functions using HUMAnN 3.04 and the UniRef90 diamond annotated full reference database (version 201901b). Results from HUMAnN for each sample were evaluated for differences among the biological groups using the Kruskal-Wallis non-parametric test with a post hoc Dunn test.

RESULTS

We found that a total of 8/11 (72.73%) human subjects were infected with assemblage A (sub-assemblage AII) of G. duodenalis, whereas 3/11 (27.27%) human subjects in the current study were infected with assemblage B of the parasite. We also found that the parasite's genetic diversity was not associated with the clinical outcome of the infection. Further phylogenetic analysis based on the tpi and gdh loci indicated that those clinical isolates belonging to assemblage A of G. duodenalis subjects clustered compactly together in a monophyletic clade despite being isolated from human subjects with asymptomatic and symptomatic human giardiasis. Using a metagenomic shotgun sequencing approach, we observed that infected individuals with asymptomatic and symptomatic giardiasis represented distinctive microbial diversity profiles, and that both were distinguishable from the profiles of healthy volunteers.

CONCLUSIONS

These findings identify a potential association between host microbiome disparity with the development of clinical disease during human giardiasis, and may provide insights into the mechanisms by which the parasite induces pathological changes in the gut. These observations may also lead to the development of novel selective therapeutic targets for preventing human enteric microbial infections.

Molecular Detection and Multilocus Genotyping of Giardia duodenalis in Pigs in Fujian Province, Southeastern China

Giardia duodenalis, an intestinal parasite, is widely distributed in humans and various animals, such as pigs, cattle and cats. The clinical symptoms of giardiasis are characterized as including abdominal pain, acute or chronic diarrhea, and bloating and weight loss in humans and animals, leading to public and veterinary health problems worldwide. However, the prevalence and genotypes of G. duodenalis in pigs in Fujian Province, southeastern China, have not been reported. In the present study, 725 fecal samples were collected from six cities (Fuqing, Putian, Nanping, Longyan, Sanming, Zhangzhou) in Fujian Province and analyzed for G. duodenalis prevalence and genotypes using nested PCR targeting the beta-giardin (bg), glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi) genes. The results shown that total occurrence rate of G. duodenalis was 26.9% (195/725) in pigs, with significant differences in the prevalence among different regions (χ2 = 86.508, p < 0.05) and groups (χ2 = 12.748, p < 0.05). 195, 11 and 6 samples were detected at the bg, tpi and gdh loci, respectively. Each one belonged to a subtype of assemblage E and was analyzed using sequences obtained in this study. Based on phylogenetic analyses of sequences from the three genetic loci, only one MLG E1 was found. The results indicated that pigs may present a potential zoonotic risk of spreading G. duodenalis infection from animals to humans in this area. The findings of the present study also provide basic data for the prevention and control of G. duodenalis infection in pigs and humans in China.

Multilocus sequence typing of Giardia duodenalis genotypes circulating in humans in a major metropolitan area

Giardia duodenalis is an intestinal protozoan parasite of humans and animal hosts and comprises eight microscopically indistinguishable molecularly-diverse lineages designated as assemblages A-H. Assemblages A and B are the primary sources of infections in humans and a wide range of mammals. Here, we identified assemblages, and inter-/intra-assemblage genetic diversity of human G. duodenalis isolates based on the multilocus sequence typing of the triosephosphate isomerase (tpi), β -giardin (bg), and glutamate dehydrogenase (gdh) loci. Multilocus sequence analysis of 62 microscopically-positive G. duodenalis fecal samples identified 26 (41.9%), 27 (43.5%), and nine (14.5%) isolates belonging to assemblages A, B, and discordant assemblages, respectively. The tpi locus assemblage-specific primers identified dual infections with A and B assemblages (45.2%). The sequence analysis of multiple alignments and phylogenetic analysis showed low genetic polymorphism in assemblage A isolates, classified as sub-assemblage AII at three loci, subtype A2 at tpi and gdh loci, and subtype A2 or A3 at bg locus. High genetic variations were found in assemblage B isolates with 14, 15, and 23 nucleotide patterns at tpi, bg, and gdh loci, respectively. Further concatenated sequence analysis revealed four multilocus genotypes (MLG) in 24 assemblages A isolates, two previously-identified (AII-1 and AII-5), with one novel multilocus genotype. However, the high genetic variations observed in assemblage B isolates among and within the three genetic loci prevented the definitive designation of specific MLGs for these isolates. Multilocus sequence typing may provide new insight into the genetic diversity of G. duodenalis isolates in Tehran, suggesting that humans are likely a potential source of G. duodenalis infection. Further host-specific experimental transmission studies are warranted to elucidate the modes of transmission within multiple host populations.

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.

Evaluation for associations amongst Giardia duodenalis assemblages and diarrhea in dogs

Giardia duodenalis is a species complex comprising at least eight assemblages. Most dogs harbor the host-adapted assemblages C and D and approximately 30 % harbor the zoonotic assemblages. Humans and dogs with giardiosis can exhibit a variety of clinical manifestations ranging from the absence of clinical signs to acute or chronic diarrhea. Human studies report conflicting results concerning associations between clinical signs and assemblage type. The objective of this study was to use results of molecular and phylogenetic analyses to evaluate associations between G. duodenalis assemblages and diarrhea in client-owned dogs from the United States. Fecal samples that were positive for Giardia cysts were classified as normal or diarrheal. Samples were analyzed by PCR assays of the beta-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes. Sequences of the three genes were analyzed by BLAST analysis and phylogenetic analysis was performed by Neighbor-Joining analysis. Two hundred and eighty-eight Giardia-positive fecal samples were evaluated by the three PCRs. One or more genes were amplified from 95 normal samples and 93 diarrheal samples, 27 samples were positive for one or more genes but could not be sequenced due to low quality DNA, and 73 samples tested negative. Ninety seven percent of the samples (182/188) in both the diarrheal and normal groups typed as dog-specific assemblages (D or C) by at least one gene. Phylogenetic analysis of the three genes placed the isolates from assemblages A, B, C and D separated from each other with strong bootstrap support. Diarrhea was not associated with the Giardia assemblage or other parasitic co-infection in this sample set. Other factors, such as the role of gut microbiota in giardiosis should be considered in future studies.

Giardia duodenalis Virulence - "To Be, or Not To Be"

Purpose of review

Here, we review recent progress made on the genetic characterization of Giardia duodenalis assemblages and their relationship with virulence. We also discuss the implications of virulence factors in the pathogenesis of giardiasis, and advances in the development of vaccines and drugs based on knowledge of virulence markers.

Recent findings

The use of transcriptomic and proteomic technologies as well as whole genome sequencing (WGS) from single cysts has allowed the assembly of the draft genome sequences for assemblages C and D of G. duodenalis. These findings, along with the published genomes for assemblages A, B, and E, have allowed comparative genomic investigations. In addition, the use of these methodologies for the characterization of the secretomes of trophozoite-epithelial cell interactions for assemblages A/B has led to the identification of virulence markers including energy metabolism enzymes, proteinases, high-cysteine membrane proteins (HCMPs), and variant surface proteins (VSPs). Recently, some drugs and vaccines, targeting virulence factors have been developed, offering possible alternatives to current treatment and prevention options against giardiasis.

