evaluation of an animal model system for cryptosporidiosis: therapeutic efficacy of paromomycin and hyperimmune bovine colostrum-immunoglobulin.several immunodeficient rodent models currently exist in which persistent, largely asymptomatic, cryptosporidium parvum infections can be established. piglets, in contrast, develop a self-limiting diarrheal illness. we have consequently developed an animal model system in which scid mice were used to screen drugs for inhibitory activity against c. parvum, after which the drugs' therapeutic potential was evaluated with piglets. paromomycin and hyperimmune bovine colostrum-immunoglobulin were sele ...19948556484
complete development of cryptosporidium parvum in bovine fallopian tube epithelial cells.cryptosporidium parvum is a coccidian parasite responsible for causing protracted and life-threatening diarrheal illness in immunocompromised humans, especially patients with aids. the lack of medications effective in treating people suffering from cryptosporidiosis has prompted the development of in vivo and in vitro models for this disease. this study is the first to demonstrate that c. parvum can complete its entire life cycle (from sporozoite to infective oocyst) in a primary culture of bovi ...19968557363
effect of three concentration techniques on viability of cryptosporidium parvum oocysts recovered from bovine feces.bovine fecal samples (1 g) negative for cryptosporidium sp. oocysts were seeded with 7 x 10(4) cryptosporidium parvum oocysts and purified by either water-ether concentration, sucrose density flotation, or zinc sulfate flotation to evaluate oocyst recovery. the effect of these purification techniques on the viability of recovered oocysts was also evaluated. significantly higher numbers of seeded oocysts were recovered by water-ether concentration (recovery rate, 46 to 75%) than by sucrose densit ...19958567888
evaluation of commercial enzyme immunoassay (eia) and immunofluorescent antibody (fa) test kits for detection of cryptosporidium oocysts of species other than cryptosporidium parvum.a commercial enzyme immunoassay (eia) (prospect rapid assay), a direct immunofluorescence antibody (ifa) test for stool testing (merifluor cryptosporidium/giardia), and an indirect ifa test for environmental testing (hydrofluor-combo cryptosporidium/giardia) were evaluated for detection of low public health risk cryptosporidium oocyst isolates, and for c. parvum oocyst isolates from human and bovine feces that represent a high public health risk. there was no cross-reactivity of eia with ova of ...19968600765
cryptosporidium parvum oocyst antigens recognized by sera from infected asymptomatic adult cattle.gel electrophoresis and western blotting were used to investigate the recognition of cryptosporidium parvum oocyst antigens by sera from asymptomatic c. parvum-seropositive cattle with or without coccidian oocysts in their faeces (c. parvum or/and eimeria spp.). most sera from coprologically c. parvum-positive animals (71%) recognized fractions in the 17-20 kda range; these fractions were not recognized by sera from coprologically negative animals. in addition, most sera with antibodies to c. pa ...19958644454
patterns of cryptosporidium antigen and oocyst excretion in calves studied by reverse passive haemagglutination and light microscopy.a reverse passive haemagglutination (rph) assay incorporating a monoclonal antibody against cryptosporidium parvum oocysts was used to follow cryptosporidium coproantigen excretion by calves. rph detected soluble antigen that passed 0.22 micron filters. non-specific reactions that occurred in some samples were markedly reduced by heat treatment of the faecal specimens and were abolished by filtration after heat treatment. results were compared with oocyst counts performed by microscopy of modifi ...19958644461
serologic responses of cattle and other animals infected with neospora examine cross-reactivity among neospora caninum and closely-related apicomplexans.19968669764
efficacy of serine protease inhibitors against cryptosporidium parvum infection in a bovine fallopian tube epithelial cell culture system.the anticryptosporidial potential of the protease inhibitors alpha-1-antitrypsin (aat), antipain, aprotinin, leupeptin, methoxysuccinyl-ala-ala-pro-valine chloromethylketone (maapvck), soybean trypsin inhibitor (sbti), and phenylmethylsulfonyl fluoride (pmsf) was evaluated in a bovine fallopian tube epithelial (bfte) cell culture system. protease inhibitor concentrations of 5, 10, 50, 100, and 500 micrograms/ ml (pmsf at 1, 2, and 3 mm) in rpmi medium were mixed with cryptosporidium parvum oocys ...19968691375
effect of pasteurization on infectivity of cryptosporidium parvum oocysts in water and milk.cryptosporidium parvum is a major cause of diarrheal disease in humans and has been identified in 78 other species of mammals. the oocyst stage, excreted in feces of infected humans and animals, has been responsible for recent waterborne outbreaks of human cryptosporidiosis. high temperature and long exposure time have been shown to render oocysts (suspended in water) noninfectious, but for practical purposes, it is important to know if high-temperature--short-time conditions (71.7 degrees c for ...19968702279
influence of hydrogen peroxide on acid-fast staining of cryptosporidium parvum oocysts.infections by the protozoan parasite cryptosporidium parvum are routinely diagnosed by modified ziehl-neelsen (acid-fast) staining of faecal preparations despite the counterstaining and ghost-like appearance of some oocysts. quantitative studies demonstrated that only a small percentage of oocysts excreted by naturally infected newborn calves displayed acid-fast characteristics, but that percentage increased when the time between excretion and sample staining was increased. the treatment of faec ...19958719960
detection of cryptosporidium parvum oocysts in faeces: comparison of conventional coproscopical methods and the polymerase chain reaction.conventional and coproscopical methods were compared with the polymerase chain reaction (pcr) for the detection of cryptosporidium oocysts in bovine faeces. oocysts were not detected in samples seeded with 10,000 oocysts following formol ether sedimentation and examination using auramine phenol (ap) or by immunofluorescent (if) staining. when oocysts were concentrated using sucrose flotation the threshold of detection was 4000 oocysts per gram for both staining methods. following salt flotation ...19968750678
complete development of cryptosporidium parvum in mdbk cells.sporozoites of cryptosporidium parvum excysted in vitro from bovine oocysts were incubated with monolayers of madin-darby bovine kidney cells. the extent of parasite colonisation was monitored by light microscopy and immunofluorescence. electron microscopy confirmed the complete development and replication of c. parvum within madin-darby bovine kidney cells.19968759799
