Giardia in a selected population of dogs and cats in Germany – diagnostics, coinfections and assemblages

Outcome of parasitological examinations in dogs in Germany: a retrospective survey

Dog faecal samples examined from January 2019 to December 2019 were retrospectively analysed for frequency of endoparasites. The examinations were performed with several different methods: 29,219 samples were examined by flotation method and sodium acetate-acetic acid-formalin concentration (SAFC) technique, 1,330 samples by Baermann-Wetzel migration technique, 12,221 samples using a Giardia coproantigen enzyme-linked-immunosorbent assay (ELISA), 1,180 samples using a Cryptosporidium coproantigen ELISA, 1,671 samples by polymerase chain reaction (PCR) testing for Giardia duodenalis and 447 samples by PCR testing for Cryptosporidium spp.. A total of 7.1% of the samples were positive for parasites in the microscopical examination using the flotation method and SAFC technique. The parasites found included Cystoisospora spp. (2.8%), Giardia duodenalis (2.3%), Ancylostomatidae (1.8%), Toxocara canis (1.6%), Trichuris vulpis (0.7%), Toxascaris leonina (0.5%), Capillaria spp. (0.2%), Angiostrongylus vasorum (0.2%), Crenosoma vulpis (0.1%), Taeniidae (0.1%), Sarcocystis spp. (0.03%), Dipylidium caninum (0.01%), Diphyllobothrium latum (< 0.01%), Spirurida (< 0.01%) and Opisthorchiidae (< 0.01%). Using the Baermann-Wetzel migration technique, Angiostrongylus vasorum was found in 0.75% and Crenosoma vulpis in 0.3% of the samples. ELISAs for Giardia duodenalis and Cryptosporidium spp. revealed 13.9% and 1.0% positive faecal samples, and Giardia duodenalis and Cryptosporidium spp. PCRs 19.4% and 2.0%, respectively. Dogs in the first year of life were more frequently infected with parasites than older animals. In the microscopic examination using flotation method and SAFC technique, the significantly highest detection rates were found in dogs up to six months of age (p < 0.001).

The Influence of Giardia duodenalis on the Occurrence of Clinical Signs in Dogs

Giardia duodenalis infections are common in dogs and are mainly caused by assemblages C and D. The aim of this study was to investigate the correlation between the presence of Giardia duodenalis and different Giardia assemblages detected in symptomatic and asymptomatic dogs and the occurrence of certain clinical signs. All the dogs included (n = 82) were clinically examined, and fecal samples were examined for other parasites and Clostridium spp. Also, G. duodenalis assemblages were detected and the occurrence of certain clinical signs was assessed. A total of 42/82 (51.2%) dogs were symptomatic and had one or more gastrointestinal signs, and 40/82 (48.8%) dogs were asymptomatic. G. duodenalis was found in 25/82 (30.5%) dogs: assemblage C in 10/25 (40%) and assemblage D in 15/25 (60%). Only Cryptosporidium spp. showed a higher coinfection rate with G. duodenalis but that did not have an influence on clinical sign appearance. There was no correlation between the presence of different assemblages of G. duodenalis and the sex of the host or the duration and appearance of certain clinical signs, except the presence of mucus in feces, which was more frequent in dogs invaded with G. duodenalis assemblage C. Further research of other assemblages is needed.

[Feline and canine giardiosis: An Update]

Giardia duodenalis is a facultative pathogenic intestinal parasite. Giardiosis in dogs and cats may appear with or without clinical signs. Typical signs include diarrhea with or without vomiting. The prevalence in young animals is high and may amount to up to 50%. There are 8 different genotypes (A - H), which are called assemblages. Assemblages C and D are most common in dogs and assemblage F most frequent in cats. However, animals may also be infected with the zoonotically effective assemblages A and B or exhibit mixed infections. The immunofluorescence test (IFA), the enzyme-linked immunosorbent assay (ELISA) and fecal centrifugation using zinc sulphate solution are currently recommended as diagnostic methods. Polymerase chain reaction (PCR) may be used to determine the corresponding assemblage. Approved treatments for giardiosis include fenbendazole and metronidazole. In addition, undertaking specific hygiene measures is warranted. Only animals showing clinical signs or those living in the same household with high-risk patients (e. g. immunosuppressed humans) are recommended to receive medication. The aim of treatment is clinical improvement of the diseased dogs and cats. Frequently, complete elimination of Giardia is not attained.

Occurrence of Giardia duodenalis in Cats from Queretaro and the Risk to Public Health

Giardia is a protozoan that affects humans as well as a wide range of domestic species. It is distributed worldwide, and the highest frequency is seen in developing countries. Due to the potential for domestic cats to be carriers of this parasite and subsequently transmit the infection to humans, it is important to know the risk of transmission. For this reason, the objective of this study was to determine the frequency of this parasite in the cat population of the city of Santiago de Queretaro, Mexico, and identify the assemblages present to determine the role this host plays in public health, this being the first study of its type to be performed in the country. This was a cross-sectional study during which 200 fecal samples were collected from cats of both sexes and varying ages and strata of origin. The samples were analyzed by microscopy following the flotation technique, having obtained a general frequency of 25%. Giardia cysts were found at higher frequency in pasty stools. The assemblages found were zoonotic, specifically assemblage A, which suggests that the cat poses an important risk for the dissemination of the parasite to humans, making it an important public health problem.