Summary

Among the nine recognized species of Giardia, G. duodenalis stands out because of its broad spectrum of hosts and its socio-economic importance. This species comprises eight genetic assemblages (A to H), of which A and B are zoonotic, and the other assemblages have narrow host specificities. Assemblages A and B may be considered as the most virulent ones, but the existence of asymptomatic carriers and considerable genetic variability within and among these assemblages hampers the definition of common virulence factors. The attachment of Giardia trophozoites to epithelial cells and structural cytoskeleton components of the adhesive disk, such as giardins or tubulins, is proposed to play key roles, but toxins have not yet been precisely defined. However, recent transcriptomic and proteomic analyses of the secretomes of trophozoites representing assemblages A and B and interacting with particular epithelial cell lines have defined a series of virulence factors, including glycolytic (e.g., enolase) and arginolytic (e.g., arginine deiminase) enzymes, cysteine proteases (e.g., giardipain-1) and VSPs (e.g., VSP9B10A). Other factors, such as HCMPs and tenascins, have been consistently found to be excreted/secreted, but their role(s) in the pathogenesis of giardiasis has not yet been elucidated. Interestingly, recent investigations of single cysts representing assemblages C and D using advanced sequencing and informatic methods have suggested that the transcription/expression profiles of virulence factors vary both within and between assemblages, thus assemblage-specific molecules might allow adaptation to the microenvironment within the host. Importantly, some drugs active against cysteine-rich proteins of Giardia, including giardipain-1, VSPs and arginine deiminase, have been shown to be targeted by cysteine-modifying compounds as disulfiram, L-canavanin and allicin. On the other hand, VSPs are presently considered as key vaccine candidates because they induce protection against Giardia in rodents and dogs. Overall, this review reveals that much more work is needed to identify, characterize, and understand the roles of virulence factors in Giardia and to assess their validity as drug and vaccine targets. Clear, advanced omics and informatic tools should assist in this future endeavor, with a focus on targeting virulence factors that are common and/or unique to distinct assemblages to develop new and effective interventions against Giardia.

Zoonotic giardiasis: an update

Giardia duodenalis is a common intestinal parasite in various hosts, with the disease giardiasis being a zoonosis. The use of molecular typing tools has improved our understanding of the distribution and zoonotic potential of G. duodenalis genotypes in different animals. The present review summarizes recent data on the distribution of G. duodenalis genotypes in humans and animals in different areas. The dominance of G. duodenalis assemblages A and B in humans and common occurrence of host-adapted assemblages in most domesticated animals suggests that zoonotic giardiasis is probably less common than believed and could be attributed mainly to contact with or contamination from just a few species of animals such as nonhuman primates, equines, rabbits, guinea pigs, chinchillas, and beavers. Future studies should be directed to advanced genetic characterization of isolates from well-designed epidemiological investigations, especially comparative analyses of isolates from humans and animals living in the same household or community. This will likely lead to better understanding of zoonotic transmission of G. duodenalis in different environmental and socioeconomic settings.

First report of novel assemblages and mixed infections of Giardia duodenalis in human isolates from New Zealand

Giardia duodenalis (syn. G. intestinalis and G. lamblia) is a protozoan parasite that cause disease (giardiasis) in humans and other animals. The pathogen is classified into eight assemblages, further divided into sub-assemblages, based on genetic divergence and host specificities. There are two zoonotic subtypes known as assemblages A and B, whilst assemblages from C to H are mainly found in domesticated animals, rodents and marine mammals. Here, we report for the first time the presence of assemblage E and sub-assemblage AIII in human isolates from the South Island in New Zealand. We identified a > 99% nucleotide similarity of assemblage E and sub-assemblage AIII with sequences of the gdh gene available in GenBank from individual human samples collected in Dunedin and Christchurch, respectively. We also performed a deep sequencing approach to assess intra-host assemblage variation. The sample from Dunedin showed evidence of mixed assemblage E and zoonotic sub-assemblage BIV. The report of two novel assemblages and mixed infections provides insights into the genetic diversity, epidemiology and transmission dynamics of Giardia duodenalis in New Zealand.

Real-Time PCR for Molecular Detection of Zoonotic and Non-Zoonotic Giardia spp. in Wild Rodents

Giardiasis in humans is a gastrointestinal disease transmitted by the potentially zoonotic Giardia duodenalis genotypes (assemblages) A and B. Small wild rodents such as mice and voles are discussed as potential reservoirs for G. duodenalis but are predominantly populated by the two rodent species Giardia microti and Giardia muris. Currently, the detection of zoonotic and non-zoonotic Giardia species and genotypes in these animals relies on cumbersome PCR and sequencing approaches of genetic marker genes. This hampers the risk assessment of potential zoonotic Giardia transmissions by these animals. Here, we provide a workflow based on newly developed real-time PCR schemes targeting the small ribosomal RNA multi-copy gene locus to distinguish G. muris, G. microti and G. duodenalis infections. For the identification of potentially zoonotic G. duodenalis assemblage types A and B, an established protocol targeting the single-copy gene 4E1-HP was used. The assays were specific for the distinct Giardia species or genotypes and revealed an analytical sensitivity of approximately one or below genome equivalent for the multi-copy gene and of about 10 genome equivalents for the single-copy gene. Retesting a biobank of small rodent samples confirmed the specificity. It further identified the underlying Giardia species in four out of 11 samples that could not be typed before by PCR and sequencing. The newly developed workflow has the potential to facilitate the detection of potentially zoonotic and non-zoonotic Giardia species in wild rodents.

First report of the prevalence and genetic characterization of Giardia duodenalis and Cryptosporidium spp. in Yunling cattle in Yunnan Province, southwestern China

Yunling cattle is an unique cattle breed distributed in Yunnan Province, southwestern China. It is yet to know whether Yunling cattle are infected with Giardia duodenalis and Cryptosporidium spp.. The objectives of the present study were to investigate the prevalence and characterize the assemblages of G. duodenalis and species of Cryptosporidium spp. in Yunling cattle in Yunnan province. The overall prevalence of G. duodenalis and Cryptosporidium spp. were 10.49% (41/391) and 0.77% (3/391), respectively. The age was considered as the risk factor for Yunling cattle infection with G. duodenalis (χ² = 8.082, OR = 2.56, P = 0.004). Two assemblages of G. duodenalis, assemblage A (n = 1) and assemblage E (n = 40), were identified by amplification of the β-giardin (bg) and glutamate dehydrogenase (gdh) gene loci using the nested PCR methods. Furthermore, Cryptosporidium andersoni (n = 1) and Cryptosporidium ryanae (n = 2) were detected by nested PCR targeting the small subunit (SSU) rRNA gene. This is the first report of G. duodenalis and Cryptosporidium spp. in Yunling cattle in China, which provided baseline date for further studies of the prevalence, genetic identity, and public health potential of these parasites in Yunling cattle.

