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the species of cryptosporidium (apicomplexa: cryptosporidiidae) infecting mammals.oocysts of cryptosporidium muris (apicomplexa: cryptosporidiidae) were obtained from the feces of naturally infected calves. oocysts were fully sporulated in fresh feces, measured 7.4 x 5.6 (6.6 - 7.9 x 5.3 - 6.5) micron, and possessed a longitudinal suture along one pole of the oocyst wall. morphologic and biologic evidence obtained from this study demonstrated that c. muris is a species distinct from cryptosporidium parvum, which has smaller oocysts.19854057006
studies of in vitro excystation of cryptosporidium parvum from calves.studies of in vitro excystation of cryptosporidium parvum from calves showed that sporozoite yields were optimum when oocysts were treated with sodium hypochlorite, then incubated at 37 degrees c for 60 min in the presence of taurocholic acid solutions at ph about 7.0. trypsin was not required for excystation and high concentrations were inhibitory. studies using protease inhibitors and direct assays for proteolysis failed to implicate proteolytic enzymes as effectors of excystation. the results ...19873123647
abomasal cryptosporidiosis in cattle.a 6-week-old calf and nine feedlot steers shed oocysts similar to cryptosporidium muris-like oocysts. there were massive populations of this cryptosporidium in the peptic glands of most of these animals. the oocysts were larger and more oval than the frequently reported type which is generated in the intestines of many animal species and thought to be similar to cryptosporidium parvum. the pattern of shedding of this newly discovered cryptosporidium in the steers was continuous over a period of ...19873603962
infectivity and neutralization of cryptosporidium parvum sporozoites.cryptosporidiosis, a diarrheal disease of calves and humans caused by the coccidian parasite cryptosporidium parvum, is terminated in hosts with normal immune systems. to assess the mechanisms of immunity in cryptosporidiosis, it is necessary to isolate and quantitate sporozoites, the infective stage of cryptosporidium spp. here we report the (i) separation of infective c. parvum oocysts from calf feces by ether extraction, sieving, and hypochlorite treatment; (ii) separation of viable c. parvum ...19873623693
neutralization-sensitive epitopes are exposed on the surface of infectious cryptosporidium parvum sporozoites.cryptosporidiosis is a diarrheal disease of humans, calves, and other mammals caused by the coccidian parasite cryptosporidium parvum. immune bovine serum and two surface-reactive antisporozoite mab with neutralizing activity were used to identify sporozoite surface ag by radioimmunoprecipitation/sds-page and immunoblotting. when isolated sporozoites were incubated with mab 18.44, 12 to 25 times the id50 for mice was completely neutralized. this mab binds diffusely to the sporozoite surface and ...19892473130
effects of colostral antibody on susceptibility of calves to cryptosporidium parvum infection.effects of colostral antibody on susceptibility of calves to cryptosporidium parvum infection were examined. six calves were fed pooled colostrum that contained c parvum antibody, 6 times daily (at 4-hour intervals) for 7 days and then milk replacer for 7 days. colostrum was obtained from healthy cows or cows inoculated parenterally with c parvum oocysts before parturition. antibody content was determined in serum and colostrum whey, using an elisa for anticryptosporidia immunoglobulin. six calv ...19892610438
efficacy of hyperimmune bovine colostrum for prophylaxis of cryptosporidiosis in neonatal calves.twelve neonatal calves were experimentally infected with oocysts of cryptosporidium parvum. six calves in group a fed hyperimmune colostrum at birth had significantly less diarrhea and shed oocysts for less time than did 6 calves in group b fed colostrum from cows that were not hyperimmune. calves in group a had diarrhea for 0-4 days (means = 2.3 days), whereas calves in group b had diarrhea for 4-6 days (means = 5.0 days). calves in group a shed oocysts for 4-9 days (means = 6.2 days), whereas ...19892723925
hyperimmune bovine colostrum neutralizes cryptosporidium sporozoites and protects mice against oocyst challenge.activity of colostral whey, produced by a cow immunized with oocysts of cryptosporidium parvum and found to provide prophylaxis against cryptosporidiosis in calves, was tested in 2 experiments. in one experiment balb/c mice were given the immune whey (hw), whey from a nonimmunized cow (cw), or a balanced salt solution (hbss) before, during, and after oral inoculation with oocysts of c. parvum. significantly fewer (p less than 0.05) c. parvum were found in mice that received hw (undiluted, 1:20 o ...19892783966
treatment with bovine hyperimmune colostrum of cryptosporidial diarrhea in aids patients.cryptosporidium parvum may cause severe, debilitating diarrhea in patients with aids. recent anecdotal reports have suggested that hyperimmune bovine colostrum may be effective. we conducted a double-blind, controlled pilot study of hyperimmune bovine colostrum for diarrhea due to cryptosporidiosis in five aids patients. the patients were randomized to receive either hyperimmune or control colostrum by continuous nasogastric infusion for 10 days. all stools were collected, graded, and weighed, a ...19902201320
in vitro cultivation of cryptosporidium parvum and screening for anticryptosporidial drugs.sporozoites of cryptosporidium parvum which were excysted in vitro from oocysts isolated from calves or patients with acquired immune deficiency syndrome underwent development in monolayers of the mouse fibroblast cell line l929. asexual multiplication occurred, with the maximum numbers of parasites usually being observed between 24 and 48 h after infection. gametocytes were also found, but their numbers were relatively small compared with those of the asexual stages. a study was made of the eff ...19902221857
some infectious causes of diarrhea in young farm animals.escherichia coli, rotaviruses, and cryptosporidium parvum are discussed in this review as they relate to enteric disease in calves, lambs, and pigs. these microorganisms are frequently incriminated as causative agents in diarrheas among neonatal food animals, and in some cases different strains or serotypes of the same organism cause diarrhea in humans. e. coli causes diarrhea by mechanisms that include production of heat-labile or heat-stable enterotoxins and synthesis of potent cytotoxins, and ...19902224836
[electron microscopic research on cryptosporidium. i. the asexual stages in the development of cryptosporidium parvum].ultrastructural studies were conducted on asexual developmental stages of c. parvum in the ileal fragment of the intestine of 10-11 day old rats experimentally infected with oocysts isolated from calf feces. a young trophozoite is covered with the typical trimembranous apicomplexan pellicle. as the parasite grows, the inner complex of its apical pellicle, facing the host enterocyte, is seen to reduce up to a unit membrane to make a complex multimembranous "feeding organelle" which is in contact ...19902275015
