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.     

Prevalence and risk factors of Giardia duodenalis in dogs from Romania

The protozoan Giardia duodenalis is a mammalian-infecting parasite that produces diarrhoea and malabsorption in its hosts. A survey to investigate canine infections with G. duodenalis in Romania was undertaken between June 2008 and December 2009. The objectives of the study were to (i) estimate the prevalence of infection in different dog populations (kennels, shelters, shepherd, household) using microscopy and a commercially available enzyme-linked immunosorbent assay (ELISA) test kit; (ii) to establish the level of agreement and characteristics of the tests; and (iii) to identify risk factors for infection by multivariate logistic regression models. Faecal samples were collected from 614 dogs aged from 1 month to 16 years (mean ± SD=2.88 ± 2.86 years). Each sample was tested for the presence of cysts using a flotation method with saturated sodium chloride solution and 416 out of 614 stool samples were further examined for the presence of G. duodenalis specific antigens using Giardia Microwell ELISA (SafePath? Laboratories). Giardia cysts were identified in 8.5% of total dogs (52/614) and statistical significantly more frequently in dogs living in communities. The cysts prevalence according with dog populations was as follows: 7.2%(9/125) in kennel dogs; 16.5%(27/164 in shelter dogs; 4.3%(2/46) in shepherd dogs; 4.8%(4/84) in household dogs from urban areas; and 5.1%(10/195) in household dogs from rural areas. The overall prevalence of Giardia infection by ELISA was 34.6% (144/416). The prevalence was significantly higher in kennel dogs (50%; 13/26), shelter dogs (47.7%; 74/155) and shepherd dogs (40.5%; 17/42) than in household dogs from urban areas (34.1%; 15/44) and household dogs from rural areas (16.8%; 25/149). It was noticed poor agreement between microscopy and ELISA (k=0.19). The microscopy performed best, with an Youden Index of 0.74, a Se of 73.68% and a Sp of 100%. ELISA had 100% Sp, but only 19.44% Se. Young dogs (up to 12 months age) and living in communities were identified as risk factors for infection by multivariate logistic regression analysis. 71.2% (37/52) Giardia cysts positive dogs presented co-infections with other intestinal parasites: Toxocara canis (14/52; 26.9%), Isospora ohioensis (12/52; 23.1%), Ancylostoma caninum (9/52; 17.3%), Uncinaria stenocephala (7/52; 13.5%), Trichocephalus vulpis (6/52; 11.5%), Hammondia heydorni/Neospora caninum (5/52; 9.6%), Sarcocystis spp. (5/52; 9.6%), Isospora canis (4/52; 7.7%), Capillaria aerophila (3/52; 5.8%), Strongyloides stercoralis (2/52; 93.8%), Dipylidium caninum (1/52; 1.9%) and Toxascaris leonina (1/52; 1.9%).     

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.     

Prevalence of Giardia duodenalis infection,co-morbidities and associated risk factors in dogs admitted to a veterinary teaching hospital in Israel

Giardia duodenalis causes gastro-intestinal (GI) disease and carries a zoonotic risk. The risk for infection depends on local prevalence and individual immunity, but clinical signs are inconsistent and the role of G. duodenalis in other GI diseases is unknown. The current study aims were to evaluate the prevalence of G. duodenalis in dogs presented to a university veterinary teaching hospital in Israel, investigate risk factors for infection and its associations with other diseases. Fecal samples from 163 dogs were tested for G. duodenalis by an antigen assay (FASTest® Giardia strip). Prevalence of G. duodenalis infection was 11.9 %. It was significantly associated with young age (≤1year) and canine parvoviral enteritis. Housing conditions, signs of GI disease or other systemic diseases were unassociated with infection. In conclusion, G. duodenalis infection prevalence is relatively low in the study population. Young age and diagnosis of co-infections are common, warranting screening for G. duodenalis.     

