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Molecular characterization of Cryptosporidium isolates from human and bovine using 18s rRNA gene in Shahriar county of Tehran, Iran. Parasitol Res 2008; 103:467-72. [DOI: 10.1007/s00436-008-1008-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Accepted: 04/17/2008] [Indexed: 10/22/2022]
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Brook EJ, Anthony Hart C, French NP, Christley RM. Molecular epidemiology of Cryptosporidium subtypes in cattle in England. Vet J 2008; 179:378-82. [PMID: 18083583 DOI: 10.1016/j.tvjl.2007.10.023] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 10/29/2007] [Accepted: 10/31/2007] [Indexed: 11/29/2022]
Abstract
Samples of Cryptosporidium spp., collected in a cross-sectional study of calves (median age 26 days) from 41 farms in Cheshire, UK, underwent molecular typing. The aim was to determine naturally occurring species/genotypes and to investigate transmission pathways within a local area. Of 60 positive samples, 54 were sequenced at an 18S rRNA locus and 51 were typed at a GP60 locus. C. parvum was identified in 50 samples, three cases were C. bovis and one was Cryptosporidium deer-like genotype. Six GP60 subgenotypes were identified. One subgenotype (IIaA15G2R1) was highly prevalent throughout the study area. A single subgenotype was identified on 20/22 farms. Two subgenotypes were found on 2/22 farms. The spatial scan statistic detected a cluster of subgenotype IIaA15G2R1 comprising seven farms. This suggests local transmission of the parasite between farms. As most of the isolates detected were the potentially zoonotic C. parvum allele IIa, intervention strategies should be considered to reduce the threat to public health. Biosecurity measures may reduce transmission between farms and result in lower levels of environmental contamination.
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Affiliation(s)
- Emily J Brook
- Department of Veterinary Clinical Science, University of Liverpool, Neston, UK.
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Bornay-Llinares F, Navarro-i-Martínez L, García-Orenes F, Araez H, Pérez-Murcia M, Moral R. Detection of intestinal parasites in pig slurry: A preliminary study from five farms in Spain. Livest Sci 2006. [DOI: 10.1016/j.livsci.2006.03.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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4
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Atwill ER, Pereira MDGC, Alonso LH, Elmi C, Epperson WB, Smith R, Riggs W, Carpenter LV, Dargatz DA, Hoar B. Environmental load of Cryptosporidium parvum oocysts from cattle manure in feedlots from the central and western United States. JOURNAL OF ENVIRONMENTAL QUALITY 2006; 35:200-6. [PMID: 16391291 DOI: 10.2134/jeq2005.0099] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The first step in assessing the risk of water contamination by Cryptosporidium parvum oocysts from feedlot cattle (Bos taurus) production systems is to quantify the number of C. parvum oocysts present in the fecal material deposited by feedlot cattle. Our primary objective for this project was to estimate the daily environmental load of C. parvum oocysts in fecal material deposited by feedlot cattle from across the central and western USA. Our secondary goal was to genotype isolates of C. parvum from feedlot cattle to help facilitate proper identification of mammalian sources of waterborne C. parvum. Based on 5274 fecal samples from 22 feedlots in seven states (California, Washington, Colorado, Oklahoma, Texas, Nebraska, and South Dakota), we estimated a point prevalence of C. parvum of 0.99 to 1.08% in fecal material from feedlot pens from a wide range of climates and a diverse range of feedlot management systems. On average, fresh fecal material from throughout feedlot systems (recent arrivals to nearing slaughter) contained about 1.3 to 3.6 oocysts/g feces, which roughly translates to about 2.8 x 10(4) to 1.4 x 10(5) oocysts/animal per day.
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Affiliation(s)
- Edward R Atwill
- Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, Univ. of California-Davis, Tulare, CA 93274, USA.
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5
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Baishanbo A, Gargala G, Delaunay A, François A, Ballet JJ, Favennec L. Infectivity of Cryptosporidium hominis and Cryptosporidium parvum genotype 2 isolates in immunosuppressed Mongolian gerbils. Infect Immun 2005; 73:5252-5. [PMID: 16041051 PMCID: PMC1201256 DOI: 10.1128/iai.73.8.5252-5255.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
One-month-old dexamethasone-immunosuppressed Mongolian gerbils were challenged with 1 oocyst to 2 x 10(5) oocysts from two isolates genotyped as Cryptosporidium hominis and C. parvum (genotype 2), respectively. A similar dose-dependent gut infection was obtained, and the initial genotype maintained for 21 to 22 days. The data suggest that immunosuppressed gerbils provide a reliable rodent model of persistent C. hominis infection.
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Affiliation(s)
- Asiya Baishanbo
- Laboratoire d'Immunologie et d'Immunopathologie, CHU Clemenceau, 14033 Caen Cedex, France
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Tate KW, Pereira MDGC, Atwill ER. Efficacy of vegetated buffer strips for retaining Cryptosporidium parvum. JOURNAL OF ENVIRONMENTAL QUALITY 2004; 33:2243-2251. [PMID: 15537947 DOI: 10.2134/jeq2004.2243] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Overland and shallow subsurface hydrologic transport of pathogenic Cryptosporidium parvum oocysts from cattle feces into surface drinking water supplies is a major concern on annual grasslands in California's central and southern Sierra Nevada foothills. Soil boxes (0.5 m wide x 1.1 m long x 0.3 m deep) were used to evaluate the ability of grass vegetated buffer strips to retain 2 x 10(8) spiked C. parvum oocysts in 200-g fecal deposits during simulated rainfall intensities of 30 to 47.5 mm/h over 2 h. Buffers were comprised of Ahwahnee sandy loam (coarse-loamy, mixed, active, thermic Mollic Haploxeralfs; 78:18:4 sand to silt to clay ratio; dry bulk density = 1.4 g/cm(3)) set at 5 to 20% land slope, and >/=95% grass cover (grass stubble height = 10 cm; biomass = 900 kg/ha dry weight). Total number of oocysts discharged from each soil box (combined overland and subsurface flow) during the 120-min simulation ranged from 1.5 x 10(6) to 23.9 x 10(6) oocysts. Observed overall mean log(10) reduction of total C. parvum flux per meter of vegetated buffer was 1.44, 1.19, and 1.18 for buffers at 5, 12, and 20% land slope, respectively. Rainfall application rate (mm/h) was strongly associated with oocyst flux from these vegetated buffers, resulting in a decrease of 2 to 4% in the log(10) reduction per meter buffer for every additional mm/h applied to the soil box. These results support the use of strategically placed vegetated buffers as one of several management strategies that can reduce the risk of waterborne C. parvum attributable to extensive cattle grazing on annual grassland watersheds.
