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human t and b cell immunoreactivity to a recombinant 23-kda cryptosporidium parvum antigen.cryptosporidial infection in humans results in parasite-specific igg, igm, and iga antibody responses, but little is known of the cell-mediated immune responses to cryptosporidial antigens. in a convenience sample of 35 haitian residents, there was a high level of cryptosporidial exposure (>90%) as determined by immunoblot reactivity of serum against cryptosporidial antigens. an attempt was made to determine if there was a relationship between antibody and t cell-mediated responses to recombinan ...200111426740
cryptosporidium parvum genotype 2 infections in free-ranging mountain gorillas (gorilla gorilla beringei) of the bwindi impenetrable national park, uganda.for behavioral research and due to growing ecotourism, some populations of free-ranging mountain gorillas (gorilla gorilla beringei) have become habituated to humans. molecular analysis of two cryptosporidium sp. oocyst isolates originating from two human-habituated gorilla groups and two oocyst isolates from non-habituated gorillas yielded positive identification of c. parvum genotype 2 (g2; i.e., "cattle", "animal-adapted", or "zoonotic"). as g2 is cross-transmissible between humans and animal ...200111403378
phenotypic and genotypic characterization of cryptosporidium species and isolates.recent outbreaks of cryptosporidiosis from contaminated water supplies have led to a need for the detection of cryptosporidium oocysts from various hosts and contaminating sources. the presence of nonpathogenic species or strains of cryptosporidium is important for diagnostic purposes as there is a potential for false- positive detection of pathogenic parasites. the present review focuses on phenotypic differences and recent advances in genotypic analyses of the genus cryptosporidium with an emp ...200111420647
chlorine dioxide inactivation of cryptosporidium parvum oocysts and bacterial spore indicators.cryptosporidium parvum, which is resistant to chlorine concentrations typically used in water treatment, is recognized as a significant waterborne pathogen. recent studies have demonstrated that chlorine dioxide is a more efficient disinfectant than free chlorine against cryptosporidium oocysts. it is not known, however, if oocysts from different suppliers are equally sensitive to chlorine dioxide. this study used both a most-probable-number-cell culture infectivity assay and in vitro excystatio ...200111425712
quantitative shedding of two genotypes of cryptosporidium parvum in california ground squirrels (spermophilus beecheyi).sixteen percent of california ground squirrels (spermophilus beecheyi) were found to be shedding an average of 53,875 cryptosporidium parvum oocysts/g of feces. male squirrels had a higher prevalence and higher intensity of shedding than did female squirrels. the majority of c. parvum isolates matched a bovine-murine genotype, with a few isolates resembling a porcine genotype. higher intensities of shedding by males may enhance dissemination and genotypic mixing of this protozoa given males' pro ...200111375204
quantification of cryptosporidium parvum oocysts in mouse fecal specimens using immunomagnetic particles and two-color flow cytometry.although single-color flow cytometry has been shown to be more sensitive than fluorescence microscopy for the quantification of cryptosporidium parvum oocysts, this method has not been optimized. monoclonal antibody ow50, specific to the cell wall of oocysts, was conjugated to superparamagnetic particles, to fluorescein isothiocyanate, and to r-phycoerythrin. the oocysts were then double stained with the fluorochrome-labeled ow50 and were placed in tubes with known numbers of highly fluorescent ...200111318573
inactivation of cryptosporidium parvum oocysts with ozone and monochloramine at low temperature.the rate of cryptosporidium parvum inactivation decreased with decreasing temperature (1-20 degrees c) for ozone and for monochloramine applied alone as well as after pre-treatment with ozone. synergy was observed at all temperatures studied for the ozone/monochloramine sequential disinfection scheme. the synergistic effect was found to increase with decreasing temperature. the inactivation rate with monochloramine after ozone pre-treatment was 5 times faster at 20 degrees c and 22 times faster ...200111257892
tracking cryptosporidium parvum by sequence analysis of small double-stranded rna.we sequenced a 173-nucleotide fragment of the small double-stranded viruslike rna of cryptosporidium parvum isolates from 23 calves and 38 humans. sequence diversity was detected at 17 sites. isolates from the same outbreak had identical double-stranded rna sequences, suggesting that this technique may be useful for tracking cryptosporidium infection sources.200111266306
