Predominance of Giardia duodenalis Assemblage AII in Fresh Leafy Vegetables from a Market in Southern Brazil

Role of rodents in the zoonotic transmission of giardiasis

Four species of Giardia out of nine have been identified in rodents based on molecular data: G. muris, G. microti, G. cricetidarum, and G. duodenalis. A total of seven G. duodenalis assemblages (A, B, C, D, E, F, G) have been identified in rodents to date. The zoonotic assemblages A and B are responsible for 74.88% (480/641) of the total identified genotypes in rodents by statistic. For sub-assemblage A in humans, AII is responsible for 71.02% (1397/1967) of the identified sub-assemblages, followed by AI with 26.39% (519/1967) and AIII with 1.17% (23/1967), indicating a significantly greater zoonotic potential for G. duodenalis infections in humans originating from animals. For sub-assemblages of type A in rodents, AI was identified in 86.89% (53/61), and AII in 4.92% (3/61). For assemblage B, 60.84% (390/641) were identified in rodents as having zoonotic potential to humans. In environmental samples, the zoonotic assemblages A and B were responsible for 83.81% (533/636) in water samples, 86.96% (140/161) in fresh produce samples, and 100% (8/8) in soil samples. The same zoonotic potential assemblage A or B simultaneously identified in humans, rodents, and environment samples had potential zoonotic transmission between humans and animals via a synanthropic environment. The infections and zoonotic potential for G. duodenalis were higher in farmed rodents and pet rodents than that in zoo, lab, and wild rodents. In conclusion, the role of rodents in zoonotic transmission of giardiasis should be noticed. In addition to rodents, dogs, cats, wild animals, and livestock could be involved in the zoonotic transmission cycle. This study aims to explore the current situation of giardiasis in rodents and seeks to delineate the role of rodents in the zoonotic transmission of giardiasis from the One Health perspective.

Evaluation of two analytical methods of detection for intestinal parasites in curly lettuce sold in food stalls

Abstract This study aimed to investigate the occurrence of parasitic structures in curly lettuce (Lactuca sativa L.) sold in food stalls open markets in Cuiabá city, in the Brazilian state of Mato Grosso (MT). For this purpose, 50 samples were evaluated using spontaneous sedimentation and centrifugal flotation methods. These techniques showed positivity in 96% (48/50) and 78% (39/50) of the samples, respectively. The sedimentation method was statistically (p ≤ 0.05) more effective in detecting parasitic structures of the pathogens as Entamoeba histolytica, Ascaris spp., Strongyloides spp., Larvae and Hookworm eggs, when comparing both methods. However, these methods did not differ significantly for the detection of Giardia lamblia. Ascaris spp and Entamoeba coli occurred in 64% (32/50) and 46% (23/50) of the positive samples, respectively, with the highest percentages observed. The occurrence of Blastocystis spp., Fasciola spp., Dipylidium caninum and Ascaris lumbricoides revealed detection exclusively by the spontaneous sedimentation method, while Iodamoeba butschlii and Enterobius vermicularis were detected by centrifugal– flotation procedure. These results could reinforce the need to use methods based on sedimentation and the fluctuation of parasite structures in the analysis of lettuce. The presence of parasites in lettuce by fecal origin, with recognized pathogenicity, represents a risk to consumer health and demonstrates a deficit in good agricultural practices in the production, distribution and commercialization of lettuce.

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.

Prevalence of Cryptosporidium and Giardia in vegetables in Iran: a nineteen-years meta-analysis review

Cryptosporidium and Giardia are two major protozoa reported from vegetables and environment. The prevalence of these parasites supposes to be different regarding the climate zones. This review aimed to evaluate the prevalence of Cryptosporidium and Giardia in vegetables according to the major climate zones in Iran. The results showed pooled prevalence 7% (95% CI: 2%, 14%) and 4% (95% CI: 3%, 6%) for Cryptosporidium spp., and Giardia spp., respectively. The prevalence of Giardia spp. in mountain, desert and semi-desert, and Mediterranean regions was 4% (95% CI: 2%, 6%), 5% (95% CI: 3%, 8%) and 7% (95% CI: 1%, 18%), respectively. Cryptosporidium spp. was reported 8% (95% CI: 0%, 65%), 6% (95% CI: 0%, 18%) and 4% (95% CI: 0%, 77%) from mountain, desert and semi-desert, and Mediterranean climate zones, respectively. This review suggests the higher prevalence of Giardia and Cryptosporidium in Mediterranean and mountain regions, respectively.