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Affiliation(s)
- Kenneth W Tate
- Department of Agronomy and Range Science, One Shields Avenue, University of California, Davis, CA 95616-8515, USA
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7
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Xiao L, Fayer R, Ryan U, Upton SJ. Cryptosporidium taxonomy: recent advances and implications for public health. Clin Microbiol Rev 2004; 17:72-97. [PMID: 14726456 PMCID: PMC321466 DOI: 10.1128/cmr.17.1.72-97.2004] [Citation(s) in RCA: 544] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There has been an explosion of descriptions of new species of Cryptosporidium during the last two decades. This has been accompanied by confusion regarding the criteria for species designation, largely because of the lack of distinct morphologic differences and strict host specificity among Cryptosporidium spp. A review of the biologic species concept, the International Code of Zoological Nomenclature (ICZN), and current practices for Cryptosporidium species designation calls for the establishment of guidelines for naming Cryptosporidium species. All reports of new Cryptosporidium species should include at least four basic components: oocyst morphology, natural host specificity, genetic characterizations, and compliance with the ICZN. Altogether, 13 Cryptosporidium spp. are currently recognized: C. muris, C. andersoni, C. parvum, C. hominis, C. wrairi, C. felis, and C. cannis in mammals; C. baïleyi, C. meleagridis, and C. galli in birds; C. serpentis and C. saurophilum in reptiles; and C. molnari in fish. With the establishment of a framework for naming Cryptosporidium species and the availability of new taxonomic tools, there should be less confusion associated with the taxonomy of the genus Cryptosporidium. The clarification of Cryptosporidium taxonomy is also useful for understanding the biology of Cryptosporidium spp., assessing the public health significance of Cryptosporidium spp. in animals and the environment, characterizing transmission dynamics, and tracking infection and contamination sources.
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Affiliation(s)
- Lihua Xiao
- Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Chamblee, Georgia 30341, USA.
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Clancy JL, Marshall MM, Hargy TM, Korich DG. Susceptibility of five strains of Cryptosporidium parvum oocysts to UV light. ACTA ACUST UNITED AC 2004; 96:84-93. [PMID: 32313290 PMCID: PMC7159772 DOI: 10.1002/j.1551-8833.2004.tb10576.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Previous evaluations of the effect of ultraviolet (UV) light on Cryptosporidium parvum oocysts have been limited to a single strain—the Iowa strain. This study investigated the response of five strains of C. parvum to UV. A collimated beam apparatus was used to apply controlled doses of monochromatic (254 nm) UV to oocysts of the Iowa, Moredun, Texas A&M, Maine, and Glasgow strains. Irradiation was measured using a calibrated radiometer and sensor. Inactivation was quantified through animal infectivity by inoculation of cohorts of CD‐1 neonatal mice with UV‐treated and untreated control oocysts of each strain followed by examination of intestinal sections for infection using hemotoxylin and eosin staining. A UV light dose of 10 mJ/cm2 achieved at least 4‐log10 inactivation of all strains evaluated. All five strains of C. parvum were shown to be highly susceptible to low levels of UV light.
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Tanriverdi S, Arslan MO, Akiyoshi DE, Tzipori S, Widmer G. Identification of genotypically mixed Cryptosporidium parvum populations in humans and calves. Mol Biochem Parasitol 2003; 130:13-22. [PMID: 14550892 DOI: 10.1016/s0166-6851(03)00138-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Genotypic analyses of Cryptosporidium parvum oocysts have divided the species into two genotypes, referred to as type 1 and type 2. Although humans are susceptible to both types, mixed type 1/type 2 infections have rarely been identified. The paucity of mixed infections could be explained by the predominance of one type over the other in mixed infections, or by the poor sensitivity of restriction fragment length polymorphism (RFLP) analyses for detecting subpopulations. Using a type-specific real-time PCR assay capable of detecting type 1 or type 2 constituting as little as 0.01% of the population, archived and new isolates of human, bovine, and mouse origin were genotyped. Mixed type 1/type 2 infections were identified in humans and calves, including in samples previously found to be homogeneous by RFLP. Isopycnic fractionation of mixed isolates revealed that type 1 and type 2 oocysts differ in their sedimentation properties. The detection of a type 1 subpopulation in serially-propagated bovine isolates indicates that type 1 and type 2 are stably maintained during long-term passage. Together with recently reported experimental bovine and ovine type 1 infections, the persistence of type 1 subpopulation in experimentally infected animals suggests that animals may play a previously unrecognized role in the maintenance of C. parvum type 1.
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Kvác M, Kvetonová D, Půzová G, Ditrich O. Comparison of selected diagnostic methods for identification of Cryptosporidium parvum and Cryptosporidium andersoni in routine examination of faeces. ACTA ACUST UNITED AC 2003; 50:405-11. [PMID: 14633212 DOI: 10.1046/j.1439-0450.2003.00694.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study involved the comparison of suitability of different methods for routine diagnostics of Cryptosporidium spp. Two staining methods, one concentration-sedimentation method, seven concentration-floatation methods and one combined floatation-sedimentation method were compared. The methods were tested with two concentrations (1 x 10(5) and 1 x 10(6)/g) of C. parvum and C. andersoni. The methods were evaluated using light microscope, magnification 400x for concentration methods and 1000x for stained samples respectively. Specificity of both staining methods was 95-100%. Ziehl-Neelsen with P < 0.01 is more suitable for identification of C. andersoni and modified Milácek-Vítovec with P < 0.01 for identification of C. parvum. Concerning specificity and sensitivity, the floatation-concentration method by Sheather was found to provide the best results of all selected methods. The merthiolate iodine formaldehyde concentration (MIFC) method was the least specific one. The least suitable method concerning sensitivity and costs was the floatation method with caesium chloride (CsCl) with a specificity of 29%.
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Affiliation(s)
- M Kvác
- Department of Anatomy and Physiology of Farm Animals, Faculty of Agriculture, University of South Bohemia in Ceské Budejovice, Studentská 13, 370 05 Ceské Budejovice, Czech Republic
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11
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Akiyoshi DE, Mor S, Tzipori S. Rapid displacement of Cryptosporidium parvum type 1 by type 2 in mixed infections in piglets. Infect Immun 2003; 71:5765-71. [PMID: 14500498 PMCID: PMC201101 DOI: 10.1128/iai.71.10.5765-5771.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2003] [Revised: 06/27/2003] [Accepted: 07/03/2003] [Indexed: 11/20/2022] Open
Abstract
Genotypes 1 and 2 of Cryptosporidium parvum are the primary types associated with infections in humans, with type 1 being by far the predominant genotype. The frequency of mixed infection with both genotypes in humans is relatively rare, while type 1, which experimentally infects other mammals, has been found to naturally infect almost exclusively humans. One possible explanation for the absence of type 1 in other mammals and the low frequency of mixed infections in humans is the inability of type 1 to compete with type 2 in nature when both occur simultaneously. To investigate this, we challenged gnotobiotic piglets with equal number of oocysts of type 1 and type 2, given either simultaneously or with type 2 given 24 or 48 h after type 1. The genotype of the oocysts excreted in feces and the relative distribution of each of the genotypes throughout the gut at necropsy were determined. Regardless of the time interval between challenges with the two genotypes, type 2 invariably displaced type 1. The rate of displacement was rapid when both genotypes were given simultaneously, after which no traces of type 1 were detected in the feces or in gut sections by PCR. Infection with type 1 24 or 48 h before challenge with type 2, while permitting type 1 to become established, was still rapidly eliminated within 3 days after challenge with type 2. These observations have major implications regarding the relative perpetuation and survival of these two genotypes in mammals.
