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Cryptosporidium parvum is a zoonotic pathogen composed of genetically distinct but morphologically identical genotypes. Recent molecular study indicates that dogs may transmit the cattle genotype, which is known to be pathogenic to humans. Although large-scale studies of Cryptosporidium infection in dogs have been performed in several countries, the isolates were not accurately identified because of the lack of a method for molecular analysis. It is important to identify the isolates harbored in dogs, which come in close contact with humans, in order to control human cryptosporidiosis. The aim of the present study was to calculate the prevalence of Cryptosporidium infection in dogs in Osaka city, Japan, and to characterize the isolates molecularly. The prevalence was determined to be 9.3% (13/140) by PCR. All isolates were found to be Cryptosporidium canis (previously known as the dog genotype), which is thought to be non-pathogenic in humans, based on the sequencing of diagnostic fragments. These results indicate that PCR-based diagnostic methods are a useful tool for the diagnosis and molecular epidemiology of Cryptosporidium infection in dogs, and that dogs living in Osaka are not a significant reservoir for human cryptosporidiosis. It is unclear why C. canis is dominant in dogs. Further study is required to understand this partial parasitism. 相似文献
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Budu-Amoako E Greenwood SJ Dixon BR Sweet L Ang L Barkema HW McClure JT 《Zoonoses and public health》2012,59(6):424-433
To determine the zoonotic potential of Cryptosporidium and Giardia in Prince Edward Island (PEI), Canada, 658 human faecal specimens were screened that were submitted to the Queen Elizabeth Hospital diagnostic laboratory. Overall, 143 (22%) samples were Cryptosporidium positive, while three (0.5%) were positive for Giardia. Successful genotyping of 25 Cryptosporidium isolates by sequence analysis of the HSP70 gene revealed that 28 and 72% were C. hominis and C. parvum, respectively. Cryptosporidium isolates from humans and previously genotyped C. parvum from beef cattle were subtyped by sequence analysis of the GP60 gene. Subtyping identified three subtypes belonging to the family IIa. All three subtypes IIaA16G2RI (55%), IIaA16G3RI (22%) and IIaA15G2RI (22%) were found in the animal isolates, while two of the subtypes found in the animals, IIaA16G2RI (80%) and IIaA15G2RI (20%), were also identified in the human isolates. Cryptosporidium infection in humans peaked in April-June. Molecular epidemiological analysis of the human data showed a C. parvum peak in the spring and a relatively smaller peak for C. hominis in July-September. The majority (57%) of human Cryptosporidium isolates were found in children between 5 and 10 years of age. All three Giardia isolates were identified as G. duodenalis assemblage A. The overall Cryptosporidium prevalence in our human samples was high relative to other studies, but because the samples were submitted to a hospital diagnostic laboratory, the results may not be representative of the general population. Further, the presence of the same zoonotic C. parvum subtypes in cattle and human isolates implies that transmission is largely zoonotic and cattle may be a source of sporadic human infections on PEI. The presence of Giardia in people on PEI is rare, and the assemblage A found in humans might originate from humans, livestock or other domestic or wild animals. 相似文献
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Cryptosporidium: a water-borne zoonotic parasite 总被引：5，自引：0，他引：5
Fayer R 《Veterinary parasitology》2004,126(1-2):37-56
Of 155 species of mammals reported to be infected with Cryptosporidium parvum or C. parvum-like organisms most animals are found in the Orders Artiodactyla, Primates, and Rodentia. Because Cryptosporidium from most of these animals have been identified by oocyst morphology alone with little or no host specificity and/or molecular data to support identification it is not known how many of the reported isolates are actually C. parvum or other species. Cryptosporidiosis is a cause of morbidity and mortality in animals and humans, resulting primarily in diarrhea, and resulting in the most severe infections in immune-compromised individuals. Of 15 named species of Cryptosporidium infectious for nonhuman vertebrate hosts C. baileyi, C. canis, C. felis, C. hominis, C. meleagridis, C. muris, and C. parvum have been reported to also infect humans. Humans are the primary hosts for C. hominis, and except for C. parvum, which is widespread amongst nonhuman hosts and is the most frequently reported zoonotic species, the remaining species have been reported primarily in immunocompromised humans. The oocyst stage can remain infective under cool, moist conditions for many months, especially where water temperatures in rivers, lakes, and ponds remain low but above freezing. Surveys of surface water, groundwater, estuaries, and seawater have dispelled the assumption that Cryptosporidium oocysts are present infrequently and in geographically isolated locations. Numerous reports of outbreaks of cryptosporidiosis related to drinking water in North America, the UK, and Japan, where detection methods are in place, indicate that water is a major vehicle for transmission of cryptosporidiosis. 相似文献
