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1.
目前，隐孢子虫有效种有20个。隐孢子虫的分子流行病学研究表明，隐孢子虫具有宿主特异性。目前，感染人的隐孢子虫种和基因型有C．horninis、C.parvum、C．meleagridis、C.felis、C.canis、C.nuris、C．suis genotype和C．cervine genotype等。水源性隐孢子虫暴发，具有重要的公共卫生意义。分子鉴定技术已广泛应用于检测水中隐孢子虫，水中检测到的隐孢子虫有9个。通过分析其分子组成特性表明，成年牛可能是水污染的主要根源，除了居民用水和农业污染外，鹿、麝鼠、田鼠、鸟和其它野生动物可能也与水污染有关。隐孢子虫分子基因型鉴定工具可能为水源保护性研究提供一个更有力的溯源追踪工具。 相似文献
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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
3.
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
4.
Morgan UM Xiao L Limor J Gelis S Raidal SR Fayer R Lal A Elliot A Thompson RC 《Australian veterinary journal》2000,78(3):182-183
OBJECTIVE: To perform a morphological and genetic characterisation of a Cryptosporidium infection in an Indian ring-necked parrot (Psittacula krameri) and to compare this with C meleagridis from a turkey. DESIGN: Tissue and intestinal sections from an Indian ring-necked parrot were examined microscopically for Cryptosporidium. The organism was also purified from the crop and intestine, the DNA extracted and a portion of the 18S rDNA gene amplified, sequenced and compared with sequence and biological information obtained for C meleagridis from a turkey as well as sequence information for other species of Cryptosporidium. RESULTS: Morphological examination of tissue sections from an Indian ring-necked parrot revealed large numbers of Cryptosporidium oocysts attached to the apical border of enterocytes lining the intestinal tract. Purified Cryptosporidium oocysts measured about 5.1 x 4.5 microns, which conformed morphologically to C meleagridis. The sequence obtained from this isolate was identical to sequence information obtained from a C meleagridis isolate from a turkey. CONCLUSION: Cryptosporidium meleagridis was detected in an Indian ring-necked parrot using morphological and molecular methods. This is the first time that this species of Cryptosporidium has been reported in a non-galliform host and extends the known host range of C meleagridis. 相似文献
5.
Gómez-Couso H Ortega-Mora LM Aguado-Martínez A Rosadio-Alcántara R Maturrano-Hernández L Luna-Espinoza L Zanabria-Huisa V Pedraza-Díaz S 《Veterinary parasitology》2012,187(3-4):414-420
The presence of Giardia and Cryptosporidium was investigated in 274 faecal samples of alpacas (Vicugna pacos) from 12 herds from Peru by immunofluorescence microscopy and PCR amplification and sequencing of fragments of the ssu-rRNA and β-giardin genes from Giardia spp., as well as the ssu-rRNA gene from Cryptosporidium spp. A total of 137 samples (50.0%) were positive for Giardia spp., and 12 samples (4.4%) for Cryptosporidium spp. In ten samples (3.6%), co-infection by both pathogens was found. Herd prevalence was found to be 91.7% (11/12 herds) for Giardia and 58.3% (7/12 herds) for Cryptosporidium. Regarding the age of the animals, although Giardia was detected in animals as young as 1 week, the prevalence increased with age, reaching 80% by 8 weeks. Similarly, the highest percentage of Cryptosporidium detection (20%) was also found in the 8 week-old group. By PCR, 92 of the 274 analysed samples were positive for Giardia. Sequencing of the amplicons showed the existence of Giardia duodenalis assemblage A in 67 samples; G. duodenalis assemblage E in 24 samples; and inconsistent results between the two molecular markers used in a further sample. Cryptosporidium was only detected by PCR in 3 of the 274 samples; Cryptosporidium parvum was identified in two samples and Cryptosporidium ubiquitum in one sample. This study is the first performing molecular characterisation of both parasites in Peruvian alpacas, and the first report of C. ubiquitum in this host. The identification of G. duodenalis assemblage A, C. parvum and C. ubiquitum, suggests that zoonotic transmission of these enteropathogens between alpacas and humans is possible. 相似文献
6.