Gastrointestinal parasites in young dogs and risk factors associated with infection

Young dogs are particularly susceptible to infections with endoparasites. The occurrence of endoparasites was investigated in young dogs from Central Germany between July 2020 and July 2022. In total, 386 fecal samples originating from 171 dogs were examined for the prevalence of endoparasites using a combined flotation- and sedimentation technique and conventional PCR. Overall, in 41.2% (159/386) of the examined samples, endoparasites were detected. The most frequently occurring endoparasites were Giardia duodenalis (29%), Cryptosporidium spp. (9.1%), Cystoisospora spp. (7.3%), and Toxocara canis (6%). Sequencing of G. duodenalis positive samples showed that most infections belonged to the host-specific assemblages C (38.4% (43/112)) and D (35.7% (40/112)). The zoonotic assemblage A was identified in 8% (9/112) of the samples. Moreover, mixed infections were observed as follows: C/D in 5 (4.5%), D/A in 4 (3.6%), and C/A in 3 (2.7%) samples. All assemblage A infections were assigned to the potentially zoonotic subassemblage AI. Co-infections of G. duodenalis and Cryptosporidium spp. were observed in 3.1% (12/386) of the samples. Analyzing several host factors for their potential association with endoparasitic infection, the origin of dogs, as well as the living environment were identified as the main risk factors for infection with endoparasites. Overall, this study shows a high infection rate with endoparasites, especially G. duodenalis, in young dogs from Germany. The results of this study contribute to further insight into the distribution and potential risk factors associated with endoparasitic infections, as well as the zoonotic potential these parasites may present.

Molecular characterisation of Giardia duodenalis from human and companion animal sources in the United Kingdom using an improved triosephosphate isomerase molecular marker

Giardia duodenalis is a protozoan parasite known for its ability to cause gastrointestinal disease in human and non-human mammals. In the UK, the full impact of this parasite has yet to be fully explored, due to the limited testing which has been undertaken in humans and the low-resolution assemblage-typing methods currently available. Rather than being primarily a travel-associated condition, a recent study has highlighted that an endemic Giardia cycle is present in the UK, although the source of human disease is unclear in the majority of cases. This study focussed on the improvement of one of the commonly used assemblage-typing assays, a nested topoisomerase phosphate (tpi) PCR, to increase the amplification success rate across both human and companion animal samples. After comparing published primers to full Giardia reference genomes, this marker protocol was optimised and then deployed to test a substantial number of human (n ​= ​79) and companion animal (n ​= ​174) samples to gain an insight into the molecular epidemiology of Giardia in the UK. One assemblage A1 and eleven assemblage A2 genotypes were detected in humans, along with and 25 assemblage B genotypes. Assemblage A1 genotypes, known to be human-infective, were found in three feline and one canine sample, while one feline sample contained assemblage A2. Additionally, four feline samples contained assemblage B, which is recognised as potentially human-infective. This study demonstrates the presence of potentially human-infective Giardia genotypes circulating in the companion animal population, notably with 17.4% (8/46) of feline-derived Giardia strains being potentially zoonotic. Using a modified tpi-based genotyping assay, this work highlights the potential for domestic pets to be involved in the endemic transmission of giardiasis in the UK and underlines the need for appropriate hygiene measures to be observed when interacting with both symptomatic and asymptomatic animals. It also serves to underline the requirement for further studies to assess the zoonotic risk of Giardia associated with companion animals in high-income countries.

Lack of efficacy of fenbendazole against Giardia duodenalis in a naturally infected population of dogs in France

Giardiosis is a worldwide intestinal parasitosis, affecting both humans and animals. Treatment in dogs remains limited and the lack of efficacy of the few approved medications is a rising concern. In this study, 23 dogs raised by veterinary students and naturally infected with Giardia duodenalis were treated in home conditions with fenbendazole (50 mg/kg orally for 5 consecutive days). Fecal samples were collected immediately before treatment (FS1), 2-4 days after treatment (FS2) and 8-10 days after treatment (FS3). Giardia duodenalis cyst excretion was measured quantitatively by direct immunofluorescence assay (DFA) at FS1, FS2 and FS3. Molecular typing with a nested PCR targeting the SSU _rDNA locus was also performed at FS1 and FS2. Fecal consistency improved in 16/21 dogs (76%) and mean cyst shedding was reduced by 84% after treatment. However, only 8/23 dogs (35%) achieved therapeutic success (≥90% reduction of cysts) and only 4/23 dogs (17%) had complete elimination of G. duodenalis. Molecular typing showed that dogs harbored only canine-specific assemblages, with a high prevalence of assemblage C in analyzed samples (30/39). We also detected different assemblages after treatment and nucleotide substitutions in assemblage C sequences that have not been described previously. Eight to ten days after treatment, high Giardia cyst excretion was measured, suggesting possible reinfection despite hygiene measures and/or multiplication. These data suggest that fenbendazole treatment may improve fecal consistency but has limited therapeutic efficacy against giardiosis in this population of dogs. Further research is still needed to assess the efficacy of fenbendazole against canine giardiosis.

Detection of Giardia and helminths in Western Europe at local K9 (canine) sites (DOGWALKS Study)

BACKGROUND

Intestinal parasite contamination from infected dogs can place other dogs and humans at risk. A study was initiated to estimate the prevalence of canine intestinal parasitism by collecting fecal samples in cities across Western Europe.

METHODS

Fresh fecal samples were collected from 2469 dogs visiting 164 parks in 33 cities across 12 countries. Each owner responded to a questionnaire focusing on their dog's signalment and recent anthelmintic treatment history. The collected samples were examined for hookworms, whipworms, ascarids and Giardia using a coproantigen diagnostic immunoassay and microscopy following centrifugal flotation.

