Publications

TitleAbstractYear
Filter
PMID(sorted descending)
Filter
[isolation and incidence of cryptosporidium and giardia from river water].a study was conducted during the period from july to october in 1999, surface water samples were collected from 13 rivers in hyogo prefecture serving as tap water sources and examined for cryptosporidium oocysts and giardia cysts using the immunomagnetic separation method. in 9 (69%) of the 13 rivers, cryptosporidium oocyst was detected. giardia cyst was detected in 5 (38%) of the 13 rivers. the cryptosporidium oocyst positive rate was comparable to that of fecal bacteriological indicators, whic ...200111321780
quantification of cryptosporidium parvum oocysts in mouse fecal specimens using immunomagnetic particles and two-color flow cytometry.although single-color flow cytometry has been shown to be more sensitive than fluorescence microscopy for the quantification of cryptosporidium parvum oocysts, this method has not been optimized. monoclonal antibody ow50, specific to the cell wall of oocysts, was conjugated to superparamagnetic particles, to fluorescein isothiocyanate, and to r-phycoerythrin. the oocysts were then double stained with the fluorochrome-labeled ow50 and were placed in tubes with known numbers of highly fluorescent ...200111318573
detection of cryptosporidium parvum oocysts in environmental water in hokkaido, japan.control of cryptosporidiosis is important in public health. rivers that are polluted with cryptosporidium and drinking water that is treated for drinking water production from polluted rivers could result in the waterborne disease of cryptosporidiosis. we carried out an epidemiological study of natural water supplies in hokkaido, one of the largest dairy prefectures in japan. to detect cryptosporidium oocysts in environmental water, the filtration method was used for 28 samples, which were colle ...200111307921
inactivation of cryptosporidium parvum oocysts in cider by flash pasteurization.cryptosporidium parvum is a well-recognized pathogen of significant medical importance, and cider (apple juice) has been associated with foodborne cryptosporidiosis. this study investigated the effect of flash pasteurization on the viability of contaminant c. parvum oocysts. cider inoculated with oocysts was heated at 70 or 71.7 degrees c for 5, 10, or 20 s, and oocyst viability was measured by a semiquantitative in vitro infectivity assay. by infecting multiple wells of confluent madin-darby bo ...200111307890
antigen incorporation on cryptosporidium parvum oocyst walls.cryptosporidium parvum oocysts are the infective stages responsible for transmission and survival of the organism in the environment. in the present work we show that the oocyst wall, far from being a static structure, is able to incorporate antigens by a mechanism involving vesicle fusion with the wall, and the incorporation of the antigen to the outer oocyst wall. using immunoelectron microscopy we show that the antigen recognized by a monoclonal antibody used for diagnosis of cryptosporidiosi ...200111285502
tracking cryptosporidium parvum by sequence analysis of small double-stranded rna.we sequenced a 173-nucleotide fragment of the small double-stranded viruslike rna of cryptosporidium parvum isolates from 23 calves and 38 humans. sequence diversity was detected at 17 sites. isolates from the same outbreak had identical double-stranded rna sequences, suggesting that this technique may be useful for tracking cryptosporidium infection sources.200111266306
genotyping cryptosporidium parvum by single-strand conformation polymorphism analysis of ribosomal and heat shock gene regions.polymerase chain reaction (pcr)-coupled single-strand conformation polymorphism (sscp) approaches utilizing nuclear dna regions of the small subunit (ssu) of ribosomal rna and heat shock protein 70 gene (hsp70) were established for genotyping cryptosporidium parvum. the regions were amplified (individually or in a multiplex reaction) by pcr from dna extracted from oocysts from ruminant or human hosts, then denatured and subjected to electrophoresis in a mutation detection enhancement (nondenatur ...200111258751
inactivation of cryptosporidium parvum oocysts with ozone and monochloramine at low temperature.the rate of cryptosporidium parvum inactivation decreased with decreasing temperature (1-20 degrees c) for ozone and for monochloramine applied alone as well as after pre-treatment with ozone. synergy was observed at all temperatures studied for the ozone/monochloramine sequential disinfection scheme. the synergistic effect was found to increase with decreasing temperature. the inactivation rate with monochloramine after ozone pre-treatment was 5 times faster at 20 degrees c and 22 times faster ...200111257892
bovine milk antibodies for health.the immunoglobulins of bovine colostrum provide the major antimicrobial protection against microbial infections and confer a passive immunity to the newborn calf until its own immune system matures. the concentration in colostrum of specific antibodies against pathogens can be raised by immunising cows with these pathogens or their antigens. immune milk products are preparations made of such hyperimmune colostrum or antibodies enriched from it. these preparations can be used to give effective sp ...200011242458
specific iga antibody response to coproantigens of cryptosporidium parvum in serum and saliva of calves after experimental infection.the antibody response to coproantigens of cryptosporidium parvum was examined in saliva and sera of calves experimentally infected with c. parvum. coproantigens of c. parvum with approximate molecular masses of 17, 15 and less than 14kda were found in the feces of infected calves on day 3 or later, and 60 and 23kda coproantigens observed between days 4 and 9 post-infection, respectively. the antibody reactivity to the coproantigens was mainly attributable to iga class antibodies in saliva and wa ...200111240095
efficacy of halofuginone lactate in the prevention of cryptosporidiosis in suckling calves.the efficacy of halofuginone lactate in the prevention of cryptosporidiosis in suckling calves was evaluated in a multicentre, control versus placebo, randomised, double-blind clinical trial. seventy-eight six- to 48-hour-old calves were treated daily with 120 microg/kg bodyweight of halofuginone lactate administered orally for seven consecutive days, while 80 calves received a placebo. faecal samples were collected on the first day of dosing and four, seven, 14 and 21 days later, and cryptospor ...200111232925
cryptosporidium parvum infection involving novel genotypes in wildlife from lower new york state.cryptosporidium, an enteric parasite of humans and a wide range of other mammals, presents numerous challenges to the supply of safe drinking water. we performed a wildlife survey, focusing on white-tailed deer and small mammals, to assess whether they may serve as environmental sources of cryptosporidium. a pcr-based approach that permitted genetic characterization via sequence analysis was applied to wildlife fecal samples (n = 111) collected from september 1996 to july 1998 from three areas i ...200111229905