antigen incorporation on cryptosporidium parvum oocyst walls.cryptosporidium parvum oocysts are the infective stages responsible for transmission and survival of the organism in the environment. in the present work we show that the oocyst wall, far from being a static structure, is able to incorporate antigens by a mechanism involving vesicle fusion with the wall, and the incorporation of the antigen to the outer oocyst wall. using immunoelectron microscopy we show that the antigen recognized by a monoclonal antibody used for diagnosis of cryptosporidiosi ...200111285502
inactivation of cryptosporidium parvum oocysts in cider by flash pasteurization.cryptosporidium parvum is a well-recognized pathogen of significant medical importance, and cider (apple juice) has been associated with foodborne cryptosporidiosis. this study investigated the effect of flash pasteurization on the viability of contaminant c. parvum oocysts. cider inoculated with oocysts was heated at 70 or 71.7 degrees c for 5, 10, or 20 s, and oocyst viability was measured by a semiquantitative in vitro infectivity assay. by infecting multiple wells of confluent madin-darby bo ...200111307890
cryptosporidium parvum infection involving novel genotypes in wildlife from lower new york state.cryptosporidium, an enteric parasite of humans and a wide range of other mammals, presents numerous challenges to the supply of safe drinking water. we performed a wildlife survey, focusing on white-tailed deer and small mammals, to assess whether they may serve as environmental sources of cryptosporidium. a pcr-based approach that permitted genetic characterization via sequence analysis was applied to wildlife fecal samples (n = 111) collected from september 1996 to july 1998 from three areas i ...200111229905
identification of 5 types of cryptosporidium parasites in children in lima, peru.cryptosporidium parvum is usually considered to be the pathogen responsible for human cryptosporidiosis. we genotyped cryptosporidium in 132 stool specimens from 80 peruvian children, representing 85 infection episodes, using techniques that differentiate cryptosporidium species and c. parvum genotypes. five types of cryptosporidium were identified: c. parvum human (67), bovine (8), and dog (2) genotypes, c. meleagridis (7), and c. felis (1). twenty-five (29%) of the 85 infection episodes were a ...200111133382
efficacies of lipophilic inhibitors of dihydrofolate reductase against parasitic protozoa.competitive inhibitors of dihydrofolate reductase (dhfr) are used in chemotherapy or prophylaxis of many microbial pathogens, including the eukaryotic parasites plasmodium falciparum and toxoplasma gondii. unfortunately, point mutations in the dhfr gene can confer resistance to inhibitors specific to these pathogens. we have developed a rapid system for testing inhibitors of dhfrs from a variety of parasites. we replaced the dhfr gene from the budding yeast saccharomyces cerevisiae with the dhfr ...200111120964
inhibition of cryptosporidium infection in mice treated with a cyclodextrin inclusion complex with diloxanide furoate.the efficacies of diloxanide furoate, beta-cyclodextrin and a cyclodextrin inclusion complex against cryptosporidium parvum were evaluated in a suckling murine model. efficacy was established by numbers of oocysts recovered from the intestinal tract of mice on day 7 postinfection. the level of infection in treated mice was significantly lower than in control mice and, surprisingly, the most efficacious treatment was beta-cyclodextrin, an excipient used in pharmaceutical technology.200111411943
chemical and physical factors affecting the excystation of cryptosporidium parvum oocysts.cryptosporidium parvum oocysts were examined to ascertain excystation requirements and the effects of gamma irradiation. oocysts and excysted sporozoites were examined for dye permeability and infectivity. maximum excystation occurred when oocysts were pretreated with acid and incubated with bile salts, and potassium or sodium bicarbonate. pretreatment with hanks' balanced salt solution or nacl lowered excystation; however, this effect was overcome with acid. sodium ions were replaceable with po ...200111426720