RESULTS

Nematodes or Giardia were detected in at least one sample from 100% of cities and in 93.3% of parks. Nematodes were detected in 57% of parks. Overall, 22.8% of dogs tested positive for an intestinal parasite, with Giardia being the most commonly identified parasites (17.3% of dogs, 83.5% of parks). For nematode infection, 7.6% of all dogs tested positive, with 9.9% of dogs aged < 1 year infected, 7.7% of those aged 1-3 years, 7.3% of those aged 4-6 years and 6.6% of those aged ≥ 7 years. Among the nematodes detected, ascarids were the most prevalent (3.6% of dogs, parks, 28.7% of parks), being most common in dogs aged < 1 year but also present in older dogs, including those aged ≥ 7 years. Hookworms and whipworms were detected in 3.2% and 2.3% of dogs of all ages, respectively, and in 37.2% and 17.7% of parks, respectively. A larger proportion of fecal samples tested positive with the coproantigen immunoassay than with centrifugal flotation. Positive test results for Giardia were sevenfold higher when both diagnostic tests were used than when centrifugal flotation alone was used, and there were 60% more positive test results for nematodes when both tests were used than when flotation alone was used. Overall, 77.2% of owners reported previous anthelmintic treatment, among whom at least 62.7% failed to follow recommended treatment frequency. Dogs receiving anthelmintic within the previous month had a lower percentage of nematode infection than those in which > 1 month had passed since the previous dose.

CONCLUSIONS

The prevalence estimates of intestinal parasite infections in dogs reported here highlight the need for owner education concerning guidelines for regular testing and treatment, even in older dogs. Failure to adhere to guidelines can result in ongoing transmission of these infections, including those with zoonotic potential. Combining coproantigen immunoassay with centrifugal flotation for diagnostic testing and regular anthelmintic treatment are important measures for ensuring optimal intestinal parasite control.

Factors affecting the occurrence of gastrointestinal parasites and lungworm in dogs and assessment of antiparasitic drug use patterns

Dogs are hosts of parasites with different pathogenicities and zoonotic risks. The aim of our study was to assess factors that could affect the occurrence of endoparasitic infections in dogs using questionnaires for owners and examining canine faeces. Based on the responses of dog owners, we evaluated ways of the preventive and therapeutic use of antiparasitic drugs. One faecal sample was obtained from each dog (391 samples total), and then examined by flotation, larvoscopic, and polymerase chain reaction (PCR) methods. We focused on zoonotic tapeworms Echinococcus multilocularis and Taenia crassiceps. The answers in the dog owners’ questionnaires showed that owners most often dewormed their dogs irregularly (96.4%), namely, twice a year (24.3%). In coprological examinations the following parasites were detected: Giardia spp., Cystoisospora ohioensis complex, Neospora caninum/Hammondia heydorni, Toxocara canis, Toxascaris leonina, Capillaria spp., Trichuris spp., Angiostrongylus vasorum, Crenosoma vulpis, Ancylostoma spp. and Taenia spp. A total of 4 out of 391 PCR investigated samples of faeces were positive for DNA of Taenia species. Sequences were obtained for 3 of them, confirming 100% identity with T. crassiceps. The zoonotic helminths Toxocara canis were the more prevalent species (9.3%, 4.3%, 1.9% group A, B, C). We consider the presence of T. crassiceps in 3 dog faecal samples to be serious due to its zoonotic potential. Data collected within this study showed that the prevention against endoparasites carried out at the breeders’ discretion is insufficient to ensure the health of their dogs or to cover the risk of zoonotic transmission.

Evaluation for associations amongst Giardia duodenalis assemblages and diarrhea in dogs

Giardia duodenalis is a species complex comprising at least eight assemblages. Most dogs harbor the host-adapted assemblages C and D and approximately 30 % harbor the zoonotic assemblages. Humans and dogs with giardiosis can exhibit a variety of clinical manifestations ranging from the absence of clinical signs to acute or chronic diarrhea. Human studies report conflicting results concerning associations between clinical signs and assemblage type. The objective of this study was to use results of molecular and phylogenetic analyses to evaluate associations between G. duodenalis assemblages and diarrhea in client-owned dogs from the United States. Fecal samples that were positive for Giardia cysts were classified as normal or diarrheal. Samples were analyzed by PCR assays of the beta-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes. Sequences of the three genes were analyzed by BLAST analysis and phylogenetic analysis was performed by Neighbor-Joining analysis. Two hundred and eighty-eight Giardia-positive fecal samples were evaluated by the three PCRs. One or more genes were amplified from 95 normal samples and 93 diarrheal samples, 27 samples were positive for one or more genes but could not be sequenced due to low quality DNA, and 73 samples tested negative. Ninety seven percent of the samples (182/188) in both the diarrheal and normal groups typed as dog-specific assemblages (D or C) by at least one gene. Phylogenetic analysis of the three genes placed the isolates from assemblages A, B, C and D separated from each other with strong bootstrap support. Diarrhea was not associated with the Giardia assemblage or other parasitic co-infection in this sample set. Other factors, such as the role of gut microbiota in giardiosis should be considered in future studies.