Genotype identification and prevalence of Giardia duodenalis in pet dogs of Guangzhou, Southern China

Giardia duodenalis is a flagellated parasite and is considered one of the most common causes of protozoal diarrhea in both humans and animals worldwide. This paper represents the first study of the prevalence of G. duodenalis in pet dogs in Guangzhou, China. Faecal samples (209 specimens) were obtained from young (<6 months old), adult (6 months to 3 years) and elder dogs (>3 years old). 8.61% (18/209) faecal samples were recorded positive using microscopy examination, and 11.00% (23/209) using PCR. The prevalence was significantly higher in diarrheic dogs (26.31%) compared with non-diarrheic dogs (5.10%), while it was higher in young (25.58%) than both adult (7.37%) and elder (7.04%) dogs and the difference was statistically significant (P<0.05). The prevalence in male dogs 11.30% (13/115) was higher than females 10.87% (10/92), and in suburban dogs (12.15%) higher than urban 9.80%, but the difference was not statistically significant (P>0.05). Sequence analysis of the 23 PCR-positive samples revealed the presence of Assemblage D (18/23), and zoonotic Assemblage A (5/23). The present investigation reported a high infection rate of G. duodenalis in pet dogs, especially in young dogs. Genotypic characterization demonstrated that the zoonotic Assemblage A was found, a fact that poses a potential risk of G. duodenalis transmission from pet dogs to humans. It is suggested that pet owners should take appropriate hygiene measures to prevent and control giardiasis in this region.     

Giardia infection in a group of experimental dogs

Twelve experimental dogs were monitored for Giardia infection over a 17 month period by both duodenal aspirate and zinc sulphate flotation of faeces. Each animal was found to be Giardia-pos-itive at least twice during this time despite treatment of positive animals. Giardia was frequently identified by both faecal examination and aspirate, but in some cases only one technique proved positive. The results indicated that faecal examinations are as effective as duodenal aspirates in the diagnosis of infection. At the end of the 17 month period six dogs were treated with corticosteroid: three of these treated dogs and one of six untreated animals became positive for Giardia.     

Genotypic analysis of Giardia duodenalis in domestic cats

BACKGROUND: Giardia duodenalis is an intestinal flagellated protozoan that affects many mammalian species often causing severe diarrheal disease. Several different genotypes have been identified (Assemblages A-G). Most isolates recovered from domestic cats have been assigned to either Assemblage A, the zoonotic form of the parasite, or Assemblage F, identified thus far only in cats. Genotypic variation within G. duodenalis may influence clinical presentation and course of disease. Therefore, host-adapted genotypes may not be responsible for diarrheal disease (eg, Assemblage F in cats). HYPOTHESIS: Multiple Giardia genotypes will be present in domestic cats, including Assemblage F, which will not be correlated with clinical signs. ANIMALS: 250 domestic cats from eastern Mississippi and northwestern Alabama. METHODS: Prevalence survey. Fecal samples evaluated for cysts using a centrifugation concentration technique and a commercially available direct immunoflourescent antibody kit. Giardia isolates were characterized by PCR amplification and sequencing of the glutamate dehydrogenase gene. RESULTS: Both Assemblage A-I (6/17) and Assemblage F (11/17) were identified. Although Assemblage was significantly associated with age and housing, no association was detected between Assemblage and a variety of other factors including the presence of gastrointestinal signs (acute vomiting, diarrhea, and constipation). CONCLUSIONS AND CLINICAL IMPORTANCE: The presence of diarrhea in domestic cats with Giardia cannot be used as a predictor of the presence of zoonotic genotypes in animals within the study area. Although Assemblage A was associated with age and housing, veterinarians should consider any isolation of Giardia from domestic cats as potentially zoonotic.     

Evaluation of the zoonotic potential of Giardia duodenalis in fecal samples from dogs and cats in Ontario

This study determined the distribution and zoonotic potential of Giardia duodenalis assemblage types among canine and feline fecal samples from Ontario. The effectiveness of Giardia assemblage typing methods by sequencing the genes of small subunit ribosomal RNA (ssu-rRNA), β-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) was evaluated simultaneously. From 2008 to 2010, 118 canine and 15 feline Giardia positive fecal samples were tested. The ssu-rRNA sequencing method typed 64% (75/118) and 87% (13/15) of the Giardia-positive canine and feline samples, respectively. Among the typeable samples, 68% (51/75) of canine samples contained G. duodenalis assemblage D and 31% (23/75) contained G. duodenalis assemblage C (both non-zoonotic assemblage types). Only 1% (1/75) of the typeable canine samples contained a potentially zoonotic assemblage B. In contrast, 100% (13/13) of the typeable feline samples contained potentially zoonotic assemblages A (n = 12) or B (n = 1).     

Giardia infection of cats and dogs in New Zealand

Giardia intestinalis is a pathogenic protozoan which infects humans and a wide range of animal hosts, including cats and dogs⁽¹⁾. However, the status of animals in New Zealand with respect to Giardia infection has not received much attention, so we undertook a preliminary study of cats and dogs in Palmerston North and Hamilton to determine the prevalence of infection, as indicated by the presence of cysts in faeces.     

