Prevalence and genetic characterization of Giardia spp. and Cryptosporidium spp. in dogs in Iqaluit, Nunavut, Canada

Giardia and Cryptosporidium in resident wildlife species in Arctic Alaska

Giardia and Cryptosporidium are zoonotic protozoan parasites that can infect humans and other taxa, including wildlife, often causing gastrointestinal illness. Both have been identified as One Health priorities in the Arctic, where climate change is expected to influence the distribution of many wildlife and zoonotic diseases, but little is known about their prevalence in local wildlife. To help fill information gaps, we collected fecal samples from four wildlife species that occur seasonally on the northern Alaska coastline or in nearshore marine waters-Arctic fox (Vulpes lagopus), polar bear (Ursus maritimus), Pacific walrus (Odobenus rosmarus divergens), and caribou (Rangifer tarandus)-and used immunofluorescence assays to screen for Giardia cysts and Cryptosporidium oocysts. We detected Giardia cysts in 18.3% and Cryptosporidium oocysts in 16.5% of Arctic foxes (n = 109), suggesting that foxes may be potentially important hosts in this region. We also detected Giardia cysts in a single polar bear (12.5%; n = 8), which to our knowledge represents the first such report for this species. Neither parasite was detected in walruses or caribou.

Cryptosporidium infection in young dogs from Germany

Cryptosporidium is an enteric protozoan parasite which is able to cause severe gastrointestinal disease and is distributed all over the world. Since information about the prevalence of cryptosporidiosis in German dogs is rare, the aim of this study was to examine the occurrence of Cryptosporidium spp. in dogs and the potential zoonotic risk emanating from these infected animals. In total, 349 fecal samples of 171 dogs were collected during the dogs’ first year of life. The samples were examined for Cryptosporidium spp. using PCR, targeting the small subunit ribosomal RNA gene (SSU rRNA). Further analysis of Cryptosporidium parvum and Cryptosporidium canis positive samples was accomplished using the 60 kDa glycoproteine gene (GP60). Overall, 10.0% (35/349) of the specimens were tested positive for Cryptosporidium. Cryptosporidium canis was found in 94.3% (33/35) of these samples and the zoonotic type C. pavum in 5.7% (2/35). Both C. parvum infections were subtyped as IIaA15G2R1. Sixteen of the C. canis positive samples were successfully amplified at the GP60 gene locus. These isolates were identified to belong to the subtype families XXd, XXe, or XXb; however, 2 samples could not be assigned to any of the described subtype families. Considering the close contact between pets and their owners, dogs may act as a potential source of infection for human cryptosporidiosis. The results of this study, in context with other studies from different countries, provide important further insights into the distribution of Cryptosporidium species in dogs and their zoonotic potential.

Multilocus genotyping analysis of 114 Giardia duodenalis isolates from different populations of domestic dogs in Japan

To determine the genotypes and zoonotic potentials of G. duodenalis isolates from different populations of domestic dogs in Japan, a total of 114 Giardia positive samples were examined using multilocus genotyping analysis at the 3 loci of glutamate dehydrogenase (gdh), beta-giardin (bg), and triose phosphate isomerase (tpi). Although the dog-adapted assemblages C and D were dominant, the zoonotic assemblage A was also demonstrated at a percentage of 23.7% (27/114). The results suggest that canine G. duodenalis isolates in Japan have the potential for zoonotic transmission

Development of HRM real-time PCR for assemblage characterization of Giardia lamblia

A total of 90 stool samples were collected from dogs, referred to a dog shelter and a veterinary clinic. In addition, 395 stool samples obtained from pet dog owners and shelter keepers, as well as individuals referred to a medical laboratory as controls, were collected in Shahryar district, Tehran, Iran. Stool samples were parasitologically examined and the positive G. lamblia isolates were tested with Nested-PCR/sequencing for the tpi, gdh, and bg genes, and HRM real-time PCR. Microscopical examination revealed 20 (22.2%) and 34 (8.6%) Giardia-positive samples from dogs and humans, respectively. Regarding HRM real-time PCR, the prevalence of assemblages A and B in humans was 55.8% and 14.7%, respectively. In addition, 14.7% of samples were mix assemblages. HRM real-time PCR detected most of microscopically-positive samples in comparison to PCR/sequencing in both humans and dogs. The high prevalence of assemblages A and B in dogs signified the importance of a same source for infection between dogs and humans.