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Matsubayashi M Abe N Takami K Kimata I Iseki M Nakanishi T Tani H Sasai K Baba E 《Veterinary parasitology》2004,120(3):171-175
Cryptosporidium species have been found in more than 150 species of mammals, but there has been no report in raccoon dogs. Here we found the Cryptosporidium organism in a raccoon dog, Nyctereutes procyonoides viverrinus, and identified this isolate using PCR-based diagnostic methods. Cryptosporidium diagnostic fragments of the 18S ribosomal RNA, Cryptosporidium oocyst wall protein and 70-kDa heat shock protein genes were amplified from the isolate and sequenced to reveal the phylogenetic relationships between it and other Cryptosporidium species or genotypes reported previously. The results showed that the raccoon dog isolate represented the C. parvum cattle genotype which could be a causative agent in human cryptosporidiosis. 相似文献
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Cryptosporidium parvum is commonly identified as infecting domestic livestock and humans. Prevalence of C. parvum in pigs has been reported, however, the duration and infection pattern of naturally acquired Cryptosporidium infections in pigs has not been reported. This study was undertaken to investigate the age of oocyst shedding and duration of natural Cryptosporidium parvum infections in pigs from weaning to market weight. Fecal samples were collected from weaned Yorkshire-Landrace piglets (n=33) twice per week until Cryptosporidium oocysts were detected. Upon oocyst detection, fecal samples were collected three times per week and pigs were monitored throughout the study for diarrhea and examined after concentration and immunofluroescent staining. Cryptosporidium isolates were genotyped by polymerase chain reaction to amplify the HSP70 gene which was subsequently sequence analyzed. All 33 pigs shed oocysts some time during the study. The mean age of initial oocyst detection was 45.2 days post-weaning with the mean duration of infection 28.7 days. Mean number of Cryptosporidium oocysts was low and declined to zero prior to study completion. Episodes of diarrhea were not associated with oocyst excretion. Genetic sequences were obtained for 10 of the pigs. All of the 10 isolates aligned as the Cryptosporidium parvum 'pig' genotype. This study demonstrates that the age and duration of oocyst shedding in pigs infected with C. parvum porcine genotype is different from other livestock species. 相似文献
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To study the diversity of Cryptosporidium spp. in various hosts, we used the variability of the small-subunit rRNA gene and the Cryptosporidium oocyst wall protein genes. Oocysts from humans, cattle, horses, dogs, field mice, chickens, reptiles, deer, goat, cat, antelope and from a sample of water reservoir were assayed. The zoonotic C. parvum bovine genotype sequence was found to be present in the most of isolates. This study shows a complex epidemiology pattern for C. parvum bovine genotype infections. The identification of cattle, horse, and deer isolates emphasizes a transmission route for C. parvum via these hosts, and identifies a potential source for human infection in the Czech Republic. Furthermore, C. andersoni from a cow, C. baileyi from a chicken, C. felis from a cat, C. meleagridis from a dog, and C. saurophilum and C. serpentis from reptiles were also identified in the isolates from the Czech Republic. 相似文献
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Gabriella Lindergard Daryl V Nydam Susan E Wade Stephanie L Schaaf Hussni O Mohammed 《Journal of veterinary diagnostic investigation》2003,15(3):262-267
A nested multiplex polymerase chain reaction (PCR) approach was adopted for the simultaneous detection of 4 human infective genotypes of the protozoan parasite Cryptosporidium. Specific PCR primers were designed for the heat shock protein 70 gene of 2 genotypes of Cryptosporidium parvum (human and bovine types), Cryptosporidium canis, and Cryptosporidium felis. These 4 genotypes have all been found in human fecal samples. The primers amplified DNA fragments of specific sizes, each representing a unique genotype. The limit of detection of the method was found to vary between 10 and 100 oocysts per 1 ml fecal material. There appeared to be no cross-reactivity with other organisms commonly present in feces and soil, and the approach has a high specificity. The rapid identification of various human infective Cryptosporidium isolates is a part of the authors' long-term aim of determining the routes of infection with oocysts and thereby increase their epidemiological understanding of Cryptosporidium infection in humans and animals. 相似文献
