High Prevalence of Giardia duodenalis Assemblage B Infection and Association with Underweight in Rwandan Children

Numerous foodborne outbreaks of diarrheal illness associated with the consumption of produce contaminated with protozoan parasites have been reported in North America in recent years. The present study reports on the presence of Cyclospora, Cryptosporidium, and Giardia in precut salads and leafy greens purchased at retail in Ontario, Canada. A total of 544 retail samples were collected between April 2009 and March 2010 and included a variety of salad blends and individual leafy greens. Most of these products were grown in the United States, with some from Canada and Mexico. Parasites were eluted and concentrated before detection by PCR and immunofluorescence microscopy. DNA sequences were aligned with reference sequences in GenBank. Cyclospora spp. were identified by PCR–restriction fragment length polymorphism in nine (1.7%) samples and by DNA sequence analysis. Cryptosporidium spp. were identified in 32 (5.9%) samples; 29 were sequenced and aligned with the zoonotic species Cryptosporidium parvum. Giardia duodenalis was identified in 10 (1.8%) samples, and of the 9 samples successfully sequenced, 7 aligned with G. duodenalis assemblage B and 2 with assemblage A, both of which are also zoonotic. The presence of Cryptosporidium oocysts and Giardia cysts was confirmed in some of the PCR-positive samples using microscopy, while Cyclospora-like oocysts were observed in most of the Cyclospora PCR-positive samples. The relatively high prevalence of these parasites in packaged salads and leafy greens establishes a baseline for further studies and suggests a need for additional research with respect to the possible sources of contamination of these foods, the determination of parasite viability and virulence, and means to reduce foodborne transmission to humans.

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Molecular Characterization of Giardia duodenalis in Children and Adults Sampled in Algeria

Microorganisms ◽

10.3390/microorganisms9010054 ◽

2020 ◽

Vol 9 (1) ◽

pp. 54

Author(s):

Salem Belkessa ◽

Daniel Thomas-Lopez ◽

Karim Houali ◽

Farida Ghalmi ◽

Christen Rune Stensvold

Keyword(s):

Real Time ◽

Molecular Characterization ◽

Real Time Pcr ◽

Intestinal Parasites ◽

Giardia Duodenalis ◽

Specific Pcr ◽

Stool Samples ◽

Pcr Targeting ◽

Assemblage B

The molecular epidemiology of giardiasis in Africa remains unclear. A study was carried out across four hospitals in Algeria. A total of 119 fecal samples from 55 children, 37 adults, and 27 individuals of undetermined age, all scored positive for intestinal parasites by microscopy, and were screened by real-time PCR for Giardia. Molecular characterization of Giardia was performed by assemblage-specific PCR and PCR targeting the triose phosphate isomerase gene (tpi). Of the 119 samples, 80 (67%) were Giardia-positive by real-time PCR. For 48 moderately-highly real-time PCR-positive samples, tpi genotyping assigned 22 samples to Assemblage A and 26 to Assemblage B. Contrary to Assemblage A, Assemblage B exhibited substantial genetic diversity and allelic heterozygosity. Assemblage-specific PCR proved to be specific for discriminating Assemblage A or B but not as sensitive as tpi genotyping. We confirmed that real-time PCR is more sensitive than microscopy for detecting Giardia in stool samples and that robust amplification and sequencing of the tpi gene is feasible when moderate-to-strongly real-time PCR-positive samples are used. This study is one of the few performed in Africa providing genotyping data on Giardia infections in humans. Both assemblages A and B were commonly seen and not associated with specific sociodemographic data.

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

Parasitology ◽

10.1017/s0031182018001117 ◽

2018 ◽

Vol 146 (9) ◽

pp. 1123-1130 ◽

Cited By ~ 4

Author(s):

Paul M. Bartley ◽

Beeke K. Roehe ◽

Sarah Thomson ◽

Hannah J. Shaw ◽

Frederieke Peto ◽

...

Keyword(s):

Sequence Analysis ◽

Beef Cattle ◽

Dairy Cattle ◽

Age Groups ◽

Giardia Duodenalis ◽

Host Age ◽

Fecal Samples ◽

Different Ages ◽

Sequence Types ◽

Assemblage B

AbstractThis 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 < 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.

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The assemblage B of Giardia duodenalis is the most common assemblage in isolates from southeast of Iran

Asian Pacific Journal of Tropical Disease ◽

10.12980/apjtd.7.2017d7-186 ◽

2017 ◽

Vol 7 (12) ◽

pp. 715-718 ◽

Cited By ~ 1

Author(s):

Akram Rostaminia ◽

◽

Adel Ebrahimzadeh ◽

Mahnaz Shahrakipoor ◽

◽

...

Keyword(s):

Giardia Duodenalis ◽

Assemblage B

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Occurrence and multilocus genotyping of Giardia duodenalis in pets and zoo animals in Shanghai, China

The Journal of Infection in Developing Countries ◽

10.3855/jidc.8421 ◽

2017 ◽

Vol 11 (06) ◽

pp. 479-486 ◽

Cited By ~ 1

Author(s):

Hua Liu ◽

Yujuan Shen ◽

Aiqin Liu ◽

Jianhai Yin ◽

Zhongying Yuan ◽

...

