Molecular Characterization of Giardia lamblia: First Report of Assemblage B in Human Isolates from Rio de Janeiro (Brazil)

Molecular investigation of ready-to-eat salads for Giardia duodenalis and Cryptosporidium spp. in Portugal

Foodborne outbreaks are often associated with the consumption of salads. However, published studies on the detection of foodborne pathogens in ready-to-eat salads are scarce. The aim of this study was to detect Giardia duodenalis and Cryptosporidium DNA in ready-to-eat salads, by applying techniques of molecular biology to study the frequency of contamination in salads. A total of 100 packages of ready-to-eat salads containing assorted leafy green vegetables were randomly purchased from hypermarkets located in central regions of Portugal (Coimbra and Viseu). Nested-PCR and qPCR methods were used to detect G. duodenalis and Cryptosporidium DNA. Species and assemblages of the parasites were identified by sequence analysis and PCR. Eighteen of the 100 samples (18%) were positive for G. duodenalis and twelve were sequenced and identified as assemblage A. Cryptosporidium spp. were not detected in any salads. Overall, pre-harvest and post-harvest preventive measures may be need for G. duodenalis control throughout the food production industry, from the field to consumers.

Giardiasis in children and dogs, and the first report of assemblage E in dogs from northeastern Brazil

Diagnosis is crucial for controlling giardiasis. We determined the prevalence and genetically characterize isolates of Giardia duodenalis of children and dogs from rural communities in northeastern Brazil. G. duodenalis cysts were concentrated by centrifugal flotation/sedimentation. Molecular characterization was carried out using the loci ssu-rRNA, bg, tpi, and gdh. By parasitological techniques, Giardia spp. infection was detected in 72/192 children (37.5%; 95% CI: 30.6%-44.7%) and 24/139 dogs (17.3%; 95% CI: 11.4%-24.6%). By molecular analysis, infection was detected in 60/141 children (42.5%; 95% CI: 34.3%-51.2%) and 26/92 dogs (28.3%; 95% CI: 19.4%-38.6%). The total prevalence of giardiasis was 54.9% in children (106/193; 95% CI: 47.1%-61.6%) and 32.9% in dogs (47/143; 95% CI: 25.2%-41.2%). Zoonotic assemblages A and B of G. duodenalis were detected in children, and assemblage E of G. duodenalis was detected in one child and two dogs. Parallel use of parasitological and molecular techniques proved to be a more effective strategy for detecting giardiasis in children and dogs from endemic areas.

First report of Giardia duodenalis assemblage F in humans and dogs in southern Brazil

The present study aimed to molecularly characterize Giardia duodenalis from stool samples of humans, dogs, and cats. Molecular analyses were performed on 59 samples that tested positive for G. duodenalis on coproparasitological examinations. After extraction, the samples were first tested by nested polymerase chain reaction (n-PCR) analysis of the SSU-rRNA gene, and for the samples that were positive, the β-giardin, TPI, and GDH genes were analyzed. The amplicons obtained in the n-PCR of the β-giardin gene were subjected to PCR-restriction length polymorphism (RFLP) analysis and subsequent digestion with the enzyme HaeIII to differentiate the assemblages. Seven (11.8 %), 34 (57.7 %), and 18 (30.5 %) out of 59 samples were from humans, dogs, and cats, respectively. Nested-PCR results showed that 49.2 % (29/59) of samples were positive for the SSU-rRNA gene, with 42.9 % (3/7) of humans, 55.9 % (19/34) of dogs, and 38.9 % (7/18) of catsve. Of the other genes analyzed, β-giardin was amplified most frequently, in 34.5 % (10/29) of samples, followed by GDH in 27.6 % (8/29) of samples, and TPI in 10.3 % (3/29) of samples. Only one sample from a dog showed the amplification of all genes. PCR-RFLP analysis showed assemblage F in a human, dog, and cat samples; and assemblage C and D in dog samples. This is the first description of assemblage F in humans from Brazil and the first description of assemblage F in dogs. Further studies are needed to verify the frequency with which these infections occur, and provide information that will contribute to the molecular epidemiological understanding of giardiasis.