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Affiliation(s)
- Donna E Akiyoshi
- Division of Infectious Diseases, Department of Biomedical Sciences, Tufts University School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA
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12
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Atwill ER, Hoar B, das Graças Cabral Pereira M, Tate KW, Rulofson F, Nader G. Improved quantitative estimates of low environmental loading and sporadic periparturient shedding of Cryptosporidium parvum in adult beef cattle. Appl Environ Microbiol 2003; 69:4604-10. [PMID: 12902248 PMCID: PMC169081 DOI: 10.1128/aem.69.8.4604-4610.2003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our primary goal was to generate an accurate estimate of the daily environmental loading rate of Cryptosporidium parvum oocysts for adult beef cattle, using immunomagnetic separation coupled with direct immunofluorescence microscopy for a highly sensitive diagnostic assay. An additional goal was to measure the prevalence and intensity of fecal shedding of C. parvum oocysts in pre- and postparturient cows as an indicator of their potential to infect young calves. This diagnostic method could detect with a > or = 90% probability oocyst concentrations as low as 3.2 oocysts g of feces(-1), with a 54% probability of detecting just one oocyst g of feces(-1). Using this diagnostic method, the overall apparent prevalence of adult beef cattle testing positive for C. parvum was 7.1% (17 of 240), with 8.3 and 5.8% of cattle shedding oocysts during the pre- and postcalving periods, respectively. The mean intensity of oocyst shedding for test-positive cattle was 3.38 oocysts g of feces(-1). The estimated environmental loading rate of C. parvum ranged from 3,900 to 9,200 oocysts cow(-1) day(-1), which is substantially less than a previous estimate of 1.7 x 10(5) oocysts cow(-1) day(-1) (range of 7.7 x 10(4) to 2.3 x 10(5) oocysts cow(-1) day(-1)) (B. Hoar, E. R. Atwill, and T. B. Farver, Quant. Microbiol. 2:21-36, 2000). Use of this highly sensitive assay functioned to detect a greater proportion of low-intensity shedders in our population of cattle, which reduced the estimated mean intensity of shedding and thereby reduced the associated environmental loading rate compared to those of previous studies.
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Affiliation(s)
- E R Atwill
- Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California-Davis, Tulare, California 93274, USA.
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Lindergard G, Nydam DV, Wade SE, Schaaf SL, Mohammed HO. A novel multiplex polymerase chain reaction approach for detection of four human infective Cryptosporidium isolates: Cryptosporidium parvum, types H and C, Cryptosporidium canis, and Cryptosporidium felis in fecal and soil samples. J Vet Diagn Invest 2003; 15:262-7. [PMID: 12735348 DOI: 10.1177/104063870301500307] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
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.
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Affiliation(s)
- Gabriella Lindergard
- Section of Epidemiology, Department of Population Medicine and Diagnostic Science, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Morgan-Ryan UM, Fall A, Ward LA, Hijjawi N, Sulaiman I, Fayer R, Thompson RCA, Olson M, Lal A, Xiao L. Cryptosporidium hominis n. sp. (Apicomplexa: Cryptosporidiidae) from Homo sapiens. J Eukaryot Microbiol 2002; 49:433-40. [PMID: 12503676 DOI: 10.1111/j.1550-7408.2002.tb00224.x] [Citation(s) in RCA: 298] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structure and infectivity of the oocysts of a new species of Cryptosporidium from the feces of humans are described. Oocysts are structurally indistinguishable from those of Cryptosporidium parvum. Oocysts of the new species are passed fully sporulated, lack sporocysts. and measure 4.4-5.4 microm (mean = 4.86) x 4.4-5.9 microm (mean = 5.2 microm) with a length to width ratio 1.0-1.09 (mean 1.07) (n = 100). Oocysts were not infectious for ARC Swiss mice, nude mice. Wistar rat pups, puppies, kittens or calves, but were infectious to neonatal gnotobiotic pigs. Pathogenicity studies in the gnotobiotic pig model revealed significant differences in parasite-associated lesion distribution (P = 0.005 to P = 0.02) and intensity of infection (P = 0.04) between C. parvum and this newly described species from humans. In vitro cultivation studies have also revealed growth differences between the two species. Multi-locus analysis of numerous unlinked loci, including a preliminary sequence scan of the entire genome demonstrated this species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further support for its species status. Based on biological and molecular data, this Cryptosporidium infecting the intestine of humans is proposed to be a new species Cryptosporidium hominis n. sp.
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Affiliation(s)
- Una M Morgan-Ryan
- Division of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, Western Australia 6150.
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Atwill ER, Hou L, Karle BM, Harter T, Tate KW, Dahlgren RA. Transport of Cryptosporidium parvum oocysts through vegetated buffer strips and estimated filtration efficiency. Appl Environ Microbiol 2002; 68:5517-27. [PMID: 12406745 PMCID: PMC129871 DOI: 10.1128/aem.68.11.5517-5527.2002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vegetated buffer strips were evaluated for their ability to remove waterborne Cryptosporidium parvum from surface and shallow subsurface flow during simulated rainfall rates of 15 or 40 mm/h for 4 h. Log(10) reductions for spiked C. parvum oocysts ranged from 1.0 to 3.1 per m of vegetated buffer, with buffers set at 5 to 20% slope, 85 to 99% fescue cover, soil textures of either silty clay (19:47:34 sand-silt-clay), loam (45:37:18), or sandy loam (70:25:5), and bulk densities of between 0.6 to 1.7 g/cm(3). Vegetated buffers constructed with sandy loam or higher soil bulk densities were less effective at removing waterborne C. parvum (1- to 2-log(10) reduction/m) compared to buffers constructed with silty clay or loam or at lower bulk densities (2- to 3-log(10) reduction/m). The effect of slope on filtration efficiency was conditional on soil texture and soil bulk density. Based on these results, a vegetated buffer strip comprised of similar soils at a slope of <or=20% and a length of >or=3 m should function to remove >or=99.9% of C. parvum oocysts from agricultural runoff generated during events involving mild to moderate precipitation.
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Affiliation(s)
- Edward R Atwill
- Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California-Davis, Tulare, California 93274, USA.
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Learmonth J, Ionas G, Pita A, Cowie R. Seasonal shift in Cryptosporidium parvum transmission cycles in New Zealand. J Eukaryot Microbiol 2002; Suppl:34S-35S. [PMID: 11906069 DOI: 10.1111/j.1550-7408.2001.tb00444.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J Learmonth
- Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand.