evidence for the emergence of a type-1-like immune response in intestinal mucosa of calves recovering from cryptosporidiosis.this study was undertaken to characterize the mucosal response to cryptosporidium parvum in infected calves that had recovered from diarrhea. flow cytometric surface phenotypes of lamina propria lymphocyte (lpl) suspensions from infected calves and age-matched controls revealed the presence of a significantly larger proportion of cd25+ lpl in infected calves than in controls. freshly isolated lpl from infected calves expressed more inos and interferon (ifn)-gamma than did controls. infected calv ...200111227908
detection of mucosally delivered antibody to cryptosporidium parvum p23 in infected calves.we have developed an assay to detect mucosally delivered antibody to cryptosporidium parvum sporozoite antigens. we absorbed a recombinant 23-kd sporozoite protein to polystyrene microspheres, and used flow cytometry to detect, titer, and determine the isotype of antibody to p23 that was shed in the feces of experimentally infected calves. noninoculated calves have low levels of mucosal antibody to p23, with igg1 as the predominant isotype. antibody titers rise in inoculated calves as the animal ...200011193650
morphologic, host specificity, and genetic characterization of a european cryptosporidium andersoni isolate.this study was undertaken in order to characterize a cryptosporidium muris-like parasite isolated from cattle in hungary and to compare this strain with other cryptosporidium species. to date, the large-type oocysts isolated from cattle were considered as c. muris described from several mammals. the size, form, and structure of the oocysts of the hungarian strain were identical with those described by others from cattle. an apparent difference between the morphometric data of c. muris-like paras ...200011191899
characterization of an intestinal epithelial cell receptor recognized by the cryptosporidium parvum sporozoite ligand csl.the protozoan parasite cryptosporidium parvum is a leading cause of diarrhea in humans and neonatal calves. the absence of approved parasite-specific drugs, vaccines, and immunotherapies for cryptosporidiosis relates in part to limited knowledge on the pathogenesis of zoite attachment and invasion. we recently reported that the c. parvum apical complex glycoprotein csl contains a zoite ligand for intestinal epithelial cells which is defined by monoclonal antibody (mab) 3e2. in the present study, ...200111179341
[cryptosporidium spp. in farms in the eastern region of venezuela].cryptosporidiosis is caused by the coccidian protozoa cryptosporidium. it is the most worldwide prevalent pathogen associated with diarrhea in young cattle and usually is caused by c. parvum which is also responsible of infections in humans, specially in immunocompromised patients. faecal samples from 75 young cattle aged between 2 to 20 weeks, were collected in four western dairy farms of venezuela and screened for the presence of cryptosporidium oocysts. positive samples were detected in 22 an ...200011155766
identification of 5 types of cryptosporidium parasites in children in lima, peru.cryptosporidium parvum is usually considered to be the pathogen responsible for human cryptosporidiosis. we genotyped cryptosporidium in 132 stool specimens from 80 peruvian children, representing 85 infection episodes, using techniques that differentiate cryptosporidium species and c. parvum genotypes. five types of cryptosporidium were identified: c. parvum human (67), bovine (8), and dog (2) genotypes, c. meleagridis (7), and c. felis (1). twenty-five (29%) of the 85 infection episodes were a ...200111133382
antibody reactivity to cryptosporidium parvum in saliva of calves after experimental infection.antibodies against cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. salivary anti-c. parvum iga antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. salivary anti-c. parvum igg antibody levels showed a gradual increase along with the change in iga antibody levels during the infection. in c ...200011129874
a factor derived from adult rat and cow small intestine reduces cryptosporidium parvum infection in infant rats.cryptosporidium parvum is an intracellular protozoan parasite of the mammalian intestine. in rats, c. parvum infection is age related; infants are susceptible, whereas adults are resistant. the transition from susceptibility to resistance usually takes place around the age of weaning. in the present study, infant rats were orally inoculated with a preparation of intestinal scrapings taken from adult rats or cows. infant rats received the scrapings daily from 3 to 14 days of age, were inoculated ...200011128521
host cell apoptosis impairs cryptosporidium parvum development in vitro.the absence of a self-sustaining in vitro propagation method for cryptosporidium parvum is a major obstacle for research on this parasite. conventional cell monolayers are unsuitable for long-term parasite propagation because the level of infection decreases over time and few oocysts, if any, are produced. the interaction between parasite and host cell was studied to identify factors limiting parasite development in vitro. loss of substrate adherence and death of parasitized host cells was obser ...200011128511
molecular characterization of a cryptosporidium isolate from a black bear.to further validate the observation of the existence of host-adapted strains of cryptosporidium parvum, we genetically characterized an isolate of cryptosporidium parasite from a black bear. sequence analysis of the ribosomal rna small subunit and the 70-kda heat shock protein (hsp70) showed that this parasite represents a new genotype of c. parvum and is related to the c. parvum dog genotype. this finding is helpful for clarifying cryptosporidium taxonomy.200011128505
unexpected activity of beta-cyclodextrin against experimental infection by cryptosporidium parvum.an unexpected activity of beta-cyclodextrin, an excipient used in pharmaceutical technology, was observed against cryptosporidium parvum. the viability and infectivity of purified oocysts, exposed for 24 hr to beta-cyclodextrin (2.5% suspension), were evaluated by inclusion/exclusion of 2 fluorogenic vital dyes and a suckling murine model, respectively. results of the viability assay showed a high proportion of nonviable oocysts (81.5%). the intensity of experimental infection, determined 7 days ...200011128490
b cells are required for the induction of intestinal inflammatory lesions in tcralpha-deficient mice persistently infected with cryptosporidium parvum.mice with targeted disruptions in the t-cell receptor alpha gene (tcralpha-/-) spontaneously develop inflammatory intestinal lesions with extensive b-cell lamina propria infiltrates. cryptosporidium parvum infection accelerates intestinal lesion formation in tcralpha-/- mice. in the present study, tcralpha-/- mice were crossed with jh-/- (b-cell-deficient) mice and challenged with c. parvum to determine if b cells are required for intestinal lesion development. tcralpha-/- x jh-/- mice challenge ...200011128483
efficacies of lipophilic inhibitors of dihydrofolate reductase against parasitic protozoa.competitive inhibitors of dihydrofolate reductase (dhfr) are used in chemotherapy or prophylaxis of many microbial pathogens, including the eukaryotic parasites plasmodium falciparum and toxoplasma gondii. unfortunately, point mutations in the dhfr gene can confer resistance to inhibitors specific to these pathogens. we have developed a rapid system for testing inhibitors of dhfrs from a variety of parasites. we replaced the dhfr gene from the budding yeast saccharomyces cerevisiae with the dhfr ...200111120964
