Preliminary Investigation of the Prevalence and Genotype Distribution of Giardia intestinalis in Dogs in Hungary

Retrospective Survey of Dog and Cat Endoparasites in Ireland: Antigen Detection

Endoparasites of dogs and cats, play an important role in both veterinary medicine and public health. Untreated and stray dogs and cats, in particular, play an important role in contaminating the environment with important zoonotic parasites. Thus, the aim of this study was to estimate the prevalence of intestinal parasites in stray dogs and cats using highly sensitive and specific copro-antigen tests. Archive faecal samples from previous surveys conducted between 2016−2019 from dogs (n = 789) and cats (n = 241) were included in this study. The IDEXX Fecal Dx™ antigen panel was used for the detection of Toxocara, hookworms, Trichuris and the SNAP™ Giardia antigen assay was used for the detection of Giardia infection. Giardia duodenalis was the most common parasite (26%, n = 205) detected in the dogs, followed by ascarids (17.6%, n = 139) and hookworms (5.3%, n = 42). Trichuris vulpis was only detected in 1 dog. Ascarids (23.2%, n = 56) was the most common parasite detected in the cats, followed by Giardia (12.9%, n = 31) and hookworms (n = 7, 2.9%). No whipworms were detected in cats. Overall, there was little difference in the positivity between sexes in both dogs and cats. However, in terms of age, adolescent dogs (<3 years) and kittens (<1 year) had the highest parasite prevalence overall, with G. duodenalis and ascarids being the most prevalent. This study shows a high prevalence of parasite infection in untreated and stray dogs and cats in the greater Dublin area in Ireland. Since they live in synanthropic conditions and can roam over vast distances they can contaminate public areas and pose a risk to both humans and owned pets that utilise these spaces. It is therefore important to raise public awareness and increase the knowledge on zoonotic parasites.

Infection rate and genetic diversity of Giardia duodenalis assemblage C in Iranian stray dogs, targeting the glutamate dehydrogenase gene

Background and Aim

Giardia duodenalis is one of the most common enteric protozoan parasites in vertebrates, such as humans, domestic and wild animals, causing giardiasis. To the best of our knowledge, little is known about the genetic diversity of G. duodenalis assemblages. This study aimed to identify genetic diversity of G. duodenalis assemblages in Iranian stray dogs.

Materials and Methods

A total of 450 fecal samples were collected from 2015 to 2016 from stray dogs of Northwest Iran. All specimens were observed microscopically following concentration and flotation techniques. Subsequently, DNA samples were extracted, amplified, and sequenced targeting the glutamate dehydrogenase gene.

Results

The overall prevalence of G. duodenalis in infected dogs was estimated at 1.6%, based on microscopic and molecular diagnoses. Sequencing and phylogenetic analyses indicated a high level of genetic diversity of assemblage C (haplotype diversity; 0.802).

Conclusion

The pairwise sequence distances between the identified isolates of assemblage C showed an intradiversity of 0.3%-1.3% and identity of 98.7%-100%. Current findings indicate that a significant genetic diversity of G. duodenalis assemblage C haplotypes is unequivocally circulates among stray dogs in Northwest Iran.

Prevalence and molecular characterization of Giardia duodenalis in dogs in Israel

Three hundred and two stool samples were collected from municipal shelters and owned dogs in different geographical locations in Israel from December 2016 to September 2017 and examined for Giardia and assemblage type by PCR targeting the 18S rRNA and β-giardin genes. Overall Giardia prevalence was 24.5 % (74/30). Giardia prevalence was 1.9-fold higher in dogs ≤ 6 months old compared to > 6 ≤ 12 months old and older dogs [25/61 (41 %), 18/73 (24.6 %) and 31/166 (18.7 %), respectively, (p = 0.001)], 2.3-fold higher in winter [32/90 (35.5 %)] compared to its prevalence during autumn [15/60 (25 %)], spring [10/62 (16.1 %)] and summer [17/89 (19.1 %), p = 0.003)], and 2.7-fold more frequent among diarrheic dogs [23/43 (53.4 %)] compared to those with formed stools [51/253 (20.1 %)], (p = 0.001)]. The Giardia sp. assemblages detected were C and D. Higher infection rates in young, diarrheic dogs, sampled during winter, and housed in municipal shelters, indicates the need for targeted preventive measures.