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Livestock are commonly infected with protozoan parasites of the genera Cryptosporidium and Giardia, and some of the species and genotypes found in these animals have zoonotic significance. We characterized isolates of both parasites recovered from the Italian water buffalo (Bubalus bubalis), an economically important species whose milk is used for the production of "buffalo mozzarella" fresh cheese. Molecular analysis of the Cryptosporidium small subunit ribosomal DNA gene and of the Giardia beta-giardin gene shows the presence of both zoonotic parasites (Cryptosporidium parvum and Giardia duodenalis assemblage A) and host-specific parasites (G. duodenalis assemblage E), suggesting that water buffaloes can contribute to environmental contamination with oocysts and cysts potentially infectious to humans if their faeces are improperly disposed of. On the other hand, mozzarella cheese is probably a safe product, given that its production involves the treatment of cheese curd at 85-95 degrees C, which is likely to kill or inactivate the parasites. 相似文献
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Dixon B Parrington L Cook A Pintar K Pollari F Kelton D Farber J 《Veterinary parasitology》2011,175(1-2):20-26
The objective of this study was to compare the occurrence and the genotypes and species of Giardia duodenalis and Cryptosporidium spp. in beef and dairy cattle from farms in the Regional Municipality of Waterloo, Ontario, in an effort to determine the potential for zoonotic transmission from these animals. Pooled manure samples were collected from 45 dairy cattle farms and 30 beef cattle farms. The presence of Giardia cysts and Cryptosporidium oocysts was determined by immunofluorescence microscopy, while nested-PCR and DNA sequencing were used to determine genotypes and species. The overall farm prevalence was very high for both Giardia and Cryptosporidium, and was similar for dairy cattle farms (96 and 64%, respectively) and beef cattle farms (97 and 63%, respectively). However, on dairy cattle farms, G. duodenalis and Cryptosporidium spp. were detected in 44% and 6% of total pooled pen manure samples, respectively, with the occurrence of both parasites being generally higher in calves than in older animals. Most Giardia isolates were identified as either the host-adapted genotype G. duodenalis Assemblage E or the zoonotic Assemblage B. Cryptosporidium parvum and Cryptosporidium andersoni were the most frequently identified species in dairy cattle, while the non-zoonotic species Cryptosporidium ryanae and Cryptosporidium bovis were also found. On beef cattle farms, 72% and 27% of the total pooled pen manure samples were positive for Giardia and Cryptosporidium, respectively, with no obvious correlation with age. All Giardia isolates in beef cattle were identified as G. duodenalis Assemblage E, while all Cryptosporidium isolates were identified by sequence analysis as C. andersoni, although microscopic analyses, and subsequent restriction fragment length polymorphism analyses, indicated that other Cryptosporidium species were also present. The results of this study indicate that although Giardia and Cryptosporidium were identified in a higher overall percentage of the pooled beef cattle manure samples than in dairy cattle, firmly established zoonotic genotypes and species were much more common in dairy cattle than in beef cattle in this region. Dairy cattle, and especially dairy calves, may, therefore, pose a greater risk of infection to humans than beef cattle. However, these results may also provide evidence of potential zooanthroponotic transmission (human to animal). 相似文献
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Cryptosporidium and Giardia as foodborne zoonoses 总被引：1，自引：0，他引：1