molecular characterization of cryptosporidium isolates obtained from human and bovine infections in japan.cryptosporidium oocysts, morphologically identified as cryptosporidium parvum, were isolated from 22 human and 14 bovine cases in japan, and were genotyped by means of a pcr/rflp analysis of the polythreonine gene. dna profiles of human isolates gave three distinct genotypes, namely an anthroponotic genotype 1, zoonotic genotype 2 and a new genotype. isolates from bovine samples gave zoonotic genotype 2. the unusual genotype of cryptosporidium was isolated from the feces of three immunologically ...200111728022
sequential inactivation of cryptosporidium parvum using ozone and chlorine.inactivation of bovine-derived c. parvum oocysts was studied at bench-scale in oxidant demand free 0.05 m phosphate buffer using free chlorine alone or ozone followed by free chlorine at temperatures of 1 degrees c, 10 degrees c and 22 degrees c at ph 6. animal infectivity using neonatal cd-1 mice was used for evaluation of oocyst viability after treatment. kinetic models based on the linear chick-watson model were developed for free chlorine inactivation and ozone/free chlorine sequential inact ...200111763036
effects of combined water potential and temperature stresses on cryptosporidium parvum oocysts.hosts infected with the parasite cryptosporidium parvum may excrete oocysts on soils in watersheds that supply public drinking water. environmental stresses decrease the numbers of oocysts after deposition on soils. however, the rates and effects of combined stresses have not been well characterized, especially for the purposes of estimating decrease in numbers. we subjected oocysts to combined stresses of water potential (-4, -12, and -33 bars), above-freezing temperatures (4 and 30 degrees c), ...200111722902
serological response to cryptosporidium parvum in adult cattle from the andean region of colombia.single faecal and serum samples were individually collected from 135 asymptomatic adult cows on seven farms in cundinamarca (colombian andean region). tests for the presence of oocysts of cryptosporidium parvum (carbol fuchsin stain) and eimeria spp (flotation in saturated saline solution) revealed that none of the animals had coccidia in their faeces. the igg antibody levels to c. parvum were measured by an enzyme-linked immunosorbent assay (elisa) technique and the reactivity to c. parvum anti ...200111411953
cloning and phylogenetic analysis of the ribosomal internal transcribed spacer-1 (its1) of cryptosporidium wrairi and its relationship to c. parvum genotypes.we have cloned and sequenced the ribosomal internal transcribed spacer-1 (its1) of cryptosporidium wrairi. phylogenetic analysis of this region provided further support to the validity of c. wrairi as a distinct species and also to the concept that many of the genotypes recently identified within c. parvum are in fact separate species. analysis placed the "cattle" and "mouse" genotypes of c. parvum as each other's closest relatives and c. wrairi as a sister group to these two genotypes, followed ...200112402523
real-time pcr for the detection of cryptosporidium parvum.real time, taqman pcr assays were developed for the cp11 and 18s rrna genes of the protozoan parasite cryptosporidium parvum. the taqman probes were specific for the genus cryptosporidium, but could not hybridize exclusively with human-infectious c. parvum species and genotypes. in conjunction with development of the taqman assays, two commercial kits, the mo bio ultraclean soil dna kit, and the qiagen qiaamp dna stool kit, were evaluated for dna extraction from calf diarrhea and manure, and pot ...200111714523
cryptosporidium canis n. sp. from domestic dogs.oocysts of cryptosporidium, from the feces of a naturally infected dog and from an hiv-infected human, were identified as the previously reported canine genotype of cryptosporidium parvum, hereafter referred to as cryptosporidium canis n. sp. also among the oocysts from the dog, a trace amount of c. parvum bovine genotype was detected. cryptosporidium canis oocysts from both the dog and human were infectious for calves. oocysts excreted by calf 1 (dog source) were approximately 90% c. canis and ...200111780831
improving the rate of infectivity of cryptosporidium parvum oocysts in cell culture using centrifugation.centrifugation was evaluated as a method to improve infectivity assays of cryptosporidium parvum in cell culture using the focus detection method, an immunofluorescence-based method for detecting infectious c. parvum oocysts in vitro. human ileocecal adenocarcinoma (hct-8) cells were grown for 48 hr on 13-mm cover slips in 24-well microtiter plates and infected with bleach-treated c. parvum oocysts. plates were centrifuged at 228 g for 10 min and incubated at 37 c for 5, 12, 18, 24, and 48 hr. f ...200111780852