role of enteric pathogens in the aetiology of neonatal diarrhoea in lambs and goat kids in spain.faeces samples from diarrhoeic and non-diarrhoeic lambs and goat kids aged 1-45 days were examined for enteric pathogens. cryptosporidium parvum was detected in both diarrhoeic lambs (45%) and goat kids (42%) but not in non-diarrhoeic animals. f5+ (k99+) and/or f41+ escherichia coli strains were isolated from 26% and 22% of the diarrhoeic lambs and goat kids, respectively, although these strains, which did not produce enterotoxins st i or lt i, were found with similar frequencies in non-diarrhoe ...19968760970
azithromycin therapy for cryptosporidium parvum infection in four children infected with human immunodeficiency virus.cryptosporidium parvum intestinal infection in immunodeficient patients can cause severe intestinal fluid losses with severe dehydration or chronic diarrhea with malnutrition. therapies tried in human beings and animals include paromomycin, clarithromycin, azithromycin, octreotide, hyperimmune bovine colostrum, and bovine transfer factor. no specific therapy has been found to be consistently beneficial to children. we report azithromycin treatment of four children with acquired immunodeficiency ...19968765631
detection of cryptosporidium parvum in raw milk by pcr and oligonucleotide probe hybridization.cryptosporidium spp. are potential contaminants of food. suspected cases of food-borne cryptosporidiosis are rarely confirmed because of the limited numbers of oocysts in the samples and the lack of sensitive detection methods adaptable to food. pcr was investigated as a means of overcoming this problem. a pcr assay was designed for the specific amplification of a previously sequenced portion of an oocyst protein gene fragment of cryptosporidium parvum (n. c. lally, g. d. baird, s. j. mcquay, f. ...19968795214
in vitro blastogenic responses and interferon-gamma production by intestinal intraepithelial lymphocytes of calves.intestinal intraepithelial lymphocytes are a large and heterogenous population of lymphocytes located strategically at the entry site of enteric pathogens into the body. their ability to proliferate and produce interferon-gamma in vitro in response to mitogens or interleukin-2 was investigated in four-week-old calves. it was found that they had similar mitogen-induced blastogenic responses and produced interferon-gamma like the peripheral blood lymphocytes of four-week-old calves. preliminary st ...19968819193
comparison of oocyst shedding and the serum immune response to cryptosporidium parvum in cattle and pigs.a comparison was made between oocyst shedding and the presence of specific serum igg antibodies to cryptosporidium parvum in 108 bovines and 90 pigs. oocysts were detected by a commercial immunofluorescence assay in feces from 26.8% of bovines and 34.4% of pigs, whereas positive titers as determined by an indirect fluorescent antibody method were found in sera from 12.9% and 48.9% of the respective animals. infection was significantly most frequent in suckling calves (82.7%) and weaned piglets ( ...19968832734
potential antifolate resistance determinants and genotypic variation in the bifunctional dihydrofolate reductase-thymidylate synthase gene from human and bovine isolates of cryptosporidium parvum.we have determined the nucleic acid sequences of a gene encoding the bifunctional enzyme dihydrofolate reductase-thymidylate synthase (dhfr-ts) from bovine and human aids isolates of cryptosporidium parvum. the dhfr-ts gene was isolated from genomic dna libraries by hybridization with a probe amplified from c. parvum genomic dna using generic ts primers in the polymerase chain reaction. genomic southern and electrophoretic karyotype analyses reveal c. parvum dhfr-ts is a single-copy gene on a 12 ...19968855552
in vitro anticryptosporidial activity of dinitroaniline herbicides.despite the evaluation of over 100 antimicrobial drugs, the diarrheal disease cryptosporidiosis has remained refractory to treatment. we report the evaluation of five dinitroaniline herbicides including trifluralin, profluralin, nitralin, pendimethalin, and fluchloralin for anticryptosporidial activity in an in vitro cultivation model of cryptosporidium parvum. all five compounds exhibited significant anticryptosporidial activities with no corresponding evidence of toxicity. the most active comp ...19968867379
a chemiluminescence immunoassay for evaluation of cryptosporidium parvum growth in vitro.a chemiluminescence immunoassay (clia) was developed to detect cryptosporidium parvum growth in madin-darby canine kidney (mdck) cell cultures. optimal results were obtained when mdck cells were plated at a density of 1 x 10(4) cells/well (96-well plate) and maintained as a monolayer for 4 days prior to infection with 2 x 10(4) parasites/well. two compounds (paromomycin and maduramicin) were evaluated and shown to have selective activity against c. parvum in a dose-dependent manner. there was ex ...19968867380
simplified methods for obtaining purified oocysts from mice and for growing cryptosporidium parvum in to 8-day-old arc/swiss mice were infected with 100,000-120,000 cryptosporidium parvum oocysts. at 8 days postinfection (pi) the jejunum, ileum, cecum, colon, and rectum were removed. using a simple extraction procedure and purification by ficoll gradient centrifugation, we rountinely obtained between 3-6 million and up to 15 million purified oocysts per mouse. for in vitro cultivation, purified oocysts were pretreated in a low ph (2.5-3) 0.5% trypsin solution for 20 min, resuspended in su ...19968885885
field testing of prophylactic measures against cryptosporidium parvum infection in calves in a california dairy test the ability of oral vaccination or probiotic treatment with lactic acid-producing bacteria to protect calves from cryptosporidium parvum infection under field conditions.19968915434
an epidemiological survey of cryptosporidium parvum infection in randomly selected inhabitants of seoul and epidemiological survey was performed to know the status of cryptosporidium sp. infection among the people in seoul and chollanam-do in 1992. one village of chollanam-do (hwasun-gun) which showed the highest oocyst positive rate was re-surveyed in 1995 for human infection and for cattle also. the subjected areas consisted of 8 urban villages ( = dongs) of seoul and 4 urban ( = dongs) and 7 rural ( = myons) villages of chollanam-do. a total of 3,146 fecal samples was collected randomly, and sme ...19968925243
treatment of severe diarrhea caused by cryptosporidium parvum with oral bovine immunoglobulin concentrate in patients with aids.we prospectively evaluated the safety and efficacy of colostrum-derived bovine immunoglobulin concentrate in the treatment of diarrhea caused by cryptosporidium parvum in patients with aids. a total of 24 patients with severe chronic diarrhea and aids were stratified to one of three cohorts: (1) c. parvum infection alone (n = 16), (2) c. parvum and a second opportunistic infection (n = 4), and (3) idiopathic aids enteropathy with no identified source of infection (n = 3) or an untreatable opport ...19968948373