prevalence of cryptosporidium parvum infection and pattern of oocyst shedding in calves in japan.cryptosporidium parvum infection and the pattern of oocyst shedding were observed in calves. a total of 480 fecal samples were collected from 30 calves (age, < or =30 days) over a period of 10 months from june 1998 to march 1999. a sucrose centrifugal flotation technique revealed 28/30 (93%) calves were passing cryptosporidium oocysts. oocyst shedding was first detected on the sixth day after birth, with 8% of the calves testing positive. this rate increased day by day and reached approximately ...200011078941
excretion patterns of mucosally delivered antibodies to p23 in cryptosporidium parvum infected calves.fecal samples obtained at intervals from six calves with acute cryptosporidiosis contained antibodies of multiple isotypes to p23. igm-, iga-, and igg(1)-isotype anti-p23 appeared before igg(2)-isotype antibodies. all anti-p23 antibodies had declined by 2 months after infection. one calf that failed to shed oocysts following initial exposure developed igg(1)-isotype anti-p23 antibodies. one calf that died following exposure to cryptosporidium parvum oocysts lacked detectable anti-p23 antibodies. ...200011044562
prevalence of giardia sp. cryptosporidium parvum and cryptosporidium andersoni (syn. c. muris) [correction of cryptosporidium parvum and cryptosporidium muris (c. andersoni)] in 109 dairy herds in five counties of southeastern new york.a cross-sectional study was undertaken to determine the prevalence of giardia sp. (g. duodenalis group), cryptosporidium parvum and cryptosporidium andersoni (c. muris) [corrected] in dairy cattle in three different age groups, and to evaluate the association of age and season with prevalence. one hundred and nine dairy farms, from a total of 212 farms, in five counties of southeastern new york volunteered to participate. on these farms, 2943 fecal samples were collected from three defined age g ...200011027856
transforming growth factor beta1 ameliorates intestinal epithelial barrier disruption by cryptosporidium parvum in vitro in the absence of mucosal t lymphocytes.exposure to oocysts of the protozoan cryptosporidium parvum causes intestinal epithelial cell dysfunction in vivo and in vitro, but effective means by which mucosal injury might be prevented remain unclear. we examined the ability of transforming growth factor beta1 (tgf-beta1)-a cytokine synthesized and released by cells in the intestine-to preserve the barrier function of human colonic epithelia when challenged with c. parvum oocysts and then studied the mechanisms involved. epithelial barrier ...200010992464
an immunoglobulin g1 monoclonal antibody highly specific to the wall of cryptosporidium oocysts.the detection of cryptosporidium oocysts in drinking water is critically dependent on the quality of immunofluorescent reagents. experiments were performed to develop a method for producing highly specific antibodies to cryptosporidium oocysts that can be used for water testing. balb/c mice were immunized with six different antigen preparations and monitored for immunoglobulin g (igg) and igm responses to the surface of cryptosporidium oocysts. one group of mice received purified oocyst walls, a ...200010973448
dna fingerprinting of cryptosporidium parvum isolates using amplified fragment length polymorphism (aflp).the genetic variability of 10 cryptosporidium parvum isolates of human and animal origin was investigated using amplified fragment length polymorphism (aflp). analysis of fluorescent dye-labeled amplified products was carried out using an abi prisms 377 dna sequencer and abi prisms genescan software. one-hundred and twelve primer combinations were evaluated using a single c. parvum isolate. the patterns generated were highly reproducible. for subsequent study, a subset of 9 primer pairs that yie ...200010958466
recovery and viability of cryptosporidium parvum oocysts and giardia intestinalis cysts using the membrane dissolution procedure.previously, the cellulose acetate membrane filter dissolution method was reported to yield cryptosporidium parvum oocyst recoveries of 70.5%, with recovered oocysts retaining their infectivity. in contrast, high spike doses (approximately 1 x 10(5) cryptosporidium parvum oocysts and giardia intestinalis cysts) yielded recoveries ranging from 0.4% to 83.9%, and 3.2% to 90.3%, respectively, in this study. recoveries with low spike doses (approximately 100 (oo)cysts) continued to demonstrate high v ...200010941515
extensive polymorphism in cryptosporidium parvum identified by multilocus microsatellite analysis.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 signific ...200010919789
in vitro infection of cryptosporidium parvum to four different cell lines.to determine a suitable condition for in vitro infection model of cryptosporidium parvum, four different cell lines, ags, mdck, hct-8 and caco-2, were used as host cell lines which were cultured at various concentrations of added supplements. these supplement include fetal bovine serum (fbs), sodium choleate, ascorbic acid, folic acid, calcium pantothenate, para-aminobenzoic acid and pyruvate and their effects on the cell lines which were infected with c. parvum were evaluated. the results of th ...200010905066
development of a novel, rapid integrated cryptosporidium parvum detection assay.the aim of this study was to develop a reverse transcription-pcr assay and lateral flow detection protocol for specific identification of cryptosporidium parvum. the method which we developed is sensitive and specific and has a low limit of detection. in our protocol a solid phase material, the xtra bind capture system, was used for extraction and purification of double-stranded rna (dsrna) specific for c. parvum. the xtra bind capture system interfaced with pellets concentrated from water sampl ...200010877759
successful hyperimmune bovine colostrum treatment of savanna monitors (varanus exanthematicus) infected with cryptosporidium sp.therapy based on the protective passive immunity of hyperimmune bovine colostrum (hbc) (raised against cryptosporidium parvum in cows) was applied to 4 savanna monitors (varanus exanthematicus) with gastric cryptosporidium sp. infections. all lizards were moderately emaciated, and their fecal and gastric lavage samples contained moderate numbers of cryptosporidium sp. oocysts. the first 3 of 7 gastric hbc treatments at 1-wk interval each decreased the numbers of oocysts in the fecal and gastric ...200010864270
natural transmission of cryptosporidium parvum between dams and calves on a dairy farm.the transmission of cryptosporidium parvum between dams and their respective calves was studied. for this purpose, fecal specimens taken from the rectum of preparturient, parturient, and postparturient dams were analyzed for c. parvum oocysts. fecal specimens were taken from the newborn calf 4 hr after birth. because the environment can be a source of contamination to the animals, specimens taken from inside and outside the barn were analyzed. the sucrose concentration method together with the z ...200010864245