Giardia duodenalis in colony stray cats from Italy

Giardia duodenalis is the most common intestinal protozoan in humans and animals worldwide, including eight morphologically identical assemblages, infecting pets, livestock, wildlife and human beings. Assemblages A and B are those with the higher zoonotic potential, and they have been detected in several mammals other than humans; the others (C to H) show a higher host specificity. Cats can harbour both the specific Assemblage F and the zoonotic ones A and B. Several studies have been carried out on G. duodenalis genotypes in cats; however, the role of this species in the epidemiology of giardiasis is still poorly understood. In this scenario, the present study carried out the detection and genetic characterization at sub‐assemblage level of G. duodenalis from colony stray cats in central Italy. In the period 2018–2019, 133 cat faecal samples were analysed for the presence of G. duodenalis cysts by a direct immunofluorescence assay. Positive samples were subsequently subjected to molecular analyses for assemblage/sub‐assemblage identification. Forty‐seven samples (35.3%) were positive for G. duodenalis cysts by immunofluorescence. G. duodenalis DNA was amplified at SSU‐rDNA locus from 39 isolates: 37 were positive for zoonotic Assemblage A and 2 showed a mixed infection (A + B). Positive results for the β‐giardin gene were achieved for 25 isolates. Sequence analysis revealed 16 isolates belonging to Sub‐assemblage AII and 8 to Sub‐assemblage AIII. One isolate resulted as ambiguous AI/AIII. Large sequence variability at the sub‐assemblage level was detected, with several double peaks and mutations, making complex a proper isolate allocation. When compared with previous studies, the 35.3% prevalence of G. duodenalis in cats reported in the present article was surprisingly high. Moreover, all positive cats resulted to be infected with zoonotic assemblages/sub‐assemblages, thus indicating stray cats as a possible source of human giardiasis and highlighting the sanitary relevance of cat colonies in the study area.

Age and Giardia intestinalis Infection Impact Canine Gut Microbiota

Giardia intestinalis is a flagellated protozoan responsible for giardiosis (also called giardiasis in humans), the most prevalent and widespread parasitic infection in humans and mammals worldwide. The intestinal microbiota is highly diverse and any alteration in its composition may impact on the health of the host. While studies on the mouse model of giardiosis described the role of the gut microbiota in host susceptibility to infection by the parasite, little is known about the gut microbiota during natural infections in dogs and particularly in puppies. In this study, we monitored naturally G. intestinalis-infected puppies for 3 months and quantified cyst excretion every 2 weeks. All puppies remained subclinically infected during the sampling period as confirmed by fecal examination. In parallel, we performed 16S Illumina sequencing of fecal samples from the different time points to assess the impact of G. intestinalis infection on gut microbiota development of the puppies, as well as gut health markers of immunity such as fecal IgA and calprotectin. Sequencing results revealed that the canine fecal microbiota of Giardia-infected puppies becomes more complex and less diverse with increasing age. In addition, significant differences in the structure of the microbiota were observed between puppies with high and low Giardia cyst excretion. Chronic subclinical G. intestinalis infection appears to be associated with some detrimental structural changes in the gut microbiota. G. intestinalis-associated dysbiosis is characterized by an enrichment of facultative anaerobic, mucus-degrading, pro-inflammatory species and opportunistic pathogens, as well as a reduction of Lactobacillus johnsonii at specific time points. Calprotectin levels increased with age, suggesting the establishment of chronic low-grade inflammation in puppies. Further work is needed to demonstrate whether these alterations in the canine gut microbiota could lead to a dysbiosis-related disease, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD).

Molecular detection of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in school children at the Thai-Myanmar border

Few data are available on the genetic identity of enteric protists Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in humans in Thailand. In this study, 254 stool samples were collected from primary school children from Ratchaburi Province at the Thai-Myanmar border and examined for Cryptosporidium spp., G. duodenalis, E. bieneusi and Cyclospora cayetanensis using PCR techniques. The genotype identity of the pathogens was determined by DNA sequence analysis of the PCR products. Cryptosporidium felis was found in 1 stool sample, G. duodenalis in 19 stool samples, and E. bieneusi in 4 stool samples. For G. duodenalis, sub-assemblage AII was the dominant genotype, but one infection with assemblage F was found. The E. bieneusi genotypes found included known genotypes D and J, and one novel genotype (HPTM1). Cyclospora cayetanensis was not detected in any samples. Results of the preliminary study indicate that children at the Thai-Myanmar border from Ratchaburi Province, Thailand are infected with diverse zoonotic genotypes of Cryptosporidium spp., G. duodenalis, and E. bieneusi.

The occurence of endoparasites in Slovakian household dogs and cats

Pets play a pivotal role as definitive or reservoir hosts for many zoonotic parasites. Dogs and cats without any clinical signs may be a carrier for the infection. In a one-year study, collected fecal samples of 257 dogs and 50 cats were examined coproscopically for endoparasite infections. Out of 307 investigated fecal samples, 107 (34.9%) were positive for the presence of the propagative stages of endoparasites In 257 dogs fecal samples, following 12 different species of endoparasites were detected: Giardia duodenalis, Cystoisospora spp., Sarcocystis spp., Hammondia/Neospora-like eggs, Angiostrongylus vasorum larvae, Capillaria aerophila, Crenosoma vulpis, Toxocara spp., Toxascaris leonina, Trichuris vulpis, Strongyloides stercoralis, and eggs from the family Ancylostomatidae. Only 4 different parasitic species were found in 50 domestic cat fecal samples - G. duodenalis cysts Cystoisospora spp., T. cati, and larvae of Aelurostrongylus abstrusus. It was confirmed that significant differences were found concerning age for G. duodenalis, T. canis, S. stercoralis, and family Ancylostomatidae. Close and frequent contact between pets and people increases the risks for the transmission of zoonotic diseases.

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.