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.     

Occurrence of Giardia duodenalis infection in chinchillas (Chincilla lanigera) from Italian breeding facilities

The present work investigated the occurrence of Giardia infection in Chinchilla lanigera reared in three Italian breeding facilities and determined their role as potential zoonotic reservoir. One hundred and four fecal samples were tested for the presence of Giardia spp. cysts using a Direct Fluorescent Assay (DFA). A high positivity rate (39.4%) was found despite all animals were asymptomatic at the time of sampling. Thirty-one positive samples were genetically characterized by sequence analysis of the ITS1-5.8S-ITS2 region of the Giardia ribosomal DNA. Assemblages B (29 isolates) and C (two isolates) were identified. These results showed that Giardia infection can be common in chinchillas, thus spurring further molecular epizootiological studies of the infection to assess the zoonotic potential or host specificity of their isolates, to determine the source of infections, to identify the routes of transmission, and to control the infection among animal populations.     

Prevalence of Giardia duodenalis genotypes in adult dairy cows

The prevalence of Giardia duodenalis genotypes was determined in adult dairy cows. Fecal specimens were collected from two farms each in Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Specimens, cleaned of fecal debris and concentrated using CsCl density gradient centrifugation, were subjected to PCR and DNA sequence analysis. The prevalence of G. duodenalis infection, ranged from 3% to 64%, with an average prevalence of 27% (144 positive cows out of 541 examined). DNA sequence analysis of the 16S rRNA gene revealed the presence of both Assemblage A and Assemblage E, G. duodenalis. Overall, Assemblage E was present in 25% of all animals tested and Assemblage A was present in 2% of the animals. As a percentage of G. duodenalis isolates, Assemblage E represented 94% and Assemblage A represented 6%. Although, most of the cows were infected with a genotype that is not known to be infectious for humans, adult cows on five farms did harbor varying levels of zoonotic Assemblage A, G. duodenalis. Therefore, although adult cows do not appear to be a significant source of human infectious cysts in the environment, the risk from this age group should not entirely be discounted.     

Prevalence of Giardia duodenalis genotypes in pre-weaned dairy calves

To determine the prevalence of Giardia genotypes in pre-weaned dairy calves, fecal samples were collected from a minimum of 18, 1-7-week-old dairy calves per farm on two farms each in the states of Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Samples cleaned of fecal debris and concentrated using CsCl density gradient centrifugation were stained and examined by immunofluorescence microscopy and also subjected to PCR and gene sequence analysis. Prevalence by PCR ranged from 9% on a farm in Pennsylvania to 93% on a farm in Vermont, with an average prevalence for 407 calves on 14 farms of 40%. Gene sequence analysis of the TPI, beta-giardin and 16S rRNA genes revealed 85% of the positive samples to be Assemblage E, while 15% were Assemblage A, although the percentages of these genotypes varied greatly from farm to farm. Some farms had no Assemblage A Giardia. Thus, while a majority of the calves were infected with a genotype that is not known to be infectious for humans, calves on 7 of 14 farms did harbor Assemblage A Giardia. Calves should be considered as a potential source of human infectious cysts in the environment.     

Infection of dogs by experimental inoculation with human isolates of Giardia duodenalis: clinical and laboratory manifestations

The susceptibility of dogs to experimental inoculation with trophozoites and cysts of human isolates of Giardia duodenalis and the clinical and laboratory profiles of infection of these animals were studied. Two groups (A and B), each comprising three dogs, were inoculated with G. duodenalis trophozoites and cysts, respectively. A third group of two dogs was not inoculated and remained as control. After inoculation feces were collected daily to determine the pre-patent period, by flotation in 33% zinc sulfate solution. Blood samples (5mL) were collected from animals at 15-day intervals during the 165 days of the experimental period and were used to carry out the hemogram and biochemical evaluation of the levels of total protein, albumin, alanine aminotransferase, gamma glutamyltransferase, urea and creatinine. A prepatent period was observed at 5-6 days post-inoculation (p.i.) in the inoculated dogs, with cysts eliminated for approximately 3 months. No alterations were seen in the clinical parameters evaluated. Anemia was observed at 15 p.i. in the inoculated dogs. The mean eosinophil count of inoculated groups was higher than that of the control (p< or =0.05) but none of the biochemical parameters analyzed presented significant differences. The results of this study show that G. duodenalis from human isolates is able to infect dogs with minimal systemic manifestations without producing clinical signs of giardiasis.     

