Giardia duodenalis in small animals and their owners in Germany: A pilot study

Giardia duodenalis is a relevant gastrointestinal protozoan pathogen of humans and animals. This species complex consists of eight genetically different assemblages. Assemblages A and B are pathogenic to humans and pets, thus confer zoonotic potential. The risk of zoonotic transmission has been controversially discussed. The aim of this monocentric cross‐sectional pilot study was to investigate G. duodenalis assemblages in humans and pets living in common households in Berlin/Brandenburg (Germany). Samples from dogs, cats and humans sharing the same households were screened for Giardia infection by antigen‐detecting assays. All human samples were additionally analysed by a Giardia‐specific qPCR. Cyst quantification and sequences of different gene loci (triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh), β‐giardin (bg) and for dogs SSUrDNA) were analysed. A total of 38 households (31 households with dogs and seven with cats) with 69 human individuals participated in the study. Initial antigen‐detecting assays revealed Giardia‐positive results for 13 (39%) canine, one (14%) feline and one human sample. Reanalysis of the human samples by qPCR revealed two more positive specimens (4%). Two of these three samples were identified as assemblage B at all tested loci. Success rate of assemblage typing for pet samples was generally low and comprised mainly the SSUrDNA locus only. Overall, six of 13 Giardia‐positive canine samples were typable (2× A, 1× co‐infection: A and B, 1× C; 2× D). One pair of samples (dog and human) from the same household had a similar but not identical assemblage B sequence at tpi locus. Assemblage A was also detected in the dog specimen, which hampered sequence analysis. In conclusion, although exhibiting limitations due to the sample size, our study highlights the need for better and standardized typing tools to distinguish G. duodenalis strains with higher resolution in order to perform proper case–control studies for a realistic estimation of zoonotic risk.     

Giardia duodenalis in primates: Classification and host specificity based on phylogenetic analysis of sequence data

Giardia duodenalis colonizes the gastrointestinal tract of a wide range of hosts, including humans and other primates. It is grouped into eight different Assemblages and, beyond that, into a number of sub‐Assemblages, defined ad hoc on the basis of genetic differences; these various groups are often considered to be associated with a specific restricted host range. The aim of this study was to use publicly available genotyping data to investigate the relatedness of human and non‐human primate (NHP) Giardia isolates in order to evaluate the usefulness of current taxonomic classification and to assess whether there is potential for zoonotic transmission between humans and NHP. Our final data set consisted of sequence data from 165 isolates, 111 from NHP and 54 from humans. Assemblages were well defined, but sub‐Assemblages across Assemblage B were not resolved. Although sub‐Assemblages AI and AII were resolved, the terms were not found to capture any useful molecular or host/deme properties. In the phylogenetic tree, NHP isolates were scattered among human isolates across Assemblages A and B, and were even found in Assemblage E. We conclude that there does not appear to be significant molecular distinction between human and NHP Giardia isolates across these four molecular markers. Thus, on the basis of these markers, we cannot exclude a risk for zoonotic and anthropozoonotic transmission of Assemblages A and B isolates, irrespective of sub‐Assemblage classification. We further evaluated the relative merit of the four genes used in genotyping studies. The tpi, gdh and bg genes gave relatively congruent tree topologies, but the SSU gene did not resolve Assemblages according to the current classification. Future genotyping efforts should aim for multilocus or whole‐genome approaches and, in particular, use of the SSU gene as the sole marker should be avoided when possible.     

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。     

Prevalence of zoonotic parasites in feral cats of Central Virginia,USA

Felis catus, the domestic cat, is the definitive host for parasites that may result in adverse health outcomes in humans. Prevalence data of zoonotic parasites in feral cats, which are free‐roaming domestic cats that are born and live in the wild, are limited. The objective of this study was to assess seroprevalence of Toxoplasma gondii antibodies and copro‐prevalence of potentially zoonotic parasites in feral cats and to evaluate risk factors for seropositivity and faecal excretion of parasites. In this cross‐sectional survey, 275 feral cats at Trap‐Neuter‐Release clinics in Central Virginia were tested for parasites via faecal flotation, direct immunofluorescence assay (faeces) and modified agglutination testing (serum). Toxoplasma gondii seroprevalence was 22.35% (95% CI: 17.47–27.86). Faecal prevalence of T. gondii‐like oocysts was 1.04% (95% CI: 0.13–3.71), Toxocara cati 58.85% (95% CI: 51.54–65.89), Ancylostoma spp. 18.75% (95% CI: 13.49–25.00), Giardia duodenalis 5.73% (95% CI: 2.89–10.02) and Cryptosporidium spp. 3.33% (95% CI: 1.37–7.24). Female cats were more likely than males to excrete faecal Ancylostoma spp. eggs (OR 2.88; 95% CI 1.34–6.17). Adults were more likely than immature cats to be seropositive (OR 2.10; 95% CI: 1.11–3.97) and to excrete faecal Ancylostoma spp. eggs (OR 2.57; 95% CI: 1.10–5.99). However, immature cats were more likely than adults to excrete T. cati eggs (OR 6.79; 95% CI: 3.31–13.90) and to excrete one or more potentially zoonotic species (OR 4.67; 95% CI: 2.28–9.55) in faeces. Results of this study have implications for human and animal health and highlight the importance of collaboration between public health, medical and veterinary communities in preventive efforts.     