Němejc K Sak B Květoňová D Hanzal V Jeníková M Kváč M 《Veterinary parasitology》2012,184(2-4):122-125
A total of 193 faecal samples of adult Eurasian wild boars were collected at 12 enclosures across the Czech Republic and examined for Cryptosporidium infection using both microscopic and molecular tools. Cryptosporidium oocysts were not detected in any of the 193 faecal samples examined using the aniline-carbol-methyl violet staining method. Thirty-two positive cases of Cryptosporidium infection were detected using either genus- or species-specific nested PCR. Mono-infection with Cryptosporidium suis and Cryptosporidium pig genotype II were found in 13 and 7 cases, respectively. Five mixed infections of C. suis and Cryptosporidium pig genotype II were detected using PCR/RFLP with genus specific primers. The number of detected mixed infections increased 2.4 fold when a species-specific PCR was employed. No other Cryptosporidium spp. was detected. Unlike cryptosporidiosis of domestic pigs, C. suis was detected as a dominant species infecting adult Eurasian wild boars. There was no association between diarrhoea and the presence of Cryptosporidium infection in the Eurasian wild boars studied. This is the first report on the Cryptosporidium infection caused by C. suis and Cryptosporidium pig genotype II in Eurasian wild boars (Sus scrofa). 相似文献
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Two species of Cryptosporidium are commonly identified in pigs: Cryptosporidium suis and Cryptosporidium pig genotype II. Detection of Cryptosporidium spp. is routinely based on molecular methods such as polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) or gene sequencing. However, most of these methods are hampered by low sensitivity to mixed infections. As a solution of this problem, novel species-specific primers were designed and tested in the present study. Sensitivity of our primers was identical to genus-specific primers, but more (1:48) mixed infections were detected using these species-specific primers on 477 DNA samples originating from naturally infected pigs of different age categories. Our results show differences in age-dependent susceptibility of pigs to the infection. Whereas C. suis was found in all tested categories of pigs (1-12 week of age and sows), Cryptosporidium pig genotype II was recorded only in animals older than 6 week of age. Usage of species-specific primers could help to better the understanding of epidemiology of pig specific Cryptosporidium spp. and its occurrence, which, on the basis of our results, is underestimated. 相似文献
10.
Maikai BV Umoh JU Kwaga JK Lawal IA Maikai VA Cama V Xiao L 《Veterinary parasitology》2011,178(3-4):241-245
Despite numerous molecular epidemiologic studies of cryptosporidiosis in dairy cattle in industrialized countries, there are very few studies on the diversity and public health significance of Cryptosporidium species in native cattle in developing countries. In this study, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the small-subunit (SSU) rRNA gene was used to detect and identify Cryptosporidium spp. in 194 fecal specimens from 2 to 365 days old calves in 20 White Fulani and Sokoto Gudali herds in Nigeria. Thirty one (16.0%) of the specimens were positive for Cryptosporidium. Restriction digestion of the PCR products showed the presence of Cryptosporidium bovis (7.2%), Cryptosporidium ryanae (4.1%), Cryptosporidium andersoni (2.5%), and concurrent occurrence of C. bovis and C. ryanae (1.5%), and C. bovis and C. andersoni (0.5%). There were no significant differences (p>0.05) in Cryptosporidium infection rates by sex, herd location, management system, breed of calves, or fecal consistency. However, calves 180 days or younger had a higher infection rate of Cryptosporidium than older calves (p=0.034). Likewise, younger calves also had higher occurrence of C. bovis and C. ryanae (p=0.022). The absence of zoonotic Cryptosporidium parvum in the calves studied suggests that native breeds of cattle may not be important in the transmission of human cryptosporidiosis in Kaduna State, Nigeria. 相似文献
11.