Keyword(s):

Giardia Duodenalis ◽

Pcr Amplification ◽

Amino Acid Sequences ◽

Giardia Infection ◽

Multilocus Genotyping ◽

High Prevalence ◽

Amplification Rate ◽

Zoo Animals ◽

First Time

Introduction: High prevalence of Giardia infections occurs in humans and animals, partly because of the increasing numbers of pets. We determined the presence and genotypes of G. duodenalis in pets and zoo animals. Methodology: A total of 84 specimens were collected from dogs and cats from a pet hospital, and 54 specimens from a zoo, which included deer, tigers, yaks, and others. All the specimens were examined by microscopy and by polymerase chain reaction (PCR) amplification and subsequent sequencing of glutamate dehydrogenase (gdh), beta-giardin (bg), and triose phosphate isomerase (tpi) genes. Results: Giardia infection was confirmed in 5.95% and 15.48% of animals by microscopy and by PCR, respectively; the detection levels were 13.33% and 26.67% for pets, and 1.85% and 9.26% for zoo animals. Four assemblages were identified: assemblage C in dogs, cats, and a sheep; D in dogs, a wolf, a yak, and a leopard; E in a sheep; and F in a cat and a leopard. PCR gave the highest amplification rate at the gdh locus. Eight, five, and four sequences were novel at the gdh, bg, and tpi loci, respectively. Two tpi sequences of dog-derived assemblage C had 100% homology with amino acid sequences from human-derived isolates. Conclusions: The molecular characterization of G. duodenalis in pets and zoo animals in China is described. Assemblage D was identified in a yak and a leopard for the first time. Multilocus genotyping analysis identified the same tpi gene sequences of assemblage C in dogs and humans, indicating potential zoonotic transmission.

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Mixed Giardia duodenalis assemblage infections in children and adults in South India

Epidemiology and Infection ◽

10.1017/s0950268811002767 ◽

2012 ◽

Vol 140 (11) ◽

pp. 2023-2027 ◽

Cited By ~ 7

Author(s):

S. LAISHRAM ◽

A. KANNAN ◽

P. RAJENDRAN ◽

G. KANG ◽

S. S. R. AJJAMPUR

Keyword(s):

South India ◽

Triosephosphate Isomerase ◽

Fragment Length Polymorphism ◽

Gastrointestinal Symptoms ◽

Giardia Duodenalis ◽

Chain Reaction ◽

Pcr Rflp ◽

Polymerase Chain ◽

Restriction Fragment Length ◽

Assemblage B

SUMMARYThe assemblages of Giardia duodenalis in 25 children with and 25 children without diarrhoea and 24 adults with gastrointestinal symptoms in South India were determined. Polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) targeting the glutamate dehydrogenase (gdh), β-giardin and triosephosphate isomerase (tpi) genes was used. The tpi PCR was the most sensitive and detected G. duodenalis in all 74 microscopy-positive samples, while gdh and β-giardin PCR were positive in 62·2% and 56·8% of the samples. Assemblage B was predominant in both children and adults (82·4%) followed by assemblage AII (9·4%); assemblage AI was not detected. Infections with both assemblages A and B (detected by tpi PCR–RFLP) were seen exclusively in children and the mixed assemblage BIII and BIV (detected by gdh PCR–RFLP) was more common in children than adults (P=0·058).

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Identification of a novel assemblage G subgenotype and a zoonotic assemblage B in rodent isolates of Giardia duodenalis in the Canary Islands, Spain

Parasitology ◽

10.1017/s003118201300139x ◽

2013 ◽

Vol 141 (2) ◽

pp. 206-215 ◽

Cited By ~ 6

Author(s):

ÁNGELA FERNÁNDEZ-ÁLVAREZ ◽

AARÓN MARTÍN-ALONSO ◽

NÉSTOR ABREU-ACOSTA ◽

CARLOS FELIU ◽

JEAN-PIERRE HUGOT ◽

...

Keyword(s):

Canary Islands ◽

Giardia Duodenalis ◽

Genetic Distances ◽

Nucleotide Sequencing ◽

Wild Rodents ◽

La Palma ◽

Common Causes ◽

Stool Samples ◽

Assemblage B

SUMMARYThe flagellated parasite Giardia duodenalis is known as one of the most common causes of protozoal diarrhoea in both humans and animals worldwide. The aim of the present work was to perform the first study of G. duodenalis in rodents in the Canary Islands (Spain) and analyse the level of genetic variation and the potential zoonotic role of the isolates. Stool samples were collected from 284 wild rodents and Giardia cysts were detected by light microscopy. The overall prevalence of giardiasis was 25·4% and ranged from 19·4% in El Hierro to 34% in Gran Canaria. Positive samples were further characterized by PCR and nucleotide sequencing of the triose phosphate isomerase (TPI), β-giardin (BG) and glutamate dehydrogenase (GDH) genes. Our study revealed assemblage G as the most frequent genotype and identified two rodent-infecting G. duodenalis haplotypes of this assemblage, HI and HII. Phylogenetic analysis supported the monophyly of haplotype HI, which we suggest to be considered as a novel G. duodenalis sub-assemblage GII, due to the high genetic distances among this sub-genotype and assemblage G. Furthermore, G. duodenalis assemblage B was detected in an inhabited area in La Palma, a fact that may pose a potential risk of G. duodenalis transmission from rodents to humans.