infectivity to experimental rodents of cryptosporidium parvum oocysts from siberian chipmunks (tamias sibiricus) originated in the people's republic of china.we isolated cryptosporidium parvum-type oocysts from naturally infected siberian chipmunks which originated in the people's republic of china and examined the infectivity to rodents as experimental animals. the naturally infected chipmunks did not show any clinical symptoms. the oocysts were 4.8 x 4.2 microm on average in size. they were ovoid and morphologically similar to the c. parvum oocysts isolated from human and cattle. experimental rodents were inoculated with 1.6 x 10(6) original oocyst ...200010852396
association of rna polymerase complexes of the parasitic protozoan cryptosporidium parvum with virus-like particles: heterogeneous system.rna polymerase complexes were purified from cryptosporidium parvum, a parasitic protozoan known to infect many species of mammals including humans. western blot analysis revealed the association of the complexes with two different proteins, encoded by large and small segments of viral double-stranded rnas. each complex was found to contain only double-stranded rna, both double- and single-stranded rna, or only single-stranded rna. maximum rna-dependent rna polymerase activity was observed within ...200010846057
activity of decoquinate against cryptosporidium parvum in cell cultures and neonatal mice.cryptosporidium parvum is an apicomplexan parasite that is an important cause of diarrhea in neonatal calves and humans. no treatment is currently available for neonatal calves. we have recently learned from colleagues in the pharmaceutical industry that dairy practitioners are sometimes using decoquinate for the treatment of neonatal bovine cryptosporidiosis. therefore, the present study was undertaken to determine whether the clinical observations in calves can be substantiated by laboratory i ...200010799844
viability and infectivity of two cryptosporidium parvum bovine isolates from different geographical location.the viability of two cryptosporidium parvum bovine isolates from spain and colombia was evaluated by in vitro excystation, inclusion/exclusion of two fluorogenic vital dyes (dapi and pi) and infectivity assay in a suckling murine model. excystation percentages were similar for both spain and colombia isolates (83% and 87%, respectively). the total viability of the spain isolate, measured by inclusion/exclusion of two fluorogenic vital dyes, was 71% in comparison with that detected for oocysts of ...200010799839
presence of double-stranded rnas in human and calf isolates of cryptosporidium parvum.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 gen ...200010780545
a microsatellite marker reveals population heterogeneity within human and animal genotypes of cryptosporidium parvum.isolates of the protozoan parasite cryptosporidium parvum have been differentiated into 2 genotypes: genotype 'h', which is associated only with human infections, and genotype 'c', which is associated with both human and animal infections. to date, the analysis of polymorphisms of genes and of the small subunit ribosomal dna have revealed no heterogeneity within the 2 genotypes. in the present study, a locus containing simple sequence repeats (microsatellites) was pcr amplified and sequenced fro ...200010759081
immunomagnetic separation of cryptosporidium parvum oocysts using macs microbeads and high gradient separation columns.we evaluated the macs immunomagnetic separation (ims) system for concentrating cryptosporidium parvum. oocysts were first labeled with fluorescein isothiocyanate (fitc) or rabbit anti-c. parvum antibodies, then linked to microbeads coated with anti-fitc or anti-rabbit igg, and separated through a high gradient separation column. results indicated that over 95% of oocysts were recovered and their fluorescence and infectivity were retained. the presence of microbeads showed no effect on genomic dn ...200010739338
specific pcr primers for cryptosporidium parvum with extra high sensitivity.one pair of high-sensitive polymerase chain reaction (pcr) primers for cryptosporidium parvum was constructed based on the sequence of random amplified polymorphic dna. pcr with this primer pair amplified only the dna of c. parvum, not the control dna including cryptosporidium muris. this primer pair had most advantageous in its sensitivity over the six pairs of primers reported elsewhere. the minimum amount of template dna required to produce visible bands after gel electrophoresis and ethidium ...200010722790
inhibition of cryptosporidium parvum in vitro by 9-(alkylthio)acridine derivatives.the synthesis of several acridinic thioethers is described. compounds prepared were tested in vitro as potential drugs against the opportunistic infection known as cryptosporidiosis. with a view to predict activity, the quantitative structure-activity relationships were investigated. correlations between experimental data and either log p or pka are discussed.200010719621
environmental and geographical factors contributing to watershed contamination with cryptosporidium parvum oocysts.cryptosporidium parvum is a waterborne parasite which infects cattle and produces life-threatening zoonosis in people with impaired immune systems. digital maps of 100-year floodplain boundaries, land use/cover, and livestock operations were used to select and characterize cattle farms in the floodplain area in lancaster county, pennsylvania, u.s.a. over 21% of the cattle farms were located within 100-year floodplain boundaries. on average, a single farm comprised 12.8 ha of pasture (including b ...200010702335
molecular characterization of cryptosporidium isolates obtained from human immunodeficiency virus-infected individuals living in switzerland, kenya, and the united states.a total of 22 cryptosporidium isolates from human immunodeficiency virus-infected patients from kenya, switzerland, and the united states were examined at three genetic loci: the 18s ribosomal dna, hsp-70, and acetyl coenzyme a synthetase genes. four distinct cryptosporidium genotypes were identified: (i) the cryptosporidium parvum "human" genotype, (ii) the c. parvum "cattle" genotype, (iii) cryptosporidium felis, and (iv) cryptosporidium meleagridis. this is the first report of c. meleagridis ...200010699017
morphologic, host specificity, and molecular characterization of a hungarian cryptosporidium meleagridis isolate.this study was undertaken in order to characterize cryptosporidium meleagridis isolated from a turkey in hungary and to compare the morphologies, host specificities, organ locations, and small-subunit rna (ssu rrna) gene sequences of this organism and other cryptosporidium species. the phenotypic differences between c. meleagridis and cryptosporidium parvum hungarian calf isolate (zoonotic genotype) oocysts were small, although they were statistically significant. oocysts of c. meleagridis were ...200010653744
cryptosporidium andersoni n. sp. (apicomplexa: cryptosporiidae) from cattle, bos taurus.a new species of cryptosporidium is described from the feces of domestic cattle, bos taurus. oocysts are structurally similar to those of cryptosporidium muris described from mice but are larger than those of cryptosporidium parvum. oocysts of the new species are ellipsoidal, lack sporocysts, and measure 7.4 x 5.5 microm (range, 6.0-8.1 by 5.0-6.5 microm). the length to width ratio is 1.35 (range, 1.07-1.50). the colorless oocyst wall is < 1 microm thick, lacks a micropyle, and possesses a longi ...200010651302