Cryptosporidium and Giardia are major causes of diarrhoeal disease in humans, worldwide and are major causes of protozoan waterborne diseases. Both Cryptosporidium and Giardia have life cycles which are suited to waterborne and foodborne transmission. There are 16 'valid'Cryptosporidium species and a further 33+ genotypes described. Parasites which infect humans belong to the Giardia duodenalis "type", and at least seven G. duodenalis assemblages are recognised. Cryptosporidium parvum is the major zoonotic Cryptosporidium species, while G. duodenalis assemblages A and B have been found in humans and most mammalian orders. In depth studies to determine the role of non-human hosts in the transmission of Cryptosporidium and Giardia to humans are required. The use of harmonised methodology and standardised and validated molecular markers, together with sampling strategies that provide sufficient information about all contributors to the environmental (oo)cyst pool that cause contamination of food and water, are recommended. Standardised methods for detecting (oo)cysts in water are available, as are optimised, validated methods for detecting Cryptosporidium in soft fruit and salad vegetables. These provide valuable data on (oo)cyst occurrence, and can be used for species and subspecies typing using appropriate molecular tools. Given the zoonotic potential of these organisms, epidemiological, source and disease tracking investigations involve multidisciplinary teams. Here, the role of the veterinarian is paramount, particularly in understanding the requirement for adopting comprehensive sampling strategies for analysing both sporadic and outbreak samples from all potential non-human contributors. Comprehensive sampling strategies increase our understanding of parasite population biology and structure and this knowledge can be used to determine what level of discrimination is required between isolates. Genetic exchange is frequent in C. parvum populations, leading to recombination between alleles at different loci, the generation of a very large number of different genotypes and a high level of resolution between isolates. In contrast, genetic exchange appears rare in Cryptosporidium hominis and populations are essentially clonal with far fewer combinations of alleles at different loci, resulting in a much lower resolution between isolates with many being of the same genotype. Clearly, more markers provide more resolution and high throughput sequencing of a variety of genes, as in multilocus sequence typing, is a way forward. Sub-genotyping tools offer increased discrimination, specificity and sensitivity, which can be exploited for investigating the epidemiology of disease, the role of asymptomatic carriers and contaminated fomites and for source and disease tracking for food and water contaminated with small numbers of (oo)cysts. 相似文献
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为阐明河南区域隐孢子虫分子流行病学特点,用PCR技术扩增分离虫株的18S rRNA基因全序列和HSP70基因序列,并对扩增片段进行测序。用PAUP 4.0和TREEPUZZLE 4.1构建进化树,试图从分子水平证明河南省不同地区不同宿主来源隐孢子虫的遗传特征,以阐明隐孢子虫病的分子流行病学特点。通过18S rRNA基因全序列和HSP70基因序列分析,其结果：河南人源隐孢子虫分离株为Cryptosporidium parvum鼠基因型;河南鹿源隐孢子虫分离株为C. parvum鹿基因型;河南猪源隐孢子虫的2个分离株均为C. parvum猪基因I型,即C. suis;河南鹌鹑源的隐孢子虫2个分离株分别为C. baileyi和C. meleagridis;河南乌鸡源隐孢子虫和鸵鸟源隐孢子虫分离株均为C. baileyi;河南牛源隐孢子虫分离株为C.andersoni。 相似文献
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Harp JA 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2003,4(1):53-62
Cryptosporidium parvum is recognized as a major cause of diarrheal disease in neonatal bovine calves. In addition, this protozoan parasite has emerged as an important cause of disease in both immunocompromised and immunocompetent humans. Despite years of research, no consistently effective means of prevention or treatment are readily available for cryptosporidiosis in any species. Infection through ingestion of contaminated water has been widely documented; C. parvum was reported to be responsible for the largest waterborne outbreak of infectious disease in US history. In addition to its role as a primary disease agent, C. parvum has potential to initiate or exacerbate other gastrointestinal disorders, such as inflammatory bowel disease. Thus, control of C. parvum infection in both animals and humans remains an important objective. Research in our laboratory has focused on understanding mechanisms of resistance to C. parvum. We have demonstrated that acquisition of intestinal flora increases resistance to C. parvum. Substances present in the intestinal mucosa of adult animals can transfer resistance when fed to susceptible infants. Both expression of intestinal enzymes and rate of proliferation of epithelial cells may be altered following C. parvum infection. These and other changes may have profound effects on host resistance to C. parvum. 相似文献
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Prevalence and molecular characterization of Cryptosporidium and Giardia species and genotypes in sheep in Maryland 总被引：3，自引：0，他引：3