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Akiyoshi DE, Feng X, Buckholt MA, Widmer G, Tzipori S. Genetic analysis of a Cryptosporidium parvum human genotype 1 isolate passaged through different host species. Infect Immun 2002; 70:5670-5. [PMID: 12228296 PMCID: PMC128364 DOI: 10.1128/iai.70.10.5670-5675.2002] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2002] [Revised: 06/20/2002] [Accepted: 06/28/2002] [Indexed: 11/20/2022] Open
Abstract
Cryptosporidium parvum TU502, a genotype 1 isolate of human origin, was passaged through three different mammalian hosts, including humans, pigs, and calves. It was confirmed to be genotype 1 by PCR-restriction fragment length polymorphism analysis of the Cryptosporidium oocyst wall protein gene, direct sequencing of PCR fragments of the small subunit rRNA and beta-tubulin genes, and microsatellite analysis. This isolate was shown to be genetically stable when passaged through the three mammalian species, with no evidence of the emergence of new subpopulations as observed by a genotype-specific PCR assay. TU502 oocysts from different sources failed to infect gamma interferon knockout mice, a characteristic of genotype 1 isolates. The genotypic and phenotypic characterization of TU502 is significant since it is the isolate selected to sequence the genome of C. parvum genotype 1 and is currently used in several research projects including human volunteer studies.
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Affiliation(s)
- D E Akiyoshi
- Division of Infectious Diseases, Tufts University School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA.
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18
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Tanriverdi S, Tanyeli A, Başlamişli F, Köksal F, Kilinç Y, Feng X, Batzer G, Tzipori S, Widmer G. Detection and genotyping of oocysts of Cryptosporidium parvum by real-time PCR and melting curve analysis. J Clin Microbiol 2002; 40:3237-44. [PMID: 12202559 PMCID: PMC130769 DOI: 10.1128/jcm.40.9.3237-3244.2002] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several real-time PCR procedures for the detection and genotyping of oocysts of Cryptosporidium parvum were evaluated. A 40-cycle amplification of a 157-bp fragment from the C. parvum beta-tubulin gene detected individual oocysts which were introduced into the reaction mixture by micromanipulation. SYBR Green I melting curve analysis was used to confirm the specificity of the method when DNA extracted from fecal samples spiked with oocysts was analyzed. Because C. parvum isolates infecting humans comprise two distinct genotypes, designated type 1 and type 2, real-time PCR methods for discriminating C. parvum genotypes were developed. The first method used the same beta-tubulin amplification primers and two fluorescently labeled antisense oligonucleotide probes spanning a 49-bp polymorphic sequence diagnostic for C. parvum type 1 and type 2. The second genotyping method used SYBR Green I fluorescence and targeted a polymorphic coding region within the GP900/poly(T) gene. Both methods discriminated between type 1 and type 2 C. parvum on the basis of melting curve analysis. To our knowledge, this is the first report describing the application of melting curve analysis for genotyping of C. parvum oocysts.
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Affiliation(s)
- Sultan Tanriverdi
- Department of Pediatric Hematology-Oncology, School of Medicine, Cukurova University, 01330 Adana, Turkey
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Widmer G, Lin L, Kapur V, Feng X, Abrahamsen MS. Genomics and genetics of Cryptosporidium parvum: the key to understanding cryptosporidiosis. Microbes Infect 2002; 4:1081-90. [PMID: 12191658 DOI: 10.1016/s1286-4579(02)01632-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This paper focuses on recent advances in the genetics and genomics of Cryptosporidium parvum. The approach to and the relevance of sequencing the genomes of C. parvum type 1 and type 2 are discussed, as well as new insights into the genetic heterogeneity of this species.
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Affiliation(s)
- Giovanni Widmer
- Tufts University School of Veterinary Medicine, Division of Infectious Diseases, 200 Westboro Road, North Grafton, MA 01536, USA.
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20
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Heitman TL, Frederick LM, Viste JR, Guselle NJ, Morgan UM, Thompson RCA, Olson ME. Prevalence of Giardia and Cryptosporidium and characterization of Cryptosporidium spp. isolated from wildlife, human, and agricultural sources in the North Saskatchewan River Basin in Alberta, Canada. Can J Microbiol 2002; 48:530-41. [PMID: 12166680 DOI: 10.1139/w02-047] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The environmental distribution of Giardia spp. and Cryptosporidium spp. is dependent upon human, agricultural, and wildlife sources. The significance of each source with regard to the presence of parasites in the environment is unknown. This 2-year study examined parasite prevalence in human sewage influent, wildlife, and agricultural sources associated with the North Saskatchewan River Basin in Alberta, Canada. Fecal samples were collected from cow-calf, dairy, and hog operations in the watershed area. Sewage-treatment facilities were sampled bimonthly during the 2-year study, and wildlife scat was collected at locations along tributaries of the North Saskatchewan River. All samples were analyzed for the presence of Giardia and Cryptosporidium, using sucrose-gradient separation followed by immunofluorescent microscopy. Giardia and Cryptosporidium were detected in all three sources. The lowest prevalence of both Giardia (3.28%) and Cryptosporidium (0.94%) was found in wildlife, with 6 of 19 species testing positive. Sewage influent had the highest prevalence of Giardia (48.80%) and Cryptosporidium parvum-like oocysts (5.42%); however, the concentration of both parasites was minimal compared with the concentration detected in cattle feces. Cow-calf sources contained the highest concentration of Giardia (mean 5800/g feces, P < 0.01), and dairy sources contained the highest concentration of C. parvum-like oocysts (mean 295/g feces, P < 0.01). Although prevalence and concentration are higher in cattle feces than in sewage, the Giardia and Cryptosporidium in animal manure do not have direct access to water draining into the North Saskatchewan River. PCR-based characterization of rDNA from isolates of Cryptosporidium collected from Alberta human, pig, calf, mature steer, dog, cat, and beaver hosts revealed distinct genetic differences that may reflect host specificity.