Symptomatic and Asymptomatic Protist Infections in Hospital Inpatients in Southwestern China

Cryptosporidium spp., Entamoeba histolytica, Giardia duodenalis, and Blastocystis sp. infections have been frequently reported as etiological agents for gastroenteritis, but also as common gut inhabitants in apparently healthy individuals. Between July 2016 and March 2017, stool samples (n = 507) were collected from randomly selected individuals (male/female ratio: 1.1, age range: 38–63 years) from two sentinel hospitals in Tengchong City Yunnan Province, China. Molecular (PCR and Sanger sequencing) methods were used to detect and genotype the investigated protist species. Carriage/infection rates were: Blastocystis sp. 9.5% (95% CI: 7.1–12.4%), G. duodenalis 2.2% (95% CI: 1.1–3.8%); and E. histolytica 2.0% (95% CI: 0.9–3.6%). Cryptosporidium spp. was not detected at all. Overall, 12.4% (95% CI: 9.7–15.6) of the participants harbored at least one enteric protist species. The most common coinfection was E. histolytica and Blastocystis sp. (1.0%; 95% CI: 0.3–2.2). Sequence analyses revealed that 90.9% (10/11) of the genotyped G. duodenalis isolates corresponded to the sub-assemblage AI. The remaining sequence (9.1%, 1/11) was identified as sub-assemblage BIV. Five different Blastocystis subtypes, including ST3 (43.7%, 21/48), ST1 (27.1%, 13/48), ST7 (18.8%, 9/48), ST4 (8.3%, 4/48), and ST2 (2.1%, 1/48) were identified. Statistical analyses confirmed that (i) the co-occurrence of protist infections was purely random, (ii) no associations were observed among the four protist species found, and (iii) neither their presence, individually or jointly, nor the patient’s age was predictors for developing clinical symptoms associated with these infections. Overall, these protist mono- or coinfections are asymptomatic and do not follow any pattern.

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.

Molecular characterization and zoonotic potential of Enterocytozoon bieneusi, Giardia duodenalis and Cryptosporidium sp. in farmed masked palm civets (Paguma larvata) in southern China

BACKGROUND

Masked palm civets are known to play an important role in the transmission of some zoonotic pathogens. However, the distribution and zoonotic potential of Enterocytozoon bieneusi, Giardia duodenalis and Cryptosporidium spp. in these animals remain unclear.

METHODS

A total of 889 fecal specimens were collected in this study from farmed masked palm civets in Hainan, Guangdong, Jiangxi and Chongqing, southern China, and analyzed for these pathogens by nested PCR and DNA sequencing.

RESULTS

Altogether, 474 (53.3%), 34 (3.8%) and 1 (0.1%) specimens were positive for E. bieneusi, G. duodenalis and Cryptosporidium sp., respectively. Sequence analysis revealed the presence of 11 novel E. bieneusi genotypes named as PL1-PL11 and two known genotypes Peru8 and J, with PL1 and PL2 accounting for 90% of E. bieneusi infections. Phylogenetically, PL4, PL5, PL9, PL10 and PL11 were clustered into Group 1, while PL1, PL2, PL3, PL6, PL7 and PL8 were clustered into Group 2. Assemblage B (n = 33) and concurrence of B and D (n = 1) were identified among G. duodenalis-positive animals. Further multilocus genotyping of assemblage B has revealed that all 13 multilocus genotypes in civets formed a cluster related to those from humans. The Cryptosporidium isolate from one civet was identified to be genetically related to the Cryptosporidium bamboo rat genotype II.

CONCLUSIONS

To the best of our knowledge, this first report of enteric protists in farmed masked palm civets suggests that these animals might be potential reservoirs of zoonotic E. bieneusi and G. duodenalis genotypes.

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.

Development of a Multilocus Sequence Typing Scheme for Giardia intestinalis

Giardia intestinalis is an intestinal protozoan most commonly found in humans. It has been grouped into 8 assemblages (A-H). Markers such as the glutamate dehydrogenase gene, triose phosphate isomerase and beta-giardin (β-giardin) have been widely used for genotyping. In addition, different genetic targets have been proposed as a valuable alternative to assess diversity and genetics of this microorganism. Thus, our objective was to evaluate new markers for the study of the diversity and intra-taxa genetic structure of G. intestinalis in silico and in DNA obtained from stool samples. We analysed nine constitutive genes in 80 complete genome sequences and in a group of 24 stool samples from Colombia. Allelic diversity was evaluated by locus and for the concatenated sequence of nine loci that could discriminate up to 53 alleles. Phylogenetic reconstructions allowed us to identify AI, AII and B assemblages. We found evidence of intra- and inter-assemblage recombination events. Population structure analysis showed genetic differentiation among the assemblages analysed.

Molecular prevalence and genotyping of Giardia duodenalis in cattle in Central Anatolia Region of Turkey

The molecular prevalence and genotypes of Giardia duodenalis in cattle were investigated. A total of 450 fecal samples were collected from cattle in three provinces of Central Anatolia from August 2017 to July 2019. Genomic DNA was extracted from the fecal samples and used in molecular analysis carried out by nested PCR analyses of the β-giardin (bg) gene of G. duodenalis. Positive samples were further analyzed by nested PCR at two gene loci (triosephosphate isomerase (tpi) and glutamate dehydrogenase (gdh)) for genotyping of G. duodenalis isolates. PCR analyses of the bg gene indicated that the overall prevalence of G. duodenalis was 30.2%. However, lower rates were determined with PCR analyses for gdh and tpi loci. The sequence analyses of the bg, gdh, and tpi genes revealed the presence of zoonotic assemblage A and livestock-specific assemblage E. Combined-sequence analyses revealed that assemblage E was the most common in the study area. Our study provides the first data on the wide prevalence of livestock-specific assemblages E in cattle in Turkey. The prevalence of assemblage A in cattle also reveals the importance of cattle for zoonotic transmission of giardiasis in Turkey.

Genotype Characteristics of Giardia duodenalis in Patients Using High Resolution Melting Analysis Technique in Khorramabad, Iran

BACKGROUND

We aimed at genotyping and evaluating the predominance of G. duodenalis assemblages isolated from patients referred to medical laboratories in Khorramabad, Iran from Nov 2015 to Sep 2016. Hence, the development of a cost-effective HRM approach to determine genotypes of G. duodenalis based on the triosephosphate isomerase (tpi) gene was examined and the genotyping results with and without diarrhea was compared.

METHODS

Seventy G. duodenalis positive fecal samples were collected. A microscopic confirmation for the presence of Giardia spp. was performed, cysts of 70 Giardia spp. positive specimens were concentrated using sucrose flotation technique and sucrose solution PCR amplification was performed on 69 of 70 (98.5%) samples, and High Resolution Melting (HRM) analysis was performed using a software.

RESULTS

The results showed two distinct genotypes (assemblages A and B) of G. duodenalis but infections with mixture of both assemblages were not detected. The genotypes of G. duodenalis showed that the sub assemblage AI, BIII and BIV were present in a proportion of 68.1%, 20.3% and 11.6% respectively in samples. Assemblage AI was significantly (P<0.05) more frequently found in patients with diarrhea.

CONCLUSION

The sub-assemblage AI, BIII, and BIV are more zoonotic potential. According to the comparison of the results of this study with the results of previous studies in this area and around of it, as well as the way people live and keep pets. This pattern established in Khorramabad city. HRM can be an ideal technique to detect and genotyping of G. duodenalis in clinical samples.

Epidemiological distribution of genotypes of Giardia duodenalis in humans in Spain

BACKGROUND

Although the distribution of Giardia duodenalis genotypes in humans has been increasingly reported in recent years, data on possible differences in pathogen transmission between age groups and virulence between genotypes are scarce. The purpose of this study is to investigate the genetic diversity of G. duodenalis in humans in Spain and compare the distribution of G. duodenalis assemblages A and B between children and adults and clinical presentations between the two genotypes.

METHODS

In the present study, 125 microscopy-positive fecal samples were collected from humans in Spain over a 7-year period. PCR and sequence analyses of the triosephosphate isomerase, β-giardin and glutamate dehydrogenase genes were used to identify the multilocus genotypes of G. duodenalis.