activation of intestinal intraepithelial t lymphocytes in calves infected with cryptosporidium parvum.the objective of this study was to identify disease-related changes in lymphocyte populations within ileal mucosae of calves with cryptosporidiosis. groups of five neonatal calves were orally infected at 3 days of age with 10(8) oocysts and maintained in enteric-pathogen-free conditions until clinical disease was established or until the animals had recovered from disease. age-matched uninfected calves were used for comparison. ileal mucosal lymphocytes were collected, quantitated, and phenotype ...19978975910
genotyping human and bovine isolates of cryptosporidium parvum by polymerase chain reaction-restriction fragment length polymorphism analysis of a repetitive dna order to define transmission routes of cryptosporidiosis and develop markers that distinguish cryptosporidium parvum isolates, we have identified 2 polymorphic restriction enzyme sites in a c. parvum repetitive dna sequence. the target sequence was amplified by polymerase chain reaction from 100 to 500 oocysts and the amplified product was subjected to restriction enzyme digestion. typing of 23 isolates showed that 10/10 calf isolates had the same profile. in contrast, 2 patterns were observe ...19968998987
[cryptosporidia associated gastroenteritis: epidemiologic study of children in tyrol and vorarlberg].stool samples from 523 children aged between 3 months and 6 years were examined for cryptosporidium parvum by means of the direct immunofluorescence technique in march 1996. the specimens were sent to the federal public health laboratory in innsbruck from general practitioners and pediatricians and from hospitals in tyrol and vorarlberg. the study was performed during the cold season in an area that does not employ surface water for the production of drinking water. oocysts of cryptosporidia wer ...19969005680
anti-oxidant enzymes in cryptosporidium parvum oocysts.oocysts of cryptosporidium parvum showed relatively low levels of sod activity. the sod which had a pi of 4.8 and an approximate molecular weight of 35 kda appeared to be iron dependent. catalase, glutathione transferase, glutathione reductase and glutathione peroxidase activity could not be detected, nor could trypanothione reductase. no nadh or nadph oxidase activity could be detected, nor could peroxidase activity be demonstrated using o-dianisidine, guaiacol, nadph or nadh as co-substrates. ...19979011070
protective monoclonal antibody defines a circumsporozoite-like glycoprotein exoantigen of cryptosporidium parvum sporozoites and merozoites.the apicomplexan protozoan parasite cryptosporidium parvum causes a diarrheal disease in humans and other mammals for which specific therapy and immunoprophylaxis are unavailable. passive immunization with abs against whole c. parvum organisms has variable efficacy in immunocompromised or neonatal hosts. because apical and surface-exposed zoite ags of the apicomplexa are critical to infectivity and targets of protective immunity, we examined the ability of mabs generated against such ags in c. p ...19979029117
recovery of waterborne oocysts of cryptosporidium from water samples by the membrane-filter dissolution method.the cellulose-acetate membrane (cam)-filter dissolution method implemented into a millipore glass microanalysis system was used for recovery of cryptosporidium parvum oocysts seeded into 25 l of drinking water in polyethylene carboy aspirator bottles. cam-entrapped oocysts were detected by immunofluorescence microscopy. from 65 to 94 oocysts/l (mean 75 oocysts/l), 34.7% overall of the inoculated oocysts, were unrecovered as determined after the water had been drained from the bottle, rinsed with ...19979039693
cryptosporidium parvum oocysts recovered from water by the membrane filter dissolution method retain their infectivity.cryptosporidium parvum oocysts infectious to neonatal balb/c mice were processed by the cellulose-acetate membrane (cam) filter dissolution method to determine if the procedure that utilizes acetone incubation and alcohol centrifugations alters their viability (determined by in vitro excystation) or infectivity (determined by infectivity bioassay). in addition, most oocysts with altered viability by desiccation, heat inactivation, and snap freezing that were processed by the cam filter dissoluti ...19979057705
specific interferon-gamma, iga and igm responses after experimental infection of neonatal calves with cryptosporidium parvum.the in vitro interferon-gamma production by peripheral blood mononuclear cells and the local antibody build up was monitored in neonatal calves experimentally infected with cryptosporidium parvum and in negative controls of the same age. from day 6 p.i. on, an infection-induced interferon-gamma response was observed in lymphocyte cultures after stimulation with cryptosporidium oocyst antigen preparation. only the cryptosporidium-infected calves developed local iga and igm responses from day 6 p. ...19979076540
lymphocyte dynamic patterns in cattle during a primary infection with cryptosporidium parvum.changes in intraepithelial (iel), lamina propria (lpl), and draining lymph node (lnl) lymphocytes were assessed in 9-day-old calves during primary infection with cryptosporidium parvum and in similarly aged noninfected calves. a very low percentage of both cd4+ and cd8+ t cells were found in iel and lpl of noninfected calves. in infected compared to controls, percentages of cd2+, cd3+, cd4+, and cd8+ t cells in iel exhibited a significant increase (p < 0.05), whereas the percentage of il2r+ incr ...19979105305
novel elisa for detection of neospora-specific antibodies in enzyme-linked immunosorbent assay (elisa) to detect antibodies to neospora species in cattle was developed. whole formalin-fixed neospora caninum (nc-liverpool) tachyzoites were used as antigen and a monoclonal antibody to bovine immunoglobulin light chain and an anti-mouse horseradish peroxidase conjugate were used to reveal bound antibody. a panel of 46 sera, negative by the immunofluorescent antibody test (ifat), were used in the elisa at a serum dilution of 1:500 to calculate the negative ...19979106971
an in vitro model of infection of human biliary epithelial cells by cryptosporidium parvum.cryptosporidium parvum infection in the immunosuppressed host is frequently complicated by biliary tract involvement. the recent production of human biliary epithelial cell lines was exploited to develop an in vitro model of biliary cryptosporidiosis. infection with c. parvum oocysts was detected by ifa and elisa and confirmed by transmission electron microscopy. inoculation of monolayers with 10(4) to 5 x 10(5) oocysts/well resulted in a dose-dependent increase in infection. time-course experim ...19979129102