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Affiliation(s)
- T L Heitman
- Department of Microbiology and Infectious Diseases, The University of Calgary, AB, Canada
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21
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Huetink RE, van der Giessen JW, Noordhuizen JP, Ploeger HW. Epidemiology of Cryptosporidium spp. and Giardia duodenalis on a dairy farm. Vet Parasitol 2001; 102:53-67. [PMID: 11705652 DOI: 10.1016/s0304-4017(01)00514-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Prevalences of Cryptosporidium spp. and Giardia duodenalis in relation to age and season were investigated on a dairy farm in The Netherlands over the course of 1year. The whole herd was sampled five times, whereas calves younger than about 2 months were sampled every 2-3 weeks. Associations between diarrhoea and presence of one or more pathogens (Cryptosporidium spp., G. duodenalis, rotavirus) were investigated. Potential transmission routes of Cryptosporidium spp. were evaluated and positive samples of Cryptosporidium spp. and G. duodenalis were identified to genotype level by PCR microsatellite identification and fingerprinting. Shedding of Cryptosporidium spp. was found in all age categories but peaked in calves 1-3 weeks old (39.1%). Herd prevalence of shedding for Cryptosporidium spp. varied from 2.4% in June to 22.2% in December. Shedding of G. duodenalis was found in all age categories but peaked in animals 4-5 months old (54.5%). Herd prevalence of shedding for G. duodenalis varied from 0.8% in June to 15.5% in February. Cryptosporidium spp. and rotavirus appeared to be significantly associated with diarrhoea in calves. Microsatellite analysis showed two different subtypes (C3 and C1) of Cryptosporidium parvum calf strains. Two genotypes of G. duodenalis were found, one positive by A lineage specific PCR and thus closely related to human genotypes and one genotype, which was negative by A and B lineage specific PCR. The results indicate that cow-to-calf and indirect calf-to-calf transmission both are important routes for acquiring infection with Cryptosporidium spp.
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Affiliation(s)
- R E Huetink
- Department of Parasitology and Tropical Veterinary Medicine, Faculty of Veterinary Medicine, University of Utrecht, P.O. Box 80.165, 3508 TD, Utrecht, The Netherlands
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22
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Nydam DV, Wade SE, Schaaf SL, Mohammed HO. Number of Cryptosporidium parvum oocysts or Giardia spp cysts shed by dairy calves after natural infection. Am J Vet Res 2001; 62:1612-5. [PMID: 11592328 DOI: 10.2460/ajvr.2001.62.1612] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the total number of Cryptosporidium parvum oocysts and Giardia spp cysts shed by dairy calves during the period when they are most at risk after natural infection. ANIMALS 478 calves naturally infected with C. parvum and 1,016 calves naturally infected with Giardia spp. PROCEDURE Oocysts or cysts were enumerated from fecal specimens. Distribution of number of oocysts or cysts versus age was used to determine the best fitting mathematic function. Number of oocysts or cysts per gram of feces for a given duration of shedding was computed by determining the area under the curve. Total number of oocysts or cysts was calculated by taking the product of the resultant and the expected mass of feces. RESULTS Intensity of Cparvum oocyst shedding was best described by a second-order polynomial function. Shedding increased from 4 days of age, peaked at day 12, and then decreased. An infected 6-day-old calf would produce 3.89 x 10(10) oocysts until 12 days old. Pattern of shedding of Giardia spp cysts was best described by exponential functions. Intensity of shedding increased from 4 days of age, peaked at day 14, and then decreased. An infected calf would produce 3.8 x 10(7) cysts from day 50 until day 56. CONCLUSIONS AND CLINICAL RELEVANCE The large number of oocysts and cysts shed indicates that shedding by dairy cattle poses a risk for susceptible calves and people. Estimates reported here may be useful to aid in designing cost-effective strategies to manage this risk.
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Affiliation(s)
- D V Nydam
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401, USA
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23
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Guyot K, Follet-Dumoulin A, Lelièvre E, Sarfati C, Rabodonirina M, Nevez G, Cailliez JC, Camus D, Dei-Cas E. Molecular characterization of Cryptosporidium isolates obtained from humans in France. J Clin Microbiol 2001; 39:3472-80. [PMID: 11574558 PMCID: PMC88374 DOI: 10.1128/jcm.39.10.3472-3480.2001] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptosporidium parvum is usually considered the agent of human cryptosporidiosis. However, only in the last few years, molecular biology-based methods have allowed the identification of Cryptosporidium species and genotypes, and only a few data are available from France. In the present work, we collected samples of whole feces from 57 patients from France (11 immunocompetent patients, 35 human immunodeficiency virus [HIV]-infected patients, 11 immunocompromised but non-HIV-infected patients) in whom Cryptosporidium oocysts were recognized by clinical laboratories. A fragment of the Cryptosporidium 18S rRNA gene encompassing the hypervariable region was amplified by PCR and sequenced. The results revealed that the majority of the patients were infected with cattle (29 of 57) or human (18 of 57) genotypes of Cryptosporidium parvum. However, a number of immunocompromised patients were infected with C. meleagridis (3 of 57), C. felis (6 of 57), or a new genotype of C. muris (1 of 57). This is the first report of the last three species of Cryptosporidium in humans in France. These results indicate that immunocompromised individuals are susceptible to a wide range of Cryptosporidium species and genotypes.
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Affiliation(s)
- K Guyot
- Ecologie du Parasitisme, Institut Pasteur de Lille, BP 245, 59019 Lille, France.
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24
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Fayer R, Morgan U, Upton SJ. Epidemiology of Cryptosporidium: transmission, detection and identification. Int J Parasitol 2000; 30:1305-22. [PMID: 11113257 DOI: 10.1016/s0020-7519(00)00135-1] [Citation(s) in RCA: 464] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
There are 10 valid species of Cryptosporidium and perhaps other cryptic species hidden under the umbrella of Cryptosporidium parvum. The oocyst stage is of primary importance for the dispersal, survival, and infectivity of the parasite and is of major importance for detection and identification. Because most oocysts measure 4-6 microm, appear nearly spherical, and have obscure internal structures, there are few or no morphometric features to differentiate species and in vitro cultivation does not provide differential data as for bacteria. Consequently, we rely on a combination of data from three tools: morphometrics, molecular techniques, and host specificity. Of 152 species of mammals reported to be infected with C. parvum or an indistinguishable organism, very few oocysts have ever been examined using more than one of these tools. This paper reviews the valid species of Cryptosporidium, their hosts and morphometrics; the reported hosts for the human pathogen, C. parvum; the mechanisms of transmission; the drinking water, recreational water, and food-borne outbreaks resulting from infection with C. parvum; and the microscopic, immunological, and molecular methods used to detect and identify species and genotypes.
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Affiliation(s)
- R Fayer
- United States Department of Agriculture, Agricultural Research Institute, LPSI, 10300 Baltimore Avenue, Beltsville, MD 20705, USA.
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25
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Torres J, Gracenea M, Gómez MS, Arrizabalaga A, González-Moreno O. The occurrence of Cryptosporidium parvum and C. muris in wild rodents and insectivores in Spain. Vet Parasitol 2000; 92:253-60. [PMID: 10996736 DOI: 10.1016/s0304-4017(00)00331-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Five rodent and two insectivore species were investigated for Cryptosporidium at seven sites in north-eastern Spain. Of the 442 animals studied, 82 Apodemus sylvaticus, 1 A. flavicollis, 5 Mus spretus, 1 Rattus rattus, 8 Clethrionomys glareolus and 13 Crocidura russula were infected with only C. parvum. Eleven A. sylvaticus and 2 C. glareolus were infected with only C. muris and 16 A. sylvaticus, 1 M. spretus and 2 C. glareolus showed mixed infections. Both cryptosporidial species were found in most study areas. No causal relationship was found between intrinsic host factors (age and sex) and the parasitic prevalence in the most captured host species (A. sylvaticus and C. russula). Extrinsic factors such as collection site of host, seasonality and covering vegetation exerted different influence on the prevalence of Cryptosporidium. Small mammals could become one of the most important sources of cryptosporidial oocysts in those areas where neither farm animals nor significant human activity are present. This is the first study to report the infection of M. spretus and C. russula by C. parvum and the first finding of C. muris in M. spretus.