分子生物学技术在隐孢子虫研究中的应用 总被引：3，自引：0，他引：3
隐孢子虫是顶复门原虫，主要寄生于人或动物的消化道上皮并引起腹泻，是寄生虫学、环境微生物学研究热点之一。分子生物学技术给隐孢子虫研究注入了强大动力，本文就其在隐孢子虫检测、分子流行病学调查、分类学以及药物设计等研究领域的应用作一综述。 相似文献
12.
Prevalence and molecular characterisation of Cryptosporidium and Giardia in lambs and goat kids in Belgium 总被引：1，自引：0，他引：1
Geurden T Thomas P Casaert S Vercruysse J Claerebout E 《Veterinary parasitology》2008,155(1-2):142-145
The prevalence of Cryptosporidium and Giardia was studied on 10 intensively reared sheep and goat farms in the province of East Flanders, Belgium. Random faecal samples were collected and examined using the Merifluor((R)) immunofluorescence assay. Cryptosporidium positive samples were withheld for molecular identification using primers targeting the 18S rDNA, 70 kDa heat shock protein and 60 kDa glycoprotein gene. For the molecular identification of Giardia the beta-giardin gene and a recently developed assemblage specific PCR based on the triose phosphate isomerase gene were used. The prevalence of Cryptosporidium in lambs was 13.1% (18/137), on 4 out of 10 farms. In goat kids the Cryptosporidium prevalence was 9.5% (14/148), on 6 out of 10 farms. The molecular characterisation of Cryptosporidium positive isolates indicated that in lambs (n=10) the cervine genotype was predominant, whereas in the goat kids (n=11) only C. parvum was identified, with subgenotypes IIaA15G2R1 and IIdA22G1. The Giardia prevalence was 25.5% (35/137) in lambs with all 10 farms being positive, and 35.8% (53/148) in goat kids with 8 out of the 10 farms being positive. Both in the goat kids and in the lambs the host specific assemblage E was most commonly identified. However, the zoonotic assemblage A was identified in 6 out of 28 goat kids and in 2 out of 8 lambs, based on the beta-giardin sequence alignment. Using the assemblage specific PCR, mixed assemblage A and E infections were additionally identified in 2 lambs and in 5 goat kids. The results of the present study indicate that both Cryptosporidium and Giardia are common parasites on intensively reared sheep and goat farms in the province of East Flanders, Belgium, and that they are a potential source for zoonotic infections. 相似文献
13.
Cryptosporidium ryanae n. sp. (Apicomplexa: Cryptosporidiidae) in cattle (Bos taurus) 总被引：1，自引：0，他引：1
A new species, Cryptosporidium ryanae, is described from cattle. Oocysts of C. ryanae, previously identified as the Cryptosporidium deer-like genotype and recorded as such in GenBank (AY587166, EU203216, DQ182597, AY741309, and DQ871345), are similar to those of Cryptosporidium parvum and Cryptosporidium bovis but smaller. This genotype has been reported to be prevalent in cattle worldwide. Oocysts obtained from a calf for the present study are the smallest Cryptosporidium oocysts reported in mammals, measuring 2.94-4.41micromx2.94-3.68microm (mean=3.16micromx3.73microm) with a length/width shape index of 1.18 (n=40). The pre-patent period for two Cryptosporidium-na?ve calves fed C. ryanae oocysts was 11 days and the patent period was 15-17 days. Oocysts were not infectious for BALB/c mice or lambs. Fragments of the SSU-rDNA, HSP-70, and actin genes amplified by PCR were purified and PCR products were sequenced. Multi-locus analysis of the three unlinked loci demonstrated the new species to be distinct from all other species and also demonstrated a lack of recombination, providing further evidence of species status. Based on morphological, molecular and biological data, this geographically widespread parasite found only in Bos taurus calves is recognized as a new species and is named C. ryanae. 相似文献
14.
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
15.