viability of cryptosporidium parvum during ensilage of perennial ryegrass.the survival of cryptosporidium parvum during ensilage of perennial ryegrass was examined in laboratory silos with herbage prepared in one of three different ways; either untreated, inoculated with a strain of lactobacillus plantarum or by direct acidification with formic acid. the ph values of all silages initially fell below 4.5, but only formic acid-treated silage remained stable at less than ph 4 after 106 d, with the ph of the untreated and inoculant-treated silages rising to above 6. the f ...19979147867
localization of alpha/beta and gamma/delta t lymphocytes in cryptosporidium parvum-infected tissues in naive and immune calves.the nature of the host's t-lymphocyte population within the intestinal villi following cryptosporidium parvum infection was characterized with a bovine model of cryptosporidiosis. in naive animals, infection with c. parvum resulted in substantial increases in the numbers of alpha/beta t cells, both cd4+ (150%) and cd8+ (60%), and of gamma/delta t cells (70%) present within the intestinal villi of the infected ileum. in immune animals, the host t-lymphocyte response to a challenge infection with ...19979169784
characterization of secretory iga responses in mice infected with cryptosporidium parvum.mice inoculated at 5, 21 and 28 days of age with 10(6) or 10(7) cryptosporidium parvum oocysts became infected but did not exhibit any clinical signs of disease. specific iga antibodies were detected in faecal extracts from all infected mice by an indirect immunofluorescent assay. these antibodies first appeared between 11 and 37 days post-infection (dpi) and persisted until the end of the experiment at 55 dpl. they appeared earlier in older mice than in newborn mice. reduction and resolution of ...19979184934
effects of manganese salts on the aids-related pathogen, cryptosporidium parvum in vitro and in vivo.the authors examined the effects of manganese salts on the interaction of the aids-related pathogen, cryptosporidium parvum, with human ileoadenocarcinoma (hct-8) cells in vitro. manganese (mn) inhibited binding of c. parvum sporozoite membrane antigens to intact, fixed hct-8 cells in a dose-dependent fashion, whereas ca++, mg++, and zn++ salts had no effect. manganese was also found to affect sporozoite penetration of live hct-8 cells, which resulted in a dose-dependent inhibition of parasite d ...19979197922
prevalence of cryptosporidium spp. oocysts in cattle and wildlife in morogoro region, tanzania.prevalences of cryptosporidium spp. oocysts in cattle (n = 486) on five selected farms in morogoro municipality and three species of herbivorous wildlife (n = 87) from mikumi national park, morogoro, tanzania, were determined using the modified ziehl-neelsen staining technique. of 486 bovine faecal samples, 5.3% were positive for cryptosporidium spp. the prevalence of cryptosporidium was higher in calves less than 3 months of age compared to weaned calves and adults. cryptosporidium spp. oocysts ...19979234442
the effect of cotrimoxazole on experimental cryptosporidium parvum infection in kids.the prophylactic and therapeutic effects of the folic acid inhibitor cotrimoxazole (trimethoprim in combination with sulfamethoxazole) was tested in goat kids experimentally infected with cryptosporidium parvum oocysts. of the twenty-four 6-day-old kids inoculated with 6 x 10(6) oocysts of c parvum, ten kids were administered cotrimoxazole prophylactically at a dose 20 mg/kg per day of trimethoprim/100 mg/kg per day of sulfamethoxazole for 14 consecutive days beginning 1 day before infection. si ...19979257448
antagonistic effect of human alpha-1-antitrypsin on excystation of cryptosporidium parvum oocysts.this study evaluated the effects of the human serine protease inhibitor alpha-1-antitrypsin (aat) on in vitro excystation and infectivity of cryptosporidium parvum. excystation was monitored at 37 c in rpmi medium in the presence of 0, 100, 500, or 1,000 micrograms/ml aat. aat significantly inhibited (p < 0.05) excystation of bleach-decontaminated oocysts in a concentration-dependent manner at incubation intervals from 15 to 90 min but did not alter the excystation dynamics of unbleached oocysts ...19979267429
nucleic acid stains as indicators of cryptosporidium parvum oocyst viability.we developed nucleic acid dye staining methodology for untreated, heat-treated and chemically inactivated c. parvum oocysts. the nucleic acid staining was compared to in vitro excystation and animal infectivity using split samples of oocysts. among the nucleic acid stains tested, syto-9, hexidium and syto-59 stained the oocysts consistently, and the staining was related to the infectivity of the oocysts to neonatal cd-1 mice but not to in vitro excystation. the nucleic acid viability assay was u ...19979279581
a new restriction fragment length polymorphism from cryptosporidium parvum identifies genetically heterogeneous parasite populations and genotypic changes following transmission from bovine to human hosts.length and restriction site polymorphism within a 2.8-kb threonine-rich open reading frame from cryptosporidium parvum was identified and used to determine the genotypes of isolates from calves and humans. in agreement with observations of other genetic loci, all calf isolates were identical at this locus. in contrast, human isolates showed two profiles, one found exclusively in humans and one a superposition of both profiles, which were indicative of heterogeneous parasite populations. pcr fing ...19979284180
synergistic anticryptosporidial potential of the combination alpha-1-antitrypsin and paromomycin.the combined effect of the serine protease inhibitor alpha-1-antitrypsin (aat) and the aminoglycoside paromomycin on cryptosporidium parvum infection in vitro was investigated. aat and paromomycin were mixed with c. parvum oocysts as either single or combined treatments and used to inoculate epithelial cell cultures. single- and combined-treatment groups had significantly lower (p < 0.01) parasite numbers than untreated controls. the mean fractional inhibitory concentration indices suggested sig ...19979303402
assessment of a dye permeability assay for determination of inactivation rates of cryptosporidium parvum oocysts.the ability to determine inactivation rates of cryptosporidium parvum oocysts in environmental samples is critical for assessing the public health hazard of this gastrointestinal parasite in watersheds. we compared a dye permeability assay, which tests the differential uptake of the fluorochromes 4'-6-diamidino-2-phenylindole (dapi) and propidium iodide (pi) by the oocysts (a. t. campbell, l. j. robertson, and h. v. smith, appl. environ. microbiol. 58:3488-3493, 1992), with an in vitro excystati ...19979327547