mechanisms of attachment and internalization of cryptosporidium parvum to biliary and intestinal epithelial cells.although infection of the intestinal and biliary tracts by cryptosporidium parvum is a major problem in patients with the acquired immunodeficiency syndrome, the specific microbial and host molecules involved in c. parvum infection are unknown. we tested the hypothesis that lectin-carbohydrate interactions and cytoskeleton reorganization are involved in the infection of biliary and intestinal epithelia by c. parvum.200010648465
phylogenetic relationships among isolates of cryptosporidium: evidence for several new species.isolates of cryptosporidium were characterized using nucleotide sequence analysis of the 18s rrna and dihydrofolate reductase genes and also random-amplified polymorphic dna analysis. phylogenetic analysis confirmed the validity of the species of cryptosporidium examined in this study such as cryptospordium muris and cryptosporidium baileyi, and also reinforced evidence from numerous researchers worldwide suggesting that cryptosporidium parvum is not a single uniform species. the data obtained p ...199910647047
cryptosporidium parvum-induced inflammatory bowel disease of tcr-beta- x tcr-delta-deficient mice.experimental inoculation of neonatal immunocompetent strains of mice with cryptosporidium parvum results in a transient, noninflammatory enteric infection. in the present study, we show that inoculation of mice deficient in alphabeta and gammadelta t cells (tcr-beta- x tcr-delta-deficient mice) with c. parvum results in persistent infection and severe inflammatory bowel disease-like lesions. the most severe lesions in these mice were in the cecum with similar yet less severe lesions in the ileum ...199910647043
cryptosporidium sp. and giardia sp. infections in mountain gorillas (gorilla gorilla beringei) of the bwindi impenetrable national park, uganda.for conservation purposes and because of growing ecotourism, some mountain gorilla (gorilla gorilla beringei) populations have been habituated to humans. fecal specimens (n = 100) of nonhabituated and human-habituated gorillas (5 populations; 6 age classes) were tested for cryptosporidium sp. oocysts and giardia sp. cysts by conventional staining and immunofluorescent antibody (ifa). cryptosporidium sp. infections (prevalence 11%) were not restricted to very young gorillas but were observed in 3 ...199910647041
effect of salinity, temperature and storage time on mouse experimental infection by cryptosporidium parvum.cryptosporidium parvum oocysts collected from a naturally infected calf were exposed to different salinity and temperature for 2, 21 and 40 days, and then inoculated intragastrically into coccidium-free neonatal mice. the intensity of infection as determined seven days later by examination of intestinal homogenates were statistically analysed. salinity, time and salinity-time interaction were the only factors with significant effect on the infection intensity.199910628695
association of herd composition, stocking rate, and duration of calving season with fecal shedding of cryptosporidium parvum oocysts in beef herds.to evaluate the association of herd demographics, parturition variables, stocking rate, and rotational grazing practices with the probability of fecal shedding of cryptosporidium parvum from beef cow-calf herds in california.199910613218
molecular analysis of the 18s rrna gene of cryptosporidium serpentis in a wild-caught corn snake (elaphe guttata guttata) and a five-species restriction fragment length polymorphism- based assay that can additionally discern c. parvum from c. wrairi.an adult wild-caught corn snake (elaphe guttata guttata) was presented for humane euthanasia and necropsy because of severe cryptosporidiosis. the animal was lethargic and >5% dehydrated but in good flesh. gastric lavage was performed prior to euthanasia. histopathologic findings included gastric mucosal hypertrophy and a hemorrhagic erosive gastritis. numerous 5- to 7-microm-diameter round extracellular organisms were associated with the mucosal hypertrophy. a pcr, acid-fast stains, giemsa stai ...199910583987
polymorphisms in the beta-tubulin gene of cryptosporidium parvum differentiate between isolates based on animal host but not geographic origin.polymerase chain reaction primers were designed to target a region of the cryptosporidium parvum beta-tubulin gene spanning an intron. amplification products contained 11 polymorphic positions, representing a sequence divergence of 1.8%, which discriminated between isolates of c. parvum found solely in humans (genotype 1) and those found in humans and animals (genotype 2). seven of the polymorphic sites were located outside of the intron and the polymorphism between isolates was readily demonstr ...199910577745
a review of the importance of cryptosporidiosis in farm animals.cryptosporidium species are coccidian parasites with a large capacity to reproduce and to disseminate. several species are known to infect farm animals, although the economic importance of cryptosporidiosis is highly host species dependent. this paper reviews the impact of cryptosporidial infections in livestock and poultry. for different farm animals, the cryptosporidium spp. that occur, as well as their clinical and pathological features, and their interactions with other pathogens, are descri ...199910576578
ultrastructure, fractionation and biochemical analysis of cryptosporidium parvum sporozoites.sporozoites of the apicomplexan parasite cryptosporidium parvum were subjected to cell disruption and subcellular fractionation using a sucrose density step gradient. with this procedure, highly enriched preparations of the parasite membrane, the micronemes, dense granules and amylopectin granules were produced. no separate fraction containing rhoptries was obtained, however this organelle was found in defined fractions of the gradient, still associated with the apical tip of the sporozoites. us ...199910576576
the identification of cryptosporidium species and cryptosporidium parvum directly from whole faeces by analysis of a multiplex pcr of the 18s rrna gene and by pcr/rflp of the cryptosporidium outer wall protein (cowp) gene.a multiplex polymerase chain reaction (pcr) procedure to amplify 18s rrna gene fragments has been developed. amplified dna fragments of the expected size were obtained which were specific for cryptosporidium parvum and cryptosporidium wrairi (422 bp), cryptosporidium baileyi (11106 bp) and cryptosporidium muris (1346 bp). criptosporidium parvum and c. wrairi can be distinguished using a pcr/restriction fragment length polymorphism (rflp) analysis of the cryptosporidium outer wall protein (cowp) ...199910576575
the norway rat as a reservoir host of cryptosporidium parvum.the potential of norway rats (rattus norvegicus) to spread the parasite cryptosporidium parvum was investigated by examining parasite prevalence in relation to the structure and movements of three permanent rat populations living on farmland in warwickshire (uk) from october 1994 to march 1997. one population lived among a group of farm buildings housing cattle, while the other two had no contact with livestock, one living around a pond and its outflowing stream and the other on a rubbish tip. o ...199910574524
comparison of fecal samples collected per rectum and off the ground for estimation of environmental contamination attributable to beef cattle.to determine whether sampling feces off the ground replicates prevalence estimates for specific pathogens obtained from fecal samples collected per rectum of adult cows, and to determine characteristics of feces on the ground (fecal pats) that are associated with subsequent identification of campylobacter spp, cryptosporidium parvum, and giardia duodenalis.199910566807