[improvement of amplification method for cryptosporidium parvum oocysts from mice].to establish a simplified amplification method for obtaining a large number of purified cryptosporidium parvum oocysts from infected c57bl/6n mice.200112572074
molecular genotyping of human cryptosporidiosis in northern ireland: epidemiological aspects and review.cryptosporidium parvum is the most common of the protozoal pathogens associated with gastrointestinal disease in northern ireland. genotyping techniques are valuable in helping to elucidate sources and modes of transmission of this parasite. there have been no reports on the prevalence of genotypes in northern ireland, mainly due to a lack of discriminatory genotyping techniques, which recently have become available.200111918331
complete development and long-term maintenance of cryptosporidium parvum human and cattle genotypes in cell culture.this study describes the complete development (from sporozoites to sporulated oocysts) of cryptosporidium parvum (human and cattle genotypes) in the hct-8 cell line. furthermore, for the first time the complete life cycle was perpetuated in vitro for up to 25 days by subculturing. the long-term maintenance of the developmental cycle of the parasite in vitro appeared to be due to the initiation of the auto-reinfection cycle of c. parvum. this auto-reinfection is characterised by the production an ...200111429168
large sequence variation at two microsatellite loci among zoonotic (genotype c) isolates of cryptosporidium parvum.the genetic polymorphism among 57 cryptosporidium parvum isolates belonging to genotype 'c' was studied by pcr amplification and the sequencing of two microsatellite loci (ml1 and ml2). a comparative analysis of dna sequences showed the presence of three (ml1-238, ml1-226, and ml1-220) and seven (ml2-231, ml2-229, ml2-227, ml2-213, ml2-193, ml2-191, and ml2-187) different alleles at these two loci. alleles differed by expansions/contractions of the microsatellite repeats that generated length po ...200111429171
evaluation and optimization of a reusable hollow fiber ultrafilter as a first step in concentrating cryptosporidium parvum oocysts from water.experiments with a small-scale hollow fiber ultrafiltration system (50,000 mwco) was used to characterize the filtration process and identify conditions that optimize the recovery of cryptosporidium parvum oocysts from 2 l samples of water. seeded experiments were conducted using deionized water as well as four environmental water sources (tap, ground, arkansas river, and rio grande river; 0-30.9ntu). optimal and consistent recovery of spiked oocysts was observed (68-81%), when the membrane was ...200111456179
glutamine transporter in crypts compensates for loss of villus absorption in bovine cryptosporidiosis.cryptosporidium parvum infection represents a significant cause of diarrhea in humans and animals. we studied the effect of luminally applied glutamine and the pg synthesis inhibitor indomethacin on nacl absorption from infected calf ileum in ussing chambers. infected ileum displayed a decrease in both mucosal surface area and nacl absorption. indomethacin and glutamine or its stable derivative alanyl-glutamine increased the net absorption of na(+) in infected tissue in an additive manner and to ...200111518676
contamination of river water by cryptosporidium parvum oocysts in western japan.in japan, only a few rivers have been inspected for cryptosporidium parvum contamination, and the methods used had low sensitivity. in 1998 and 1999, we used a method with higher sensitivity to examine all large rivers used as sources of water supply in one prefecture (which we divided into four areas) in western japan for cryptosporidium oocysts. one sample was collected at each of 156 sites along 18 rivers, and samples were tested for cryptosporidium oocysts by immunomagnetic separation. sampl ...200111525974
molecular characterization of cryptosporidium isolates obtained from humans in france.cryptosporidium parvum is usually considered the agent of human cryptosporidiosis. however, only in the last few years, molecular biology-based methods have allowed the identification of cryptosporidium species and genotypes, and only a few data are available from france. in the present work, we collected samples of whole feces from 57 patients from france (11 immunocompetent patients, 35 human immunodeficiency virus [hiv]-infected patients, 11 immunocompromised but non-hiv-infected patients) in ...200111574558