Genotypic and Epidemiologic Profiles of Giardia duodenalis in Four Brazilian Biogeographic Regions

Human infections with gut protozoan parasites are neglected and not targeted by specific control initiatives, leading to a knowledge gap concerning their regional diversity and epidemiology. The present study aims to explore Giardia duodenalis genetic diversity and assess the epidemiologic scenario of subclinical infections in different Brazilian biogeographic regions. Cross-sectional surveys (n = 1334 subjects) were conducted in four municipalities in order to obtain fecal samples and socioenvironmental data. Microscopy of non-diarrheal feces and nucleotide sequencing of a β-giardin gene fragment were performed. From a total of 51 samples that could be sequenced, 27 (52.9%) β-giardin sequences were characterized as assemblage A and 24 (47.1%) as assemblage B. In the Amazon, assemblage B was the most frequently detected, predominantly BIII, and with two novel sub-assemblages. Assemblage A predominated in the extra-Amazon region, with five novel sub-assemblages. Prevalence reached 17.8% (64/360) in the Amazon, 8.8% (48/544) in the Atlantic Forest, 7.4% (22/299) in Cerrado and 2.3% (3/131) in the Semiarid. People living in poverty and extreme poverty presented significantly higher positivity rates. In conclusion, subclinical giardiasis is endemic in Brazilian communities in different biogeographic regions, presenting high genetic diversity and a heterogeneous genotypic distribution.

Comparison of gdh polymerase chain reaction-restriction fragment length polymorphism and tpi assemblage-specific primers for characterization of Giardia intestinalis in children

Background:

Aim and objectives:

Materials and Methods:

Results:

Conclusions:

Prevalence of intestinal parasites with molecular detection and identification of Giardia duodenalis in fecal samples of mammals, birds and zookeepers at Beni-Suef Zoo, Egypt

The current study aimed to investigate the prevalence of intestinal parasites from various species of mammals and birds housed in a zoological garden in Beni-Suef province, Egypt. A total of 77 fecal samples were collected from various primates (16), carnivores (7) and herbivores (54). Meanwhile, 123 fecal samples were collected from two Ostrichs (Struthio camelus), five Numida meleagris (Numida meleagris), twoIndian Peafowls (Pavo cristatus), two Emu (Dromaius novaehollandiae) 101 Pigeons (Columba livia domestica) and 11 Swan Goose (Anser sygnoides). In addition, seven stool samples from zookeepers who had been in close contact with animals and birds were examined. Salt flotation and formol ether sedimentation techniques were applied for parasitological examination. Positive samples of Giardia cysts were preserved in alcohol and kept at 4 °C until DNA extraction. Parasitological findings revealed that 48.05% of zoo animals were infected with intestinal parasites; 11.69% were positive with helminths and 27.27% with protozoa, however 9.09% had mixed infection. It was found that 75%, 57.14% and 38.89% of primates, carnivores and herbivores respectively were infected with intestinal parasites. In Primates the most prevalent parasites were Giardia spp. (43.75%) then Entamoeba histolytica/dispar (12.5%), Entamoeba coli (12.5%) and Trichuris spp. (6.25%). For carnivores, Ancylostomatidae had the highest prevalence (42.86%) followed by Spirometra spp. (14.29%). Meanwhile, Eimeria spp. (20.37%) was the most prevalent parasite in herbivores, followed by Blantidium coli (7.41%) and Tricuris spp. (7.41%), then Toxocara spp. (3.70%). Furthermore, the prevalence of infection in zoo birds was 21.95%. The identified parasites were Eimeria spp., Giardia spp., Capillaria spp., Ascaridia spp., Isospora spp. and Sublura brumpti. Stool examination of zookeepers revealed the presence of G. doudenalis and E. histolytica/ dispar cysts. The gdh gene of G. duodenalis was successfully amplified from fecal samples of zoo mammalsand zookeepers. In conclusion, the application of preventive and control measures against the propagation of infectious intestinal parasites is essential to prevent the spread of these parasites among zoo animals or to humans.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-020-01341-2.

Occurrence of Giardia duodenalis in selected stations and tributary rivers of Laguna Lake, Philippines

Fecal pollution is a major contributor to the progressive degradation of Laguna Lake, the Philippines' largest inland lake used for aquaculture, recreation, and as a source of irrigation and domestic water. Consequently, intestinal parasites may be present in this body of water, posing risks to water safety and human health. This study was able to detect the protozoan parasite, Giardia duodenalis, in three Laguna Lake stations and seven tributary rivers in a 13-month monitoring period by PCR amplification of the small subunit ribosomal RNA (SSU rRNA) gene of Giardia cysts concentrated from water samples. The pathogen was present in 37.7% of tributary samples (n = 69) and 16.7% of lake samples (n = 36). Notable frequencies of detection were observed in four tributary rivers -Bagumbayan, Taguig (66.7%); Santa Rosa, Laguna (55.6%); San Cristobal, Cabuyao, Laguna (44.4%); and Biñan, Laguna (42.9%). All test SSU rRNA gene sequences were identified as human-infective genotypes of G. duodenalis predominated by Assemblage A (94.1%). Furthermore, analysis of the glutamate dehydrogenase (gdh) gene revealed the possible presence of mixed genotypes in at least two samples. These results support the pressing need to include protozoan pathogen monitoring in Laguna Lake and its tributaries to prevent Giardia infection in humans and animals. This study also recommends microbial source tracking to identify fecal pollution sources and aid in regulation of waste discharges into the lake and its tributaries.