The Prevalence and Assemblages of Giardia Duodenalis in Dogs: A Systematic Review in Europe

Giardiasis is one of the most frequent causes of diarrhoeic diseases in the world. Giardia cysts are most commonly transferred via ingestion of contaminated water or food. On the basis of genetic characteristics Giardia duodenalis is classified in eight assemblages A—H. Zoonotic assemblages A and B are increasingly found in isolates from dogs which may constitute the reservoir of human giardiasis. This article presents a brief review of G. duodenalis assemblages detected in dogs that were documented in European countries.

Review of Cryptosporidium and Giardia in the eastern part of Europe, 2016

This paper reviews the current knowledge and understanding of Cryptosporidium spp. and Giardia spp. in humans, animals and the environment in 10 countries in the eastern part of Europe: Bosnia and Herzegovina, Croatia, Czech Republic, Estonia, Hungary, Latvia, Poland, Romania, Serbia and Slovenia. Methods: Published scientific papers and conference proceedings from the international and local literature, official national health service reports, national databases and doctoral theses in local languages were reviewed to provide an extensive overview on the epidemiology, diagnostics and research on these pathogens, as well as analyse knowledge gaps and areas for further research. Results: Cryptosporidium spp. and Giardia spp. were found to be common in eastern Europe, but the results from different countries are difficult to compare because of variations in reporting practices and detection methodologies used. Conclusion: Upgrading and making the diagnosis/detection procedures more uniform is recommended throughout the region. Public health authorities should actively work towards increasing reporting and standardising reporting practices as these prerequisites for the reported data to be valid and therefore necessary for appropriate control plans.

Gastrointestinal Parasites in Shelter Dogs: Occurrence, Pathology, Treatment and Risk to Shelter Workers

Dogs entering shelters can carry gastrointestinal parasites that may pose serious risks to other animals, shelter staff and visitors. Shelters provide an environment that could facilitate the spread of parasitic infections between animals. Nematodes and protozoa that transmit through ingestion or skin penetration are major enteric parasites of concern in shelter settings. Ancylostoma spp., Uncinaria stenocephala, Toxocara canis, Toxascaris leonina, Trichuris vulpis and Dipylidium caninum are the major helminths while Giardia, Cryptosporidium, Isospora spp. and Sarcocystis spp. are the most prevalent protozoan parasites in shelter dogs. The prevalence of gastrointestinal parasites in shelter dogs is typically higher than in owned dogs. A range of cost-effective drugs is available for prevention and control of helminths in shelters, notably fenbendazole, pyrantel, oxantel, and praziquantel. Parasiticide options for protozoan parasites are often cost-prohibitive or limited by a lack of veterinary registration for use in dogs. Environmental control measures reliant upon hygiene and facility management are therefore a mainstay for control and prevention of protozoan parasites in shelters. This philosophy should also extend to helminth control, as integrated parasite control strategies can allow anthelmintics to be used more sparingly and judiciously. The purpose of this article is to comprehensively review the current knowledge on the prevalence of gastrointestinal parasites most commonly found in dogs in shelters, canvass recommended treatment programs in shelter dogs, and to explore the likelihood that parasiticide resistance might emerge in a shelter environment.

Prevalence and genotypes of Giardia lamblia from stray dogs and cats in Guangdong, China

Giardia lamblia is a worldwide zoonotic intestinal parasite that infects humans and a wide range of mammals including dogs and cats, causing giardiasis with diarrhea. To investigate the infection and distribution of G. lamblia genotypes from stray dogs and cats in Guangdong, China according to different districts, gender and ages, fecal samples were collected and examined by microscopy, and all isolates were genotyped by PCR amplification using beta-giardin (bg) and triose phosphate isomerase (tpi) genes as molecular markers. The results showed that the prevalence of dogs and cats was 10.8% (57/527) and 5.8% (6/104), respectively. Sixty-one samples were detected by microscopy and 63 were amplified and successfully sequenced by the PCR. Based on the phylogenetic analysis, 25 canine isolates (24 assemblages AI and 1 assemblage D) were genotyped by tpi gene and 57 canine isolates (26 assemblages AI, 18 assemblages C and 13 assemblages D) genotyped by bg gene; 6 feline isolates were identified as assemblage AI by tpi gene, and as 3 assemblages AI and 3 assemblages F by bg gene. The dominant genotypes were assemblage AI in younger dogs (assemblage C in adult dogs) and assemblage C in male dogs (assemblage AI in female dogs). Mixed genotype infections were found in different age and gender groups. The results indicated that G. lamblia from stray dogs and cats in Guangdong province had a zoonotic potential with assemblage AI as the prevalent genotype. The different risk factors (age and sex) may have an impact on the infection of different genotypes.