Wang R Qi M Jingjing Z Sun D Ning C Zhao J Zhang L Xiao L 《Veterinary parasitology》2011,175(1-2):151-154
Few data are available on the molecular characterization of Cryptosporidium spp. in ostriches. The objective of this study was to determine the prevalence of Cryptosporidium species or genotypes in ostriches. A total of 452 fecal samples from five farms, a zoo, and an animal rescue center in Zhengzhou, Henan Province, China were examined for Cryptosporidium oocysts by microscopy of wet mount of fecal materials concentrated by the Sheather's sugar flotation technique. Fifty-three samples were Cryptosporidium-positive from four farms, with an overall prevalence of 11.7%. The percentage of animals shedding oocysts was 0, 16.2%, 7.2%, and 0 in 1-3 weeks, 4-8 weeks, 3-12 months, and more than 12 months ostriches, respectively (χ(2)=17.74; ρ<0.01). PCR-restriction fragment length polymorphism (RFLP) analysis of the small subunit (SSU) rRNA gene of the 53 Cryptosporidium-positive samples showed the presence of only Cryptosporidium baileyi, which was confirmed by DNA sequencing of the SSU rRNA PCR products from 16 positive samples. Cross-transmission studies demonstrated that the C. baileyi isolate could infect chickens and quails. Thus, ostriches are commonly infected with C. baileyi that is genetically and biologically similar to C. baileyi found in other birds. 相似文献
16.
Kang&#;ethe Erastus K. Mulinge Erastus K. Skilton Robert A. Njahira Moses Monda Joseph G. Nyongesa Concepta Mbae Cecilia K. Kamwati Stanley K. 《Tropical animal health and production》2012,44(1):25-31
A total of 1,734 cattle faecal samples from 296 dairy-keeping households were collected from urban settings in Nairobi, Kenya. Modified Ziehl–Neelsen staining method and an immunofluorescence assay were used to identify those samples with Cryptosporidium oocyst infection. Oocysts from positive faecal samples were isolated by Sheather's sucrose flotation method and picked from the concentrate using cover slips. Genomic DNA was extracted from 124 of the faecal samples that were positive for Cryptosporidium and was used as template for nested PCR of the 18S rRNA gene. Twenty-five samples (20 %) were PCR-positive for Cryptosporidium, and 24 of the PCR products were successfully cloned and sequenced. Sequence and phylogenetic analysis identified 17 samples (68 %) as Cryptosporidium parvum-like, four samples (16 %) as Cryptosporidium ryanae, three samples (12 %) as Cryptosporidium andersoni and one sample (4 %) as Cryptosporidium hominis. To the best of our knowledge, this is the first genotyping study to report C. parvum-like, C. andersoni and C. hominis in cattle from Kenya. The results of this study show Cryptosporidium infections in calves and cattle may be potential zoonotic reservoirs of the parasite that infects humans. 相似文献
17.
Prevalence and age-related variation of Cryptosporidium species and genotypes in dairy calves 总被引：8，自引：0，他引：8
Fifteen dairy farms in seven states on the east coast of the US were each visited on two consecutive years to determinate the prevalence of Cryptosporidium species in pre-weaned (5 days to 2 months) and post-weaned calves (3-11 months), respectively. After each of 971 fecal specimens collected directly from each calf was sieved and subjected to density gradient centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy, and polymerase chain reaction (PCR). For all PCR-positive specimens the 18S rRNA gene of Cryptosporidium was sequenced. Cryptosporidium was identified from all farms. Types of housing appeared to have no influence with regard to prevalence of infection. Of 971 calves, 345 were infected with Cryptosporidium (35.5%), but more pre-weaned calves (253 of 503; 50.3%) than post-weaned calves (92 of 468; 19.7%) were found to be infected. A total of 278 PCR-positive specimens characterized by gene sequencing revealed Cryptosporidium parvum, Cryptosporidium andersoni, and two unnamed Cryptosporidium genotypes Bovine B (AY120911) and deer-like genotype (AY120910). The prevalence of these Cryptosporidium species and genotypes appeared to be age related between pre- and post-weaned calves. C. parvum, the only zoonotic species/genotype, constituted 85% of the Cryptosporidium infections in pre-weaned calves but only 1% of the Cryptosporidium infections in post-weaned calves. These findings clearly demonstrate that earlier reports on the presence and prevalence of C. parvum in post-weaned cattle that were based solely on oocyst morphology must be reassessed using molecular methods to validate species and genotype. This finding also indicates that persons handling or otherwise exposed to calves under 2 months of age are at greater risk of zoonotic infection from Cryptosporidium than the risk of infection from exposure to older calves. 相似文献
18.