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.     

Zoonotic disease transmission associated with feral cats in a metropolitan area: A geospatial analysis

Feral cats raise public health concerns due to their large population numbers and ability to harbour pathogens that cause disease in people, pets, and wildlife. Information regarding the potential for feral cats to intersect with areas frequented by humans is lacking. This study examined the potential for feral cats and human territories to overlap in the Richmond metropolitan area of Central Virginia. Feral cats (n = 275) were trapped for monthly trap‐neuter‐release (TNR) clinics from July to November 2016. A geographic information system (GIS) was used to map feral cat trapping locations, elementary and preschools, public parks, and community gardens, and to evaluate the potential for cat interaction with these areas, presuming a maximum habitat radius of 0.44 miles. We found that 8.0% of feral cats in the Richmond metropolitan area had potential to range onto public elementary or preschool property, and 81.5% of feral cats trapped in Richmond City had potential to roam into one or more places of interest, including elementary and preschool grounds, public parks, and community gardens. This provides public health, veterinary, and human health professionals with important information that can be used to focus resources in an effort to reduce zoonosis associated with feral cat populations.     

Occurrence and genotype characterization of Giardia duodenalis in goat kids from the Canary Islands, Spain

Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis) is a wide-spread intestinal protozoa of both humans and animals. Although giardiosis in goat is commonly asymptomatic, young kids may bear an enteric disease associated with persistent diarrhoea and delayed weight gain. In the present study we have analysed the occurrence of Giardia in 315 young goat kids (2–6 months old) from Gran Canaria Island (Spain) through visualization of faecal cysts. The identification of genotypes of G. duodenalis among the farms was attained by nested PCR of the triophosphate isomerase (TPI) and single PCR of β-giardin genes and subsequent sequencing. Positive samples were found in 42.2% of the animals and 95.5% of the farms. Goat faecal specimens were positive for only livestock-associated G. duodenalis assemblage E genotype for both TPI and β-giardin genes. The genetic analysis of these two loci revealed the presence of different haplotypes among the farms included in the survey and high homology with homologous genes from cattle and sheep. Altogether, the data presented here provide additional information to the prevalence and genetic characterization of Giardia isolates. The absence of assemblages A and B in this study suggests that zoonotic transmission of Giardia from goats could be of low epidemiological significance, although these findings should be validated in studies including other geographical areas, age groups and larger number of samples.     

Prevalence and genetic characterization of Giardia and Cryptosporidium in cats from Italy

One hundred and eighty one cats living in central Italy were tested for the presence of Giardia and Cryptosporidium infection by IFAT test and specific PCRs. Overall eight (4.4%) samples were IFAT-positive for Giardia. All the IFAT-positive samples for Giardia scored positive for the PCRs, and three more samples IFAT-negative generated PCR products leading to a total 6.1% molecular positivity rate for Giardia. All the examined samples were negative for Cryptosporidium. Sequencing of samples molecularly positive to Giardia indicated that three cats harbored the zoonotic Giardia duodenalis Assemblage A, whereas all other positive animals were infected with the feline-specific G. duodenalis Assemblage F. Phylogenetic analysis carried out on the sequences obtained supported the clustering of the isolates within Assemblages A and F. The results here presented provide data on the occurrence of Giardia genotypes in cats living in close contact with humans highlighting the potential importance of this protozoan disease for the public health.     

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.     

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.     

Antibodies to Neospora caninum in stray cats from north Italy

Antibodies to Neospora caninum were determined in serum samples from 282 stray cats coming from four colonies near Turin (north-west Italy). Sera were tested using a Neospora Agglutination Test (NAT). Seroprevalence was 24.8% at 1:80, 12.8% at 1:160 and 5.3% at 1:320 dilution. Seroprevalence in females and males, in different colonies and in different age classes, did not differ significantly. Our results confirm that domestic cats are exposed to N. caninum and the observed seroprevalences suggest that risk of exposure is high and N. caninum should be considered in differential diagnosis in cats with neurological signs.     