Development and evaluation of a protocol for control of Giardia duodenalis in a colony of group-housed dogs at a veterinary medical college

OBJECTIVE To develop and evaluate a protocol for control of Giardia duodenalis in naturally infected group-housed dogs at a veterinary medical college. DESIGN Prospective evaluation study. ANIMALS 34 dogs. PROCEDURES All dogs were tested for evidence of G duodenalis infection. Dogs were treated with fenbendazole on study days 1 through 10. On day 5, dogs were bathed and moved into clean, disinfected kennels in a different room to allow for disinfection and drying of their assigned kennels at 26.7°C (80°F) for 24 hours on day 6. After treatment, dogs were returned to their original housing; fecal samples were collected weekly from days 8 through 41 and then every 3 weeks until day 209. Samples were fixed in formalin and examined by direct immunofluorescence assay. Additionally, 1 pretreatment sample underwent PCR assay and DNA sequencing to determine the assemblage (genotype) of the organism. Normal handling routines for the dogs and their use in teaching activities were not changed. RESULTS Initially, all dogs in the colony shed G duodenalis cysts. During and immediately after treatment (days 8 and 13), no cysts were detected in any dogs. On day 20, 1 cyst was observed in the fecal sample from 1 dog; results for all subsequent fecal analyses were negative. The G duodenalis cysts collected from the pretreatment sample had an assemblage C genotype. CONCLUSIONS AND CLINICAL RELEVANCE The integrated protocol was successful in controlling G duodenalis infection in this dog colony, despite exposure of dogs to a variety of environments and frequent handling by multiple individuals. Sequence analysis identified an assemblage typically found in dogs but not in people, indicating that zoonotic transmission would be unlikely.

Multilocus sequence typing of canine Giardia duodenalis from South Eastern European countries

Giardia duodenalis is a worldwide occurring protozoan that can infect various mammalian hosts. While living conditions are getting closer between pet animals and owners, there is discussion whether dogs may contribute to the transmission of these pathogens to humans. The present study was conducted in order to identify the Giardia assemblages in dogs from South Eastern Europe. For this purpose, 1645 faecal samples of household and shelter dogs from Albania, Bulgaria, Hungary, Macedonia, Romania and Serbia were tested for Giardia coproantigen by enzyme-linked immunosorbent assay (ELISA). A subset of 107 faecal samples demonstrating Giardia cysts by direct immunofluorescence assay (IFA) or microscopy (15-22 per country) plus 26 IFA-positive canine faecal samples from Croatia were used for DNA extraction and multilocus sequence typing with nested PCRs targeting five different gene loci: SSU rRNA, ITS1-5.8S-ITS2, beta giardin (bg), glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi). One third (33.7%) of the samples tested positive for Giardia antigen in the coproantigen ELISA. Shelter dogs were infected more frequently than household dogs (57.2 vs. 29.7%, p < 0.01). Amplification was obtained in 82.0, 12.8, 11.3, 1.5, and 31.6%, of the investigated samples at the SSU rRNA, bg, gdh and tpi loci and the ITS1-5.8S-ITS2 region, respectively. The dog-specific assemblages C and D were identified in 50 and 68 samples, respectively. The results demonstrate that G. duodenalis should be considered as a common parasite in dogs from South Eastern Europe. However, there was no evidence for zoonotic Giardia assemblages in the investigated canine subpopulation.

The prevalence of Giardia infection in dogs and cats, a systematic review and meta-analysis of prevalence studies from stool samples