Comparative analysis of routine parasitological methods for recovery of cysts, molecular detection, and genotyping of Giardia duodenalis

In order to improve the diagnosis of giardiasis, fecal samples (high/medium/low concentration of cysts) were processed by the parasitological methods used in the routine: Faust, Lutz e Ritchie modified (replacement of formaldehyde by distilled water). The cysts were quantified; the DNA was extracted and amplified by semi-nested PCR (GDH gene). Fifteen clinical samples were analyzed to validate the study by PCR-RFLP. The results showed that the parasite was only detected and genotyped correctly when samples from children with high, medium, and low parasitic load, belonging to genotype AII, were processed by the modified Ritchie method, different from what was observed for the other methods used in laboratory routine (Faust and Lutz). The modified Ritchie method proved to be more suitable, recovering a greater number of cysts from samples, regardless of parasitic load, which reduces the chance of false negative results and has epidemiological repercussions since individuals with low parasite load are usually asymptomatic and the main disseminators of this infection.

Occurrence of faecal endoparasites in reindeer (Rangifer tarandus) in two grazing areas in northern Norway

Background

Semi-domesticated reindeer represent an important livestock industry and livelihood for a proportion of the human population in northern Fennoscandia. Reindeer husbandry is considered an extensive animal husbandry, where the animals are kept mostly on natural pastures, although sometimes kept in fenced areas for shorter periods. These reindeer may harbour a variety of parasites that may affect animal health and production. The relatively limited close contact between herds and owners gives limited opportunities for diagnosis and treatment of diseases in general. Furthermore, the effects of subclinical parasitism in livestock are commonly expressed as a reduction in productivity rather than clinical disease and mortality. Thus, specific knowledge of endoparasites and parasitic infections in these herds is scarce. This study investigated the occurrence of various endoparasites in reindeer by analysis of a total of 114 faecal samples from winter-slaughtered reindeer from two different grazing areas in Troms and Finnmark, Norway.

Results

Using a McMaster method, a Baermann technique, and a direct immunofluorescent antibody test, the following parasites were identified in the faecal samples with the occurrence data given as percentages: Strongylid eggs (62%), Nematodirinae spp. eggs (24%), Capillaria sp. eggs (42%) and Moniezia spp. eggs (17%), Dictyocaulus spp. larvae (14%) protostrongylid larvae (40%), Eimera spp. oocysts (23%), and Giardia duodenalis cysts (5%). Cryptosporidium oocysts were not detected. Parasite eggs, oocysts, and cysts were quantified.

Molecular analysis revealed G. duodenalis sub-assemblage AI, a potentially zoonotic genotype not previously reported in reindeer from this region. Morphological analyses of Eimeria oocysts identified two species, Eimeria mayeri and Eimeria rangiferis, and molecular analyses of the cytochrome C oxidase I (coi) gene and 18 s rRNA (18SSU) gene of Eimeria confirmed the presence of Eimeria species that are specific to reindeer.

Conclusions

A high prevalence, but low burden, of endoparasites was detected in samples from these semi-domesticated reindeer. The samples were collected during winter, when adult gastrointestinal parasites usually produce only low numbers of transmission stages. Therefore, together with the low number of samples, detailed and definitive conclusions regarding parasite status of semi-domesticated reindeer are avoided. Nevertheless, these data provide a snapshot overview of parasite occurrence in a semi-domesticated animal group vulnerable to the various environmental changes to which they are exposed.

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

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

Epidemiology of Giardia duodenalis assemblages in Brazil: there is still a long way to go

Giardia duodenalis infection is distributed worldwide and can achieve prevalence around 60%, especially in developing countries. This protozoan is divided into eight assemblages, in which A and B have high zoonotic potential, whereas C to H are host-specific. This scenario is changing as molecular studies progress, highlighting that knowledge on host-specificity still has a long way to go. Understanding the players involved in transmission routes enables rational designs of control strategies. Considering the high prevalence of giardiasis, this review aims to gather together the data on available studies on the distribution of G. duodenalis assemblages in Brazil until September 2020.