prevalence of and associated risk factors for shedding cryptosporidium parvum oocysts and giardia cysts within feral pig populations in california.populations of feral pigs (sus scrofa) may serve as an environmental reservoir of cryptosporidium parvum oocysts and giardia sp. cysts for source water. we conducted a cross-sectional study to determine the prevalence of and associated demographic and environmental risk factors for the shedding of c. parvum oocysts and giardia sp. cysts. feral pigs were either live-trapped or dispatched from 10 populations located along the coastal mountains of western california, and fecal samples were obtained ...19979327560
spontaneous cryptosporidiosis in captive white-tailed deer (odocoileus virginianus).in august 1994, cryptosporidiosis was diagnosed in a diarrheic fawn from a captive white-tailed deer (odocoileus virginianus) herd maintained for research purposes at the university of georgia's warnell school of forest resources in athens, georgia (usa). from june through august 1995, 11 captive female white-tailed deer were housed in individual barn stalls where they gave birth to 18 fawns. feces collected at 2 or 3 day intervals from the 18 neonatal fawns for at least 21 days and from 11 adul ...19969359061
giardia and cryptosporidium in dairy calves in british columbia.a study was undertaken to determine the prevalence of giardia infections in dairy calves and to compare giardia and cryptosporidium infections in calves of different ages. fresh fecal samples were collected from 386 male and female holstein calves (newborn to 24 wk) in 20 dairies located in the lower fraser river valley area of british columbia. giardia intestinalis, cryptosporidium parvum, and cryptosporidium muris were enumerated in each sample after concentration by sucrose gradient centrifug ...19979360789
genetic polymorphism among cryptosporidium parvum isolates: evidence of two distinct human transmission cycles.we report the results of molecular analysis of 39 isolates of cryptosporidium parvum from human and bovine sources in nine human outbreaks and from bovine sources from a wide geographic distribution. all 39 isolates could be divided into either of two genotypes, on the basis of genetic polymorphism observed at the thrombospondin-related adhesion protein (trap-c2) locus. genotype 1 was observed only in isolates from humans. genotype 2, however, was seen in calf isolates and in isolates from a sub ...19979366611
differentiation between human and animal isolates of cryptosporidium parvum using rdna sequencing and direct pcr analysis.sequence analysis of a polymerase chain reaction (pcr)-amplified 298-bp region of the cryptosporidium parvum 18s rrna gene was carried out on 10 human and 9 animal isolates. eight of the 9 animal isolates and 3 human isolates displayed the recognition sequence tatattt, whereas 7/10 human isolates exhibited the recognition sequence ttttttttttt. sequence analysis of the ninth animal isolate, which was recovered from a koala, revealed this isolate to be different from both human and animal isolates ...19979379285
efficacy of different methods for detection of low cryptosporidium parvum oocyst numbers or antigen concentrations in stool specimens.the detection of cryptosporidium parvum oocysts in stool specimens by acid-fast (af) stains or immunofluorescence assays (ifa) requires the presence of large numbers of oocysts. to determine whether new commercially available enzyme immunoassays (eias) are more sensitive alternatives, three eias, a direct ifa, and the modified cold kinyoun af stain were compared, particularly with respect to detection of low oocyst numbers or antigen concentrations. thirty-one negative and 31 calf stool-enriched ...19979405942
sexual and asexual development of cryptosporidium parvum in five oocyst- or sporozoite-infected human enterocytic cell lines.the human enterocytic cell lines caco-2, ht29, hct8 and the caco-2 clones tc7 and pf11 were studied for their ability to support cryptosporidium parvum development. following the addition in cultures of either oocysts or excysted sporozoites, immunofluorescent and transmission electron microscopy revealed the presence of all stages of the parasite life cycle by both procedures, and no difference in the ratio of infected cells was found among cell lines. more oocysts were seen in cell monolayers ...19979435129
cryptosporidium parvum--propagation of oocyst in neonatal calves.shedding of cryptosporidium parvum oocyst was studied in experimentally infected jersey-sindhi cross bred calves. three 7 day old bull calves housed in isolation were orally infected with 10(8) oocysts of cryptosporidium parvum. the prepatent and patent period of the experimental infection were 5 and 4 days respectively. maximum oocyst output [2 x 10(5) oocyst per gram (opg) was observed on the 7th day post inoculation (pi). the mean total oocyst output was 2.5 x 10(7). diarrhoea started on the ...19979444857
nosocomial transmission of cryptosporidium in a veterinary outbreak of cryptosporidiosis occurred at a veterinary hospital, involving multiple species, including humans. the index case was an infected dairy calf that presented with diarrhea. several other cases of cryptosporidial diarrhea subsequently developed during a 1-month period. the key features of this outbreak were the multiple species affected, the increased morbidity in immunocompromised neonates, and the failure of implemented control measures to contain the disease.19979470158
[the prevalence of cryptosporidia among agricultural animals in azerbaijan].in the paper are presented the data on revealement of cryptosporidian oocysts (apicomplexa, sporozoa) in feces of cattle, swine and sheep of different ages and results of the experimental infection of laboratory animals (rats, mice, rabbits, coypus) with the oocysts detected as well. the latters were attributed to cryptosporidium parvum species. the analysis of the size characteristic in the isolates of naturally and artificially infected hosts has shown that the oocysts dimensions might vary bo ...19969480451
local ileal cytokine responses in cattle during a primary infection with cryptosporidium the present study, localized changes in cytokine transcription profiles were examined in neonatal calves following a primary infection with cryptosporidium parvum, using competitive reverse transcriptase polymerase chain reaction (rt-pcr). total rna was prepared from ileocecal lymph nodes (ln), lamina propria lymphocytes (lpl), and intraepithelial lymphocytes (iel) isolated from neonatal calves 7 days after c. parvum infection. competitive rt-pcr performed on cdna samples containing internal ...19989488349
enteric beta-defensin: molecular cloning and characterization of a gene with inducible intestinal epithelial cell expression associated with cryptosporidium parvum infection.a growing body of evidence suggests that endogenous antibiotics contribute to the innate defense of mammalian mucosal surfaces. in the cow, beta-defensins constitute a large family of antibiotic peptides whose members have been previously isolated from the respiratory and oral mucosa, as well as circulating phagocytic cells. a novel bovine genomic clone with beta-defensin-related sequence [corrected] related to those of these alpha-defensins was isolated and characterized. the corresponding cdna ...19989488394