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Affiliation(s)
- J Torres
- Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Avda Joan XXIII Sn, 08028, Barcelona, Spain.
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26
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Feng X, Rich SM, Akiyoshi D, Tumwine JK, Kekitiinwa A, Nabukeera N, Tzipori S, Widmer G. Extensive polymorphism in Cryptosporidium parvum identified by multilocus microsatellite analysis. Appl Environ Microbiol 2000; 66:3344-9. [PMID: 10919789 PMCID: PMC92153 DOI: 10.1128/aem.66.8.3344-3349.2000] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Restriction fragment length polymorphism and DNA sequence analysis discern two main types of Cryptosporidium parvum. We present a survey of length polymorphism at several microsatellite loci for type 1 and type 2 isolates. A total of 14 microsatellite loci were identified from C. parvum DNA sequences deposited in public databases. All repeats were mono-, di-, and trinucleotide repeats of A, AT, and AAT, reflecting the high AT content of the C. parvum genome. Several of these loci showed significant length polymorphism, with as many as seven alleles identified for a single locus. Differences between alleles ranged from 1 to 27 bp. Karyotype analysis using probes flanking three microsatellites localized each marker to an individual chromosomal band, suggesting that these markers are single copy. In a sample of 19 isolates for which at least three microsatellites were typed, a majority of isolates displayed a unique multilocus fingerprint. Microsatellite analysis of isolates passaged between different host species identified genotypic changes consistent with changes in parasite populations.
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Affiliation(s)
- X Feng
- Tufts University School of Veterinary Medicine, Division of Infectious Diseases, North Grafton, MA 01536, USA
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27
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Yang S, Benson SK, Du C, Healey MC. Infection of immunosuppressed C57BL/6N adult mice with a single oocyst of Cryptosporidium parvum. J Parasitol 2000; 86:884-7. [PMID: 10958482 DOI: 10.1645/0022-3395(2000)086[0884:ioicam]2.0.co;2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The present study was designed to determine the minimum number of Cryptosporidium parvum oocysts capable of producing patent infections in immunosuppressed C57BL/6N adult mice. Sixty-four female mice were divided into 6 groups of 8 mice each, except group 1 that contained 24 mice. Mice in groups 1-3 were immunosuppressed with dexamethasone and inoculated with 1, 5, and 10 oocysts per mouse, respectively. The accuracy of the inoculum size was microscopically confirmed. Mice in groups 4-6 served as controls: they received either only oocyst inoculation (group 4), or immunosuppression (group 5), or no treatments (group 6). Fecal oocyst shedding was monitored daily for each mouse using an indirect immunofluorescent assay. Parasite colonization in the terminal ileum of each mouse was evaluated histologically. Four of 24 mice in group 1 developed patent infections, with a prepatent period of approximately 6 days. All mice in groups 2 and 3 developed patent infections, with prepatent periods ranging from 4 to 7 days. Mice in groups 4-6 remained uninfected. Parasite colonization was observed in the terminal ilea of all mice in groups 1-3 that shed fecal oocysts. The present study experimentally demonstrates that a single viable oocyst can induce patent C. parvum infections in immunosuppressed C57BL/6N adult mice and indicates that this mouse model could be used for the parasite genotype or isolate cloning.
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Affiliation(s)
- S Yang
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan 84322-5600, USA
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28
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Khramtsov NV, Chung PA, Dykstra CC, Griffiths JK, Morgan UM, Arrowood MJ, Upton SJ. Presence of double-stranded RNAs in human and calf isolates of Cryptosporidium parvum. J Parasitol 2000; 86:275-82. [PMID: 10780545 DOI: 10.1645/0022-3395(2000)086[0275:podsri]2.0.co;2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We examined the occurrence of 2 virus-like double-stranded (ds)RNAs in human and calf isolates of Cryptosporidium parvum senso latu and other microorganisms, including 7 other members of the genus. A total of 32 isolates of C. parium, 16 from humans (5 from acquired immune deficiency syndrome patients) and 16 from calves, were analyzed. Ethidium bromide staining, or Northern blot analysis, or reverse transcription/polymerase chain reaction, or all 3 methods, revealed that both genotype 1 and genotype 2 isolates of C. parvum possessed these dsRNAs. No other Cryptosporidium spp. or other organisms examined possessed these dsRNAs. Comparison analysis of partial cDNA sequences of dsRNAs from human and calf isolates revealed a high degree of similarity (>92% and >93% identical nucleotides for large and small dsRNAs, respectively). Slight, consistent differences in nucleotide sequences could be seen at select sites and were associated with an isolate being either genotype 1 or 2. Because of the widespread distribution of the dsRNAs, the similarity of these molecules between isolates, and high host specificity, these nucleic acids may prove to represent species-specific molecular markers for C. parvum. Evidence also suggests that the dsRNA can be utilized for molecular genotyping of C. parvum.
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Affiliation(s)
- N V Khramtsov
- Division of Biology, Kansas State University, Manhattan 66506, USA
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29
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Awad-El-Kariem FM. Does Cryptosporidium parvum have a clonal population structure? PARASITOLOGY TODAY (PERSONAL ED.) 1999; 15:502-4. [PMID: 10557152 DOI: 10.1016/s0169-4758(99)01567-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cryptosporidiosis, the disease caused in humans by the opportunistic parasite Cryptosporidium parvum, is the result of zoonotic or anthroponotic transmission. Molecular characterization of different isolates from humans and other mammalian species has recently shown this species to be heterogeneous; this heterogeneity has been linked to the host of isolation, suggesting that the parasites causing zoonotic cryptosporidiosis and those propagated by anthroponotic transmission are genetically distinct. Here, Fatih Awad-El-Kariem provides an update on the taxonomic and epidemiological significance of these observations, and discusses evidence for and against the clonality hypothesis as a model to explain strain variation in this species.
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Affiliation(s)
- F M Awad-El-Kariem
- Department of Biology, Imperial College of Science, Technology and Medicine, Prince Consort Road, London, UK SW7 2BB.