cloning and expression of a dna sequence encoding a 41-kilodalton cryptosporidium parvum oocyst wall protein.this study was conducted to produce a recombinant species-specific oocyst wall protein of cryptosporidium parvum. antigens unique to c. parvum were identified by gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of oocyst proteins from several different cryptosporidium species. antiserum was then prepared against a 41-kda antigen unique to c. parvum and used to identify a recombinant dna clone, designated rcp41. expression of cp41 mrna in c. parvum oocysts was ...199910548585
assessment of drugs against cryptosporidium parvum using a simple in vitro screening method.a rapid semi-quantitative screening method was devised for assessing the anticryptosporidial and cytotoxic effects of putative chemotherapeutic compounds. the method is suitable as an initial rapid screening procedure from which compounds demonstrating anticryptosporidial activity can be identified for further analysis. it has the advantages of speed, low cost and concurrent assessment of anticryptosporidial and cytotoxic effects and allows accurate determination of minimum lethal concentrations ...199910499272
house flies (musca domestica) as transport hosts of cryptosporidium parvum.refuse and promiscuous-landing synanthropic filth flies, such as house flies (musca domestica), are recognized as transport hosts for a variety of protozoan and metazoan parasites in addition to viral and bacterial pathogens of public health importance. exposure of adult m. domestica to 20 ml of bovine diarrheal feces containing cryptosporidium parvum oocysts (2.0 x 10(5) oocysts/ml) resulted in intense deposition of the oocysts through fly feces on the surfaces visited by the flies (mean = 108 ...199910497998
role of cryptosporidium parvum as a pathogen in neonatal diarrhoea complex in suckling and dairy calves in france.this study was carried out to find the importance of cryptosporidium parvum in diarrhoea of neonatal calves in two types of breeding - suckling and dairy calves - in france. different agents causing neonatal diarrhoea, e. coli, rotavirus, coronavirus, salmonella and cryptosporidium were systematically researched in faeces. 1. suckling calves: in 40 livestock farms selected for diarrhoea, 311 calves 4 to 10 days old which had diarrhoea for less than 24h or no diarrhoea, were included in the study ...199910488727
cryptosporidium parvum induces apoptosis in biliary epithelia by a fas/fas ligand-dependent mechanism.although the clinical features of sclerosing cholangitis from opportunistic infections of the biliary tree in patients with acquired immunodeficiency syndrome (aids) are well known, the mechanisms by which associated pathogens, such as cryptosporidium parvum, cause disease are obscure. using an in vitro model of biliary cryptosporidiosis, we observed that c. parvum induces apoptosis in cultured human biliary epithelia. both caspase protease inhibitors and neutralizing antibodies to either fas re ...199910484385
[prevalence and importance of endoparasites in calves raised in swiss cow-calf farms].a longitudinal study was performed to establish estimates of prevalence of selected endoparasites in swiss cow-calf operations and to investigate the importance of an infection with endoparasites on diarrhea and weight gain until weaning. three hundred and eighty-six calves raised in 67 larger cow-calf herds were included in the study. faecal samples were collected during the first three months of life and at weaning. parasitological analyses were performed according to standard procedures inclu ...199910481370
virulence of three distinct cryptosporidium parvum isolates for healthy adults.the infectivity of three cryptosporidium parvum isolates (iowa [calf], ucp [calf], and tamu [horse]) of the c genotype was investigated in healthy adults. after exposure, volunteers recorded the number and form of stools passed and symptoms experienced. oocyst excretion was assessed by immunofluorescence. the id50 differed among isolates: iowa, 87 (se, 19; 95% confidence interval [ci], 48.67-126); ucp, 1042 (se, 1000; 95% ci, 0-3004); and tamu, 9 oocysts (se, 2.34; 95% ci, 4.46-13.65); tamu vers ...199910479158
accumulation of mucosal t lymphocytes around epithelial cells after in vitro infection with cryptosporidium parvum.we had previously shown that ileal intraepithelial lymphocytes isolated from calves with cryptosporidiosis include significantly increased numbers of cd8+ t lymphocytes and activated cd4+ cells. these increases could result from redistribution of resident mucosal lymphocytes or from homing of peripheral t cells to ileal mucosa. to determine whether resident mucosal lymphocytes can redistribute to cryptosporidium parvum-infected epithelium, oocysts were inoculated in vitro onto ileum explants tak ...199910461968
serological differences in neospora caninum-associated epidemic and endemic abortions.a sandwich enzyme-linked immunosorbent assay (elisa) for the sensitive and specific detection of bovine antibodies to neospora caninum was developed and evaluated using sera from cattle experimentally infected with n. caninum, toxoplasma gondii, sarcocystis cruzi, sarcocystis hominis, sarcocystis hirsuta, eimeria bovis, cryptosporidium parvum, babesia divergens, and field sera from naturally exposed animals. field sera were classified using a gold standard that included the results from an indir ...199910461950
the fate of cryptosporidium parvum oocysts ingested by dung beetles and their possible role in the dissemination of cryptosporidiosis.the fate of oocysts of cryptosporidium parvum ingested by dung beetles and the possible role these beetles serve in the dissemination of cryptosporidiosis were tested on the following species: anoplotrupes stercorosus, aphodius rufus, and onthophagus fracticornis. ten specimens of each species were offered cattle dung supplemented with 5.9 x 10(6) oocysts of c. purvum. after 24 hr of feeding, the beetles were examined for the presence of oocysts on their external surfaces, in their gastrointesti ...199910461948
chlorine disinfection of recreational water for cryptosporidium parvum.we examined the effects of chlorine on oocyst viability, under the conditions of controlled ph and elevated calcium concentrations required for most community swimming pools. we found that fecal material may alter the ct values (chlorine concentration in mg/l, multiplied by time in minutes) needed to disinfect swimming pools or other recreational water for cryptosporidium parvum.199910458969
characterization of cryptosporidium parvum in human and animal feces by single-tube nested polymerase chain reaction and restriction analysis.a dna isolation and purification method is described that produced dna free of inhibitory substances in 148 of the 159 analyzed fecal samples. the polymerase chain reaction (pcr) product from a sensitive single-tube nested pcr that amplifies a part of an oocyst protein was used to characterize cryptosporidium parvum genotypes by a simple restriction analysis. genotype 1 was solely detected in human-derived oocysts, genotype 2 was present in both animal and human-derived oocysts. the ratio betwee ...199910431737