detection of cryptosporidium parvum oocysts in bovine feces by monoclonal antibody capture enzyme-linked immunosorbent assay.a monoclonal antibody enzyme-linked immunosorbent assay (elisa) was developed to detect cryptosporidium parvum oocysts in bovine feces. fecal oocysts were concentrated by centrifugation through formalin-ethyl acetate solution and captured with monoclonal antibody 18.280.2 reactive with c. parvum oocysts. captured oocysts were detected with goat anti-oocyst serum, following the addition of a peroxidase conjugate of rabbit anti-goat immunoglobulin and o-phenylenediamine substrate. the assay was sp ...19902280009
kinetics of cryptosporidium parvum sporozoite neutralization by monoclonal antibodies, immune bovine serum, and immune bovine colostrum.monoclonal antibodies, immune bovine serum, and immune bovine colostral whey neutralized infectivity of cryptosporidium parvum sporozoites for mice in a time-dependent manner. immune colostral whey neutralized sporozoites more rapidly and completely than immune serum, monoclonal antibody (mab) 18.44, or a combination of mab 18.44 and mab 17.41. mice were partially protected against oral challenge with c. parvum oocytes when treated with immune colostral whey, mab 17.41, or a combination of mab 1 ...19902294054
resistance of calves to cryptosporidium parvum: effects of age and previous exposure.cryptosporidium parvum is a coccidian parasite that causes diarrheal disease in many vertebrate species, including young (less than or equal to 1 month old) calves. older calves and adult cattle are resistant to infection. in this study, newborn calves were raised in isolation from c. parvum for 1 week to 3 months before experimental challenge with the parasite. calves orally challenged with c. parvum at 1 week of age shed oocysts in their feces and had diarrhea after challenge exposure. when th ...19902365460
immunotherapeutic efficacy of bovine colostral immunoglobulins from a hyperimmunized cow against cryptosporidiosis in neonatal mice.infection with cryptosporidium parvum, a ubiquitous protozoan parasite of virtually all mammals, can cause mild to severe diarrhea in immunocompetent hosts and life-threatening diarrhea in immunocompromised hosts. passive immunotherapy of experimentally infected animals and naturally infected humans with hyperimmune bovine colostrum has been reported to be efficacious, whereas chemotherapy has not. in this study, the efficacy of specific immunoglobulin isotypes purified from bovine colostrum fro ...19902387630
cryptosporidium parvum (apicomplexa: cryptosporidiidae) oocyst and sporozoite antigens recognized by bovine colostral antibodies.colostral whey from seven hyperimmunized and two control cows (hyperimmune bovine colostrum) was examined by western immunoblotting for the presence of antibody against oocysts and sporozoites of cryptosporidium parvum, using rabbit anti-bovine immunoglobulin a (iga), igg1, igg2, and igm antibodies, followed by a horseradish peroxidase goat anti-rabbit polyvalent antibody. although considerable variation was found in binding activity between cows on different immunization protocols, iga and igg1 ...19902387631
a controlled trial of bovine dialyzable leukocyte extract for cryptosporidiosis in patients with aids.cryptosporidial infection causes severe diarrheal disease in patients with aids. fourteen patients with aids and symptomatic cryptosporidiosis were treated with a specific bovine dialyzable leukocyte extract (immune dle) prepared from lymph node lymphocytes of calves immunized with cryptosporidia or a nonspecific (nonimmune) dle prepared from nonimmunized calves. six of 7 patients given immune dle gained weight and had a decrease in bowel movement frequency, with eradication of oocysts from stoo ...19902404072
restriction fragment length polymorphism analysis of cryptosporidium parvum isolates of bovine and human origin.cryptosporidium parvum oocysts isolated from different hosts and geographical areas were compared by restriction endonuclease analysis of repetitive dna: iowa (bovine), florida (bovine), new york (bovine), peru (human), brazil (human), and mexico (human). southern blot hybridization analysis was performed using the restriction endonuclease enzyme eco ri and the dna probe pv47-2. the probe hybridized with 18 bands present in all the isolates. the brazilian, mexican, and peruvian human isolates ha ...19911687825
identification of a 15-kilodalton surface glycoprotein on sporozoites of cryptosporidium parvum.an immunoglobulin a monoclonal antibody (mab5c3) was developed against a 15-kda surface glycoprotein (gp15) of cryptosporidium parvum sporozoites. indirect immunofluorescence and colloidal gold immunoelectron microscopy revealed that the antibody reacted with both the sporozoite and merozoite surface plasma membranes. on western immunoblots, mab5c3 binding was found to be strongly inhibited when 200 mm n-acetylglucosamine was used as a competing sugar. n-acetylgalactosamine inhibited binding of ...19911705238
characterization of microneme antigens of cryptosporidium parvum (protozoa, apicomplexa).two monoclonal antibodies (mabs) raised against purified excysted oocysts and sporozoites of cryptosporidium parvum reacted in an immunofluorescence assay with antigens located at the anterior pole of the zoites. on western blots of purified oocysts, these mabs reacted with a series of bands between 210 and 40 kda; several of these bands were recognized by both mabs; others were specific. one mab (tou) did not react after periodic acid treatment and was therefore considered to recognize a carboh ...19911708357
dna sequences for the specific detection of cryptosporidium parvum by the polymerase chain reaction.the objective of this project was to construct specific and sensitive molecular probes and amplification primers for cryptosporidium parvum that could be used in diagnosis, retrospective tissue studies, and in epidemiologic surveys. whole genomic dna was extracted from oocysts of c. parvum purified from human and bovine feces. a genomic library was constructed in plasmid puc18 and propagated in escherichia coli dh5 alpha. transformants were screened by colony hybridization and autoradiography. t ...19911763795
hemolytic properties of lytic peptides active against the sporozoites of cryptosporidium parvum.cryptosporidium parvum is a protozoan parasite that causes mildto-severe diarrheal disease in animals and humans. there are currently no effective chemotherapeutic agents available for the treatment of cryptosporidiosis. recently, small, naturally occurring antimicrobial lytic peptides with anti-protozoal activities have been described. in the present study, we compare the in vitro anti-cryptosporidial activities of synthetic lytic peptides and their corresponding hemolytic activities after a 30 ...19911818150
characterization of anti-cryptosporidium iga antibodies in sera from immunocompetent individuals and hiv-infected patients.human antibody response to cryptosporidium parvum has been previously shown as involving immunoglobulin (ig)m and igg isotypes. the interest in anti-cryptosporidial iga antibody response has been recently stimulated by studies on the therapeutic effects of secretory iga antibodies to cryptosporidium in animal models and in patients. in the present study, isotypes of serum anti-cryptosporidium antibodies have been characterized in donors of the following categories: (a) healthy adults, (b) health ...19911818157