RESULTS

Sequence analysis of three genetic loci identified both G. duodenalis assemblages A (29) and B (66), with co-infections of the two in two patients. Among the sequences obtained in this study, four multilocus genotypes (MLGs) of the sub-assemblage AII were observed within assemblage A. In contrast, 19 MLGs were detected within assemblage B due to the high sequence diversity at each locus. One MLG, however, was found in 51.9% (27/52) of assemblage B samples. Children were more commonly infected by assemblage B (44/53 or 83%) than adults (22/42 or 52.4%; χ2 = 10.371, df = 1, P = 0.001). Asymptomatic infection was more common in patients with assemblage A (4/29 or 13.8%) than in those with assemblage B (1/66 or 1.5%; χ2 = 6.091, df = 1, P = 0.029), and the frequency of abdominal pain occurrence was higher in assemblage B patients (65/66 or 98.5%) than assemblage A patients (25/29 or 86.2%; χ2 = 6.091, df = 1, P = 0.029).

CONCLUSIONS

These results illustrate the existence of differences in genotype distribution between children and adults and clinical presentations between G. duodenalis genotypes. They are useful in understanding the transmission of G. duodenalis in humans in Spain.

Intestinal parasitic infections and associated factors in children of three rural schools in Colombia. A cross-sectional study

Rural children are one of the populations that are most vulnerable to gastrointestinal parasite infections. Such diseases decrease the quality of life and result in growth and cognitive delays in the long term. This cross-sectional study was conducted to determine the frequency of intestinal parasite infections among rural schoolchildren in the municipality of Apulo, Colombia. A total of 97 stool samples from children aged between 5 and 15 years were collected and examined via direct light microscopy. Microscopic examination was repeated with sediments obtained using a fecal parasite concentrator, and the Kato–Katz test was performed. Frequency of intestinal parasite infection was 100%. Endolimax nana (77.35%), Blastocystis sp. (71.1%), Giardia intestinalis (39.1%), Entamoeba coli (25.7%), and the Entamoeba histolytica/dispar/moshkovskii complex (9.2%) were the most prevalent protozoa. Trichuris trichiura was the most prevalent helminth (12.3%), followed by Enterobius vermicularis (6.15%) and Ascaris lumbricoides (5.1%). Among the analyzed associated factors, consumption of untreated water increased the risk of acquiring pathogenic intestinal parasites. Finally, because G. intestinalis was the most prevalent pathogenic protozoan, molecular analysis was conducted to establish genetic assemblages and subassemblages of Giardia through sequence-based genotyping of the glutamate dehydrogenase, triose phosphate isomerase, and beta-giardin genes. A total of 14 G. intestinalis-positive samples were genotyped, which revealed the presence of subassemblages AI (n = 1), AII (n = 7), BIII (n = 2), BIV (n = 2), and BIII/BIV (n = 1) as well as a mixed subassemblage AII + BIII (n = 1). Our results indicate that gastrointestinal parasite infections in the tested population were mainly caused by suboptimal water quality. Moreover, molecular typing of G. intestinalis suggested contamination of water by animal- and human-derived cysts.

Molecular Genotyping of Giardia duodenalis in Humans in the Andimeshk County, Southwestern Iran

INTRODUCTION

Giardia duodenalis, one of the most common intestinal protozoa, infects a wide range of vertebrates, including humans and animals.

MATERIALS AND METHODS

In this study, 84 Giardia duodenalis positive stool samples were collected from 3580 patients attending the Imam Ali Hospital and two public health centers in Andimeshk County, southwestern Iran. Stool samples were examined initially by microscopy, and then G. duodenalis was confirmed by SSU rRNA gene and genotypes were determined by amplification of the gdh and β-giardin genes.

RESULTS

The SSU rRNA, gdh, and β-giardin genes were successfully amplified in 89.3%, 58.3%, and 51.2% samples, respectively. Of the positive samples for gdh and β-giardin, 40 isolates were successfully sequenced. Twenty-three isolates belonged to assemblage A, sub-assemblage AII, and 17 belonged to assemblage B. Of the 24 successfully amplified asymptomatic cases, 12 belonged to assemblage A and 12 belonged to assemblage B.

CONCLUSION

The current study found that 64.3% of the patients were asymptomatic. From an epidemiological point of view, the high percentage of asymptomatic patients is important because of their role in the transmission of Giardia. The predominant assemblage was assemblage A, sub-assemblage AII. In general, therefore, it seems that most infections are probably transmitted by anthroponotic pathways in the region.

Parasitic infections of the gut in children

Parasitic infections of the gut have major implications for child health, but many questions remain unanswered. Protozoal parasites, especially cryptosporidiosis and giardiasis, cause diarrhoea and contribute to impaired growth, neurocognitive development and mortality. Entamoeba histolytica causes dysentery and may have more subtle effects on child growth. Helminth infections are mostly asymptomatic, and untargeted mass deworming has not been shown to be beneficial. However, children with heavy infections certainly benefit from antihelminthic treatment. Hepatosplenic schistosomiasis is a neglected problem on a massive scale, which causes portal hypertension and lifelong morbidity in individuals who get infected in childhood. Neurocysticercosis causes epilepsy and is a significant consequence of taeniasis solium, another neglected disease which is entirely preventable. Parasitic infections of the gut contribute to child health problems on a large scale. Fresh approaches are needed to prevention and treatment.

Giardiasis Pattern among Different Age Categories: Childhood Assemblage B Proclaim Endemicity

BACKGROUND

Giardiasis is one of the commonest intestinal parasitic diseases that affects wide range of age groups. We aimed to detect the pattern of Giardia intestinalis assemblages among symptomatic patients at the age of 2 up to 40 years.

METHODS

Stool samples were collected from 278 patients and examined microscopically and genetically for giardiasis. Giardia was diagnosed using wet mount examination and subjected to molecular assays targeting three genes, glutamate dehydrogenase (gdh) using semi-nested PCR (nPCR), β-giardin (bg) and triose phosphate isomerase (tpi) using nPCR. Amplified products were subjected to genotyping using PCR-restriction fragment length polymorphism (PCR-RFLP) targeting gdh and bg genes.

RESULTS

Among 48 samples positive by microscopy and by a minimum of one of the three used genes, genotyping was successful among 23 samples (47.9%). Assemblage B was more prevalent (16/23, 69.6%), than assemblage A (4/23, 17.4%) and 3 (13%) isolates were identified as assemblage B at gdh locus which later were identified as assemblage A at bg locus. Sub-assemblage AII (3/4, 75%) and sub-assemblage BIII (12/15, 66.7%) were predominate at gdh locus. Age groups was an estimated risk factor for infection with assemblage B with a peak (87.5%) during 6 to 12 years (P< 0.05), diarrhea and abdominal pain (OR (95%CI) = .654 (.094, .963); .201 (.048, 1.009), respectively) were significantly associated with assemblage B.

CONCLUSION

It is recommended to suspect infection with giardiasis assemblage B by physicians during late childhood presenting with diarrhea and abdominal pain.

Molecular characterisation and taxon assemblage typing of giardiasis in primary school children living close to the shoreline of Lake Albert, Uganda

As part of an epidemiological survey for gastrointestinal parasites in school children across five primary schools on the shoreline of Lake Albert, the prevalence of giardiasis was 87.0% (n = 254) as determined by real-time PCR analysis of faecal samples with a genus-specific Giardia 18S rDNA probe. Faecal samples were further characterised with taxon assemblage-specific triose phosphate isomerase (TPI) Taqman® probes and by sequence characterisation of the β-giardin gene. While less sensitive than the 18S rDNA assay, general prevalence by TPI probes was 52.4%, with prevalence by taxon assemblage of 8.3% (assemblage A), 35.8% (assemblage B) and 8.3% co-infection (A & B assemblages). While assemblage B was dominant across the sample, proportions of assemblages A and B, and co-infections thereof, varied by school and by age of child; mixed infections were particularly common at Runga school (OR = 6.9 [95% CI; 2.5, 19.3]) and in children aged 6 and under (OR = 2.7 [95% CI; 1.0, 7.3]). Infection with assemblage B was associated with underweight children (OR = 2.0 [95% CI; 1.0, 3.9]). The presence of each assemblage was also confirmed by sequence analysis of the β-giardin gene finding sub-assemblage AII and further genetic diversity within assemblage B. To better explore the local epidemiology of giardiasis and its impact on child health, additional sampling of school children with assemblage typing would be worthwhile.