evaluation of quantitative latex agglutination for detection of cryptosporidium parvum, e. coli k99, and rotavirus in calf feces.a new methodology for detection of rotavirus, escherichia coli k99, and cryptosporidium parvum in bovine fecal samples was developed based on a quantitative latex agglutination technique (qlat). calibrated microspheres coated with specific antibodies to 1 of the enteric pathogens are quantitatively agglutinated by the antigens present in diluted fecal sample. the test is performed in a 96-well flat-bottom plate. the samples were tested with a commercial enzyme-linked immunosorbent assay kit prio ...199910424645
a random survey of the cryptosporidium parvum genome.cryptosporidium parvum is an obligate intracellular pathogen responsible for widespread infections in humans and animals. the inability to obtain purified samples of this organism's various developmental stages has limited the understanding of the biochemical mechanisms important for c. parvum development or host-parasite interaction. to identify c. parvum genes independent of their developmental expression, a random sequence analysis of the 10.4-megabase genome of c. parvum was undertaken. tota ...199910417162
long-term survival of cryptosporidium parvum oocysts in seawater and in experimentally infected mussels (mytilus galloprovincialis).transmission of infectious oocysts of cryptosporidium parvum via surface- and drinking-water supplies has been reported and many surface waters flow into the sea, potentially causing runoff of animal-infected faeces. eating raw mussels is a common practice in many countries, increasing the public's risk of acquiring enteric pathogens. the aims of the present study were to estimate how long c. parvum oocysts remain infectious in artificial seawater, to determine if the oocysts are retained in mus ...199910404265
risk factors associated with cryptosporidium parvum infection in dairy cattle in southeastern new york state.an observational analytical epidemiologic study was carried out to identify factors associated with the risk of infection with cryptosporidium parvum in dairy herds in southeastern new york state. a random sample of 2943 cattle on 109 farms was selected from the target population. fecal samples were collected from animals in three different age groups and examined for the presence of c. parvum using a quantitative centrifugation concentration flotation method. data on intrinsic, preweaning, post ...199910392763
hyperimmune bovine colostrum specific for recombinant cryptosporidium parvum antigen confers partial protection against cryptosporidiosis in immunosuppressed adult mice.preparturient cows were immunized three times over a six-week period with recombinant plasmid dna encoding the cryptosporidium parvum cp15/60 antigen by injecting the dna in the mammary gland. serum was collected at each immunization and first colostrum was collected after parturition; all were assayed for cryptosporidium-specific antibodies (ab). a serological response to c. parvum sporozoite and oocyst antigen was detected in cows immunized with pcp15/60 plasmid dna. colostrum from these cows, ...199910392628
comparison of sensitivity of immunofluorescent microscopy to that of a combination of immunofluorescent microscopy and immunomagnetic separation for detection of cryptosporidium parvum oocysts in adult bovine feces.a direct immunofluorescence assay (dfa) (merifluor; meridian diagnostics, inc., cincinnati, ohio) was compared to an immunomagnetic separation (ims) assay (dynabeads; dynal, inc., lake success, n.y.) coupled with immunofluorescent microscopy (waterborne, inc., new orleans, la.) for their ability to detect low concentrations of cryptosporidium parvum oocysts in adult bovine fecal material. ims-dfa resulted in a 2-log-unit increase in sensitivity (10 oocysts/g) compared to dfa alone (1,000 oocysts ...199910388728
method for detection and enumeration of cryptosporidium parvum oocysts in feces, manures, and soils.eight concentration and purification methods were evaluated to determine percentages of recovery of cryptosporidium parvum oocysts from calf feces. the nacl flotation method generally resulted in the highest percentages of recovery. based on the percentages of recovery, the amounts of fecal debris in the final oocyst preparations, the relatively short processing time (<3 h), and the low expense, the nacl flotation method was chosen for further evaluation. extraction efficiency was evaluated by u ...199910388670
phylogenetic analysis of cryptosporidium isolates from captive reptiles using 18s rdna sequence data and random amplified polymorphic dna analysis.sequence alignment of a polymerase chain reaction-amplified 713-base pair region of the cryptosporidium 18s rdna gene was carried out on 15 captive reptile isolates from different geographic locations and compared to both cryptosporidium parvum and cryptosporidium muris isolates. random amplified polymorphic dna (rapd) analysis was also performed on a smaller number of these samples. the data generated by both techniques were significantly correlated (p < 0.002), providing additional evidence to ...199910386447
aging of cryptosporidium parvum oocysts in river water and their susceptibility to disinfection by chlorine and monochloramine.cryptosporidium parvum oocysts were aged in waters from both the st. lawrence river and the ottawa river. in situ survival experiments were carried out by incubating the oocysts in either dialysis cassettes or microtubes floated into an overflow tank. a significant portion of the oocysts survived in the test waters for several weeks. oocyst survival in the st. lawrence river was better in membrane-filtered (0.2 microm-pore diameter) water than in unfiltered water, suggesting that biological anta ...199810383227
protection of calves against cryptosporidiosis with immune bovine colostrum induced by a cryptosporidium parvum recombinant protein.the purpose of the study was to determine if immunization with a recombinant protein (rc7) of cryptosporidium parvum would induce immune bovine colostrum that protected calves against cryptosporidiosis following oral challenge with c. parvum oocysts. late gestation holstein cows with low titers of antibody to the p23 antigen of c. parvum were immunized three times with 300 microg affinity purified rc7 c. parvum recombinant protein (immune cows), or left nonimmunized (control cows). colostrum was ...199910367947
intestinal parasites in patients with diarrhea and human immunodeficiency virus infection in zimbabwe.to determine the prevalence of intestinal parasites and risk factors for infection associated with diarrhea in hiv-infected patients in harare, zimbabwe.199910357381
new cryptosporidium genotypes in hiv-infected persons.using dna sequencing and phylogenetic analysis, we identified four distinct cryptosporidium genotypes in hiv-infected patients: genotype 1 (human), genotype 2 (bovine) cryptosporidium parvum, a genotype identical to c. felis, and one identical to a cryptosporidium sp. isolate from a dog. this is the first identification of human infection with the latter two genotypes.199910341184
inactivation of cryptosporidium parvum oocyst infectivity by disinfection and sterilization processes.cryptosporidium parvum is a common cause of self-limited gastroenteritis in the normal host but may cause severe disease in immunocompromised persons. person-to-person transmission has been well documented in households, child care centers, and hospitals. because contaminated environmental surfaces and medical devices such as endoscopes may play a role in disease transmission, we studied the susceptibility of c parvum to chemical agents commonly used for disinfection and evaluated the efficacy o ...199910228259