quantitation of cryptosporidium parvum infection in cell culture using a colorimetric in situ hybridization assay.a quantitative colorimetric in situ hybridization assay was developed for detecting cryptosporidium parvum infection in cell cultures using a digoxigenin-labeled probe targeting 18s rrna. intra-cellular developmental stages of c. parvum such as trophozoites and meronts were clearly discerned by light microscopy as localized areas of dark purple/black precipitate against a colorless background. infections developed focally and the term infectious focus was applied to each cluster of developmental ...200111596921
the utilization of sodium taurocholate in excystation of cryptosporidium parvum and infection of tissue culture.the present work deals with optimization of excystation of cryptosporidium parvum oocysts and the infection process of tissue culture cells by the parasite. it was shown that presence of the bile salt sodium taurocholate in the incubation medium expedited excystation of the tested gch1 isolate and enhanced it, as compared with bleaching of the oocysts. this bile salt had no effect on the viability of tissue culture cell lines mdbk and hct-8 at the tested concentration of 0.375% for up to 2 hr of ...200111695421
comparison of fluorescence, antigen and pcr assays to detect cryptosporidium parvum in fecal specimens.to optimize routine screening for cryptosporidiosis, 198 stool samples from patients at risk and from calves were examined by enzyme immunoassay (eia), a direct fluorescent-antibody (dfa) and a modified immunofluorescence assay. ninety-nine samples were positive in at least one assay, whereas 99 were negative in all three assays. sensitivity of antigen eia and dfa were similar (94%, 95% ci: 88-98%, and 91%, 95% ci: 84-95%). the modified immunofluorescence was significantly less sensitive (64%, 9 ...200212151188
detection and genotyping of oocysts of cryptosporidium parvum by real-time pcr and melting curve analysis.several real-time pcr procedures for the detection and genotyping of oocysts of cryptosporidium parvum were evaluated. a 40-cycle amplification of a 157-bp fragment from the c. parvum beta-tubulin gene detected individual oocysts which were introduced into the reaction mixture by micromanipulation. sybr green i melting curve analysis was used to confirm the specificity of the method when dna extracted from fecal samples spiked with oocysts was analyzed. because c. parvum isolates infecting human ...200212202559
cryptosporidium infection in dogs in osaka, japan.cryptosporidium parvum is a zoonotic pathogen composed of genetically distinct but morphologically identical genotypes. recent molecular study indicates that dogs may transmit the cattle genotype, which is known to be pathogenic to humans. although large-scale studies of cryptosporidium infection in dogs have been performed in several countries, the isolates were not accurately identified because of the lack of a method for molecular analysis. it is important to identify the isolates harbored in ...200212237137
pcr-restriction fragment length polymorphism analysis of a diagnostic 452-base-pair dna fragment discriminates between cryptosporidium parvum and c. meleagridis and between c. parvum isolates of human and animal origin.genomic dnas from human cryptosporidium isolates previously typed by analysis of the 18s ribosomal dna locus (cryptosporidium parvum bovine genotype, c. parvum human genotype, cryptosporidium meleagridis, and cryptosporidium felis) were used to amplify the diagnostic fragment described by laxer et al. (m. a. laxer, b. k. timblin, and r. j. patel, am. j. trop. med. hyg., 45:688-694, 1991). the obtained 452-bp amplified fragments were sequenced and aligned with the homologous cryptosporidium wrair ...200211916736
a study of cryptosporidiosis in a cohort of neonatal calves.during calving time on an experimental farm, 32 newborn calves were selected at random and monitored for infection with cryptosporidium parvum for the first 30 days of their lives. the animals were fed pooled colostrum for 2-3 days after birth and housed in individual pens, which were washed daily using a pressure hose. fecal smears were examined by microscopy after staining with carbol fuschin for visualization of oocysts. oocyst shedding was scored semiquantitatively according to the average n ...200211992707
identification of genotypes of cryptosporidium parvum isolates from a patient and a dog in japan.cryptosporidium parvum (c. parvum) is recognized as a significant pathogen in humans and animals, primarily as a cause of diarrheal illness. recent genetic and biological studies indicate that c. parvum is not a single species but composed of genetically distinct multiple genotypes. thus, it is valuable to distinguish between genotypes in the epidemiology of cryptosporidium infection in humans and animals. although c. parvum has been detected in humans and animals in japan, the genotype of isola ...200211913556