effect of hyperimmune bovine colostrum raised against cryptosporidium parvum on infection of guinea pigs by cryptosporidium wrairi.oocysts shedding was markedly reduced in guinea pigs inoculated intraintestinally with cryptosporidium wrairi sporozoites that had been incubated with hyperimmune bovine colostrum raised to c. parvum when compared with shedding in guinea pigs inoculated with sporozoites incubated in either non-immune bovine colostrum or buffered saline. however oocyst shedding was apparently not reduced in guinea pigs inoculated by gavage with oocysts of c. wrairi and subsequently treated twice daily per os with ...19911818160
cryptosporidium merozoite isolation and purification using differential centrifugation techniques.simple modifications to a recently published merozoite purification procedure (bjorneby et al., j. immunol. 145:298, 1990) increased yields 3- to 5-fold. calves were infected with 2.5 x 10(8) cryptosporidium parvum oocysts and sacrificed 65 h post-infection. the ilium and caecum were removed. the tissue was sieved through a large strainer (2 mm2) to produce a homogeneous suspension. red blood cells were removed by differential centrifugation (600 g); merozoites remained in the supernatant. the m ...19911818170
in vitro screening of therapeutic agents against cryptosporidium: hyperimmune cow colostrum is highly inhibitory.an in vitro model of cryptosporidium parvum infection was developed utilizing an adherent human intestinal epithelial cell line ht29.74. the efficacy of potential immunologic therapy in the form of cryptosporidium-specific hyperimmune bovine colostrum was evaluated for the ability to inhibit in vitro infection. oocysts were purified from stool of chronically infected aids patients. hyperimmune colostrum obtained from cows immunized with cryptosporidium and nonimmune conventional colostrum were e ...19911818181
production and preparation of hyperimmune bovine colostrum for passive immunotherapy of cryptosporidiosis.pregnant cows were immunized to produce hyperimmune bovine colostrum (hbc) by intramuscular injection or intramammary infusion (ti) followed by 3 successive ti boosters with cryptosporidium parvum (cp) oocyst antigen mixed with freund's (f) or ribi (r) adjuvant. control cows received no cp. colostrum from all cows was skimmed of butterfat and tested for specific anti-cp immunoglobulin isotypes by elisa. the hbc from cp-f and cp-r immunized cows had igg1 titers exceeding 1:400,000 and 1:800,000, ...19911818191
identification and isolation of cryptosporidium parvum genes encoding microtubule and microfilament proteins.microtubules and microfilaments are highly conserved cytoskeletal polymers hypothesized to play essential biomechanical roles in the unusual gliding motility of apicomplexan zoites and in their invasion of, and development within, host epithelial cells. we have identified and isolated cryptosporidium parvum genes encoding the microtubule proteins alpha- and beta-tubulin and the microfilament protein actin by screening a lambda gt11 c. parvum genomic dna library with degenerate oligonucleotide an ...19911818196
effects of carbohydrates and lectins on cryptosporidial sporozoite penetration of cultured cell monolayers.cryptosporidium parvum first interacts with enterocytes when sporozoites penetrate the host plasma membrane. we have developed a shell vial assay using human embryonic intestine 407 cells and purified c. parvum sporozoites to study this process. sporozoites were incubated in culture medium with various carbohydrates and lectins, and the suspensions were then added to the cell monolayers. following incubation, the monolayers were fixed and stained and the number of schizonts were counted. no decr ...19911818216
construction of genomic libraries of cryptosporidium parvum and identification of antigen-encoding genes.genomic libraries have been constructed from bovine c. parvum dna in the lambda zap and lambda dash vectors. based on an estimated genome size of 2 x 10(4) kilobases (kb), each recombinant library contains greater than 10 genomic equivalents. the average recombinant size for the lambda zap library is 2.1 kb and for the lambda dash library is 14 kb. we have identified genes to major antigens recognized by hyperimmune bovine antiserum. these recombinants are currently being purified and characteri ...19911818217
[livestock manure as a vector for parasites--a report of experiences].analysing the results of own investigations and informations in literature a review is given about the role of manure specially in stables of high-intensity cattle and pig production as a vector for exogenic parasite stages. in the course of investigations--in most cases simulating practice conditions--so-called indicator germs were used as test material. in cattle stables manure is significant as a vector for eimeria species, cryptosporidium parvum, sarcocystis species, taenia saginata and fasc ...19911914947
efficacy of halofuginone lactate against cryptosporidium parvum in calves.the efficacy of halofuginone lactate against natural cryptosporidium parvum infection in 150 neonatal market calves of a mixed belgian breed was tested. the drug was administered orally in the milk replacer over a period of 3 to 14 days at doses ranging from 30 to 500 micrograms/kg of body weight. over a period of 4 weeks, the animals were examined twice a week for shedding of c. parvum oocysts and were scored semiquantitatively for diarrhea. weight gain was assessed after 2 and 4 weeks. subclin ...19912024962
immunogold labeling of stages of cryptosporidium parvum recognized by immunoglobulins in hyperimmune bovine colostrum.ultrathin sections of mouse ileum infected with cryptosporidium parvum were stained by immunogold techniques. sections first were stained with polyvalent antibodies in whey from hyperimmune bovine colostrum (hbc), then stained by secondary antibodies in rabbit antibovine iga, igm, igg1, and igg2, and lastly labeled by goat anti-rabbit gold conjugate. examination of the immunostained specimens by electron microscopy revealed that each bovine immunoglobulin isotype in the whey recognized antigens ...19912040961
incorporation of exogenous uracil by cryptosporidium parvum in vitro.oocysts of cryptosporidium parvum were used to infect madin-darby bovine kidney cells. cultures were incubated in a reduced-oxygen atmosphere in candle jars or in a 5% co2-95% air atmosphere. at 72 h, parasites were quantitated microscopically and found to be enhanced 5.5-fold in the reduced-oxygen atmosphere. using candle jars, we then determined that c. parvum was amenable to [3h]uracil incorporation assays and easily quantitated with this method.19912056042
characterization of bovine cellular and serum antibody responses during infection by cryptosporidium parvum.cellular and serum antibody responses of calves were monitored for 23 days after oral inoculation of the calves with oocysts of cryptosporidium parvum. in vitro blastogenic responses of peripheral blood lymphocytes were assessed after stimulation with a c. parvum preparation. specific lymphocyte blastogenic responses to the parasite were detected 2 days after inoculation. parasite-specific antibody titers were demonstrable 7 days after inoculation with oocysts and achieved peak levels 9 days aft ...19911997443