use of a sentinel system for field measurements of cryptosporidium parvum oocyst inactivation in soil and animal waste.a small-volume sentinel chamber was developed to assess the effects of environmental stresses on survival of sucrose-percoll-purified cryptosporidium parvum oocysts in soil and animal wastes. chambers were tested for their ability to equilibrate with external chemical and moisture conditions. sentinel oocysts were then exposed to stresses of the external environment that affected their viability (potential infectivity), as indicated by results of a dye permeability assay. preliminary laboratory ...199910223991
constitutive expression of small subunit ribosomal rna transcripts in cryptosporidium parvum oocysts and intracellular stages.as in other apicomplexan protozoa, the ribosomal genes of cryptosporidium parvum are present in small number and dispersed on several chromosomes. two types of ribosomal small subunit genes have been identified in bovine isolates by sequencing and sequence-specific polymerase chain reaction. using denaturing gradient gel electrophoresis, ribosomal gene expression was investigated in c. parvum oocysts and intracellular stages grown in tissue culture. in a calf-propageted c. parvum isolate, extra ...199910219300
differential mrna display cloning and characterization of a cryptosporidium parvum gene expressed during intracellular development.differential mrna display was used to detect differences in gene expression between mock-infected and cryptosporidium parvum-infected human adenocarcinoma cells. a reproducible band present only in c. parvum-infected cells, ddhc-10 was isolated and cloned. northern blot analysis was used to confirm the differential expression of the hc-10 mrna. as differential mrna display does not differentiate between parasite and host mrnas, southern blot analysis was used to demonstrate that ddhc-10 represen ...199910219298
age, geographic, and temporal distribution of fecal shedding of cryptosporidium parvum oocysts in cow-calf herds.to evaluate fecal shedding of cryptosporidium parvum from california cow-calf herds with respect to age, geographic region, temporal effects, and association with watery feces.199910211683
biallelic polymorphism in the intron region of beta-tubulin gene of cryptosporidium parasites.nucleotide sequencing of polymerase chain reaction amplified intron region of the cryptosporidium parvum beta-tubulin gene in 26 human and 15 animal isolates revealed distinct genetic polymorphism between the human and bovine genotypes. the separation of 2 genotypes of c. parvum is in agreement with our previous genotyping data based on the thrombospondin-related adhesion protein (trap-c2) gene, indicating these genotype characteristics are linked at 2 genetic loci. characterization of cryptospo ...199910207387
the cryptosporidium "mouse" genotype is conserved across geographic areas.a 298-bp region of the cryptosporidium parvum 18s rrna gene and a 390-bp region of the acetyl coenzyme a synthetase gene were sequenced for a range of cryptosporidium isolates from wild house mice (mus domesticus), a bat (myotus adversus), and cattle from different geographical areas. previous research has identified a distinct genotype, referred to as the "mouse"-derived cryptosporidium genotype, common to isolates from australian mice. comparison of a wider range of australian mouse isolates w ...199910203475
isoenzyme activities of different strains of cryptosporidium parvum.different isoenzyme activities have been assayed in three strains of cryptosporidium parvum, c1 (c. parvum from infected calves, uk), c2 (c. parvum from infected calves, egypt) and c3 (c. parvum from infected goats, egypt). the electrophoretic variations of five enzymes; lactate dehydrogenase (ldh), glucose phosphate isomerase (gpi), hexokinase (hk), malate dehydrogenase (mdh) and glutamate dehydrogenase (gldh) were compared among the three different isolates using native polyacrylamide gel-elec ...199910190863
oocysts, igg levels and immunoblot patterns determined for cryptosporidium parvum in bovine examined during a visit to a farm (northeastern spain).single fecal and serum samples were individually collected from 101 bovines selected at random during a visit to a farm in northeastern spain (group i, 26 animals aged 2-36 days; group ii, 34 animals aged 1.5-4.5 months; group iii, 41 animals aged 20-24 months). testing for the presence of cryptosporidium parvum oocysts in feces (monofluo kit cryptosporidium, diagnostics pasteur, france) indicated that 26% animals were infected (81% of group i, 15% of group ii and 0% of group iii). serological t ...199910190862
beta-tubulin mrna as a marker of cryptosporidium parvum oocyst viability.determining the viability of waterborne cryptosporidium parvum oocysts remains a technical challenge. rrna and mrna were evaluated in a reverse transcription (rt)-pcr assay as potential markers of oocyst viability. the rationale for this approach is the rapid turnover and postmortem decay of cellular rna. the beta-tubulin mrna and an anonymous mrna transcript were chosen as potential markers because they are the only mrna species in c. parvum known to possess introns. this feature facilitated th ...199910103254
phylogenetic analysis of cryptosporidium parasites based on the small-subunit rrna gene locus.biological data support the hypothesis that there are multiple species in the genus cryptosporidium, but a recent analysis of the available genetic data suggested that there is insufficient evidence for species differentiation. in order to resolve the controversy in the taxonomy of this parasite genus, we characterized the small-subunit rrna genes of cryptosporidium parvum, cryptosporidium baileyi, cryptosporidium muris, and cryptosporidium serpentis and performed a phylogenetic analysis of the ...199910103253
three sample preparation protocols for polymerase chain reaction based detection of cryptosporidium parvum in environmental samples.cryptosporidium parvum is a protozoan parasite responsible for an increasing number of outbreaks of gastrointestinal illness worldwide. in this report, we describe development of sample preparation protocols for polymerase chain reaction (pcr)-based detection of c. parvum in fecal material and environmental water samples. two of these methods were found adequate for isolation of cryptosporidium dna from filtered water pellet suspensions. the first involved several filtration steps, immunomagneti ...199910076632
cryptosporidium parvum sporozoite pellicle antigen recognized by a neutralizing monoclonal antibody is a beta-mannosylated glycolipid.the protozoan parasite cryptosporidium parvum is an important cause of diarrhea in humans, calves, and other mammals worldwide. no approved vaccines or parasite-specific drugs are currently available for the control of cryptosporidiosis. to effectively immunize against c. parvum, identification and characterization of protective antigens are required. we previously identified cps-500, a conserved, neutralization-sensitive antigen of c. parvum sporozoites and merozoites defined by monoclonal anti ...199910024577
Refresh
firstprev
1234567
nextlast
Displaying items 401 - 500 of 695