[cloning of a species-specific gene fragment from cryptosporidium parvum and the development of diagnostic pcr primers].to develop a pair of diagnostic pcr primers for cryptosporidium parvum.200212567561
[cloning and sequencing of the gp23 gene encoding a surface antigen on sporozoites of cryptosporidium parvum].to clone and sequence the gp23 gene encoding a surface antigen on the sporozoites of cryptosporidium parvum.200212567995
oral bovine serum concentrate improves cryptosporidial enteritis in calves.cryptosporidium parvum produces a prolonged watery diarrhea unresponsive to conventional antimicrobials. because of reported efficacy of antibody-based immunotherapy, we studied the effect of inexpensive, commercially available oral bovine serum concentrate (bsc) in experimental cryptosporidiosis. twenty-four calves were treated with 57 g/d bsc (n = 12) or soy protein (n = 12) added to their standard whey protein-based milk replacer (227 g/2 l twice daily). of the 24, 9 were also treated with l- ...200211861944
genetic analysis of a cryptosporidium parvum human genotype 1 isolate passaged through different host species.cryptosporidium parvum tu502, a genotype 1 isolate of human origin, was passaged through three different mammalian hosts, including humans, pigs, and calves. it was confirmed to be genotype 1 by pcr-restriction fragment length polymorphism analysis of the cryptosporidium oocyst wall protein gene, direct sequencing of pcr fragments of the small subunit rrna and beta-tubulin genes, and microsatellite analysis. this isolate was shown to be genetically stable when passaged through the three mammalia ...200212228296
molecular characterization of danish cryptosporidium parvum isolates.the genetic polymorphism among 271 danish cryptosporidium isolates of human and animal origin was studied by partial amplification and sequencing of the cryptosporidium oocyst wall protein (cowp) gene, the 1 8s rdna, and a microsatellite locus. furthermore, the microsatellite locus was studied directly using fragment analysis. a comparative analysis of dna sequences showed the presence of 3 different subgenotypes (cl, c2 and c3) in c. parvum isolates from danish cattle, with prevalences of 16.7, ...200212403321
[the epidemiology of human cryptosporidiosis].cryptosporidiosis, as an emerging disease, has generated a tremendous amount of research. our purpose is a survey of the epidemiology of this disease, emphasizing: the features of the parasites and the species and genotypes that may infect man, the most frequent of which is cryptosporidium parvum and its two genotypes "cattle" and "human"; the means of dissemination of the infective stage and of human contamination; the factors that put man at risk of catching a severe infection; the basis of a ...200212412376
prevalence of and risk factors involved in the spread of neonatal bovine cryptosporidiosis in galicia (nw spain).an epidemiological study was carried out on farms in galicia (nw spain) to investigate the prevalence of and the risk factors associated with the spread of infection by cryptosporidium parvum in calves of less than 3 weeks of age. a total of 22 cattle farms (10 beef herds and 12 dairy herds) were visited once every 21 days between january and december 2000. a faecal sample was collected directly from the rectum of each of the 844 calves born during the study period. each sample was studied macro ...200211992706
controlling the onset of natural cryptosporidiosis in calves with paromomycin sulphate.a prospective, controlled-blind field trial was conducted to evaluate the efficacy and safety of paromomycin sulphate, given for 10 days from birth, in preventing natural cryptosporidiosis in calves. in the untreated control group, oocyst shedding and diarrhoea followed the pattern that had occurred on the farm before the trial, consistent with a perinatal infection, whereas in the treated group, the prepatent period was significantly longer than in the control group (p < 0.01) and oocyst sheddi ...200212463536
[importance of the different species and genotypes of cryptosporidium in public health].until recently, only the bovine and human genotypes of cryptosporidium parvum had been considered to infect man and to be potential pathogens. lately, symptomatic infections with c. felis, c. meleagridis, and dog c. parvum-like genotype have been described in immunocompetent and immunosuppressed individuals. these findings suggest that zoonotic parasites could also play an important role in public health.200212108027