In the United Kingdom and Australia sheep have been implicated as sources of Cryptosporidium and Giardia that infect humans, but no such studies have been conducted in North America. Therefore, a study was undertaken to investigate the prevalence of these parasites in sheep on a farm in Maryland. Feces were collected from 32 pregnant ewes 1, 2, and 3 days after parturition and from each of their lambs 7, 14, and 21 days after birth. The presence of Cryptosporidium oocysts and Giardia cysts was determined by both immunofluorescence microscopy and PCR/gene sequence analysis. PCR was consistently more sensitive than microscopy. The prevalence, by PCR, of Cryptosporidium in ewes and lambs was 25 and 77.4%, respectively. Three species/genotypes of Cryptosporidium were identified: C. parvum, a novel C. bovis-like genotype, and Cryptosporidium cervine genotype. Cryptosporidium parvum and the cervine genotype have been reported worldwide in human infections. The novel C. bovis-like genotype is reported here for the first time. The prevalence of Giardia in ewes and lambs was 12 and 4%, respectively. Most infections were Assemblage E which is not zoonotic; however, one ewe was infected with zoonotic Assemblage A. The identification of only two lambs infected with C. parvum and one ewe infected with G. duodenalis Assemblage A suggests a low prevalence of these zoonoses. However, the high prevalence of the zoonotic cervine genotype indicates that sheep should be considered a potential environmental source of this human pathogen. 相似文献
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To estimate the prevalence of enteric parasites and selected vector-borne agents of dogs and cats in San Isidro de El General, Costa Rica, fecal and serum samples were collected from animals voluntarily undergoing sterilization. Each fecal sample was examined for parasites by microscopic examination after fecal flotation and for Giardia and Cryptosporidium using an immunofluorescence assay (IFA). Giardia and Cryptosporidium IFA positive samples were genotyped after PCR amplification of specific DNA if possible. The seroprevalence rates for the vector-borne agents (Dirofilaria immitis, Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum) were estimated based on results from a commercially available ELISA. Enteric parasites were detected in samples from 75% of the dogs; Ancylostoma caninum, Trichuris vulpis, Giardia, and Toxocara canis were detected. Of the cats, 67.5% harbored Giardia spp., Cryptosporidium spp., Ancylostoma tubaeforme, or Toxocara cati. Both Cryptosporidium spp. isolates that could be sequenced were Cryptosporidium parvum (one dog isolate and one cat isolate). Of the Giardia spp. isolates that were successfully sequenced, the 2 cat isolates were assemblage A and the 2 dog isolates were assemblage D. D. immitis antigen and E. canis antibodies were identified in 2.3% and 3.5% of the serum samples, respectively. The prevalence of enteric zoonotic parasites in San Isidro de El General in Costa Rica is high in companion animals and this information should be used to mitigate public health risks. 相似文献
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本试验以编码线粒体功能性蛋白Chaperonin 60(CPN60)的核基因作为研究对象,对隐孢子虫分离株CPN60基因进行扩增测序,用Clustal X1.81对扩增序列与GenBank相关参考序列进行比对,然后用PAUP4.0程序中邻接法(Neighbor-joining,NJ)、最大简约法(Parsimony,MP)构建基因树,同时用TREEPUZZLE程序Version4.1构建最大似然树(Maximum likelihood,ML),以确定不同隐孢子虫虫株之间的进化关系,并以18S rRNA和HSP70基因构建的进化树作参照,评价CPN60是否更适合作为隐孢子虫基因分型和进化关系的分子标记。结果显示:基于CPN60构建的进化树将隐孢子虫分为两大类:C.baileyi和C.meleagridis处于一个分枝,C.hominis、C.suis、C.parvum牛基因型和C.parvum鼠基因型处于另一个分枝上。不同隐孢子虫之间的同源性介于96%~100%,能有效区分隐孢子虫不同基因型。因此,CPN60基因序列也可作为隐孢子虫分离株种系发育的遗传标记。 相似文献
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Follet J Guyot K Leruste H Follet-Dumoulin A Hammouma-Ghelboun O Certad G Dei-Cas E Halama P 《Veterinary research》2011,42(1):116
ABSTRACT: Feces from 142 animals were collected on 15 farms in the region of Brittany, France. Each sample was directly collected from the rectum of the animal and identified with the ear tag number. Animals were sampled three times, at 5, 15 and 22 weeks of age. After DNA extraction from stool samples, nested PCR was performed to amplify partial 18S-rDNA and 60 kDa glycoprotein genes of Cryptosporidium. The parasite was detected on all farms. One hundred out of 142 calves (70.4%) were found to be parasitized by Cryptosporidium. Amplified fragments were sequenced for Cryptosporidium species identification and revealed the presence of C. parvum (43.8%), C. ryanae (28.5%), and C. bovis (27%). One animal was infected with Cryptosporidium ubiquitum. The prevalence of these species was related to the age of the animal. C. parvum caused 86.7% of Cryptosporidium infections in 5-week-old calves but only 1.7% in 15-week-old animals. The analysis of the results showed that animals could be infected successively by C. parvum, C. ryanae, and C. bovis for the study period. C. parvum gp60 genotyping identifies 6 IIa subtypes of which 74.5% were represented by IIaA15G2R1. This work confirms previous studies in other countries showing that zoonotic C. parvum is the dominant species seen in young calves. 相似文献