Giardia duodenalis in the UK: current knowledge of risk factors and public health implications

Giardia duodenalis is a ubiquitous flagellated protozoan parasite known to cause giardiasis throughout the world. Potential transmission vehicles for this zoonotic parasite are both water and food sources. As such consumption of water contaminated by feces, or food sources washed in contaminated water containing parasite cysts, may result in outbreaks. This creates local public health risks which can potentially cause widespread infection and long-term post-infection sequelae. This paper provides an up-to-date overview of G. duodenalis assemblages, sub-assemblages, hosts and locations identified. It also summarizes knowledge of potential infection/transmission routes covering water, food, person-to-person infection and zoonotic transmission from livestock and companion animals. Public health implications focused within the UK, based on epidemiological data, are discussed and recommendations for essential Giardia developments are highlighted.

Detection of potentially human infectious assemblages of Giardia duodenalis in fecal samples from beef and dairy cattle in Scotland

This study aimed to determine the prevalence and assemblages of Giardia duodenalis present in Scottish beef and dairy cattle at different ages, to try to ascertain if cattle could play a role in the spread of zoonotic assemblages of Giardia. A total of 388 fecal samples (128 beef and 253 dairy, seven of unknown breed) were collected from 19 farms in Scotland. Samples were sub-divided by host age, 1, 2, 3, 4, 5 and 6, 7-24 and ⩾25 weeks. DNA was extracted and tested by PCR to detect G. duodenalis DNA. Of the 388 samples, 126 tested positive, giving an overall prevalence of 32.5%, with positive samples being observed in all age groups tested. The prevalence in dairy cattle was 44.7% (113/235), which was significantly higher (P &lt; 0.001) than the prevalence in beef cattle 10.1% (13/128). Sequence analysis demonstrated the presence of assemblage E (77.2%, sequence types E-S1-E-S5), assemblage B (18.2%) and assemblage A (sub-assemblages AI-AII) (4.6%). These data demonstrate that G. duodenalis is found routinely in both dairy and beef cattle throughout Scotland; the presence of assemblages A and B also indicates that cattle may play a role in the spread of potentially zoonotic assemblages of Giardia.

Multilocus genotyping of Giardia duodenalis infecting rabbits in Ogun State, Nigeria

Giardiasis is a cosmopolitan gastrointestinal protozoal parasite that infects humans and various animals worldwide. To assess the zoonotic transmission potential of Giardia, molecular characterization is required. We are unaware of any report on the genotypes of Giardia infecting rabbits in Nigeria. Molecular detection and genotyping of Giardia duodenalis were conducted in a herd of adult Chinchilla rabbits (Oryctolagus cuniculus) managed on the Teaching and Research farm of the Federal University of Agriculture, Abeokuta located in a southwestern state of Nigeria by analysis of the small-subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and beta-giardin (bg) genes. An overall prevalence of 72.3% (60/83) was recorded in the rabbits with no statistically significant (p > .05) influence of sex on the distribution of the infection in the herd. All the 19 isolates amplified at the four genetic loci were identified as G. duodenalis assemblage BIV by multiple alignment analysis of their consensus sequences. Novel nucleotide substitutions were identified in two isolates at the ssu rRNA locus. Phylogenetic analysis revealed that all ssu rRNA genotypes were closely related to G. duodenalis assemblage B of cattle and human origin. Findings of this study suggest that the rabbits harbour potentially zoonotic assemblage BIV that portends a high risk to students and staff of the University who are in regular contact with the animals.

Occurrence and molecular characterization of Giardia duodenalis cysts and Cryptosporidium oocysts in raw water samples from the Rímac River, Peru

Giardia and Cryptosporidium are potentially pathogenic protozoa which are ubiquitous in ambient surface water. The present study included 60 samples of surface water from three sampling sites from the Rímac River, Lima and Callao, Peru, to detect the occurrence of Giardia spp. and Cryptosporidium spp. and to perform molecular characterization of specimens found. Water samples were concentrated using the membrane filtration technique, and following elution, cysts and oocysts were visualized by direct immunofluorescence assay (IFA). For molecular characterization, tpi and bg gene fragments and 18S rRNA were amplified by nested PCR for Giardia and Cryptosporidium, respectively, followed by sequencing and phylogenetic analysis. Giardia cysts were found in 93.3% of the analyzed samples, whereas Cryptosporidium oocysts were detected in 15%. The positivity of the Giardia cysts was 86.6% (n = 26) in 2014, while Cryptosporidium oocysts were not detected. In 2015, both protozoa were found in raw water samples, with all 30 samples collected positive for Giardia cysts (100.0%) and 9 positive for Cryptosporidium oocysts (30.0%). Oocysts were detected in 20.0% of water samples from sites 1 (mean 5.25 oocysts/L) and 2 (mean 52.3 oocysts/L), while at site 3, oocysts were detected in 50.0% of raw water samples (mean 193.6 oocysts/L). The presence of Giardia duodenalis assemblage A was confirmed in several samples by the phylogenetic positioning of the bg and tpi genes, and the sub-assemblage AII was predominant (8/9). Sequencing for Cryptosporidium resulted in profiles compatible with Cryptosporidium hominis, Cryptosporidium meleagridis, and Cryptosporidium baileyi. This is the first time that the presence of G. duodenalis assemblage A/sub-assemblage AII and Cryptosporidium species has been reported in surface water samples in Peru. These Cryptosporidium species and the Giardia duodenalis assemblage are associated with human disease which highlights the potential risk to public health and the need to increase environmental monitoring measures to protect this water body.

The first multilocus genotype analysis of Giardia intestinalis in humans in the Czech Republic

To date, genotyping data on giardiasis have not been available in the Czech Republic. In this study, we characterized 47 human isolates of Giardia intestinalis from symptomatic as well as asymptomatic giardiasis cases. Genomic DNA from trophozoites was tested by PCR-sequence analysis at three loci (β-giardin, glutamate dehydrogenase and triose phosphate isomerase). Sequence analysis showed assemblages A and B in 41 (87.2%) and six (12.8%) isolates, respectively. Two of the 41 assemblage A samples were genotyped as sub-assemblage AI, and 39 were genotyped as sub-assemblage AII. Four previously identified multilocus genotypes (MLGs: AI-1, AII-1, AII-4 and AII-9) and six likely novel variations of MLGs were found. In agreement with previous studies, sequences from assemblage B isolates were characterized by a large genetic variability and by the presence of heterogeneous positions, which prevent the definition of MLGs. This study also investigated whether there was a relationship between the assemblage and clinical data (including drug resistance). However, due to the large number of genotypes and the relatively small number of samples, no significant associations with the clinical data were found.