Giardia has a wide range of host species and is a common cause of diarrhoeal disease in humans and animals. Companion animals are able to transmit a range of zoonotic diseases to their owners including giardiasis, but the size of this risk is not well known. The aim of this study was to analyse giardiasis prevalence rates in dogs and cats worldwide using a systematic search approach. Meta-analysis enabled to describe associations between Giardia prevalence and various confounding factors. Pooled prevalence rates were 15.2% (95% CI 13.8-16.7%) for dogs and 12% (95% CI 9.2-15.3%) for cats. However, there was very high heterogeneity between studies. Meta-regression showed that the diagnostic method used had a major impact on reported prevalence with studies using ELISA, IFA and PCR reporting prevalence rates between 2.6 and 3.7 times greater than studies using microscopy. Conditional negative binomial regression found that symptomatic animals had higher prevalence rates ratios (PRR) than asymptomatic animals 1.61 (95% CI 1.33-1.94) in dogs and 1.94 (95% CI 1.47-2.56) in cats. Giardia was much more prevalent in young animals. For cats >6 months, PRR=0.47 (0.42-0.53) and in dogs of the same age group PRR=0.36 (0.32-0.41). Additionally, dogs kept as pets were less likely to be positive (PRR=0.56 (0.41-0.77)) but any difference in cats was not significant. Faecal excretion of Giardia is common in dogs and slightly less so in cats. However, the exact rates depend on the diagnostic method used, the age and origin of the animal. What risk such endemic colonisation poses to human health is still unclear as it will depend not only on prevalence rates but also on what assemblages are excreted and how people interact with their pets.

Molecular characterization of Giardia duodenalis in dogs from Brazil

The intestinal protozoan parasite Giardia duodenalis (syn. Giardia intestinalis and Giardia lamblia) is a widespread enteric pathogen in human and domestic animals. This organism is one of the most common parasites in domestic dogs in Brazil. In this study, we determined the occurrence and genetic characterization of G. duodenalis isolated from dogs from south-central São Paulo state, Brazil. A total of 300 fecal samples were collected. Fecal specimens were screened for the presence of G. duodenalis using microscopy (zinc sulfate solution flotation technique) and polymerase chain reaction (PCR) targeting the small subunit ribosomal (SSU-rDNA) and glutamate dehydrogenase (GDH) genes. Genetic characterization was performed using restriction fragment length polymorphisms (RFLP) and sequencing analysis of the GDH gene. In addition, selected samples were further characterized by RFLP and sequencing of the β-giardin gene. The overall occurrence of G. duodenalis was 17.3% (52/300). The occurrence was higher in stray dogs (28%) than in household dogs (6.25%). Of the 36 PCR-positive samples that were selected for genotyping, only dog-specific genotype C (20 isolates), D (11 isolates) and mixed C + D (five isolates) isolates were detected in the study. This study provides current information on the infection rates of G. duodenalis genotypes in canine populations and describes for the first time the presence of mixed infections within host-specific C and D genotypes in dogs in Brazil. These genotypes were widespread and commonly found in domestic dogs living in urban and suburban environments of the studied area and confirmed the endemic status of Giardia in this region.

Prevalence, molecular typing and risk factor analysis for Giardia duodenalis infections in dogs in a central London rescue shelter

A cross-sectional survey to investigate canine infections with Giardia duodenalis was undertaken at a central London rescue shelter between October 2006 and March 2007. The objectives of the study were to (i) estimate the prevalence of infection in dogs admitted to a London dog shelter using a commercially available ELISA-based test kit; (ii) identify the relative importance of potential dog level risk factors for infection; and (iii) identify the occurrence of different G. duodenalis assemblages present in this population in order to identify presence of any potentially zoonotic assemblages. A faecal sample was collected from each dog entering the shelter within 1 day of arrival. Each sample was tested for the presence of parasite cyst wall protein using the Giardia SNAP test kit (Idexx Laboratories). Samples were graded for faecal consistency on a standard scale and data on age, breed, categorized breed group, sex and neutered status were collected for each dog. Associations between infection status and each dog level variable were investigated using univariable and multivariable logistic regression. Selected G. duodenalis-positive samples were genotyped using previously described primers targeting the 18S rDNA gene and the beta-giardin gene. Samples from a total of 878 dogs were collected and the true prevalence found to be 21.0% (95% CI 16.7-25.4%). In the present study, the odds of infection decreased with increasing age (adjusted odds ratio 0.66, 95% CI 0.54-0.80, p<0.0001) and was increased for Rottweilers (adjusted odds ratio 2.12, 95% CI 1.03-4.34, p=0.04). Of the 51 samples selected for genotyping, 41 samples yielded a good amplification at one or both of the targeted genes, demonstrating the occurrence of mainly dog-specific assemblages C and D. The potentially zoonotic assemblage A and a mixed template C/D were found in two individual dogs. The results of the present study illustrate the high prevalence of G. duodenalis in shelter dogs. Although predominantly infected with dog-specific assemblages, the identification of assemblage A suggests that appropriate precautions should be taken to minimize the risk of transmission to staff.