cryptosporidium parvum in cattle, sheep and pigs in galicia (n.w. spain).infection by cryptosporidium parvum has been detected for the first time in cattle and swine in galicia (n.w. spain). the organisms were also found in one of 69 sheep examined. although in most cases the parasite was found in young diarrhoeic animals, its presence in asymptomatic mature cattle and piglets was also detected.19911858293
cryptosporidium: different behaviour in calves of isolates of human origin.the behaviour in calves of 3 cryptosporidium human isolates was analysed in comparison with a bovine isolate. twenty-four neonatal calves were infected. an isolate from a patient infected with human immunodeficiency virus (hiv) and showing mild cryptosporidiosis caused severe diarrhoea with a high production of oocysts in neonatal calves, as did a bovine isolate (group 1). two human isolates, obtained from hiv patients with severe cryptosporidiosis, caused mild diarrhoea with low oocyst producti ...19921287926
[experimental cryptosporidium parvum infection in a korean native calf isolated from a korean mouse].this study was performed to investigate experimental transmission of cryptosporidium parvum in a calf. a 25-day-old korean native calf was inoculated per os with 1 x 10(6) c. parvum oocysts isolated from a korean mouse. the calf commenced oocyst discharge in feces on post-inoculation day 4, and continued until the day 11. the number of discharged oocysts peaked (4.9 x 10(5)) on post-inoculation day 6. however, the calf did not show signs of diarrhea. the present results indicate that c. parvum i ...19921297415
comparison of the host ranges and antigenicity of cryptosporidium parvum and cryptosporidium wrairi from guinea pigs.oocysts of a cryptosporidium isolate from guinea pigs were not infectious for adult mice, but were infectious for two of three newborn calves and for suckling mice. however, oocysts isolated from calves or mice infected with guinea pig cryptosporidium were not infectious for guinea pigs. four isolates of c. parvum from calves were incapable of infecting weanling guinea pigs. microscopic examination of tissue from the colon and cecum of suckling guinea pigs inoculated with c. parvum revealed spar ...19921386385
identification and partial purification of a lectin on the surface of the sporozoite of cryptosporidium parvum.a human-derived isolate of cryptosporidium parvum from a symptomatic patient with the acquired immunodeficiency syndrome was expanded in vivo by infecting a neonatal calf with 10(8) oocysts. sporozoites were isolated from 4 x 10(10) oocysts harvested from this single infection, and the characteristics of mixed hemagglutination (ha) with rabbit erythrocytes were determined. sporozoite ha was inhibited by bovine submaxillary mucin (bsm), hog gastric mucin, and orosomucoid, but not by simple sugars ...19921403433
characterization of a > 900,000-m(r) cryptosporidium parvum sporozoite glycoprotein recognized by protective hyperimmune bovine colostral immunoglobulin.cryptosporidium parvum, a zoonotic apicomplexan pathogen, causes profound diarrhea, malnutrition, and dehydration in patients with aids. a less severe, self-limited disease occurs in immunocompetent individuals, particularly children, animal handlers, and residents of the developing world. very little is known about the biology of the organism, the pathophysiology of the disease process, or the mechanism of protective immunity. there is no effective therapy for cryptosporidiosis, but hyperimmune ...19921452347
bovine humoral immune response to cryptosporidium parvum.cryptosporidiosis is a diarrheal disease predominantly affecting cattle and humans. sera from experimentally infected calves and calves of various ages with no histories of exposure were evaluated for immunoglobulin g to cryptosporidium parvum. an age-associated increase in immunoglobulin g was present in experimental calves and in calves with no histories of infection from 1 to 3, but not > 3, months of age.19921452716
malabsorption of vitamin a in preruminating calves infected with cryptosporidium parvum.serum retinol, retinyl palmitate, and total vitamin a concentrations, and jejunoileal morphology were examined in neonatal calves infected with cryptosporidium parvum. group-1 calves served as noninfected controls and, after an adjustment period, were given 50 ml of saline solution i.v. every 12 hours for 6 days. group-2 calves were inoculated with 10(7) c parvum oocysts and, after the onset of diarrhea, were given 50 ml of saline solution i.v. every 12 hours for 6 days. group-3 calves were inoc ...19921456546
efficacy of activated sludge in removing cryptosporidium parvum oocysts from sewage.primary clarifier effluent (procedure b) and final effluent (procedure a) from a wastewater treatment plant were enriched with cryptosporidium parvum oocysts obtained from the feces of naturally infected calves. procedure b samples alone were subjected to a laboratory simulation of activated-sludge treatment. coccidium-free neonatal cd-1 mice were then inoculated intragastrically with procedure a or procedure b samples. seven days after inoculation, the intensity of oocyst infection in procedure ...19921482177
comparative study of the antigenic composition of oocyst isolates of cryptosporidium parvum from different hosts.an investigation was made of the antigenic composition of oocyst isolates of cryptosporidium parvum by immunoblotting using rabbit polyclonal or murine monoclonal antibodies (moabs) developed against this parasite. using the polyclonal antibodies in blots, a common antigenic profile was obtained from a number of human oocyst isolates from aids patients and immunocompetent children in the uk and portugal. antigenic differences were observed, however, between a human isolate from turkey and these ...19921570174
cryptosporidium parvum in calves: kinetics and immunoblot analysis of specific serum and local antibody responses (immunoglobulin a [iga], igg, and igm) after natural and experimental infections.fecal and serum anti-cryptosporidium parvum immunoglobulin a (iga), igm, and igg were monitored by an enzyme-linked immunosorbent assay after experimental and natural infection of calves with c. parvum. although all experimentally infected calves showed high levels of colostral antibodies in the feces, they acquired c. parvum infection. three of five animals died. calves which acquired natural infection showed only diarrhea. levels of colostral coproantibodies dropped quickly. experimental infec ...19921587597
identification and initial characterization of five cryptosporidium parvum sporozoite antigen genes.cryptosporidium parvum, an apicomplexan parasite of gastrointestinal epithelial cells, causes severe disease in persons with aids and is a common cause of self-limited diarrhea in children, animal handlers, and residents of developing countries. no approved therapy exists; in research studies, however, hyperimmune bovine colostrum raised to cryptosporidium oocysts and sporozoites has eradicated disease or decreased parasite burden in some aids patients. although the protective antigens recognize ...19921587601