Recirculation of Giardia lamblia Assemblage A After Metronidazole Treatment in an Area With Assemblages A, B, and E Sympatric Circulation

Giardia lamblia is an intestinal protozoan subdivided into eight assemblages, labeled alphabetically from A to H. Assemblages A, B, and E infect humans and can have a sympatric circulation. We investigated the assemblage recirculation in children living within a high prevalence area of Giardia infection. One hundred and ninety-four children were evaluated and 85 tested positive for Giardia by PCR. These infected individuals were recruited, treated with metronidazole and then reexamined for infections at 20 and 40 days after treatment that included PCR and the genotyping was performed by sequencing beta-giardin and glutamate dehydrogenase gene targets. Giardia assemblages A (n = 43), B (n = 21), E (n = 17), and A/E (n = 4) were identified in infected children. Assemblage A was found in all reoccurrences of infection, including four that had been infected by assemblages B and E. Since both persistence and reinfection could account for the results, the level of nucleotide homology was determined before and after treatment. Most suggested that reinfections were by the same strain, but four presented a distinct genotypic profile. The results suggest that the differences in the genotypic profiles were due to reinfections, which appear to occur with frequency in high Giardia burden areas and soon after the end of therapy. It is not yet possible to define whether the recurrent cases were related to parasite resistance. However, the evidence of rapid reinfections and ready availability of treatment raises the potential for creating resistant strains. This highlights the need to address how Giardia burden is maintained within high prevalence areas.

The Predominance of Giardia duodenalis AII sub-assemblage in young children from Salvador, Bahia, Brazil

Introduction.

Giardia duodenalis is an intestinal protozoan with a high prevalence in children of developing countries. Molecular studies revealed a great genetic diversity of G. duodenalis, with assemblages A and B found mainly in humans. Despite its importance, the information on the molecular epidemiology of human giardiasis is still limited in Brazil.

Objective.

To characterize G. duodenalis molecular isolates in children from Salvador, Bahia, Brazil.

Materials and methods.

Giardia duodenalis positive fecal samples were obtained from 71 children from two day care centers and 39 users of a clinical analysis laboratory. Samples were analyzed by PCR-RFLP of the glutamate dehydrogenase (gdh) and beta-giardin genes and by the sequencing of beta-giardin.

Results.

Of the 110 G. duodenalis samples, 80 (72.7%) amplified one or both target genes. Of these, 62 (77.5 %) were identified as assemblage A and 18 (22.5%) as assemblage B. The subassemblage AII was identified in 58.8% (n=47) of isolates followed by the sub-assemblage AI (18.8%, n=15), BIV (11.2%, n=9), and BIII (5.0%, n=4). The AII sub-assemblage was the most frequent in children of both day care centers whereas AI was found only in the group attended at the clinical laboratory. Sub-assemblage AII predominated in children under two years.

Conclusions.

The higher frequency of AII sub-assemblage suggests that anthroponotic transmission is more common in Salvador, but that zoonotic transmission pathways are also present and a change in susceptibility to different molecular patterns of Giardia may occur during child growth.

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.

Prevalence and genotypic characterization of Giardia duodenalis isolates from asymptomatic school-going children in Lusaka, Zambia

Giardia duodenalis is one of the most common causes of diarrhea in humans with about 250–300 million cases per year. It is considered to be a species complex comprising of eight genetic assemblages (A to H), with assemblages A and B being the major causes of human infections. In this study we carried out genotypic characterization of G. duodenalis isolates detected in asymptomatic school-going children aged 3–16 years. Between May and September 2017, a total of 329 fecal samples were collected from school-going children from Chawama compound of Lusaka City and were screened for Giardia by microscopic examination. All microscopically positive fecal samples were analyzed by semi-nested polymerase chain reaction (PCR) targeting the glutamate dehydrogenase (gdh) gene. Genotyping of amplified PCR products was conducted by restriction fragment length polymorphism (RFLP) and DNA sequence analysis. Microscopically, Giardia was found in 10% (33/329) of fecal samples. The PCR-RFLP analysis of the gdh gene revealed assemblages A and B in 27.3% (9/33) and 72.7% (24/33), respectively. Furthermore, analysis with restriction enzymes identified sub-assemblages AII (27.3%, 9/33), BIII (12.1%, 4/33), BIV (51.5%, 17/33) and mixed infections of BIII and BIV (9.1%, 3/33). Phylogenetic analysis showed the clustering of 27.6% (8/29) and 72.4% (21/29) of Zambian Giardia gdh gene sequences into assemblages A and B, respectively. This study has revealed the presence of both assemblage A and B and that spread of G. duodenalis in school-going children appears to be mostly through anthroponotic transmission. To our knowledge, this is the first report of genotypic characterization of G. duodenalis identified in Zambia.