Molecular epidemiology of Giardia duodenalis infection in humans in Southern Ethiopia: a triosephosphate isomerase gene-targeted analysis

Background

Giardia duodenalis is a species complex consisting of multiple genetically distinct assemblages. The species imposes a major public health crisis on developing countries. However, the molecular diversity, transmission dynamics and risk factors of the species in these countries are indeterminate. This study was conducted to determine the molecular epidemiology of G. duodenalis infection in asymptomatic individuals in Southern Ethiopia.

Methods

From March to June 2014, fresh stool samples were collected from 590 randomly selected individuals. Socio-demographic data were gathered using a pre-tested structured questionnaire. The genotyping was done using triosephosphate isomerase gene-based nested polymerase chain reaction and DNA sequencing. The genetic identity and relatedness of isolates were determined using the basic local alignment search tool and phylogenetic analysis. Risk factors associated with G. duodenalis infection were analysed using binary and multinomial logistic regression models.

Results

The results showed that 18.1% (92/509) of the study subjects were infected by G. duodenalis. Among the isolates, 35.9% (33/92) and 21.7% (20/92) were sub-typed into assemblages A and B, respectively, whereas 42.4% (39/92) showed mixed infections of A and B. Most of the assemblage A isolates (94%,31/33) were 100% identical to sequences registered in GenBank, of which the majority belonged to sub-assemblage AII. However, the high genetic variability and frequency of double peaks made sub-genotyping of assemblage B more problematic and only 20% (4/20) of the isolates matched 100% with the sequences. The risk factors of age (P = 0.032) and type of drinking water source (P = 0.003) both showed a significant association with the occurrence G. duodenalis infection.

Conclusions

This study established the endemicity of G. duodenalis in Southern Ethiopia. Infection with assemblage A was more frequent than with assemblage B, and the rate of infection was higher in children and in municipal/tap and open spring water consumers than the other groups. Sub-typing of assemblage B and determining the origin of double peaks were challenging. The present study confirms the need for further inclusive studies to be conducted focusing on sub-types of assemblage B and the origin of heterogeneity.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0397-4) contains supplementary material, which is available to authorized users.

Molecular epidemiologic tools for waterborne pathogens Cryptosporidium spp. and Giardia duodenalis

Molecular diagnostic tools have played an important role in improving our understanding of the transmission of Cryptosporidium spp. and Giardia duodenalis, which are two of the most important waterborne parasites in industrialized nations. Genotyping tools are frequently used in the identification of host-adapted Cryptosporidium species and G. duodenalis assemblages, allowing the assessment of infection sources in humans and public health potential of parasites found in animals and the environment. In contrast, subtyping tools are more often used in case linkages, advanced tracking of infections sources, and assessment of disease burdens attributable to anthroponotic and zoonotic transmission. More recently, multilocus typing tools have been developed for population genetic characterizations of transmission dynamics and delineation of mechanisms for the emergence of virulent subtypes. With the recent development in next generation sequencing techniques, whole genome sequencing and comparative genomic analysis are increasingly used in characterizing Cryptosporidium spp. and G. duodenalis. The use of these tools in epidemiologic studies has identified significant differences in the transmission of Cryptosporidium spp. in humans between developing countries and industrialized nations, especially the role of zoonotic transmission in human infection. Geographic differences are also present in the distribution of G. duodenalis assemblages A and B in humans. In contrast, there is little evidence for widespread zoonotic transmission of giardiasis in both developing and industrialized countries. Differences in virulence have been identified among Cryptosporidium species and subtypes, and possibly between G. duodenalis assemblages A and B, and genetic recombination has been identified as one mechanism for the emergence of virulent C. hominis subtypes. These recent advances are providing insight into the epidemiology of waterborne protozoan parasites in both developing and developed countries.

Prevalence of Giardia infection in households of Giardia cases and risk factors for household transmission

Background

Giardia is a leading but neglected cause of infectious gastroenteritis worldwide and is treatable. There is a substantial burden of undetected Giardia in the UK and for every one case of Giardia reported to national surveillance there are 14 cases in the community. We aimed to ascertain the prevalence of, and risk factors associated with secondary household Giardia infections to assess the burden of infection and inform control measures.

Methods

We identified all giardiasis cases notified in nine local authorities in Lancashire between June 2014 and June 2015, and invited their household contacts to submit faecal specimens for Giardia testing and complete a risk factor questionnaire. We estimated the proportion of households with additional Giardia infection. We compared household risk factors between households with and without additional Giardia using Fisher’s exact test. We used multivariable logistic regression to identify independent risk factors for additional Giardia infections.

Results

We identified additional Giardia infections in 30% (27/91) of included households. A total of 41 infections were found from 212 household members, of which 37 were asymptomatic. The majority of infections were assemblage B (57%) but there were also a high number of mixed infections (20%). Risk factors significantly associated with additional household infections were; having children under 5 years in the household (odds ratio 42; 95% confidence intervals 10–178) and the presence of gastrointestinal illness in the household before the onset of the index case (odds ratio 9; 95% confidence intervals 1.5–48).

Conclusions

Our finding of a high household prevalence of asymptomatic infection has raised the public health question of whether treatment of asymptomatic household contacts may be justified in preventing Giardia re-infection of the index case or in preventing secondary cases and household clusters. We recommend the communication of this risk in household contacts of Giardia and reinforcement of standard hygiene controls.

New multilocus genotypes of Giardia lamblia human isolates

Giardia lamblia is considered a species complex, whose members show little differences in their morphology, but have remarkable genetic variability. The aim of this study was to identify inter- and intra-assemblage genetic variation in G. lamblia among patients in Rio de Janeiro. The parasitological study was performed on faeces, and DNA was extracted from the samples which tested positive for G. lamblia. The genetic assemblages and subtypes were determined via multilocus sequence typing (MLST) using β-giardin, triose phosphate isomerase and glutamate dehydrogenase gene loci. Fourteen assemblage A samples were successfully genotyped at the three MLST loci (bg/tpi/gdh). Two previously identified multilocus genotypes were found (AII-1 and AII-4), and two novel multilocus genotypes are proposed (AII-8, profile A2/A2/A4; AII-9, profile A3/A2/A2). Sequence analysis showed that assemblage B isolates have a higher nucleotide variation than those from assemblage A. Novel assemblage B sequences are described and most (66.7%) have heterogeneous nucleotides, which prevent the definition of multilocus genotypes. This is the first time that MLST has been used to characterise G. lamblia isolates in human clinical samples from Rio de Janeiro. In addition, MLST has enabled the detection of novel subtypes in both assemblages and the description of two novel multilocus genotypes in assemblage A. This study provides new insights into the genetic diversity of assemblage A and shows that MLST should be used to characterise G. lamblia both in Brazil and globally.

First detection and genotyping of Giardia intestinalis in stool samples collected from children in Ghazni Province, eastern Afghanistan and evaluation of the PCR assay in formalin-fixed specimens

It is estimated that faecal-orally transmitted diseases are common in Afghanistan, as a consequence of poor hygienic standards of life and widespread contamination of water and food with both human and animal faeces. However, there is little information in the literature concerning infections caused by intestinal parasites in the Afghan population. In this study, we report the occurrence of Giardia intestinalis assemblages (A and B) in formalin-fixed stool samples collected from 245 Afghan schoolchildren living in Ghazni Province in eastern Afghanistan. Detection of the parasite’s DNA and genotyping was performed using real-time PCR, specific to the β-giardin gene of G. intestinalis. Positive results were recorded in 52 (21.2%) samples. Genotyping was successful in 39 faecal samples and showed the predominance of assemblage B of G. intestinalis in this population (15 assemblage A and 24 assemblage B). Co-infection with both genotypes A and B was detected in four samples. Additionally, we evaluated the effect of 10% buffered formalin fixative on the detection of G. intestinalis DNA using real-time PCR and nested PCR characterised by different lengths of PCR products (74 and 479 bp, respectively). The human faeces containing the Giardia cysts were tested for 16 weeks. Amplification of G. intestinalis DNA with real-time PCR was possible up to 6 weeks of preservation of stool sample in formalin, compared to only 2 weeks with nested PCR. This suggests that real-time PCR is a more suitable tool in cases where stool samples have to be kept in formalin for longer periods of time.