Genotypes of Giardia duodenalis in Household Dogs and Cats from Poland

BACKGROUND

Giardia duodenalis is a widespread protozoan parasite affecting humans and many species of animals, including dogs and cats. Due to its zoonotic potential, it is important to know the frequency of this parasite in companion animals. The aim of this study was to determine current epidemiological status of G. duodenalis in household dogs and cats.

METHODS

In this study, 293 fecal samples from pet dogs and cats were collected from January 2017 to July 2019 and tested for G. duodenalis by PCR (using β-giardin gene). The animals were divided into groups depending on their age, breed and fecal consistency.

RESULTS

The examination allowed for detection of G. duodenalis in 6.0% of canine and 3.9% of feline fecal samples. The highest frequency was revealed in young (under one-year old) dogs. Sequencing confirmed the presence of assemblages C and D in dogs and A and F in cats.

CONCLUSION

The study showed current frequency of G. duodenalis in dogs and cats and also revealed the occurrence of host-specific assemblages as well as zoonotic assemblage A.

Clams and potential foodborne Toxoplasma gondii in Nunavut, Canada

The prevalence of Toxoplasma gondii exposure in Inuit living in Nunavut (20%) is twice that of the US (11%); however, routes of exposure for Inuit communities in North America are unclear. Exposure to T. gondii in humans has been linked with consumption of raw or undercooked shellfish that can accumulate environmentally resistant oocysts. Bivalve shellfish, such as clams, are an important, nutritious, affordable and accessible source of food in many Northern Communities. To date, presence of T. gondii in clams in Northern Canada has not been reported. In this study, we tested for T. gondii presence in clams (Mya truncata) that were harvested in Iqaluit, Nunavut over a 1-week period in September 2016. Of 390 clams, eight (2.1%) were confirmed to contain T. gondii DNA (≥99.7% identity), as determined using polymerase chain reaction (PCR) and sequence confirmation. Additionally, three clams (0.8%) were confirmed to contain Neospora caninum-like DNA (≥99.2% identity). While N. caninum is not known to be a zoonotic pathogen, its presence in shellfish indicates contamination of the nearshore with canid faeces, and the potential for marine mammal exposure through marine food webs. Notably, the PCR assay employed in this study does not discriminate between viable and non-viable parasites. These findings suggest a possible route for parasite exposure through shellfish in Iqaluit, Nunavut. Future research employing viability testing will further inform public health messaging on the infectious potential of T. gondii in shellfish.

Assessment of next generation amplicon sequencing of the beta-giardin gene for the detection of Giardia duodenalis assemblages and mixed infections

Giardia duodenalis is an enteric protozoan parasite commonly found in humans and many other animals around the world. The parasite is grouped into genetically related strains called assemblages which display differing degrees of host specificity. Although mixed assemblage infections have been documented the full extent of the occurrence and importance of mixed infections remains to be characterized as current sequencing technologies lack the sensitivity to readily detect mixed infections. Here we have developed a next generation amplicon sequencing (NGS) protocol and analysis pipeline for detecting Giardia assemblages using the beta-giardin gene. NGS was validated using 37 isolates that included Giardia muris and six assemblages (A-F) of Giardia duodenalis obtained from seven different hosts. NGS was compared to traditional PCR and direct Sanger sequencing for its ability to detect Giardia species, assemblages, and mixed assemblage infections. We demonstrate that NGS works as well as PCR and Sanger sequencing for assemblage detection as the same assemblage was observed in all samples by both methods. NGS has the further benefit of detecting mixed assemblage infections, low abundance assemblages, and intra-assemblage variation in samples which would have been missed using direct Sanger sequencing alone. NGS represents a powerful new tool for exploring Giardia infections not only in infected hosts but also in environmental specimens which may aide in understanding Giardia epidemiology.

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Developed a next generation sequencing (NGS) protocol to detect Giardia

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Comparison of NGS to Sanger sequencing for sensitivity and accuracy

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NGS improved detection of mixed assemblages and detects low abundance assemblages

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NGS allowed detection of intra-assemblage variabilities

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Mixed assemblages may be far more common than previously thought