strategies for the control of cryptosporidium parvum infection in calves.cryptosporidium parvum is a protozoan parasite that is now recognized as one of the leading causes of diarrhea in young calves. to date, there are no drugs or preventive measures available for the control of this disease. we have developed an oral vaccine that, when given to calves at birth, protects against experimental challenge with c. parvum. however, when field tested on a large dairy operation with heavy endemic c. parvum infection, the vaccine failed to provide protection. the difference ...19989493106
survival of infectious cryptosporidium parvum oocysts in seawater and eastern oysters (crassostrea virginica) in the chesapeake bay.oocysts of cryptosporidium parvum placed in artificial seawater at salinities of 10, 20, and 30 ppt at 10 degrees c and at 10 ppt at 20 degrees c were infectious after 12 weeks. those placed in seawater at 20 ppt and 30 ppt at 20 degrees c were infectious for 8 and 4 weeks, respectively. these findings suggested that oocysts could survive in estuarine waters long enough to be removed by filter feeders such as oysters. thereafter, 30 eastern oysters, crassostrea virginica, were collected with a d ...19989501446
cryptosporidium parvum infection in bovine neonates: dynamic clinical, parasitic and immunologic patterns.twenty-six experimentally infected calves were monitored daily for oocyst excretion. all began excreting oocysts 3-6 days p.i. most calves (n = 23) excreted oocysts for 6-9 days, with a daily range from 4 x 10(2) to 4.15 x 10(7) oocysts g(-1) of faeces. over half the calves excreted peak numbers of oocysts 6-8 days p.i. diarrhoea, observed intermittently beginning as early as day 3 p.i., lasted 4-16 days and varied greatly in severity from calf to calf. in a second study, nine of 18 calves were ...19989504334
in-vitro activities of paromomycin and lasalocid evaluated in combination against cryptosporidium parvum.using a chemiluminescence immunoassay, paromomycin and lasalocid were shown to inhibit cryptosporidium parvum growth in madin-darby canine kidney cells in a concentration-dependent manner. the median effective concentrations (ec50s) for paromomycin and lasalocid were 1184 mg/l and 0.4 mg/l, respectively. neither drug was cytotoxic to host cells at concentrations up to five times their ec50s. drug combination studies were conducted and the resulting data were analysed by the median-effect princip ...19989533476
effects of an allicin-based product on cryptosporidiosis in neonatal evaluate effectiveness of an allicin-based product in neonatal calves inoculated with cryptosporidium parvum.19989540869
dna sequence similarity between california isolates of cryptosporidium parvum.we evaluated whether nucleic acid amplification with primers specific for cryptosporidium parvum followed by automated dna sequence analysis of the pcr amplicons could differentiate between california isolates of c. parvum obtained from livestock, humans, and feral pigs. almost complete sequence identity existed among the livestock isolates and between the livestock and human isolates. dna sequences from feral pig isolates differed from those from livestock and humans by 1.0 to 1.2%. the referen ...19989546195
antibody-based immunotherapy of cryptosporidiosis.passive antibody immunotherapy (pai) for cryptosporidiosis is a treatment strategy that has been actively pursued in laboratory studies and early-stage clinical studies for the last decade. several experimental approaches have been initiated, including use of bovine colostrum and colostral antibodies (hyperimmune and natural), monoclonal antibodies, chicken egg yolk antibodies, and even orally administered human plasma antibodies. most studies have employed oral administration to treat or preven ...19989554072
therapeutic efficacy of hyperimmune bovine colostrum treatment against clinical and subclinical cryptosporidium serpentis infections in captive snakes.therapy based on the protective passive immunity of hyperimmune bovine colostrum (hbc) (raised against cryptosporidium parvum in dairy cows immunized during gestation) was tested for heterologous efficacy in subclinical and clinical infections of 12 captive snakes with c. serpentis. six gastric hbc treatments of 1% snake weight at 1-week intervals each, have histologically cleared c. serpentis in three subclinically infected snakes, and regressed gastric histopathological changes in one of these ...19989561700
differentiation between human and animal isolates of cryptosporidium parvum using molecular and biological markers.isolates of cryptosporidium parvum obtained from infected humans, calves and lambs were typed using arbitrary primed polymerase chain reaction (ap-pcr) and isoenzyme electrophoresis. all animal isolates tested (n = 17) showed similar profiles in ap-pcr and isoenzyme typing. in ap-pcr assays, 9 out of 15 human isolates showed a distinct "human" profile while the remaining 6 isolates showed the "animal" profile. in isoenzyme typing, 5 human isolates which had shown "human" profiles in ap-pcr demon ...19989569095
differentiation of cryptosporidium parvum isolates by a simplified randomly amplified polymorphic dna technique.genomic dna was isolated from cryptosporidium parvum oocysts by a specific immunomagnetic separation-in vitro excystation procedure and subjected to randomly amplified polymorphic dna analysis using sequence-independent primers. an estuary c. parvum isolate was easily differentiated from several bovine isolates, while five bovine isolates of the same origin were indistinguishable from each other.19989572980
randomly amplified polymorphic dna pcr analysis of bovine cryptosporidium parvum strains isolated from the watershed of the red river of the north.cryptosporidium parvum is a protozoan parasite that causes the disease cryptosporidiosis in a variety of mammals, including neonatal calves and humans. millions of oocysts are shed during acute cryptosporidiosis, and zoonotic transmission is inferred, though not proven, to be a general phenomenon. very little is known about the degree of strain variation exhibited by bovine and human isolates, though such knowledge would enable the amount of bovine-to-human transmission to be more precisely anal ...19989603845
prophylactic effect of bovine anti-cryptosporidium hyperimmune colostrum immunoglobulin in healthy volunteers challenged with cryptosporidium parvum.bovine hyperimmune anti-cryptosporidium colostrum immunoglobulin (baci) decreases the intensity of cryptosporidium parvum infection in vitro. we investigated the prophylactic effect of baci in healthy adults challenged with c. parvum. after we established an oocyst dose that resulted in 100% infection in four volunteers (baseline group), 16 volunteers were randomized to receive (1) baci prior to c. parvum challenge (baci group) and a nonfat milk placebo 30 minutes later, (2) baci prior to and 30 ...19989636857