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Giardia duodenalis infection observed in asymptomatic children

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First report of genotypes circulating in Zambia

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Presence of sub-assemblages AII, BIII and BIV

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Co-infection with sub-assemblages BIII and BIV reported

Occurrence and molecular characterization of Giardia duodenalis in child population from Colombia

Giardia duodenalis is one of the most prevalent human intestinal parasite, with children living in developing countries being particularly at risk of infection. The occurrence and molecular diversity of G. duodenalis was investigated in stools specimens from 307 individuals aged one to nineteen years in Colombia. Samples were collected in three educational establishments (n: 163) and two hospital laboratories (n: 144) from urban and rural areas. Feces were concentrated using a biphasic sedimentation method and wet mounts of the sediment were examined by light microscopy. G. duodenalis assemblages and sub-assemblages were determined on positive samples by PCR of the triose phosphate isomerase (tpi), β-giardin (bg) and small-subunit (ssu) rRNA genes. G. duodenalis infection was detected by microscopy in 23 individuals (7.5%). The protozoan was more prevalent among specimens collected in educational establishments (11.6%) than in those obtained from hospital laboratories (2.8%). Infection was most common in individuals from urban areas and children aged 1-5 years. No significant association between diarrhea and infection could be demonstrated. Twenty Giardia-positive samples were successfully allocated to assemblage B (n: 11), sub-assemblage AII (n: 7), and assemblage A (n: 2). Results indicate the potential for transmission of G. duodenalis infection in children attending educational establishments and individuals from urban areas, where transmission seems to be primarily anthroponotic.

Prevalence and multilocus genotypes of Giardia duodenalis infecting pigs in Ogun state, Nigeria

Giardia duodenalis is an intestinal flagellated protozoan parasite that is infectious to humans and a wide range of animals worldwide. While varying prevalence rates have been reported in pigs worldwide, there are currently no published reports on the genotypes of Giardia infecting pigs in any African country. The present study is on the prevalence and genotypes of G. duodenalis in 209 pigs raised on four farms in Ogun State Nigeria. Using an enzyme-linked immunosorbent assay (ELISA) kit, Giardia duodenalis coproantigens were detected on all farms and in 25.4% (53/209) of pigs sampled. However, there was no significant influence (p > 0.05) of age, sex and stool consistencies of the pigs on the distribution of the infection. Genotyping of Giardia duodenalis in all ELISA-positive samples, achieved by the amplification of the small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and beta giardin (bg) genes, identified 14 and 37 assemblage B and E isolates respectively while mixed infection by both assemblages was recorded in two isolates. Novel nucleotide substitutions were identified in four assemblage B isolates at the ssu rRNA locus. Genetic diversity was observed among the assemblage B isolates after multiple alignment analyses of the gdh, tpi and bg sequences whereby sub-assemblages BII (n = 2), BIII (n = 9) and BIV (n = 3) were identified. The assemblage B isolates from pigs in this study were phylogenetically related to isolates from humans, marmoset and cattle while the assemblage E isolates were related to isolates from sheep, goats and cattle. These findings suggest that pigs in southwest Nigeria predominantly harbour G. duodenalis isolates that could be infectious to other animal species and to a lesser extent, isolates that may be of zoonotic importance.

Prevalence of intestinal parasites, with emphasis on the molecular epidemiology of Giardia duodenalis and Blastocystis sp., in the Paranaguá Bay, Brazil: a community survey

Background

Intestinal protozoan parasites are major contributors to the global burden of gastrointestinal disease causing significant socioeconomic consequences. Children living in resource-poor settings with restricted access to water and sanitary services are particularly at risk of these infections.