Urban public squares as potential hotspots of dog-human contact: A spatial analysis of zoonotic parasites detection in Gran Santiago, Chile

Zoonotic parasites are a major public health problem globally, representing a hazard to human health. The infections occur through contact with different parasite forms. Public squares are a common meeting place for people and dogs, becoming a risk area for transmission to other dogs and humans. A spatial analysis of zoonotic parasite distribution in urban public squares in Gran Santiago, Chile was performed to elucidate its importance, exploring spatial aggregation on positivity rates at commune level. A total of 170 stool samples were analysed; 54 (31.7%) were positive for gastrointestinal-zoonotic parasites. Positivity was detected in 27 (79.4%) squares. Diversity of parasite species was variable across sites. Toxocara canis was the most frequently detected (27 samples, 21/34 squares), followed by Toxascaris leonina (13 samples, 10/34 squares), cestode eggs (10 samples, 9/34 squares), Giardia sp. (6 samples, 5/34 squares), Ancylostomatidae-like eggs (4 samples, 4/34 squares), Cryptosporidium spp. (2 samples, 2/34 squares) and Entamoeba spp. (1 sample, 1/34 square). Spatial autocorrelation (SA) was observed at commune level. The local indicators of the spatial association test showed statistical significance for cestode eggs (p < 0.001) with a negative SA (Moran's I Index = -0.2929, CI-95% = -0.3869--0.1989) and Ancylostomatidae (p = 0.046) with a positive SA (Moran's I Index = 0.1404, CI-95% = 0.0499-0.2309). Toxocara canis is the most prevalent geo-helminth in public places of Santiago, Chile. Spatial autocorrelation was detected for cestode eggs and Ancylostomatidae. Diagnosis and detection of parasites is key for the establishment of control/eradication of environmental dissemination following One Health guidelines.

FELINE GIARDIASIS IN TURKEY: PREVALENCE AND GENETIC AND HAPLOTYPE DIVERSITY OF GIARDIA DUODENALIS BASED ON THE β-GIARDIN GENE SEQUENCE IN SYMPTOMATIC CATS

Giardia duodenalis is a common zoonotic protozoan parasite with a broad host distribution. The main objectives of the present study were to determine the prevalence of giardiasis and to reveal the genetic and haplotype diversity of G. duodenalis in symptomatic cats in Turkey. Fecal samples were collected from cats (n = 102) with diarrhea that were admitted to different pet clinics in the Central Anatolia region of Turkey. All samples were analyzed by microscopic examination (ME), rapid immunochromatographic test (ICT), and PCR targeting the β-giardin (bg) loci of the parasite. Phylogenetic, haplotype, and network analyses of G. duodenalis based on the bg gene were carried out. Overall, G. duodenalis was detected in 70/102 (68.6%) of the cats with diarrhea by ME (38/102, 37.3%), ICT (51/102, 50%), and PCR (30/102, 29.4%). According to sequence analyses of the bg gene region, all isolates were identified as G. duodenalis assemblage B. Haplotype analyses revealed 2 known and 8 novel haplotypes for G. duodenalis assemblage B. This study provides first prevalence and genetic and haplotype diversity data on G. duodenalis assemblage B from cats in Turkey.

Enterocytozoon bieneusi of animals-With an 'Australian twist'

Enterocytozoon bieneusi is a microsporidian microorganism that causes intestinal disease in animals including humans. E. bieneusi is an obligate intracellular pathogen, typically causing severe or chronic diarrhoea, malabsorption and/or wasting. Currently, E. bieneusi is recognised as a fungus, although its exact classification remains contentious. The transmission of E. bieneusi can occur from person to person and/or animals to people. Transmission is usually via the faecal-oral route through E. bieneusi spore-contaminated water, environment or food, or direct contact with infected individuals. Enterocytozoon bieneusi genotypes are usually identified and classified by PCR-based sequencing of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA. To date, ~600 distinct genotypes of E. bieneusi have been recorded in ~170 species of animals, including various orders of mammals and reptiles as well as insects in >40 countries. Moreover, E. bieneusi has also been found in recreational water, irrigation water, and treated raw- and waste-waters. Although many studies have been conducted on the epidemiology of E. bieneusi, prevalence surveys of animals and humans are scant in some countries, such as Australia, and transmission routes of individual genotypes and related risk factors are poorly understood. This article/chapter reviews aspects of the taxonomy, biology and epidemiology of E. bieneusi; the diagnosis, treatment and prevention of microsporidiosis; critically appraises the naming system for E. bieneusi genotypes as well as the phylogenetic relationships of these genotypes; provides new insights into the prevalence and genetic composition of E. bieneusi populations in animals in parts of Australia using molecular epidemiological tools; and proposes some areas for future research in the E. bieneusi/microsporidiosis field.

Multilocus genotyping of Giardia intestinalis in pet dogs of Medellín Colombia

According to a few parasitological and epidemiological studies, Giardia is the most prevalent parasitic infection among pet dogs in the city of Medellín, the second-largest city in Colombia. This study determined the assemblages of Giardia in the fecal samples of dogs obtained from 18 veterinary centers of Medellín. One hundred fecal samples of dogs diagnosed with Giardia using microscopy were analyzed via nested polymerase chain reaction (PCR) using three genes (gdh, bg, and tpi). The PCR products were purified and sequenced, and phylogenetic analyses were conducted using the maximum likelihood algorithm of the three loci. From the 100 samples analyzed, 47 were Giardia-positive via PCR. Genotypes C and D were detected in six samples, neither of which were associated with human infection. However, the zoonotic potential of Giardia cannot be ruled out because of the small number of samples that could be sequenced for assemblage assignation.