Abundance, zoonotic potential and risk factors of intestinal parasitism amongst dog and cat populations: The scenario of Crete, Greece

Background

The objectives of this study were to evaluate the prevalence and infection intensity of intestinal parasites in different dog and cat populations in Crete, Greece, estimate the zoonotic risk and identify risk factors.

Methods

Faecal samples from shelter, household and shepherd dogs and shelter and household cats were analyzed using sedimentation/flotation techniques. Giardia and Cryptosporidium were detected by a quantitative direct immunofluorescence assay (IFA). PCR and sequencing was performed to evaluate the zoonotic potential of Giardia and Cryptosporidium positive samples.

Results

Totals of 879 dog and 264 cat faecal samples were examined. In dogs, the overall prevalence was 25.2% (CI: 22.4–28.1) for Giardia spp.; 9.2% (CI: 7.3–11.1) for Ancylostoma/Uncinaria spp.; 7.6% (CI: 5.9–9.4) for Toxocara spp.; 5.9% (CI: 4.4–7.5) for Cryptosporidium spp.; 4.6% (CI: 3.2–5.9) for Cystoisospora spp.; 2.7% (CI: 1.7–3.8) for Toxascaris leonina; 1.7% (CI: 0.9–2.6) for Capillaria spp.; 0.8% (CI: 0.2–1.4) for taeniid eggs; 0.2% (CI: 0–0.5) for Dipylidium caninum; and 0.1% (CI: 0–0.3) for Strongyloides stercoralis. In cats, the prevalence was 20.5% (CI: 15.6–25.3) for Giardia spp.; 9.5% (CI: 5.9–13.0) for Cystoisospora spp.; 8.3% (CI: 5.0–11.7) for Toxocara spp.; 7.6% (CI: 4.4–10.8) for Ancylostoma/Uncinaria spp.; 6.8% (CI: 3.8–9.9) for Cryptosporidium spp.; 4.2% (CI: 1.8–6.6) for Capillaria spp.; 0.8% (CI: 0–1.8) for taeniid eggs; and 0.4% (CI: 0–1.1) for Hammondia/Toxoplasma. Concerning the risk factors evaluated, there was a negative association between age and Giardia infection and between age and T. leonina infection intensity for dogs. Sequencing results revealed the presence of mainly animal-specific G. duodenalis assemblages C and D in dogs and assemblages F, C and BIV-like in cats, with only a limited number of (co-)infections with assemblage A. As for Cryptosporidium, the dog-specific C. canis and the pig-specific C. scrofarum were detected in dogs and the cat-specific C. felis was detected in cats.

Conclusions

High levels of parasitism in both dogs and cats were recorded. Giardia was the most prevalent parasite in all dog and cat populations except for shepherd dogs. Genotyping results suggest a limited zoonotic risk of Giardia and Cryptosporidium infections from dogs and cats in Crete. Taeniid eggs were more prevalent in shepherd dogs suggesting access to carcasses and posing a threat for cystic echinococcosis transmission. Infection rates of Toxocara spp. in both dogs and cats show that companion animals could be a significant source of infection to humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-1989-8) contains supplementary material, which is available to authorized users.

The presence of Giardia intestinalis in donkeys, Equus asinus, in China

Background

Giardia intestinalis is one of the most important zoonotic enteric parasites. As no information regarding prevalence and genotype of G. intestinalis in donkeys (Equus asinus) in China is available, 181 faecal samples from 48 donkeys from Jilin Province, from 104 from Shandong Province and from 29 from Liaoning Province were examined between May and December 2015.

Findings

Twenty-eight (15.47%) out of 181 donkey samples were tested G. intestinalis-positive by nested amplification of the triosephosphate isomerase (tpi) gene. The prevalence in different regional groups varied from 10.42 to 18.27%. The prevalence in adult and young donkeys was 14.29 and 22.92%, respectively. Otherwise, the prevalence was 11.69% in summer and 18.27% in winter. However, no statistically significant differences were found in relation to region or age group. Sequence analysis of the tpi, glutamate dehydrogenase (gdh) and beta giardin (bg) loci identified 4, 1 and 3 subtypes of assemblage B, respectively. Moreover, four novel multilocus genotypes (MLGs novel-1 to novel-4) were identified in assemblage B.

Conclusions

This first report of G. intestinalis in donkeys in China indicates that further studies of nation-wide molecular epidemiology and geographical distribution of Giardia in donkeys are warranted. Effective strategies should be implemented to control G. intestinalis infection in donkeys, other animals and humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1936-0) contains supplementary material, which is available to authorized users.

Strong genetic structure revealed by multilocus patterns of variation in Giardia duodenalis isolates of patients from Galicia (NW-Iberian Peninsula)

We report a survey of genetic variation at three coding loci in Giardia duodenalis of assemblages A and B obtained from stool samples of patients from Santiago de Compostela (Galicia, NW-Iberian Peninsula). The mean pooled synonymous diversity for assemblage A was nearly five times lower than for assemblage B (0.77%±0.30% and 4.14%±1.65%, respectively). Synonymous variation in both assemblages was in mutation-drift equilibrium and an excess of low-frequency nonsynonymous variants suggested the action of purifying selection at the three loci. Differences between isolates contributed to 40% and 60% of total genetic variance in assemblages A and B, respectively, which revealed a significant genetic structure. These results, together with the lack of evidence for recombination, support that (i) Giardia assemblages A and B are in demographic equilibrium and behave as two genetically isolated populations, (ii) infections are initiated by a reduced number of individuals, which may be genetically diverse and even belong to different assemblages, and (iii) parasites reproduce clonally within the host. However, the observation of invariant loci in some isolates means that mechanisms for the homogenization of the genetic content of the two diploid nuclei in each individual must exist.

Prevalence of Giardia duodenalis assemblages and sub-assemblages in symptomatic patients from Damascus city and its suburbs

Giardia duodenalis is one of the most important human enteric parasites worldwide and is endemic throughout the world with a vast range of mammalian hosts. However, there is limited information on the prevalent genetic variability of G. duodenalis in Syria. This study aimed to evaluate the predominance of G. duodenalis assemblages/sub-assemblages causing humans infection in the city of Damascus and its suburbs. 40 symptomatic giardiasis patients were recruited in this study. Fecal samples were genotyped using PCR/RFLP assay targeting the β-giardin and glutamate dehydrogenase (gdh) genes. HaeIII, BspL1 and RsaI restriction enzymes were used to differentiate between G. duodenalis assemblages/sub-assemblages. Our data showed that 65% of isolates were of assemblage A; 45% belonged to sub-assemblage AII and 20% to sub-assemblage AI. Assemblage B was detected in 27.5% of isolates; 12.5% fit in sub-assemblage BIV, 5% fit in sub-assemblage BIII and 10.5% fit in Discordant genotype BIII/BIV. Mixed genotypes (AII+BIII and AI+BIV) were identified in 3 isolates (7.5%). Significant correlation was found between Giardia AII sub-assemblage and weight loss symptom (P-value=0.05) as well as between contact with domestic animals (cats, P-value=0.027). Moreover, a significant correlation was found between sub-assemblage AI and livestock breeding (P-value=0.000). In conclusion genotyping of human Giardia duodenalis isolates suggests anthroponotic transmission for the route of infection in Damascus and its suburbs. Further studies are needed to screen a wide geographic areas in Syria and to estimate the prevalence of G. duodenalis infection in our population.