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30
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Morgan UM, Xiao L, Fayer R, Lal AA, Thompson RC. Variation in Cryptosporidium: towards a taxonomic revision of the genus. Int J Parasitol 1999; 29:1733-51. [PMID: 10616920 DOI: 10.1016/s0020-7519(99)00109-5] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cryptosporidium is an important cause of enteric disease in humans and other animals. Limitations associated with conventional diagnostic methods for cryptosporidiosis based on morphological features, coupled with the difficulty of characterising parasites isolated in the laboratory, have restricted our ability to clearly identify species. The application of sensitive molecular approaches has obviated the necessity for laboratory amplification. Such studies have found considerable evidence of genetic heterogeneity among isolates of Cryptosporidium from different species of vertebrate, and there is now mounting evidence suggesting that a series of host-adapted genotypes/strains/species of the parasite exist. In this article, studies on the molecular characterisation of Cryptosporidium during the last 5 years are reviewed and put into perspective with the past and present taxonomy of the genus. The predictive value of achieving a sound taxonomy for the genus Cryptosporidium with respect to understanding its epidemiology and transmission and controlling outbreaks of the disease is also discussed.
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Affiliation(s)
- U M Morgan
- World Health Organisation Collaborating Centre for the Molecular Epidemiology of Parasitic Infections, and State Agricultural Biotechnology Centre, Murdoch University, Australia.
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31
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Johnson EH, Muirhead DE, Windsor JJ, King GJ, Al-Busaidy R, Cornelius R. Atypical outbreak of caprine cryptosporidiosis in the Sultanate of Oman. Vet Rec 1999; 145:521-4. [PMID: 10576626 DOI: 10.1136/vr.145.18.521] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
An outbreak of cryptosporidiosis occurred in goats ranging in age from two days to adult, on a well-managed closed farm. None of the other animals on the farm, including sheep, cows and buffalo, were affected. Morbidity approached 100 per cent in goats less than six months of age. Despite intensive supportive care, 238 goats died, ranging in age from two days to over one year. Cryptosporidia were detected in large numbers in the intestinal contents of dead animals and in faecal smears of animals with diarrhoea. Massive numbers of the organisms were also demonstrated histopathologically and by electronmicroscopy, and no other significant pathogens were detected. The outbreak was unique in terms of the extreme virulence of the organism, its apparent species-specificity, and the shedding of the organism by animals over four weeks of age.
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Affiliation(s)
- E H Johnson
- Department of Animal and Veterinary Sciences, College of Agriculture, Sultan Qaboos University, Muscat, Sultanate of Oman
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32
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McLauchlin J, Pedraza-Díaz S, Amar-Hoetzeneder C, Nichols GL. Genetic characterization of Cryptosporidium strains from 218 patients with diarrhea diagnosed as having sporadic cryptosporidiosis. J Clin Microbiol 1999; 37:3153-8. [PMID: 10488169 PMCID: PMC85515 DOI: 10.1128/jcm.37.10.3153-3158.1999] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Samples of whole feces in which Cryptosporidium oocysts were recognized by hospital laboratories were collected from 218 patients with diarrhea. All samples were reexamined by light microscopy, and oocysts were detected in 211 samples. A simple and rapid procedure for the extraction of DNA from whole feces was developed, and this was used to amplify fragments of the Cryptosporidium outer wall protein (COWP), the thrombospondin-related adhesive protein C1 (TRAP-C1), and the 18S rRNA genes by PCR. For seven samples oocysts were not detected by microscopy and DNA failed to be amplified by the three PCR procedures. Among the 211 samples "positive" by microscopy, the sensitivities of PCRs for the 18S rRNA, COWP, and TRAP-C1 gene fragments were 97, 91, and 66%, respectively. The sensitivities of all three PCR procedures increased with increasing numbers of oocysts as observed by microscopy. Two genotypes of the COWP and TRAP-C1 genes can be detected by PCR-restriction fragment length polymorphism analysis. With this series of samples, the same genotypes of the COWP and TRAP-C1 genes always segregated together. A combined genotyping data set was produced for isolates from 194 samples: 74 (38%) were genotype 1 and 120 (62%) were genotype 2. Genotype 2 was detected in a significantly greater proportion of the samples with small numbers of oocysts, and genotype 1 was detected in a significantly greater proportion of the samples with larger numbers of oocysts. There were no significant differences in the distribution of the genotypes by patient sex and age. The distribution of the genotypes was significantly different both in patients with a history of foreign travel and in those from different regions in England.
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Affiliation(s)
- J McLauchlin
- Food Hygiene Laboratory, Division of Gastrointestinal Infections, PHLS Central Public Health Laboratory, London NW9 5HT, United Kingdom.
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33
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Abstract
Sources of human microsporidial infection remain speculative, but possible animal reservoirs are emerging. Of the common human microsporidial infections, Enterocytozoon bieneusi has now been identified in non-human primates, pigs, dogs and a cat; Encephalitozoon intestinalis in dogs, pigs, cows, goats and donkeys and Encephalitozoon hellem in budgerigars and parrots. Evidence of species heterogeneity is also emerging suggesting that some animal isolates may be distinctive. Further molecular epidemiological studies need to be undertaken to clarify which animal genotypes can also infect humans. Some of the less common microsporidial infections found in humans, such as those involving Pleistophora-like species, may be the result of infrequent accidental exposure (for example, inadequately cooked infected fish muscle) and establishment, particularly if the individual is severely immunocompromised.
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Affiliation(s)
- A Curry
- Public Health Laboratory, Withington Hospital, Manchester, UK
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34
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Abstract
This review consists of 11 papers presented at the Consensus Conference on Cryptosporidium in Water (Parasitology Stream), held in Melbourne, Australia, from 5 to 6th October 1998. The conference was sponsored by the Water Services Association of Australia, the Australian Water and Wastewater Association, and the Collaborative Research Centre for Water Quality and Treatment. The papers summarise the advantages and disadvantages of various contemporary technologies applicable to parasite propagation and biochemical/molecular characterisation. Studies have detected distinct genetic differences between clinical isolates from humans and animals, and it is hoped that comprehensive documentation studies will facilitate the identification of environmental isolates in the not too distant future.
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Affiliation(s)
- R B Gasser
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia
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35
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de Graaf DC, Spano F, Petry F, Sagodira S, Bonnin A. Speculation on whether a vaccine against cryptosporidiosis is a reality or fantasy. Int J Parasitol 1999; 29:1289-306. [PMID: 10576579 PMCID: PMC7130201 DOI: 10.1016/s0020-7519(99)00082-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/1999] [Revised: 06/03/1999] [Accepted: 06/03/1999] [Indexed: 11/28/2022]
Abstract
In this paper the authors question whether the development of a vaccine against cryptosporidiosis could be taken into consideration. The necessity and feasibility of such a vaccine for human and veterinary application is discussed. Developmental stages within the life cycle of the parasite that might act as possible targets for vaccine development are summarised, as well as the target antigens offered by molecular biology and immunology studies. Vaccination trials against cryptosporidiosis carried out so far, including the active and passive immunisation approach, are also overviewed. It seems that with respect to a Cryptosporidium vaccine two target groups can be considered: children of the developing world and neonatal ruminants. Antigens representing possible candidates for a subunit vaccine were identified based on their function, location and/or the immune response they evoke. While the active vaccination of newborn calves, lambs and goat kids has to face a number of important limitations, the passive immunisation approach, where dams were immunised to protect their progeny by colostral transfer, was proven to be a valuable alternative. Finally, a number of points of action for the near future are put forward.