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High prevalence of intestinal zoonotic parasites in dogs from Belgrade, Serbia — Short communication

Acta Veterinaria Hungarica ◽

10.1556/avet.56.2008.3.7 ◽

2008 ◽

Vol 56 (3) ◽

pp. 335-340 ◽

Cited By ~ 23

Author(s):

Aleksandra Nikolić ◽

Sanda Dimitrijević ◽

Sofija Katić-Radivojević ◽

Ivana Klun ◽

Branko Bobić ◽

...

Keyword(s):

Intestinal Parasites ◽

Giardia Duodenalis ◽

Toxocara Canis ◽

Stray Dogs ◽

Significant Difference ◽

High Prevalence ◽

Working Dogs ◽

Baseline Knowledge ◽

Zoonotic Parasites ◽

Military Working Dogs

To identify areas of risk for canine-related zoonoses in Serbia, the aim of this study was to provide baseline knowledge about intestinal parasites in 151 dogs (65 household pets, 75 stray and 11 military working dogs) from Belgrade. The following parasites, with their respective prevalences, were detected: Giardia duodenalis (14.6%), Ancylostomatidae (24.5%), Toxocara canis (30.5%), Trichuris vulpis (47.0%) and Taenia -type helminths (6.6%). Of all examined dogs, 75.5% (114/151) were found to harbour at least one parasite species. Of these, mixed infections with up to four species per dog occurred in 44.7% (51/114). Infections with all detected species were significantly higher (p < 0.05) in military working (100%) and stray dogs (93.3%) versus household pets (50.8%). Among all parasites, agents with zoonotic potential including Giardia , Ancylostomatidae and Toxocara were detected in 58.3% (88/151) of all examined dogs with a significant difference (p < 0.05) among the subgroups (100%, 62.7% and 46.2% for military working dogs, stray dogs and household pets, respectively). The high prevalence of zoonotic parasites registered in the dog population from a highly urban area in south-eastern Europe indicates a potential risk to human health. Thus, veterinarians should play an important role in helping to prevent or minimise zoonotic transmission.

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Hidden Diversity within Common Protozoan Parasites Revealed by a Novel Genomotyping Scheme

Applied and Environmental Microbiology ◽

10.1128/aem.02275-20 ◽

2021 ◽

Author(s):

Matthew H. Seabolt ◽

Konstantinos T. Konstantinidis ◽

Dawn M. Roellig

Keyword(s):

High Resolution ◽

Molecular Typing ◽

Giardia Duodenalis ◽

Molecular Techniques ◽

Microbial Pathogens ◽

Whole Genome ◽

Genome Sequences ◽

Phylogenetic Resolution ◽

Typing Methods ◽

Assemblage B

Giardia duodenalis (syn. G. lamblia, G. intestinalis) is the causative agent of giardiasis, one of the most common diarrheal infections in humans. Evolutionary relationships among G. duodenalis genotypes (or subtypes) of assemblage B, one of two genetic assemblages causing the majority of human infections, remain unclear due to poor phylogenetic resolution of current typing methods. Here, we devised a methodology to identify new markers for a streamlined multi-locus sequence typing (MLST) scheme based on comparisons of all core genes against the phylogeny of whole-genome sequences (WGS). Our analysis identified three markers with comparable resolution to WGS data. Using newly designed PCR primers for our novel MLST loci, we typed an additional 68 strains of assemblage B. Analyses of these strains and previously determined genome sequences showed that genomes of this assemblage can be assigned to 16 clonal complexes, each with unique gene content that is apparently tuned to differential virulence and ecology. Obtaining new genomes of Giardia spp. and other eukaryotic microbial pathogens remains challenging due to difficulties in culturing the parasites in the laboratory. Hence, the methods described here are expected to be widely applicable to other pathogens of interest and advance understanding of their ecology and evolution. IMPORTANCE Giardia duodenalis assemblage B is a major waterborne pathogen and the most commonly identified genotype causing human giardiasis worldwide. The lack of morphological characters for classification requires the use of molecular techniques for strain differentiation, however, the absence of scalable and affordable NGS-based typing methods has prevented meaningful advancements in high resolution molecular typing for further understanding of the evolution and epidemiology of Assemblage B. Prior studies have reported high sequence diversity but low phylogenetic resolution at standard loci in Assemblage B, highlighting the necessity of identifying new markers for accurate and robust molecular typing. Data from comparative analyses of available genomes in this study identified three loci that together form a novel high-resolution typing scheme with high concordance to whole-genome-based phylogenomics and which should aid in future public health endeavors related to this parasite. In addition, data from newly characterized strains suggest evidence of biogeographic and ecologic endemism.

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