A survey of the prevalence and genotypes of Giardia duodenalis infecting household and sheltered dogs

Giardia duodenalis (syn. G. intestinalis, G. lamblia) is an intestinal protozoan parasite that infects humans and a wide range of mammals that includes dogs. Highly significant genetic heterogeneity has been found within this species, while only genotypes from assemblages A and B have zoonotic potential. Although Giardia infection in dogs has been reported worldwide, there is increasing molecular evidence that dogs may be infected with host-specific genotypes (C and D) as well as zoonotic ones (A and B). Therefore, dogs play a role as a potential source of Giardia infection impacting humans and other Canidae. Fecal samples from privately owned dogs and from dogs kept in two shelters in the west-central region of Poland were examined using a microscope and polymerase chain reaction. The total prevalence of Giardia in specimens was 1.9%. Deoxyribonucleic acid was extracted only from two out of the three Giardia-positive fecal samples. After amplification using the G7 and G759 beta-giardin primers, 753 bp amplicons were obtained, and both amplification products were sequenced. Sequence and phylogenetic analyses showed that both G. duodenalis isolates were dog-specific genotypes (C and D).

Giardia and other intestinal parasites in different dog populations in Northern Belgium

The objectives of this study were to obtain data on the prevalence of intestinal parasites in different dog populations in northern Belgium, to estimate the zoonotic risk associated with these infections and to identify potential risk factors. Between 2004 and 2007 a total of 1159 faecal samples were collected from 451 household dogs, 357 dogs from breeding kennels and 351 dogs with gastrointestinal disorders. The samples from dogs with gastrointestinal disorders were sent to the diagnostic Laboratory for Parasitology at Ghent University by veterinary practitioners. In household dogs the prevalence of intestinal parasites was relatively low. Giardia was the most commonly found parasite (9.3%, CI 5.5-13.1), followed by Toxocara canis (4.4%, CI 2.7-6.8). Much higher infection rates were observed in kennel dogs, especially for Giardia spp. (43.9%, CI 37.8-50.0); T. canis (26.3%, CI 21.8-31.2) and Cystoisospora spp. (26.3%, CI 21.8-31.2). Also in dogs with gastrointestinal problems, Giardia spp. (18.1%, CI 13.1-23.1), Cystoisospora spp. (8.8%, CI 6.1-12.3) and T. canis (7.4%, CI 4.9-10.7) were the most frequently detected parasites. In all dog populations pups were more frequently infected with Cystoisospora (P<0.0001 to P<0.05), Giardia (P<0.001 to P<0.05), and T. canis (P<0.0001 to P<0.001) than adult dogs, except for T. canis in household dogs, where this correlation was not significant. A significant association of anthelmintic treatment with T. canis infections was only observed within the household population. Household dogs with a higher number of treatments per year were more frequently infected with T. canis (P<0.05). There was a significant difference between the different breeding kennels for the occurrence of Cystoisospora, Giardia and T. canis (P<0.0001) and large kennels harboured relatively more infected animals than smaller breeding facilities (P<0.05). However, this was not significant for Giardia spp. Breed and gender did not affect the risk of an infection in any of the study populations. Toxocara and Giardia present a zoonotic risk, especially in household dogs, where the majority of Giardia positive samples (80%) belonged to the zoonotic assemblage A. In kennel dogs and clinically affected dogs the host-specific Giardia assemblages C and D were most prevalent (94% and 80%, respectively).

A study of the prevalence and genotypes of Giardia duodenalis infecting kennelled dogs

Giardia duodenalis is a protozoan parasite of animals that is zoonotic. Given the capacity of this organism to spread via the faecal-oral route, animals held in overcrowded and unhygienic conditions are at high risk of infection. Faecal samples from dogs in three kennels in Rome were examined by microscopy and PCR for G. duodenalis, and the prevalence data generated were correlated with variables such as kennel identity, age of dog, length of time the dog had been kennelled and clinical signs. The overall prevalence of the parasite in the faecal samples was 20.5% and was higher in samples from the largest kennel, which had the greatest turnover of dogs, and in faecal samples from younger animals. Giardia cysts were found more frequently in diarrhoeic animals but were also found in dogs with no clinical signs. Although the finding that the majority of isolates were dog-specific rather than zoonotic genotypes suggests that the zoonotic risk from this pathogen is less than previously thought, the higher prevalence of infection in younger dogs may pose a specific public health issue as such animals are more frequently re-homed with families.