Survey of Helicobacter infection in domestic and feral cats in Korea

Discovery of Helicobacter (H.) pylori has led to a fundamental change in our understanding of gastric diseases in humans. Previous studies have found various Helicobacter spp. in dogs and cats, and pets have been questioned as a zoonotic carrier. The present study surveyed the Helicobacter infections and investigated the presence of H. felis and H. pylori infections in domestic and feral cats in Korea. Sixty-four domestic cats and 101 feral cats were selected from an animal shelter. Saliva and feces were evaluated by Helicobacter genus-specific polymerase chain reaction (PCR). Genus-specific PCR positive samples were further evaluated for H. felis and H. pylori using specific primer pairs. Thirty-six of 64 (56.3%) samples from domestic cats and 92 of 101 (91.1%) samples from feral cats were PCR positive; the positive rate of feces samples was higher than that of saliva samples in both groups. H. felis and H. pylori species-specific PCR was uniformly negative. The prevalence of Helicobacter spp. in feral cats was approximately two-fold higher than that of domestic cats. The fecal-oral route may be more a common transmission route not only between cats but also in humans.     

广东省猪十二指肠贾第虫感染现状和分子特征分析

【目的】 了解广东省不同地区猪源十二指肠贾第虫(Giardia duodenalis,简称贾第虫)的流行现状和分子特征,并评估其人兽共患风险。【方法】 从广东省10个地区采集新鲜猪粪样品,采用显微镜镜检,并应用巢式PCR对贾第虫谷氨酸脱氢酶(glutamate dehydrogenase,gdh)基因进行扩增,根据扩增结果计算不同地区和生长阶段猪贾第虫的阳性率。对所有的PCR阳性产物进行测序,将获得的贾第虫gdh基因序列进行BLAST比对,确定贾第虫的基因型;运用Mega 7.0软件的最大似然法构建进化树。【结果】 贾第虫包囊呈椭圆形,囊壁较厚,大小为(10~14)μm ×(7~10)μm,具有明显纵向轴柱,细胞核分布于轴柱两侧。521份受检样品中共检测出94份PCR阳性样品,阳性率为18.04%(94/521),其中茂名和清远的阳性率较高,分别达40.00%(10/25)和35.06%(27/77);肇庆和韶关的阳性率较低,分别为3.90%(3/77)和8.57%(3/35);佛山、江门、阳江、河源、广州和惠州的阳性率分别为11.11%(2/18)、15.31%(15/98)、11.43%(4/35)、13.33%(4/30)、9.38%(3/32)和24.47%(23/94)。不同饲养阶段的猪群的阳性率调查发现,母猪的贾第虫阳性率(24.55%)显著高于断奶仔猪(13.30%)(P<0.05),与育肥猪的贾第虫阳性率(19.23%)差异不显著(P>0.05)。基于gdh基因序列的基因分型和系统进化分析共发现5种贾第虫亚集聚体,即集聚体AⅠ和集聚体E的4种不同亚型,包括集聚体E1、E2、E10和E13,其中61.70%(58/94)测序阳性样品属于集聚体AⅠ,38.30%(36/94)属于集聚体E的不同亚型。【结论】 广东猪源贾第虫的感染较普遍,不同地区和不同生长阶段的猪感染率存在一定差异。其中,人兽共患性集聚体AⅠ为优势亚集聚体,表明广东省猪源贾第虫存在人兽跨物种传播的风险,应重视该病可能引起的公共卫生问题。     

High prevalence of Giardia detected in cats by PCR

Microscopy, PCR and a Giardia CELISA test were used to determine the prevalence of Giardia in 40 faecal samples obtained from domestic cats in the Perth metropolitan area. A prevalence of 5, 80 and 60% was found by the tests, respectively. The results show that more sensitive techniques such as PCR may be necessary, and may yield more reliable results, in the detection of low levels of Giardia in domestic cats.     

长春狐狸、貉和家兔养殖场十二指肠贾第虫基因型分析

为了解长春地区狐狸、貉和家兔养殖场的十二指肠贾第虫感染情况,基于十二指肠贾第虫GDH基因位点分别设计2对引物,对养殖场的120份狐狸粪便样品、60份貉粪便样品和148份家兔粪便样品十二指肠贾第虫进行检测和基因型分析。结果表明,在来自狐狸的粪便中检测出阳性样品44份,阳性率为36.7%,基因型均为基因亚型AI;6份貉阳性样品,阳性率为10.0%,基因型均为集聚体D;41份家兔阳性样品,阳性率为27.7%,其中4份是集聚体B,其他是集聚体A中的基因亚型AI。结果发现在长春地区貉感染贾第虫集聚体D,长春地区的狐狸感染人兽共患型的集聚体A,家兔感染人兽共患型的集聚体A和B。研究结果为该地区十二指肠贾第虫病的防控提供了参考。     

Detection of Invasive Borrelia burgdorferi Strains in North‐Eastern Piedmont,Italy