activity of sulfadimethoxine against cryptosporidiosis in dairy calves.of 13 neonatal calves inoculated orally with 1.5 x 10(6) oocysts of cryptosporidium parvum, 7 in group a were fed 5-g boluses of sulfadimethoxine for 21 consecutive days beginning 1 day before infection, and 6 calves in group b were untreated controls. calves in group a had diarrhea for 6-18 days (mean = 11 days); those in group b had diarrhea for 4-14 days (mean = 8.7 days). the severity of diarrhea, based on a daily numerical scoring system, was similar for both groups. calves in group a shed ...19921597803
in vitro multiplication of cryptosporidium parvum in mouse peritoneal macrophages.cryptosporidium parvum of bovine origin was developed in vitro in unsensitized mouse peritoneal macrophages. macrophages growing in rpmi medium were infected with sporozoites or with oocysts, and after staining infections were studied by light microscopy. a high parasitic index was obtained with multiple infections occurring commonly. this is a simple method for the study of cryptosporidium biology, and for in vitro assays of pharmacological activity.19921615629
cloning and expression of a cdna encoding epitopes shared by 15- and 60-kilodalton proteins of cryptosporidium parvum sporozoites.a cdna (cp15/60) encoding epitopes of cryptosporidium parvum 15- and 60-kda sporozoite proteins was isolated and expressed in escherichia coli toward the goal of developing an immunogen for producing high-titer anticryptosporidial colostrum. antisera prepared in rats to native c. parvum 15-kda protein and used to identify the cp15/60 bacteriophage clone recognized both 15- and 60-kda in vitro translation products derived from sporozoite rna. antisera specific for recombinant cp15/60 antigen reco ...19937684726
antigenic characterization of human isolates of cryptosporidia.isolates of cryptosporidia from immunodeficient patients and from immunocompetent children suffering from diarrhoea were sources for preparation of antigens. altogether, antigens from 21 isolates were obtained, 19 from children and 2 from aids patients. with one exception, all children were under 4 years old and most of them were between 1 and 2 years old. the probable source of infection was found in 11 cases. in 8 cases, as well as in both aids patients, the source of infection was not determi ...19938013932
detection of neospora caninum in tissue sections using a murine monoclonal antibody.a murine monoclonal antibody (mab 6g7), isotype igg2a, produced against tachyzoites of neospora caninum (isolate nc-1) reacted specifically with tachyzoites of n. caninum in an indirect immunofluorescent antibody test. mab 6g7 did not react with tachyzoites of toxoplasma gondii, sporozoites of isospora suis, eimeria bovis, or e. tenella, or merozoites of e. bovis in the indirect immunofluorescent antibody test. mab 6g7 reacted positively with both tachyzoites and bradyzoites of n. caninum in an ...19938286458
[carriers and excretors of protozoa].causative agents of intestinal infections in humans are about 10 pathogenic or facultative pathogenic species of protozoa of which giardia lamblia, entamoeba histolytica, cryptosporidium parvum and enterozytozoon bieneusi are discussed. g. lamblia from humans is morphologically indistinguishable from giardia isolates originating from several species of domestic and wild mammals. swiss giardia isolates of human, sheep, cattle and dog origin could be transmitted to giardia-free rodents and were ra ...19938333895
induction of folds or sutures on the walls of cryptosporidium parvum oocysts and their importance as a diagnostic feature.the proportion of oocysts of cryptosporidium parvum showing a fold on oocyst walls when incubated with either fluorescent monoclonal antibody or a surface-reactive fluorescent dye was increased by incubating suspensions of oocysts with dimethyl sulfoxide, sucrose, or hanks' balanced salt solution. further incubation of sucrose-incubated oocysts with water showed this to be a reversible phenomenon. oocysts demonstrating this fold after incubation in dimethyl sulfoxide were of the same viability a ...19938368850
anti-cryptosporidium parvum antibodies inhibit infectivity in vitro and in vivo.cryptosporidium parvum causes acute diarrhea in immunocompetent individuals and a severe life-threatening disease in immunocompromised individuals, including aids patients. no efficacious therapy for cryptosporidiosis has yet been reported. however, treatment of some patients with cryptosporidiosis with hyperimmune bovine colostrum has ameliorated or eliminated clinical symptoms. consequently, it is important to identify and characterize c. parvum antigens which are the targets of protective ant ...19938406795
specific serum and local antibody responses against cryptosporidium parvum during medication of calves with halofuginone lactate.fecal and serum anti-cryptosporidium parvum immunoglobulin a (iga), igm, and igg were monitored by an enzyme immunoassay in c. parvum-infected calves after medication with halofuginone lactate. in a first experiment, four groups of five 1-day-old colostrum-fed calves were inoculated with 10(6) oocysts of c. parvum. they were medicated with 0, 30, 60, or 120 micrograms of halofuginone lactate per kg from days 2 to 8 postinfection (p.i.). unmedicated calves passed large numbers of oocysts between ...19938406835
paromomycin is effective as prophylaxis for cryptosporidiosis in dairy calves.of 16 experimentally infected neonatal dairy calves, 12 were fed paromomycin twice daily in their milk for 11 consecutive days beginning 1 day before oral inoculation with 1.5-2.0 x 10(6) oocysts of cryptosporidium parvum. four calves each in groups a, b, c, and d received total daily doses of 100, 50, 25, and 0 mg of paromomycin per kilogram of body weight, respectively. from birth until 28 days of age feces from each calf were examined for diarrhea, and oocysts were enumerated, rectal temperat ...19938410552
[one more biological characteristic of coccidia in the genus cryptosporidium (sporozoa: apicocomplexa)].suckling rats were used as a model host for our previous em studies of the endogenous development of cryptosporidium parvum isolated from spontaneously infected calves (beĭer e. a., 1990; beĭer, sidorenko, 1990). in the course of repeated infections it was noticed that the oocysts discharged by the recipient host (rat) were obviously larger than those in the donor's (calf's) isolates. keeping in mind the presumable taxonomic significance of coccidian oocysts as a constant and rather reliable too ...19938414650
isoenzyme variation within the genus cryptosporidium.soluble extracts of the oocysts of cryptosporidium parvum had demonstrable, but low, activities of malate dehydrogenase (mdh, ec. 1.1.1.37), carboxylesterase (es, ec 3.1.1.1) and lactate dehydrogenase (ldh, ec. 1.1.1.27) following thin-layer starch-gel electrophoresis. much higher activities of glucose phosphate isomerase (gpi, ec. 5.3.1.9) and phosphoglucomutase (pgm, ec. 2.7.5.1) were found, and zymograms of these two enzymes were used to characterise isolates of c. parvum from human, bovine, ...19938415544
effect of ultraviolet disinfection of drinking water on the viability of cryptosporidium parvum oocysts.demineralized water was enriched with a known number of cryptosporidium parvum oocysts obtained from fresh calf feces, which were purified and exposed to ultraviolet (uv) light (15,000 mw/sec) for different lengths of time. coccidium-free litters of cd-1 neonatal mice then were inoculated intragastrically with the treated water. seven days postinoculation mice were killed and c. parvum infection prevalence and intensity determined. in mice inoculated with c. parvum-enriched water that had been e ...19938437060