determination of immuno-cross-reactivity between cryptosporidium parvum and eimeria spp.immuno-cross-reactivity between cryptosporidium parvum and eimeria spp. was studied by the indirect fluorescent antibody test (ifat) and western blot procedure. thirty-seven sera from asymptomatic (non-diarrheic) cattle, with known coprological (presence-absence of coccidia) and serological data respecting c. parvum, were tested by ifat using eimeria oocysts as antigen. most sera (54%) displayed immunofluorescence around the surface of the eimeria oocysts. simultaneously, serum samples from rabb ...19989653985
paromomycin and geneticin inhibit intracellular cryptosporidium parvum without trafficking through the host cell cytoplasm: implications for drug delivery.cryptosporidium parvum, which causes intractable diarrhea and lethal wasting in people with aids, occupies an unusual intracellular but extracytoplasmic niche. no reliable therapy for cryptosporidiosis exists, though the aminoglycoside paromomycin is somewhat effective. we report that paromomycin and the related compound geneticin manifest their major in vitro anti-c. parvum activity against intracellular parasites via a mechanism that does not require drug trafficking through the host cell cyto ...19989673275
cryptosporidium parvum infection in experimentally infected mice: infection dynamics and effect of immunosuppression.the effect of mouse strain, age, sex, and the size of infective dose on the susceptibility to infection with the coccidium cryptosporidium parvum tyzzer, 1912 was determined using several murine models. mice were infected with c. parvum oocysts originally of cervine origin, maintained by repeat passage in calves. all mice in the experimental groups proved susceptible to infection, though this resulted asymptomatic in all cases. c. parvum infection in balb/c and porton mice exhibited some variati ...19989684319
molecular characterization of cryptosporidium from various hosts.a 298 bp region of the cryptosporidium parvum 18s rdna and a 390 bp region of the acetyl-coa synthetase gene were sequenced for a range of human and animal isolates of cryptosporidium from different geographical areas. a distinct genotype is common to isolates from cattle, sheep and goats and also an alpaca from peru and is referred to here as the 'calf'-derived cryptosporidium genotype. another genotype of 'human'-derived isolates also appears to be conserved amongst human isolates although hum ...19989695098
bovine t cell responses to cryptosporidium parvum better understand the immune mechanisms important for clearing of the primary infection and the subsequent development of resistance to cryptosporidium parvum infection, several groups have recently characterised changes within the lymphoid cell population of the intestinal mucosa and associated lymphoid tissue in calves with cryptosporidiosis. in naive animals, infection results in a significant increase in the number of cd4+ and cd8+ t cells present within the intraepithelial lymphocyte pop ...19989724879
genotypic and phenotypic characterization of cryptosporidium parvum isolates from people with aids.genotypic analysis of cryptosporidium parvum has demonstrated the presence of two subgroups within the species, whereas biochemical and antigenic characterization have shown more heterogeneity. the clinical relevance of these observations is unknown. c. parvum isolates from people with aids were studied with respect to parasite genotypes and virulence in cell monolayers and laboratory animals. ten of 13 oocyst samples had a characteristic human-associated (h) genotype; 3 had a genotype typical o ...19989728554
evaluation of periparturient dairy cows and contact surfaces as a reservoir of cryptosporidium parvum for calfhood determine whether periparturient cows or contact surfaces to which newborn calves are exposed are reservoirs of cryptosporidium parvum oocysts.19989736387
establishing the cryptosporidium parvum karyotype by noti and sfii restriction analysis and southern hybridization.the molecular karyotype of the coccidian parasite cryptosporidium parvum has proven difficult to study because chromosomes of similar sizes migrate together when submitted to pulsed-field gel electrophoresis (pfge). in the present work, the karyotype was studied by restriction of chromosome-sized dna with the rare-cutting enzymes noti and sfii, followed by pfge separation of the restriction fragments and southern hybridization. these experiments showed that the c. parvum karyotype is formed by e ...19989757000
prevalence of and risk factors for shedding of cryptosporidium parvum in holstein freisian dairy calves in central méxico.a total of 31 dairy farms from three states in central méxico were selected for this study in order to determine the prevalence of and risk factors for cryptosporidium parvum shedding in young holstein freisian calves. fecal samples were obtained once from each calf for acid-fast staining for detection of c. parvum oocysts. information on each calf and on each dairy's management practices regarding the maternity pen, calf hutches and calf feeding was obtained by personal interview using a standa ...19989762732
cryptosporidium parvum: an attempt at experimental infection in rainbow trout oncorhynchus mykiss.a study was carried out on rainbow trout oncorhynchus mykiss fed with a commercial feed contaminated with bovine-isolated cryptosporidium parvum oocysts whose viability and infectivity were previously tested by inoculation of oocysts to neonatal swiss cd-1 mice. histological examination of hematoxylin-eosin-stained gastrointestinal sections from control and c. parvum-exposed fish revealed no life-cycle stages of cryptosporidium in any part of the apical border of the digestive tract. however, se ...19989794634
susceptibility differences to cryptosporidium parvum infection in two strains of gamma interferon knockout mice.differences in susceptibility to cryptosporidial infections were investigated between 2 strains of gamma interferon knockout (gko) mice. male c57bl/6j-ifg and balb/c-ifg (gko) mice, ages 8-10 wk, were inoculated with infectious oocysts at various doses. c57bl/6j-ifg mice developed overwhelming infections and died 9-12 days after infection. low inoculum doses (1 x 10(3)) did not increase the survival time significantly. the infection intensity in c57bl/6j-ifg mice inoculated with 1 x 10(5) oocyst ...19989794653