Giardia duodenalis infection in dogs from the metropolitan area of Lisbon, Portugal: prevalence, genotyping and associated risk factors

Abstract

Giardia duodenalis is a cosmopolitan enteric protozoan that affects a wide range of vertebrates, including humans and dogs. Genetic characterisation reveals eight different assemblages, with A and B having been found mainly in humans and several other animals, and thus considered potentially zoonotic, while C and D are adapted to infect dogs. This study aimed to determine the prevalence of G. duodenalis, their distribution into assemblages, and risk factors associated with their infection of dogs from the metropolitan area of Lisbon. Giardia duodenalis cysts were microscopically identified in 33.8% (27/80) of the faecal samples analysed. Multivariate logistic regression analysis revealed that dogs under 6 months of age and from both breeders and shelters, had a significantly higher risk of being infected with G. duodenalis. Based on phylogenetic analysis of the partial coding sequences for β-giardin, glutamate dehydrogenase, and triosephosphate isomerase, the parasites found in three dog isolates were typed as G. duodenalis assemblage C, 11 were typed as D, and four were typed as C or D, depending on the targeted genes. The risk to public health seems to be reduced, as no genotypes with zoonotic potential have been detected. Nevertheless, better health management towards a minimisation of the environmental faecal pollution, as well as an increase in the awareness of health professionals, dog owners, dog breeders and caregivers regarding the risks posed by this protozoan to the health of animals and humans, are recommended.

Graphic abstract

Companion animals as a potential source of Giardia intestinalis infection in humans in the Czech Republic - A pilot study

Giardia intestinalis is a common enteric single-celled parasite infecting both humans and animals. Its eight morphologically identical but genetically distinct groups called assemblages differ from each other in host range. While assemblages A and B infect a wide range of hosts, including humans, the other assemblages (C to H) limit their host preferences to particular animal groups only. In companion animals as Giardia hosts, genotyping data have previously shown various results depending on pet species, location, environmental or breeding conditions, and the study design. To strengthen available epidemiological data from developed countries and to evaluate the role of pets in Giardia zoonotic transmission, we investigated Giardia-positive stool samples of three pet species (54 dogs, 18 cats, and 18 chinchillas) by a sequence-based analysis of three Giardia genes (β-giardin, glutamate dehydrogenase and triose phosphate isomerase). In dog samples, we confirmed assemblage C (21/54), assemblage D (32/54), and one case of a mixed infection C + D (1/54). In cats, we found assemblage F (16/18) and assemblage A, specifically sub-assemblage AI (2/18). All Giardia samples from chinchillas were characterised as assemblage B, specifically sub-assemblage BIV (18/18). These results indicate that in the Czech Republic, pet dogs may not represent a source of Giardia infection for humans because of the presence of only canid-specific genotypes C and D. In contrast, other pets, namely, chinchillas and, to a lesser extent, cats, may pose a potential risk of Giardia transmission to owners or breeders because they can host zoonotic Giardia genotypes.

Multilocus genotyping of Giardia duodenalis from pigs in Korea

Giardia duodenalis (syn. G. intestinalis, G. lamblia) is an important zoonotic parasite infecting livestock (including pigs) through ingesting cysts in contaminated food or water. This parasite has been classified into eight different genetic assemblages, A to H. Here, we examined the individual-level prevalence of G. duodenalis in domestic pig farms and confirmed host specificity by genotype comparisons. Samples were collected from southern and central Korea, between May 2017 and January 2019. DNA directly extracted from 745 pig fecal specimens were tested by PCR for G. duodenalis small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), and β-giardin gene sequences. Based on ssu rRNA PCR, 110 (14.8%) were positive for G. duodenalis. Infection risk was the highest in the fattener group (31/139, 22.3%) and during the autumn season (52/245, 21.2%: p < .001). No statistically significant differences in risk for infection were observed between fecal types (normal versus diarrheal). Fifty ssu rRNA samples, three gdh samples, and five β-giardin samples were successfully sequenced and genotyped. Ssu rRNA assemblage sequence analysis identified E (40.0%, 20/50), D (34.0%, 17/50), C (24.0%, 12/50), and A (2.0%, 1/50). The gdh locus identified three samples as assemblage E, and the β-giardin locus identified four samples as assemblage E and one as assemblage C. Assemblage A sequences obtained (ssu rRNA; MK430919) had 100% identity with Giardia sequences isolated from a Korean individual (AJ293301), indicating the potential of zoonotic transmission. Continuous management and monitoring for prevention of transmission and protection of animal and human health are essential.

Giardia and Cryptosporidium infections in Danish cats: risk factors and zoonotic potential

Giardia and Cryptosporidium infections are common in cats, but knowledge is limited about their clinical importance, risk factors, and the role of cats as a reservoir for human infections. Here, we collected faeces and questionnaire data from 284 cats from shelters and veterinary clinics in the Copenhagen Metropolitan Region (= study population). Additionally, 33 samples were analysed separately from catteries with gastrointestinal clinical signs (= cases). (Oo-)cysts were quantified by immunofluorescence microscopy. All Giardia (n = 34) and Cryptosporidium (n = 29) positive samples were analysed by sequencing of the 18S rRNA, gdh and hsp70 loci, and co-infections were detected by McMaster/inverted microscopy. In the study population, 7.0% and 6.7% were positive for Giardia and Cryptosporidium respectively; 48.5% and 36.4% of the breeder cats (cases) were infected. Increased odds of diarrhoea were demonstrated in Giardia (p = 0.0008) and Cryptosporidium (p = 0.034) positive cats. For Giardia, the odds were positively correlated with infection intensity. Co-infection with Cryptosporidium (OR 12.79; p < 0.001), parasitic co-infections other than Cryptosporidium (OR 5.22; p = 0.009), no deworming (OR 4.67; p = 0.035), and male sex (OR 3.63; p = 0.025) were risk factors for Giardia. For Cryptosporidium, co-infection with Giardia was the only risk factor (OR 11.93; p < 0.0001). Genotyping revealed G. duodenalis assemblages A and F, and C. felis, all of them previously detected in humans. In conclusion, excretion of Giardia and Cryptosporidium was associated with clinical disease. Although a public health risk is likely, studies including larger sample sizes, more discriminatory markers and samples from other animals and humans are needed to reveal the full zoonotic potential.