the effect of halofuginone lactate on experimental cryptosporidium parvum infections in calves.the chemoprophylactic effects of halofuginone lactate were tested against calf experimental cryptosporidiosis. twenty 2-day-old calves, divided into four groups, were orally inoculated with 1 x 10(6) oocysts of cryptosporidium parvum. the infected control group was unmedicated whereas the three other groups were medicated with the drug at 30, 60 and 120 micrograms kg-1 day-1, respectively, for 7 days, from day (d) 2 to d8 post-inoculation (d 0 was inoculation day). the calves were weighed twice ...19938447063
ultrastructural study of cryptosporidium development in madin-darby canine kidney cells.transmission electron microscope studies have been made into phases of the life cycle of a bovine isolate of cryptosporidium cultured in vitro on madin-darby canine kidney cells. the cytoplasm of parasitized cells was noticeably altered, including marked vacuolization and the appearance of membrane structures close to the developing parasites. these changes suggest that the protozoan may release cytopathogenic factors.19938447069
enhancement of resistance to cryptosporidium parvum by pooled bovine colostrum during murine retroviral infection.the therapeutic efficacy of pooled bovine colostrum for the control of cryptosporidiosis was investigated during murine acquired immunodeficiency syndrome in female c57bl/6 mice. mice were infected with lp-bm5 murine leukemia retrovirus for four months and then inoculated with cryptosporidium parvum oocysts. persistent cryptosporidiosis was established in all retrovirus immunosuppressed mice, while control mice were refractory to infection. parasite colonization of intestinal villi was significa ...19938480860
detection of oocysts and igg antibodies to cryptosporidium parvum in asymptomatic adult cattle.infection by cryptosporidium was detected in 94 (71.75%) asymptomatic adult cattle from 131 fecal samples examined microscopically. in two cases cryptosporidium oocysts were observed which were distinctly larger (5.5-6.5 microns x 6.6-7.0 microns) than those we had seen in the majority of feces examined (4.0-4.5 microns x 4.0-4.5 microns) and these specimens were considered to be cryptosporidium muris; it is possible that the other oocysts should be considered as cryptosporidium parvum. the sero ...19938493772
[infectious diarrhea of calves: therapeutic and preventive possibilities based on etiological, pathophysiological and immunological data].in this article the current knowledge on the development mechanisms of bacterial, viral and cryptosporidial neonatal calf diarrhoea are briefly reviewed as basis for an efficacious prophylaxis strategy. hygienic measures will prevent the infection of the calf before colostrum intake and will diminish the infection pressure during the first weeks of life. moreover, local intestinal immunity will be provided by early administration of immune colostrum for the prevention of e.coli diarrhoea and pro ...19938266306
enterotoxic effect of stool supernatant of cryptosporidium-infected calves on human jejunum.the clinical pattern of cryptosporidial diarrhea suggests an enterotoxic mechanism. no evidence for this mechanism has been reported thus far. this study aimed to look for enterotoxic effect elaborated by cryptosporidium.19948276202
cryptosporidium parvum infection of intestinal epithelium: morphologic and functional studies in an in vitro model.a monolayer of mature polarized colonic epithelial cells (t84) able to generate and maintain a barrier to macromolecular flow was used to study pathophysiologic events that occur on microvillus cell exposure to cryptosporidium parvum. by 24-48 h, several life cycle forms were seen in parasitophorous vacuoles near the apical cell surface, along with a time- and oocyst dose-dependent reduction in epithelial barrier function. as few as 10(5) organisms constituted a successful infecting dose, and he ...19948277178
major antigens of cryptosporidium parvum recognised by serum antibodies from different infected animal species and man.serum humoral immune response to cryptosporidium parvum was evaluated in six species: mouse, rabbit, lamb, calf, pig and man. electrophoretic and immunoblot analysis showed that specific animal antibody response appeared between day 4 and day 15 post inoculation. the two main target antigens had apparent molecular weights of 15-17 and 23 kda. they were recognised by each species studied. serum iga intensively recognised the 15-17 kda antigen, except in rabbit. this study demonstrates that these ...19947886907
treatment of experimental ovine cryptosporidiosis with ovine or bovine hyperimmune colostrum.ovine or bovine colostrums with different antibody titers were tested for their ability to prevent cryptosporidiosis in five groups of neonatal lambs experimentally infected with 10(6) cryptosporidium parvum oocysts 2 days after birth (day 0). in a control group (group 1), six lambs were deprived of ewe colostrum and exclusively fed with milk replacer. two groups of six lambs were allowed to suckle their non-hyperimmunized (group 2) or hyperimmunized (group 3) dams throughout the experiment. two ...19947975113
a simple and reliable method of producing in vitro infections of cryptosporidium parvum (apicomplexa).a variety of techniques have been used to infect cell monolayers in culture with the protozoan, cryptosporidium parvum. however, most of these methods rely on the use of trypsin and/or bile salts to excyst sporozoites in vitro, followed by washing sporozoites free of excystation solution prior to their addition to subconfluent monolayers. this method not only increases the amount of time required to establish infections in vitro, but also results in prolonged exposure of free sporozoites to envi ...19948013881
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
comparative development of cryptosporidium parvum (apicomplexa) in 11 continuous host cell lines.using standardized media, incubation, and parasite inoculating procedures, we compared development of cryptosporidium parvum between madin-darby bovine kidney (mdbk) cells and 10 additional host cell lines available through the american type culture collection. parasite development was assessed by counting parasite numbers atop monolayers in 25 random oil fields 68 h post-infection using nomarski interference-contrast optics. results revealed that the human ileocecal adenocarcinoma (hct-8) cell ...19948020747
serological evidence implicating neospora species as a cause of abortion in british cattle.by means of an immunofluorescence antibody test (ifat), using in vitro cultured parasites as antigen, antibodies to neospora species at titres > or = 1/1280 were found in 11 of 120 scottish cattle that had recently aborted but in only one of 97 cattle from herds in which there had been no recent abortions (p < 0.01). the specificity of the antibodies was confirmed by the lack of cross reactivity between samples with high titres to neospora and toxoplasma antigen in a direct agglutination test, a ...19948036769