Methods

A prospective, community-based, cross-sectional survey was conducted in Paraná (southern Brazil) between May 2015 and May 2016. A total of 766 stool samples were individually collected from volunteers (male/female ratio: 0.99; age range: 0–76 years) and used for investigating the presence of intestinal helminth and protozoan species by routine microscopic procedures including the Kato-Katz and modified Ritchie concentration methods and the Ziehl-Neelsen stain technique. Quantitative real-time PCR confirmed microscopy-positive samples for Giardia duodenalis and the assemblages and sub-assemblages determined by multilocus sequence-based genotyping of the glutamate dehydrogenase (gdh) and β-giardin (bg) genes of the parasite. Identification of Blastocystis subtypes was carried out by amplification and sequencing of a partial fragment of the small-subunit ribosomal RNA gene (SSU rDNA) of this heterokont microorganism.

Results

Overall, 46.1% (353/766) of the participants were infected/colonised by at least one intestinal parasite/commensal species. Protozoan and helminth species were detected in 42.7% and 10.1% of the surveyed population, respectively. Blastocystis sp. (28.2%), Endolimax nana (14.9%), and Giardia duodenalis (11.0%) were the most prevalent species found among protozoans and Ascaris lumbricoides (5.0%), Trichuris trichiura (4.6%) and hookworms (1.0%) among helminths. A total of 38 G. duodenalis-positive samples were genotyped at gdh and bg markers, revealing the presence of the sub-assemblages AII (47.4%), AII/AIII (2.6%), BIII (5.3%), BIV (26.3%) and BIII/BIV (13.1%). Two samples (5.3%) were only identified as assemblage B. AII was predominantly found in females aged 5–9 years and was associated with a higher likelihood of reporting gastrointestinal symptoms. A total of 102 Blastocystis-positive samples were successfully subtyped at the SSU rRNA gene revealing the presence of ST1 (36.3%), ST2 (15.7%), ST3 (41.2%), ST4 (2.9%), ST6 (1.0%) and ST8 (2.9%).

Conclusions

Data presented here indicate that enteric parasites still represent a pressing health concern in Paraná, Brazil, probably due to sub-optimal water, sanitation and hygiene conditions. A mostly anthroponotic origin is suspected for G. duodenalis and Blastocystis sp. infections.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3054-7) contains supplementary material, which is available to authorized users.

The presence of Giardia lamblia assemblage A in dogs suggests an anthropozoonotic cycle of the parasite in Rio de Janeiro, Brazil

BACKGROUND

Giardia lamblia is a zoonotic protozoan that is classified into 8 genotypes and is distributed worldwide. Assemblages A and B were found to infect dogs and humans, whereas assemblages C and D are dog host-specific. Our objective was to investigate the G. lamblia genotypes circulating in a canine population in Rio de Janeiro, RJ.

RESULTS

Sixty stool samples positive for G. lamblia from street dogs were characterized. Fragments of the conserved genes encoding beta-giardin (β-gia) and glutamate dehydrogenase (gdh) were used as targets. The sequences from beta-giardin and glutamate dehydrogenase genes obtained from all 60 dog samples were 100% similar to G. lamblia genotype A.

CONCLUSION

The detection of genotype A suggests that G. lamblia transmission in Rio de Janeiro has a predominantly anthropozoonotic cycle.

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.

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.

Associations of Giardia lamblia assemblages with HIV infections and symptomatology: HIV virus and assemblage B were they born to each other?

Giardia lamblia is an intestinal parasite that has an extensive genetic variation among isolates. This species is divided into eight different assemblages (A-H), but only assemblages A and B have been associated with human infections. Studies on the associations of G. lamblia assemblages and symptoms have been done but were inconclusive. The aim of this study was to correlate G. lamblia assemblages with symptoms in patients with and without HIV/AIDS and its association with the CD4T cell count. The cross-sectional survey was conducted among patients attending the Evandro Chagas National Institute of Infectious Diseases (INI/FIOCRUZ) in Rio de Janeiro from January 2011 to February 2015. Thirty-eight of 65 microscopically positive stool samples for G. lamblia were from HIV positive patients and 27 were from HIV negative patients. Of the HIV infected patients, 19 (55.9%) were genotyped as assemblage B of which 9 (47.4%) had a CD4Tcell count below 200cells/mm³. In addition, we found a greater number of samples belonging to assemblage B in symptomatic cases (11 of 19; 57.9%). Our data suggest that assemblage B is very likely to be found in HIV infected patients and probably the lower CD4T count gives advantages for assemblage B replication. Furthermore, assemblage B seems to be associated with symptomatology, particularly abdominal pain, asthenia, diarrhea, fever, headache and myalgia. This study provides information on G. lamblia assemblages and symptoms in patients with and without HIV/AIDS virus and their association with CD4Tcell counts.

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.