influence of pretreatment and experimental conditions on electrophoretic mobility and hydrophobicity of cryptosporidium parvum oocysts.surface properties of cryptosporidium parvum oocysts were investigated by using electrophoretic mobility and hydrophobicity measurements. oocysts purified from calf feces by several sucrose flotation steps and deionized water (di) washes (dis method) had an electrophoretic mobility (neutral surface charge) near 0.0 m2 v-1 s-1 over a ph range of 2 to 10. the mean electrophoretic mobility of oocysts stored in di containing a mixture of antibiotics had a lower standard deviation (sigma = 0.36) than ...19989797304
sedimentation of free and attached cryptosporidium oocysts and giardia cysts in water.experimental analysis of the sedimentation velocity of cryptosporidium parvum oocysts and giardia lamblia cysts was compared with mathematical description of their sedimentation velocities by using measurements of (oo)cyst size and density and the density and viscosity of the sedimentation medium to determine if the sedimentation kinetics of freely suspended oocysts of c. parvum and cysts of g. lamblia can be described by stokes' law. the theoretically calculated sedimentation kinetics showed a ...19989797307
sequence polymorphism in the beta-tubulin gene reveals heterogeneous and variable population structures in cryptosporidium parvum.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 polymorphis ...19989797309
prevalence of and risk factors for fecal shedding of cryptosporidium parvum oocysts in determine prevalence of and risk factors for fecal shedding of cryptosporidium parvum oocysts among 3 populations of horses.19989810386
efficacy of select antivirals against cryptosporidium parvum in vitro.cryptosporidium parvum is an intestinal pathogen associated with diarrheal disease in both humans and animals. currently, no effective therapy exists to eliminate the parasite in the absence of a healthy, intact immune system. we used an in situ, enzyme-linked immunosorbent assay (elisa) as a primary screen to examine the effects of 13 antivirals on the development of c. parvum in human ileocecal adenocarcinoma (hct-8) cells in vitro. six of the compounds displayed some efficacy, and dose-respon ...19989812363
cryptosporidiosis in bovine and human health.cryptosporidiosis, which is caused by cryptosporidium parvum and was discovered in mice at the turn of the century, emerged as a frequently reported intestinal disease of animals and humans in the 1980s when its zoonotic potential was recognized. in recent years, the public has become aware of severe cryptosporidiosis because of its incidence in aids patients and because of massive outbreaks of cryptosporidial enteritis among the general populace worldwide from contaminated drinking water. lives ...19989839243
a case control study of potential enteric pathogens for calves raised in cow-calf herds.a matched case control study was performed to describe the epidemiological features of potential enteric pathogens for calves reared in 53 cow-calf herds located in western switzerland. a total of 106 diarrhoeic calves and 126 healthy control calves were collected, all calves were less than 4 months old. faecal samples were analysed for presence of infectious agents related to calf diarrhoea including enterotoxigenic e. coli, verotoxin producing e. coli (vtec), campylobacter sp., yersinia sp., s ...19989852767
calves as a potential reservoir of cryptosporidium parvum and giardia sp.studies on cryptosporidiosis and giardiosis were carried out between march and april 1997 on 75 calves from 9 selected farms of wielkopolska macroregion. faecal specimens from calves, 3-13 days old, were screened for oocysts of c. parvum using ziehl-neelsen staining and both for oocysts of c. parvum and cysts of giardia sp. using direct immunofluorescent (merifluor cryptosporidium/giardia) assay. the oocysts of c. parvum assessed by ziehl-neelsen staining were revealed on 6 (67%) of 9 farms exam ...19989860815
differentiating human from animal isolates of cryptosporidium parvum.we analyzed 92 cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. used as a molecular marker, this method can differentiate between the two genotypes of c. parvum and elucidate the transmission of infection to humans.19989866750
a role for host phosphoinositide 3-kinase and cytoskeletal remodeling during cryptosporidium parvum infection.cryptosporidium parvum preferentially infects epithelial cells lining the intestinal mucosa of mammalian hosts. parasite development and propagation occurs within a unique intracellular but extracytoplasmic parasitophorous vacuole at the apical surface of infected cells. parasite-induced host cell signaling events and subsequent cytoskeletal remodeling were investigated by using cultured bovine fallopian tube epithelial (bfte) cells inoculated with c. parvum sporozoites. indirect-immunofluoresce ...19999916099
infectivity of cryptosporidium parvum oocysts stored in water at environmental temperatures.oocysts of cryptosporidium parvum obtained from calves were cleaned of fecal debris by density gradient centrifugation and suspended in deionized water in microcentrifuge tubes. the tubes were placed in circulating water baths at temperatures of -10, -5, 0, 5, 10, 15, 20, 25, 30, or 35 c, and 2 tubes were removed from each water bath 1, 2, 4, 8, 12, 16, 20, and 24 wk later. oocysts from 1 tube were administered at the rate of 1.5 x 10(5) oocysts per mouse to 2 litters of neonatal balb/c mice and ...19989920307
ultrastructural details of cryptosporidium parvum development in calf intestine.cryptosporidium parvum and c. muris appear to be different species found in calves, with different oocysts size and distribution on the gastrointestinal tract. this work presents new images of c. parvum ultrastructure in calf intestine, mainly its development in nonmicrovillous cells and the presence of microtubular structures in the membrane enveloping the macrogamonts and immature oocysts.19989921314
a cryptosporidium parvum oocyst low molecular mass fraction evokes a cd4+ t-cell-dependent ifn-gamma response in bovine peripheral blood mononuclear cell cultures.t-cell antigens that induce the in-vitro interferon-gamma response during cryptosporidium parvum infection of neonatal calves were identified. a total oocyst extract was separated into a high and a low mr fraction by a microfiltration technique. both the high and low mr fractions evoked an in-vitro interferon-gamma response in naturally infected animals, although strong individual differences between the hosts were observed. using a complement-mediated technique cd4+ t-cells or wc1+gammadelta t- ...19989925266
duration of naturally acquired giardiosis and cryptosporidiosis in dairy calves and their association with determine duration of infection and association of infection with diarrhea for dairy calves with naturally acquired cryptosporidiosis and giardiosis.199910023403
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
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
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
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
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
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