detection and species identification of cryptosporidium oocysts using a system based on pcr and endonuclease restriction.the polymerase chain reaction (pcr) was used to produce a 556 bp nucleotide stretch, employing primers based on the published sequence of the 18s rrna genes in cryptosporidium parvum and c. muris. this sequence was found to contain 3 mae i endonuclease restriction sites, 1 of which was present only in c. parvum. mae i restriction of pcr products from 2 c. parvum isolates (one of human origin and the other of bovine origin), 1 c. muris isolate, and 1 c. baileyi isolate, showed a specific and repr ...19948058364
both cp15 and cp25 are left as trails behind gliding sporozoites of cryptosporidium parvum (apicomplexa).sporozoites of cryptosporidium parvum were examined after gliding upon glass microscope slides using monoclonal antibodies to the 15 and 25 kda surface molecules and immunogold-silver enhancement. both antibodies bound to surface antigen deposited as trials behind parasites, suggesting that both surface molecules are involved in substrate attachment.19948076803
effect of high temperature on infectivity of cryptosporidium parvum oocysts in water.cryptosporidium parvum oocysts suspended in 0.5 ml of distilled water were pipetted into plastic vials which were inserted into wells in the heated metal block of a thermal dna cycler. block temperatures were set at 5 degrees c incremental temperatures from 60 to 100 degrees c. at each temperature setting four vials containing c. parvum oocysts were placed into wells and held for 15 s before time was recorded as zero, and then pairs of vials were removed 1 and 5 min later. upon removal, all vial ...19948085816
identification of low-molecular-mass coproantigens of cryptosporidium parvum.cryptosporidium parvum coproantigens (ccag) of 18 and 20 kda were identified in the stool eluates of calves and humans infected with cryptosporidium species. monospecific antibodies raised against the 20-kda antigen recognized both 18- and 20-kda ccag in all positive but no negative control samples. these antibodies reacted with c. parvum sporozoites in an immunofluorescence assay. human immune sera recognized the 20-kda antigen in infected calf stool eluates. both 18- and 20-kda ccag remained i ...19948106785
a comparative study of lipid compositions of cryptosporidium parvum (apicomplexa) and madin-darby bovine kidney cells.membrane lipid compositions of cryptosporidium parvum and madin-darby bovine kidney cells, an epithelial-like cell line commonly used to study coccidia in vitro, were analyzed using both thin-layer chromatography and gas-liquid chromatography. phosphatidylcholine was the predominant lipid in both c. parvum and madin-darby bovine kidney cells, comprising 65% and 41% of the total phospholipids, respectively. phospholipids of c. parvum contained twice the level of 16:0 and twenty-fold more 18:2 tha ...19948124271
excretion of cryptosporidium parvum oocysts by a herd of beef suckler cows. 19948160334
[isolation of cryptosporidium parvum oocysts from fecal samples--the combination of ether extraction and discontinuous sucrose gradients].a calf and 50 mice were infected with cryptosporidium parvum, and their fecal materials were collected and treated with ether extraction (ee), followed by discontinuous sucrose gradients (dsg) method. ee method was to remove some of fat or lipid from feces. sediments were washed by centrifugation (1,500 x g for 10 min., 3 times) in phosphate-buffered saline and then these washed sediments were sieved sequentially through stainless steel screens with a final mesh of 250 (61 microns porosity) to r ...19948167112
bovine antibody against cryptosporidium parvum elicits a circumsporozoite precipitate-like reaction and has immunotherapeutic effect against persistent cryptosporidiosis in scid mice.control of cryptosporidiosis is currently hampered by the absence of drugs or vaccines proven consistently effective against cryptosporidium parvum. on the basis of observations that anti-c. parvum antibody has therapeutic effect against cryptosporidiosis, cows were immunized with c. parvum to produce hyperimmune colostral antibody. an antibody-rich fraction was prepared and differentiated from control (nonhyperimmune) antibody by enzyme-linked immunosorbent assay, immunofluorescence assay, immu ...19948168959
infection pattern of cryptosporidium and giardia in calves.faecal samples were collected weekly over a 3 month period from 0- to 20-week-old calves on an ohio dairy farm, and examined for cryptosporidium oocysts and giardia cysts by a quantitative direct immunofluorescence assay. oocysts and cysts were detected as early as 4 days of age. shedding of cryptosporidium oocysts peaked at 1 week and was low by 3 weeks. some calves, however, continued to pass low numbers of oocysts. shedding of giardia cysts peaked at 2 weeks of age with high levels maintained ...19947879383
characterization of a high molecular weight antigen of cryptosporidium parvum micronemes possessing epitopes that are cross-reactive with all parasitic life cycle stages.crossreacting antigens between life cycle stages of cryptosporidium parvum (protozoa, apicomplexa) were detected using monoclonal antibodies (mabs). shared epitopes were demonstrated by immunoelectron microscopy, at the level of micronemes of the sporozoite and merozoite stages; some dense granules were also labelled but not so intensively. the parasitophorous vacuole membranes of all intracellular stages, the wall-forming bodies of macrogametes and the outer oocyst walls all shared these epitop ...19947522083
diagnosis of bovine cryptosporidiosis by indirect immunofluorescence assay using monoclonal antibody.two hybridoma cell lines against cryptosporidium parvum oocysts (vri-cn91) were produced. the isotype of these 2 monoclonal antibodies (mabs) was igg2b (1e7.2) and and igm (c6). enzyme immuno-transfer blotting analysis showed that 1e7.2 reacted specifically to 36 kda protein and c6 reacted to 67 and 70 kda proteins. c. parvum was bound specifically to the surface region of oocysts by these mabs. no cross-reactivity was observed with tachyzoites of toxoplasma gondii and oocysts of eimeria zuernii ...19957551801
[cryptosporidium parvum (apicomplexa: sporozoa, coccidia)--the optimization of a technic for isolating a large number of oocysts].the waldman e. a. (1986) method of separation of cryptosporidium spp. oocysts from feces by using a percoll discontinuous density gradient appeared a method of choice for obtaining large numbers of oocysts of c. parvum free of fecal contamination. feces of 7-12 day old calves, spontaneously infected with c. parvum, were concentrated and purified by the above technique. the purified oocysts were shown to be infectious by inoculation of 6-9 day old rats with an average dose of 20,000 oocysts per a ...19957567079
monoclonal antibodies identify a subset of dense granules in cryptosporidium parvum zoites and gamonts.two monoclonal antibodies raised against purified oocysts and excysted sporozoites of cryptosporidium parvum identified antigens located in the anterior half of sporozoites by indirect immunofluorescence microscopic assay. the monoclonal antibodies also reacted with triton-x-100-insoluble antigens of asexual and sexual stage parasites developing in epithelial cells in vitro and identified a 110 kilodalton antigen on immunoblots of sodium dodecyl sulfate-extracted oocysts. immunoblotting reactivi ...19957620464