Following reports of human cases of Lyme borreliosis from the Ossola Valley, a mountainous area of Piemonte, north‐western Italy, the abundance and altitudinal distribution of ticks, and infection of these vectors with Borrelia burgdorferi sensu lato were evaluated. A total of 1662 host‐seeking Ixodes ricinus were collected by dragging from April to September 2011 at locations between 400 and 1450 m above sea level. Additional 104 I. ricinus were collected from 35 hunted wild animals (4 chamois, 8 roe deer, 23 red deer). Tick density, expressed as the number of ticks per 100 m², resulted highly variable among different areas, ranging from 0 to 105 larvae and from 0 to 22 nymphs. A sample of 352 ticks (327 from dragging and 25 from wild animals) was screened by a PCR assay targeting a fragment of the 16S rRNA gene of B. burgdorferi s.l. Positive samples were confirmed with a PCR assay specific for the 5S‐23S rRNA intergenic spacer region and sequenced. Four genospecies were found: B. afzelii (prevalence 4.0%), B. lusitaniae (4.0%), B. garinii (1.5%) and B. valaisiana (0.3%). Phylogenetic analysis based on the ospC gene showed that most of the Borrelia strains from pathogenic genospecies had the potential for human infection and for invasion of secondary body sites.     

Cryptosporidium and Giardia in locally harvested clams in Iqaluit,Nunavut

High prevalences of Cryptosporidium and Giardia were recently found in enteric illness patients in the Qikiqtaaluk region of Nunavut, Canada, with a foodborne, waterborne or animal source of parasites suspected. Clams (Mya truncata) are a commonly consumed, culturally important and nutritious country food in Iqaluit; however, shellfish may concentrate protozoan pathogens from contaminated waters. The goal of this work was to investigate clams as a potential source of Cryptosporidium and Giardia infections in residents in Iqaluit, Nunavut. The objectives were to estimate the prevalence and genetically characterize Cryptosporidium and Giardia in locally harvested clams. Clams (n = 404) were collected from Iqaluit harvesters in September 2016. Haemolymph (n = 328) and digestive gland (n = 390) samples were screened for Cryptosporidium and Giardia via PCR, and amplified products were further processed for sequence analyses for definitive confirmation. Giardia DNA was found in haemolymph from 2 clams, while Cryptosporidium was not detected. The two Giardia sequences were identified as zoonotic Giardia enterica assemblage B. The overall prevalence of Giardia in clams near Iqaluit was low (0.6%) compared with other studies in southern Canada and elsewhere. The presence of Giardia DNA in clams suggests human or animal faecal contamination of coastal habitat around Iqaluit in shellfish harvesting waters. Results from this study are intended to inform public health practice and planning in Inuit Nunangat.     

Prevalence and molecular characterization of Giardia duodenalis and Cryptosporidium spp. in dairy cattle in Ontario, Canada

Giardia duodenalis and Cryptosporidium spp. are intestinal protozoan parasites that infect a wide range of host species, including humans. Molecular characterization of these parasites has demonstrated that a number of genotypes and species are common to both humans and animals, and that zoonotic transmission may occur. Numerous studies have reported a high prevalence of G. duodenalis and Cryptosporidium spp. in cattle, particularly calves, and these animals are frequently associated with zoonotic transmission. In the present study, a total of 143 faecal samples from adults, heifers and calves were collected from two dairy cattle farms in eastern Ontario, Canada. The prevalence and molecular characteristics of G. duodenalis and Cryptosporidium spp. in these animals were determined in order to investigate the potential for transmission between cattle and humans in this region. Following DNA extractions from faecal samples, nested-PCR protocols were used to amplify fragments of the 16S rRNA gene and the heat-shock protein 70 (HSP-70) gene for determining the prevalence of G. duodenalis and Cryptosporidium spp. infections, respectively. Genotypes of G. duodenalis, and species of Cryptosporidium, were determined by means of DNA sequencing of amplicons, and subsequent sequence alignment. Cattle on both farms showed a high prevalence of G. duodenalis (42.0%) and Cryptosporidium spp. (27.3%). G. duodenalis infections were more prevalent in calves and heifers than in adults, and Cryptosporidium spp. infections were only observed in calves and heifers. The zoonotic genotype, G. duodenalis Assemblage B was isolated from 24.5% of the cattle tested, while G. duodenalis Assemblage E was found in 17.5% of the cattle tested. The overall prevalence of the zoonotic species Cryptosporidium parvum in the animals tested was found to be 21.7%, while only 1.4% were infected with C. bovis. These findings suggest that there is a potential risk of zoonotic and/or zooanthroponotic transmission of G. duodenalis and C. parvum infections between cattle and humans in eastern Ontario, likely by means of contaminated water or food, or through direct faecal-oral transmission in the case of farmers and veterinary staff.