Detection of human intestinal protozoan parasites in vegetables and fruits: a review

Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important nutrients and minerals, but are also common sources of some food-borne human pathogenic microorganisms. The contamination of raw vegetables and fruits with human pathogenic parasites are now a global public health threat, despite the health benefits of these foods in non-pharmacological prophylaxes against diseases. A large number of reports have documented the contamination of vegetables or fruits with human pathogenic microorganisms. In this paper, we reviewed the contamination and detection methods of human pathogenic intestinal protozoans that are frequently recovered from raw vegetables and fruits. The protozoan parasites include Cryptosporidium spp., Giardia duodenalis, Cyclospora cayetanensis, Entamoeba spp., Toxoplasma gondii, Balantioides coli, Blastocystis sp., Cystoisospora belli and Enterocytozoon bieneusi. The risk factors involved in the contamination of vegetables and fruits with parasites are also assessed.

Detection of Giardia spp. with formalin/ether concentration in Brassica oleracea (cabbage) and Lactuca sativa (lettuce)

Methods to detect protozoa are needed for food safety monitoring. We evaluated protocols to recover Giardia spp. cysts in Brassica oleracea (cabbage) and Lactuca sativa (lettuce) and then detection was performed by concentrating with formalin/ether solutions and microscopy or immunofluorescence or DNA amplification via PCR. To evaluate this methodology, G. duodenalis cysts were inoculated in triplicate (10 cysts) in 35-g samples of lettuce and cabbage. The method obtaining the highest percentage of recovery in cabbage was sulfamic acid solution plus stirring with stomacher (47.7% ± 7.5). For lettuce, the best method was glycine solution plus stirring with stomacher (46.6% ± 5.3). Inter-observer agreement was of 0.99. Giardia was detected by amplifying specific sequences for the DNA coding SSU rRNA. In 27 lettuce samples and 27 cabbage samples, obtained from supermarkets and street vendors, two lettuce samples (7.4%) and one cabbage sample (3.7%) were positive for Giardia via PCR assay and were sequenced, determining that they were two of assemblage B and one of lettuce to assemblage E. This method is proposed to detect Giardia in vegetables by PCR detection, enabling public health authorities to identify genotypes circulating in food, which will help to establish measures that reduce outbreaks of parasitic diseases associated with contaminated food.

Giardia: an under-reported foodborne parasite

Foodborne zoonotic pathogens are a serious public health issue and result in significant global economic losses. Despite their importance to public health, epidemiological data on foodborne diseases including giardiasis caused by the enteric parasite, Giardia duodenalis, are lacking. This parasite is estimated to cause ∼28.2 million cases of diarrhoea each year due to contamination of food, but very few foodborne outbreaks have been documented due to the limitations of current detection as well as surveillance methods. The current method for the recovery of Giardia cysts from food matrices using immunomagnetic separation requires further standardisation and cost reduction before it can be widely used. It also should incorporate downstream molecular procedures for genotyping, and traceback and viability analyses. Foodborne giardiasis can be potentially controlled through improvements in national disease surveillance systems and the establishment of Hazard Analysis and Critical Control Point interventions across the food chain. Studies are needed to assess the true prevalence and public health impact of foodborne giardiasis.

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.

Comparative study of effects of assemblages AII and BIV of Giardia duodenalis on mucosa and microbiota of the small intestine in mice

AIMS

Giardiasis is one of the major causes of diarrhea worldwide and its symptoms vary in intensity, which can be attributed to different parasite assemblages. The goal of the present study was to compare the effects of infection caused by assemblages AII and BIV ofGiardia duodenalis on the response of the small intestine, microbiota, and behavioral parameters in mice.

MAIN METHODS

Swiss mice were infected with assemblages AII and BIV of G. duodenalis for 15 days. Leucometry, pain, intestinal microbiota and histological parameters of the duodenum and jejunum were evaluated in the experimental groups.

KEY FINDINGS

Both assemblages modified the composition of the intestinal microbiota. Infection with assemblage AII promoted leukocytosis, reflected by increasing number of polymorphonuclear cells, intraepithelial lymphocytes and pain-related behavior, indicating that this was the more aggressive assemblage with regard to its effects on the intestinal mucosa and duodenum.

SIGNIFICANCE

The specific assemblage of the parasite is an important parameter that affects symptomatology in the host.