cloning and analysis of a cryptosporidium parvum gene encoding a protein with homology to cytoplasmic form hsp70.an intronless gene encoding a protein of 674 amino acid residues with a molecular mass of 73,403 da showing homology to the cytoplasmic form of the 70 kda heat shock proteins has been cloned and sequenced from the intestinal pathogen cryptosporidium parvum. monospecific polyclonal antibodies obtained to recombinant protein recognized a single band with an approximate molecular mass of 70 kda on a western blot of c. parvum proteins, as well as the 70 kda heat shock protein from bovine brain. sout ...19957620467
sequence analysis and comparison of ribosomal dna from bovine neospora to similar coccidial parasites.the nuclear small subunit ribosomal rna (nss-rrna) gene sequence of neospora spp. isolated from cattle was analyzed and compared to the sequences from several closely related cyst-forming coccidial parasites. double-stranded dna sequencing of 5 bovine neospora spp. isolates (bpa1-4), 2 neospora caninum isolates (nc-1 and nc-3), and 3 toxoplasma gondii isolates (rh, gt-1, ct-1) were performed and compared to each other, as well as to other sequences available in genbank for the nc-1 isolate, sarc ...19957623193
an epidemiological study of cryptosporidium parvum in two herds of adult beef cattle.prevalences of cryptosporidium parvum oocysts in faeces and of isotype-specific anti-c. parvum antibodies in serum of apparently healthy adult cattle on two farms were determined. on farm 1 cryptosporidial diarrhoea had been recorded in more than 80% of calves born over the previous 5 years, whereas on farm 2 cryptosporidiosis had never been reported. no differences were demonstrated in oocyst excretion or presence of antibodies between the two farms. c. parvum oocysts were detected in 62.4% of ...19957660565
murine infection model for maintenance and amplification of cryptosporidium parvum oocysts.propagation of cryptosporidium parvum is problematic because in vitro development of the parasite is poor and animals are only briefly susceptible as neonates. at present oocysts of the parasite are usually procured by passage in neonatal sheep or cattle. in the present study, large numbers of oocysts of c. parvum could be isolated following infection of dexamethasone-treated adult c57bl/6 mice. the amount of immunosuppressive drug and the regimen of administration were critical for successful m ...19957665672
activity of benzimidazoles against cryptosporidiosis in neonatal balb/c mice.the need for an effective compound for the prevention and treatment of cryptosporidiosis in humans and animals has led to the testing of benzimidazoles based on reports that albendazole was clinically effective against related protozoan parasites causing microsporidiosis in humans. albendazole and other benzimidazole derivatives were tested for prophylactic efficacy against cryptosporidiosis at dosage levels 1-3x the levels found effective for treatment of cattle or sheep for helminth infections ...19957472880
differentiation between human and animal strains of cryptosporidium parvum using isoenzyme typing.isoenzyme typing was used to study a number of oocyst isolates of cryptosporidium parvum from different geographical locations and of human or animal origin. all isolates showed identical enzyme motility when glucose phosphate isomerase (gpi; 23 isolates tested) or lactate dehydrogenases (ldh; 20 isolates tested) was assayed. however, two isoenzyme forms were observed with phosphoglucomutase (pgm; 9 animal isolates showed one form, while 8/9 human isolates showed a second form) and hexokinase (h ...19957885731
effects of select medium supplements on in vitro development of cryptosporidium parvum in hct-8 cells.surface-sterilized oocysts of cryptosporidium parvum were applied to subconfluent monolayers of human adenocarcinoma (hct-8) cells grown on coverslips in six-well cluster plates. parasite-infected cultures were then incubated in rpmi 1640 with 10% fetal bovine serum, 15 mm hepes (n-2-hydroxyethylpiperazine-n'-2-ethanesulfonic acid) buffer, and antibiotics at 37 degrees c in a 5% co2-95% air incubator for 2 h to allow sporozoites to excyst and enter cells. after cultures were washed free of debri ...19957714194
development of a microtitre elisa to quantify development of cryptosporidium parvum in vitro.an in situ enzyme-linked immunosorbent assay (elisa) was developed to evaluate growth of cryptosporidium parvum in vitro. ninety-six-well tissue culture microtitre plates were each seeded with 4.0 x 10(4) human ileocecal adenocarcinoma (hct-8) cells, then infected with cscl-purified oocysts 24 h later. the growth medium consisted of rpmi 1640 supplemented with 10% fetal bovine serum, 15 mm hepes (n-2-hydroxyethylpiperazine n'-2-ethanesulfonic acid), 50 mm glucose, 1 microgram ml-1 folic acid, 4 ...19957744242
effects of cryptosporidium parvum infection on lymphocyte phenotype and reactivity in calves.cryptosporidium parvum is a protozoan parasite now recognized as a significant cause of neonatal diarrhea in calves, and infection is also widespread in both immunocompetent and immunocompromised humans. no effective treatment or preventive measures against c. parvum infection are available, owing largely to the lack of understanding of immunologic mechanisms of resistance to and recovery from this parasite. in the present study, we compared phenotypes of lymphocytes from peripheral blood, splee ...19957747401
cryptosporidia--who is at risk?cryptosporidium parvum is a coccidian parasite originally described a century ago and, until recently, not considered to be a human pathogen. it has a complex life cycle, including both sexual and asexual reproduction, an auto-infectious cycle, and the ability to complete its development within a single host. the transmission form is a robust, environmentally resistant oocyst, excreted in the stool, which can exist for long periods of time in the environment. because animals, in particular domes ...19957770751
protection of calves with a vaccine against cryptosporidium parvum.cryptosporidium parvum causes enteric infection and diarrhea in calves, other species of economically important livestock, and humans. there are no effective treatments currently licensed for this parasite, and preventive measures are difficult. in addition to direct economic losses to the cattle industry, infected calves may contaminate water supplies with oocysts and contribute to human cryptosporidiosis. we have developed a vaccine offering partial protection against c. parvum infection in ca ...19957876978
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
localization of actin and myosin in cryptosporidium parvum using immunogold staining.the location of actin and myosin of the several stages of cryptosporidium parvum was observed. the tissue antigen of c. parvum was prepared through immunosuppression of icr mice with depomedrol. the thin sectioned specimens, which were incubated with the igg fraction of the rabbit polyclonal antibodies raised against chicken back muscle actin and bovine uterus myosin, were treated with 10 nm gold-conjugated goat anti-rabbit igg. electrodense particles were located mainly on the pellicles of all ...19958528621
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