Giardia duodenalis infection in dogs affected by primary chronic enteropathy

Background:

Canine primary chronic enteropathy (CE) includes a heterogeneous group of diseases characterized by chronic gastrointestinal signs.

Aim:

This study evaluated the occurrence of Giardia duodenalis infection in primary CE-affected dogs.

Methods:

Forty-seven CE-affected dogs of different age and sex were enrolled in the study. For each dog, frequency of defecation, fecal consistency, and eventual fecal abnormalities were evaluated. A clinical scoring index of CE severity (clinical chronic enteropathy activity index) was also assessed, and the type of enteropathy was retrospectively classified. For parasitological analysis, fresh fecal samples collected from each dog were examined by fresh and Lugol stained smears, flotation test, and a rapid immunoassay. Giardia duodenalis genotypes were identified by molecular analysis. Differences of clinical parameters between G. duodenalis positive and G. duodenalis negative dogs were statistically evaluated.

Results:

Among the CE canine patients, 16 out of 47 (34%) dogs were found positive for G. duodenalis and assemblages C and D were identified. No statistical differences emerged according to the types of CE between G. duodenalis-positive and G. duodenalis-negative dog groups. The clinical index of CE severity was indicative of significant less severe clinical forms in G. duodenalis-positive dogs (p = 0.037).

Conclusion:

Results here obtained shows how G. duodenalis may be present in primary CE-affected dogs and further investigations are needed to clarify the real significance of mild clinical presentation in G. duodenalis-positive dogs affected by CE.

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.

Host factors associated with Giardia duodenalis infection in dogs across multiple diagnostic tests

Background

The aim of this study was to assess potential associations between Giardia duodenalis infection in dogs, as determined by three diagnostic tests, and dog’s group of origin, fecal consistency, age, sex, neuter status, and co-infections with other gastrointestinal parasites.

Methods

Fecal samples from 1291 dogs from four groups (household, shelter, hunting and clinical dogs) were tested with qPCR, rapid enzyme immunochromatographic assay (IDEXX SNAP^®Giardia), and direct immunofluorescence (DFA, Merifluor) for presence of G. duodenalis. Moreover, fecal samples were tested with centrifugation sedimentation flotation (CSF) coproscopical analysis for presence of gastrointestinal parasites. Associations were expressed as odds ratios (ORs).

Results

Several significant associations were found, of which a few were consistent for all three tests and Giardia positivity in general (positive with at least one of these tests). Dogs older than one year were significantly less likely to test positive for Giardia than younger dogs. Group-housed dogs, especially hunting dogs, were significantly more likely to test positive for Giardia compared to household and clinical dogs. A consistently significant association with Trichuris appeared to be driven by the high prevalence in hunting dogs. Although there was no significant association between loose stool and Giardia infection in the overall population, household dogs were significantly more likely to test Giardia-positive when having loose stool. Overall, Giardia-positive dogs with loose stool shed significantly more cysts, both determined semi-quantitatively with CSF and quantitatively by qPCR, than positive dogs with no loose stool. When other gastrointestinal parasites were present, significantly fewer cysts were detected with CSF, but this was not confirmed with qPCR.

Conclusion

Giardia is the most common gastrointestinal parasite in Dutch dogs, except for hunting dogs, in which Trichuris and strongyle-type eggs (hookworms) prevailed. Giardia infection was not significantly associated with loose stool, except for household dogs. Young dogs and group-housed dogs were significantly more often Giardia-positive. These associations were consistent across diagnostic tests. Young dogs, clinical dogs and dogs with loose stool shed Giardia cysts in the highest numbers. If another gastrointestinal parasite was present lower numbers of cysts were observed by microscope (CSF), but not with a molecular method (qPCR).

Multilocus genotyping and risk factor analysis of Giardia duodenalis in dogs in Korea

Giardia duodenalis (syn. G. intestinalis, G. lamblia), a protozoan parasite that infects most mammals (including humans), has recently been classified into eight different groups/assemblages (A to H) based on host range and genetic characteristics. Assemblages A and B have been reported in humans and in many other animals, including dogs. This study analyzed Giardia infections, implementing multilocus genotyping, including the 18S rRNA, gdh, and β-giardin genes, in sheltered, companion, and special-purpose dogs throughout Korea. Of 640 dog stool samples, 99 (15.5%) were G. duodenalis-positive; this prevalence was similar to that previously reported in Korean calves. In addition, the prevalence was significantly higher in the southern region, and lower in non-sheltered dogs, older dogs, and in the autumn season. Phylogenetic analysis revealed that all G. duodenalis-positive samples belonged to assemblages C and D. Although no G. duodenalis assemblages A and B (mainly found in humans) were identified in this study, assemblage C was detected in the main types of dogs in contact with humans. Assemblage C, thought to be dog-specific, was recently identified in humans. As Giardia (including zoonotic assemblages) is distributed throughout Korea, dog living environments and the potential for dog-human transmission should be monitored.

Successful use of secnidazole to manage a giardiosis outbreak in a shelter

Giardia duodenalis is a common parasite in dogs in shelters where new introductions, including numerous juvenile individuals, are ongoing. A safe and effective single dose parasiticide is highly desirable for shelters experiencing disease caused by G. duodenalis (giardiosis). Secnidazole is an efficacious, low-cost medication used for the treatment of giardiosis in humans and has the advantage of requiring only a single oral dose. The aim of this study was to determine retrospectively the effectiveness of secnidazole on dogs of all ages during an outbreak of giardiosis in a shelter. Patients recruited into this retrospective study were divided into two groups. Group A consisted of adult dogs and weaned dogs (>10 weeks-of-age). Group B was comprised of puppies (<10 weeks-of-age). Giardiosis resolved in all 14 patients in Group A within 13 days following a single oral dose of secnidazole (30 mg/kg). There were no individuals with both gastrointestinal signs and a positive G. duodenalis antigen test at the time of the first and second follow-up examination. For the young puppies in Group B, giardiosis was reduced by 90% (9/10) within 22 days following two consecutive doses of secnidazole (30 mg/kg; 2 weeks apart). No adverse reactions were observed in any patients treated with secnidazole. Secnidazole is an effective and easily administered drug for the treatment of clinical canine giardiosis.