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Affiliation(s)
- D C de Graaf
- Veterinary and Agrochemical Research Centre, Brussels, Belgium.
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36
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Abstract
DNA technology is having a major impact in many areas of veterinary parasitology. In particular, the polymerase chain reaction (PCR) has found broad applicability because its sensitivity permits enzymatic amplification of gene fragments from minute quantities of nucleic acids derived from limited amounts of parasite material. This paper discusses some recent applications of PCR-based methods to parasites and highlights their usefulness or potential for those of veterinary importance. The focus is on PCR tools for the accurate identification of parasites and their genetic characterisation, the diagnosis of infections, the isolation and characterisation of expressed genes, the detection of anthelmintic resistance, and mutation scanning approaches for the high resolution analysis of PCR products.
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MESH Headings
- Animals
- DNA, Helminth/analysis
- DNA, Helminth/chemistry
- DNA, Protozoan/analysis
- DNA, Protozoan/chemistry
- Drug Resistance
- Eukaryota/classification
- Eukaryota/genetics
- Eukaryota/isolation & purification
- Expressed Sequence Tags
- Helminthiasis, Animal/diagnosis
- Helminths/classification
- Helminths/genetics
- Helminths/isolation & purification
- Microsatellite Repeats
- Parasitic Diseases, Animal/diagnosis
- Parasitic Diseases, Animal/therapy
- Polymerase Chain Reaction/methods
- Polymerase Chain Reaction/veterinary
- Polymorphism, Restriction Fragment Length
- Polymorphism, Single-Stranded Conformational
- Protozoan Infections, Animal/diagnosis
- Random Amplified Polymorphic DNA Technique/veterinary
- Sequence Analysis, DNA/veterinary
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Affiliation(s)
- R B Gasser
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia.
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Xiao L, Morgan UM, Limor J, Escalante A, Arrowood M, Shulaw W, Thompson RC, Fayer R, Lal AA. Genetic diversity within Cryptosporidium parvum and related Cryptosporidium species. Appl Environ Microbiol 1999; 65:3386-91. [PMID: 10427023 PMCID: PMC91508 DOI: 10.1128/aem.65.8.3386-3391.1999] [Citation(s) in RCA: 420] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To assess the genetic diversity in Cryptosporidium parvum, we have sequenced the small subunit (SSU) rRNA gene of seven Cryptosporidium spp., various isolates of C. parvum from eight hosts, and a Cryptosporidium isolate from a desert monitor. Phylogenetic analysis of the SSU rRNA sequences confirmed the multispecies nature of the genus Cryptosporidium, with at least four distinct species (C. parvum, C. baileyi, C. muris, and C. serpentis). Other species previously defined by biologic characteristics, including C. wrairi, C. meleagridis, and C. felis, and the desert monitor isolate, clustered together or within C. parvum. Extensive genetic diversities were present among C. parvum isolates from humans, calves, pigs, dogs, mice, ferrets, marsupials, and a monkey. In general, specific genotypes were associated with specific host species. A PCR-restriction fragment length polymorphism technique previously developed by us could differentiate most Cryptosporidium spp. and C. parvum genotypes, but sequence analysis of the PCR product was needed to differentiate C. wrairi and C. meleagridis from some of the C. parvum genotypes. These results indicate a need for revision in the taxonomy and assessment of the zoonotic potential of some animal C. parvum isolates.
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Affiliation(s)
- L Xiao
- Division of Parasitic Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia 30341, USA.
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38
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Cacciò S, Homan W, van Dijk K, Pozio E. Genetic polymorphism at the beta-tubulin locus among human and animal isolates of Cryptosporidium parvum. FEMS Microbiol Lett 1999; 170:173-9. [PMID: 9919666 DOI: 10.1111/j.1574-6968.1999.tb13371.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Sequence analysis of a fragment of the beta-tubulin gene was performed on 13 isolates of the parasite Cryptosporidium parvum, eight from humans and five from animals. A total of 12 synonymous substitutions and a deletion of two bases within the intron sequence were found. This genetic variation defined two alleles at the beta-tubulin locus, which can be identified by a simple polymerase chain reaction-restriction fragment length polymorphism assay. A total of 20 isolates were also tested using four available molecular markers. These analyses showed congruently that the C. parvum isolates segregate into two groups, one found exclusively in humans and the other found in both humans and animals. Since no recombinant genotypes were observed, the results are consistent with the hypothesis of a substantially clonal reproduction in this parasite.
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Affiliation(s)
- S Cacciò
- Laboratory of Parasitology, Istituto Superiore di Sanità, Rome, Italy.
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Widmer G, Tchack L, Chappell CL, Tzipori S. Sequence polymorphism in the beta-tubulin gene reveals heterogeneous and variable population structures in Cryptosporidium parvum. Appl Environ Microbiol 1998; 64:4477-81. [PMID: 9797309 PMCID: PMC106671 DOI: 10.1128/aem.64.11.4477-4481.1998] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Restriction fragment length polymorphism (RFLP) analysis of isolates of Cryptosporidium parvum has revealed two subgroups, termed H and C. The limited resolution of the RFLP method precludes an in-depth study of the genetic structure of C. parvum populations. Published C. parvum restriction polymorphisms lie within protein-coding regions known to be more homogeneous than noncoding sequences. To better assess the degrees of heterogeneity between and within C. parvum isolates, sequence polymorphism in the beta-tubulin intron, the only C. parvum intron described to date, was investigated. In contrast to the two genotypes distinguished by multilocus RFLP, several alleles were detected by sequence and RFLP analysis of the beta-tubulin intron and adjacent exon 2. Isolates carrying different beta-tubulin alleles were found. Significantly, one of the beta-tubulin alleles present in two geographically unrelated isolates combined features of C- and H-type isolates, suggesting that it might have arisen from a recombination event. A comparison of multiple samples of a calf-propagated laboratory isolate showed that the ratio of different beta-tubulin alleles fluctuated during serial passage.
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Affiliation(s)
- G Widmer
- Division of Infectious Diseases, Tufts University School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA.
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Gibbons CL, Gazzard BG, Ibrahim MA, Morris-Jones S, Ong CS, Awad-El-Kariem FM. Correlation between markers of strain variation in Cryptosporidium parvum: Evidence of clonality. Parasitol Int 1998. [DOI: 10.1016/s1383-5769(98)00012-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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41
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Detection of Cryptosporidium parvum and C. muris Oocysts in Spiked Backwash Water using Three PCR-Based Protocols. Protist 1998. [DOI: 10.1016/s1434-4610(98)70017-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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