Occurrence and multilocus genotyping of Giardia intestinalis assemblage C and D in farmed raccoon dogs, Nyctereutes procyonoides, in China

Background

Giardia intestinalis, the only causative agent of human giardiasis, can infect a wide range of animals. As no information concerning the prevalence and genotyping of G. intestinalis in raccoon dogs in China is available, examination of 305 faecal samples from raccoon dogs in Jilin Province (n = 110), Heilongjiang Province (n = 40), Liaoning Province (n = 72), Hebei Province (n = 54) and Shandong Province (n = 29) was conducted to estimate the prevalence of G. intestinalis in raccoon dogs in northern China and identify their genotypes using a genetic approach.

Findings

Of 305 faecal samples from farmed raccoon dogs, 22 (7.21 %) were detected G. intestinalis-positive by nested PCR amplification of the triosephosphate isomerase (tpi) gene. The prevalence of G. intestinalis was strongly related to the region and season of sampling. All 22 samples were analysed at the tpi, the glutamate dehydrogenase (gdh) and the beta giardin (bg) gene loci, showing 13, 3, 2 subtypes, respectively. The results also demonstrated that two raccoon dogs harboured mixed infections of assemblage C and assemblage D (or mixed C/D), whereas only assemblage C was detected in the remaining 20 samples. Moreover, five new multilocus genotypes, named as MLGs C1-C5, were observed in the assemblage C in the present study.

Conclusions

This is the first report of G. intestinalis infection in raccoon dogs in China. DNA sequence analysis of the tpi, gdh and bg gene indicated that 13, 3, 2 subtypes were found at these loci, respectively. Furthermore, this is also the first report of five new multilocus genotypes (MLGs C1-C5) in farmed raccoon dogs, which provides baseline data for further studies of the distribution of G. duodenalis in different hosts.

Giardiasis in NSW: Identification of Giardia duodenalis assemblages contributing to human and cattle cases, and an epidemiological assessment of sporadic human giardiasis

Two genetic assemblages (A and B) of the protozoan parasite species, Giardia duodenalis, infect humans, domestic animals and wildlife. In New South Wales, Australia, over 2000 sporadic human giardiasis cases are reported annually, but parasite sources and links between sporadic cases are unknown. This study describes G. duodenalis assemblages contributing to human and cattle cases in NSW, and examines demographic, spatial, and temporal distributions of NSW human infections and G. duodenalis assemblages. Genotyping by PCR-restriction fragment length polymorphism of the glutamate dehydrogenase (gdh) gene identified G. duodenalis assemblage B as the most common (86%) cause of infection among human cases (n=165). Approximately 37% of cattle DNA samples were PCR positive (18S rRNA, gdh), and G. duodenalis assemblages E (69%) or B (31%) were identified from these samples. Human assemblage A was more common among older age groups, and seasonality in the geographic dispersal of human assemblage A was observed. The results of this study indicate G. duodenalis assemblage B is highly prevalent among humans in NSW, and the potential for cross-species transmission exists between humans and cattle in this region. Spatio-temporal and demographic distributions of human assemblage A and B are highlighted, and risk factors associated with these dispersal patterns warrants further research.

Multilocus genotyping of Giardia duodenalis isolates from children in Oromia Special Zone, central Ethiopia

BACKGROUND

Giardia duodenalis is the etiologic agent of giardiasis in humans and other mammals worldwide. The burden of disease is high among children in developing countries where sanitation is inadequate. However, the epidemiology and genetic diversity of this parasite is poorly understood in Ethiopia. This study aimed to determine the prevalence and genetic diversity of G. duodenalis in asymptomatic children in Oromia Special Zone, central Ethiopia.

RESULTS

A total of 286 fresh fecal specimens were collected from children and screened using microscopy and PCR. The prevalence of Giardia duodenalis was 10.8 % (31/286) and 16.8 % (48/286) as detected by microscopy and nested PCR, respectively. The infection rate by the study area, sex and age group difference was not significant (P > 0.05). Genotyping results showed that 22.9 % (11/48) of the isolates belonged to assemblage A while 77.1 % (37/48) belonged to assemblage B. Although double peaks were observed at the chromatogram level, no mixed assemblage or sub-assemblage infections were demonstrated. Isolates of assemblage A mostly belonged to the sub-assemblage AII and showed similarity with previously described isolates. However, there was great genetic variability within assemblage B that showed heterogeneous nucleotide positions. Fifteen of them were new genotypes: 5 at the triose phosphate isomerase (tpi), 2 at the β-giardin (bg), and 8 at the glutamate dehydrogenase (gdh) genes.

CONCLUSIONS

Giardia duodenalis mainly assemblage B infection was predominant among the asymptomatic children in the study area. The high polymorphism found in isolates of assemblage B warrants a more defining tool to discriminate assemblage B at the sub-assemblage level. The findings of the present study indicate that there is a need to carry out national screening programs aiming to detect asymptomatic infections to minimize the reservoir of the disease.

Genotypes of Cryptosporidium spp., Enterocytozoon bieneusi and Giardia duodenalis in dogs and cats in Shanghai, China

Background

Controversies exist on the potential role of companion animals in the transmission of enteric pathogens in humans. This study was conducted to examine the genotype distribution of Cryptosporidium spp., Enterocytozoon bieneusi, and Giardia duodenalis in companion animals in Shanghai, China, and to assess their zoonotic potential.

Methods

Fecal specimens from 485 dogs and 160 cats were examined for the occurrence and genotype distribution of the three pathogens by PCR. PCR products were sequenced to determine the species and genotypes. The χ² test was used to compare differences in infection rates between living conditions or age groups.

Results

Cryptosporidium spp., E. bieneusi and G. duodenalis were found in 39 (8.0 %), 29 (6.0 %) and 127 (26.2 %) of dogs, and 6 (3.8 %), 9 (5.6 %) and 21 (13.1 %) of cats, respectively. Infection rates of the pathogens in dogs from pet shops and a clinic were higher than those in household dogs, and higher in cats from one animal shelter than from pet shops. No significant differences in infection rates were detected among age groups. Cryptosporidium canis and C. felis were the only Cryptosporidium species found in dogs and cats, respectively. Enterocytozoon bieneusi genotype PtEb IX was the dominant genotype in dogs, whereas Type IV and D were the most common ones in cats. Multi-locus sequence typing at the glutamate dehydrogenase, β-giardin, and triosephosphate isomerase loci revealed the presence of G. duodenalis assemblages A (n = 23), B (n = 1), C (n = 26), and D (n = 58) in dogs (only A in household dogs) and assemblages A (n = 2), B (n = 6), C (n = 2), D (n = 1), and F (n = 7) in cats. Co-infection was detected in 24 dogs and 5 cats, especially those living in crowded conditions.

Conclusions

Living condition is a major risk factor affecting the occurrence of enteric protists in companion animals in China, and although dogs and cats can be potential sources of human infections, the different distribution of pathogen species and genotypes between dogs and cats suggests that inter-species transmission of these pathogens is probably rare in the study area.