Prevalence of Giardia and Cryptosporidium in young livestock and dogs in Magude District of Maputo Province, Mozambique

BACKGROUND

Giardia and Cryptosporidium species are significant zoonotic parasites of humans and domesticated animals.

OBJECTIVES

The study aimed to determine the prevalence of Giardia and Cryptosporidium in livestock and dogs of the Magude District.

METHOD

The flotation technique (Willis), modified Ziehl-Neelsen (mZN) and direct and indirect immunofluorescence (DIF and IIF) techniques were applied to determine the prevalence of Giardia and Cryptosporidium species in faecal samples of dog pups (156), goat kids (60) and calves (480) from the Magude District of Mozambique from February to September 2015.

RESULTS

Using Willis, IIF and DIF, the prevalence of Giardia in calves was 0%, 8.1%, and 6.0%; in dogs 0.6%, 8.3% and 5.7% and for goats 0% and 13.3% (IIF was not performed), respectively. The prevalence of Cryptosporidium in calves using Willis, mZN, IIF and DIF was 0%, 3.8%, 4.7% and 0.4% and in dogs 0%, 0.6%, 6.4% and 0.6%, respectively. The parasite was not detected in goats.

CONCLUSION

Results from the present study showed that IIF performed better diagnosis of Giardia and Cryptosporidium, and that the mZN can be used as an alternative for Cryptosporidium because of the high cost of IIF. There is a need for identification of genotypes or subtypes of these parasites through application of molecular techniques in order to determine their zoonotic potential, and we advocate a 'one health' approach in the control and prevention of these parasites.

Molecular epidemiology of giardiasis from a veterinary perspective

A total of eight Giardia species are accepted. These include: Giardia duodenalis (syn. Giardia intestinalis and Giardia lamblia), which infects humans and animals, Giardia agilis, Giardia ardeae, Giardia psittaci, Giardia muris, Giardia microti, Giardia peramelis and G. cricetidarum, which infect non-human hosts including amphibians, birds, rodents and marsupials. Giardia duodenalis is a species complex consisting of eight assemblages (A-H), with assemblages A and B the dominant assemblages in humans. Molecular studies to date on the zoonotic potential of Giardia in animals are problematic and are hampered by lack of concordance between loci. Livestock (cattle, sheep, goats and pigs) are predominantly infected with G. duodenalis assemblage E, which has recently been shown to be zoonotic, followed by assemblage A. In cats and dogs, assemblages A, B, C, D and F are commonly reported but relatively few studies have conducted molecular typing of humans and their pets and the results are contradictory with some studies support zoonotic transmission but the majority of studies suggesting separate transmission cycles. Giardia also infects a broad range of wildlife hosts and although much less well studied, host-adapted species as well as G. duodenalis assemblages (A-H) have been identified. Fish and other aquatic wildlife represent a source of infection for humans with Giardia via water contamination and/or consumption of undercooked fish and interestingly, assemblage B and A predominated in the two molecular studies conducted to date. Our current knowledge of the transmission dynamics of Giardia is still poor and the development of more discriminatory typing tools such as whole genome sequencing (WGS) of Giardia isolates is therefore essential.

Gastrointestinal parasites in shelter cats of central Italy

In Italy, the limited resources and the large number of cats living in feline shelters may facilitate the spread of parasite infections that may affect the health of cats and expose shelter workers and adoptive owners to zoonosis. Prevalence and risk factors of potential zoonotic and host-specific gastrointestinal parasite infections were assessed in cats living in public and private shelters of central Italy. Individual fecal samples were examined macroscopically and then screened microscopically by fresh and Lugol stained fecal smears and by flotation and the Baermann tests. A commercial rapid immune-chromatographic assay was used to detect Giardia duodenalis and Cryptosporidium spp. All animals were clinically examined to evaluate presence of clinical signs compatible to parasitic infections. Data were statistically analysed by multivariate analysis with logistic regression and chi square testing for bivariate analysis. The overall prevalence of gastrointestinal parasites in the shelter cats surveyed was 22% (29/132), with 26/132 (19.7%) of the animals infected with potentially zoonotic organisms. Upon statistical analysis, parasite infections were identified in significantly more cats younger than 18 months of age (p <0.05), and most often associated with the presence of compatible clinical signs (p <0.05). A higher prevalence of protozoan infections (18.1%, 24/132) than of helminth infections (12.9%, 17/132) was observed. Identified parasites were Giardia duodenalis (10.6%, 14/132), Toxocara cati (9%, 12/132), Cystoisospora felis (3%, 4/132), Cystoisospora rivolta (2.3%, 3/132), hookworms (2.3%, 3/132), Cryptosporidium spp. (1.6%, 2/132), Aonchotheca putorii (0.75%, 1/132), Tritrichomonas foetus (0.75%, 1/132) and Strongyloides sp. (0.75%, 1/132). Co-infections were identified in the 7.6% of animals surveyed. Results obtained from this study indicate high gastrointestinal parasite risk to shelter cats and public health in the examined areas and suggest the need for more effective control measures in shelters surveyed.