Prevalence and genotypes of Giardia duodenalis in post-weaned dairy calves

To determine the prevalence of Giardia genotypes in post-weaned dairy calves, fecal specimens were collected from 3 to 11-month-old dairy calves per farm on two farms in Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Specimens cleaned of fecal debris and concentrated using CsCl density gradient centrifugation were stained and examined by immunofluorescence microscopy and also subjected to PCR and DNA sequence analysis. Overall, PCR provided more sensitive detection than IFA. Prevalence of Giardia infection, as detected by PCR ranged from 20% on NC-2 to 81% on VT-2, with an overall prevalence of 52% (237 positive samples out of 456 total). DNA sequence analysis of the 16S rRNA gene revealed 87% of the 237 Giardia isolates were Assemblage E, and 13% were Assemblage A although the prevalence of these genotypes varied greatly from farm to farm, with five farms having no Assemblage A Giardia. Therefore, Assemblage E was present in 45% of all animals tested and Assemblage A was present in 7% of the animals. Thus, while many of the calves were infected with a genotype that is not known to be infectious for humans, post-weaned calves on nine of 14 farms did harbor Assemblage A Giardia. Therefore calves should be considered as a potential source of human infectious cysts in the environment, with some farms representing a much higher risk than others.     

Prevalence of Giardia intestinalis infection in dogs of breeding kennels in Japan

Giardia intestinalis antigen in fecal samples was examined in 361 dogs of 14 breeding kennels located at various areas in Japan, using a commercial enzyme-linked immunosorbent assay (ELISA) kit. G. intestinalis antigen was detected in 37.4% of the fecal specimens. All of the 14 breeding kennels were positive for G. intestinalis antigen with the range from 6.7 to 59.3%. The prevalence in puppies (54.5%) was significantly (p < 0.01) higher than that in adults (30.9%). There was no difference in prevalence between males and females, and between the puppies from the mother dogs positive and negative for Giardia antigen. In conclusion, G. intestinalis widely invaded the breeding kennels in Japan.     

牛十二指肠贾第虫的分子流行病学研究进展

贾第虫是一类在全球范围内广泛分布的寄生虫,包括7个虫种。其中的十二指肠贾第虫（Giardia duodenalis）是一种重要的肠道寄生虫,能感染人和大多数哺乳动物,可引起腹泻、营养不良和体重减轻等症状。分子分型工具的发展促进了贾第虫检测、基因分型和溯源的发展,大大改变了人们对贾第虫人兽共患潜力的理解。利用分子分型工具可将十二指肠贾第虫分为8种集聚体（A~H）,8种集聚体的宿主范围都存在差异,其中,集聚体A和B是人兽共患型。牛是十二指肠贾第虫的重要宿主,但目前对牛十二指肠贾第虫病的分子流行病学认识不够,其公共卫生意义也一直被忽视。本文汇总了国内牛十二指肠贾第虫的分子流行病学调查结果。结果发现,我国牛十二指肠贾第虫的感染是普遍存在的,其中,集聚体E为优势集聚体,集聚体A和B呈散发流行。近年来,一些国家出现了集聚体E感染人的报道,同时,集聚体A在牛中的感染率有上升的迹象,牛十二指肠贾第虫的人兽共患潜力正在逐步得到认识。     

Molecular characterization of potentially zoonotic isolates of Giardia duodenalis in horses

Giardia isolates from eight horses from New York State (NY), USA and two horses from Western Australia (WA) were genetically characterized at the SSU-rDNA and triose-phosphate isomerase (TPI) genes. Phylogenetic analysis of the TPI gene provided strong support for the placement of both isolates of Giardia from horses in WA and a single isolate from a horse in NY within the assemblage AI genotype of G. duodenalis. Another two isolates from horses in NY placed within the assemblage AII genotype of G. duodenalis. Phylogenetic analysis of the TPI gene also provided strong bootstrap support for the placement of four G. duodenalis isolates from horses in NY into a potentially host-specific sub-assemblage of assemblage BIV. The results of this study are consistent with previous studies showing that assemblages AI and AII of G. duodenalis provide the greatest potential zoonotic risk to humans. Horses may therefore constitute a potential source for human infection of Giardia either directly or via watersheds.