隐孢子虫病检测技术研究进展 总被引：2，自引：1，他引：1
隐孢子虫是动物和人腹泻的重要病原,也是人类艾滋病患者的主要致死因素之一.当前,对隐孢子虫病的研究已成为全球寄生虫学研究领域的热点由,于迄今尚无治疗隐孢子虫病感染的特效药物,因此,快速、简便、准确地发现隐孢子虫是控制该病的关键.随着分子生物学技术的应用,隐孢子虫病的检测技术得到了极大的发展.笔者就近年来隐孢子虫病检测技术进行了简要综述. 相似文献
19.
Vítovec J Hamadejová K Landová L Kvác M Kvetonová D Sak B 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2006,53(5):239-243
A total of 4338 faecal samples, 135 of sows, 3368 of pre-weaned and 835 of post-weaned piglets from eight farms in South Bohemia, Czech Republic were collected and examined for Cryptosporidium infection. No sow, but 5.7% pre-weaned and 24.1% post-weaned piglets were positive for Cryptosporidium infection. No relationship was found between diarrhoea and Cryptosporidium infection in any of the different age groups (pre- and post-weaned piglets). Four piglets, which were sporadically shedding cryptosporidia in faeces, were necropsied. Neither clinical signs of diarrhoea nor macroscopical changes were found. Histologically, a moderate infection of cryptosporidia was detected in the glandular epithelium along the large intestine, with predisposition to the ansa centralis of the colon. No inflammatory response in the lamina propria was observed. Cryptosporidia were also commonly found in the glandular epithelium of submucosal lymphoglandular complexes in the colon. Cryptosporidium isolates from all farms were identified as Cryptosporidium suis using molecular markers (SSU rRNA). All of the C. suis strains obtained were larger [6.2 (6.0-6.8) x 5.5 (5.3-5.7) microm] than any isolate described so far [4.6 (4.4-4.9) x 4.2 (4.0-4.3) microm] and did not appear to be infective for neonatal BALB/c mice. 相似文献
20.
Suárez-Luengas L Clavel A Quílez J Goñi-Cepero MP Torres E Sánchez-Acedo C del Cacho E 《Veterinary parasitology》2007,148(3-4):231-235
A total of 142 stool specimens from pigs on 24 farms from the province of Zaragoza (northeastern Spain) were screened for Cryptosporidium spp. Samples were first analysed by routine techniques (formalin-ethyl acetate sedimentation method and modified Ziehl-Neelsen stain) selecting those microscopically positive for genetic characterization. Cryptosporidium species and genotypes were determined by a nested PCR-RFLP technique at the 18S ribosomal DNA locus and sequencing of the PCR-positive secondary products. Cryptosporidium oocysts were microscopically identified in the faeces of 32 pigs (22.5%) from 15 farms (62.5%). Infected animals included 23 weaned piglets (30.7%), 5 fattening pigs (11.9%) and 4 sows (16%). Diarrhoea was not detected in any of the infected pigs. The molecular characterization was successfully performed in 26 samples from 14 farms. Cryptosporidium suis was found in 10 specimens from 7 farms (nine weaned piglets and one sow) and the Cryptosporidium pig genotype II in 16 samples from 10 farms (13 weaned piglets and 3 fattening pigs). Both C. suis and the pig genotype II were concurrently detected on three farms. 相似文献