association of il-10 expression by mucosal lymphocytes with increased expression of cryptosporidium parvum epitopes in infected epithelium.the objective of this study was to determine whether changes in the ileal intraepithelial lymphocyte (tel) phenotype and function occurred prior to development of diarrhea in cryptosporidium parvum-infected calves. calves were orally inoculated with 10(8) oocysts and maintained in enteric pathogen-free conditions until their use in experiments. age-matched uninfected calves were used for comparisons. ileal iels were isolated and phenotyped to determine whether changes in lymphocyte population dy ...200212053998
cattle near the bwindi impenetrable national park, uganda, as a reservoir of cryptosporidium parvum and giardia duodenalis for local community and free-ranging gorillas.the prevalence and intensity of shedding of cryptosporidium parvum oocysts and giardia duodenalis cysts was investigated in cattle grazing in the vicinity of the bwindi impenetrable national park, uganda. the prevalence of cryptosporidiosis and giardiosis was 38% and 12%, respectively, with 10% concomitant infections. shedding intensity varied from 130 to 450 oocysts/g (mean of 215 oocysts/g) and from 110 to 270 cysts/g (mean of 156 cysts/g). significantly more pre-weaned than post-weaned cattle ...200211999029
three drinking-water-associated cryptosporidiosis outbreaks, northern ireland.three recent drinking-water-associated cryptosporidiosis outbreaks in northern ireland were investigated by using genotyping and subgenotyping tools. one cryptosporidium parvum outbreak was caused by the bovine genotype, and two were caused by the human genotype. subgenotyping analyses indicate that two predominant subgenotypes were associated with these outbreaks and had been circulating in the community.200212023922
cryptosporidium hominis n. sp. (apicomplexa: cryptosporidiidae) from homo sapiens.the structure and infectivity of the oocysts of a new species of cryptosporidium from the feces of humans are described. oocysts are structurally indistinguishable from those of cryptosporidium parvum. oocysts of the new species are passed fully sporulated, lack sporocysts. and measure 4.4-5.4 microm (mean = 4.86) x 4.4-5.9 microm (mean = 5.2 microm) with a length to width ratio 1.0-1.09 (mean 1.07) (n = 100). oocysts were not infectious for arc swiss mice, nude mice. wistar rat pups, puppies, k ...200212503676
zoonotic species of cryptosporidium are as prevalent as the anthroponotic in hiv-infected patients in thailand.the epidemiology of chronic diarrhoea in adults with late-stage hiv infection was investigated in a prospective study in bangkok, thailand. during this investigation, 34 cryptosporidium isolates were obtained from the faeces of 36 patients, with mean cd4(+) counts of only 14 x 10(6) cd4(+) cells/litre (range = 2 x 10(6) - 53 x 10(6)/litre), who had symptomatic cryptosporidiosis. genotyping of these isolates, by rflp analysis and dna sequencing of the hypervariable region of the 18s rrna gene, in ...200212625934
release of cryptosporidium and giardia from dairy calf manure: impact of solution salinity.studies were initiated to determine the release behavior of cryptosporidium oocysts and giardia cysts from dairy calf manure to waters of various salinities. experiments were conducted by sprinkling a particular aqueous solution over a manure disk and collecting the runoff water. effluent concentrations of manure and (oo)cysts were initially several orders of magnitude below their starting concentration in the manure, after continued application of water the concentrations gradually decreased, a ...200212269743
evaluation of in vitro and in vivo activity of benzindazole-4,9-quinones against cryptosporidium parvum.a series of benzindazole-4,9-quinones was tested for growth-inhibitory effects on cryptosporidium parvum in vitro and in vivo. most compounds showed considerable activity at concentrations from 25 to 100 micro m. for instance, at 25 micro m the derivatives 5-hydroxy-8-chloro-n1-methylbenz[f]-indazole-4,9-quinone and 5-chloro-n2-methylbenz[f]indazole-4,9-quinone inhibited growth of c. parvum 78-100%, and at 50 micro m seven of the 23 derivatives inhibited growth > or = 90%. the activity of the fo ...200212461020
successful in vitro cultivation of cryptosporidium andersoni: evidence for the existence of novel extracellular stages in the life cycle and implications for the classification of cryptosporidium.the present study describes the complete development of all life cycle stages of cryptosporidium andersoni in the hct-8 cell line. the in vitro cultivation protocols were the same as those used for the successful growth of all life cycle stages of cryptosporidium parvum (int. j. parasitol. 31 (2001) 1048). under these culture conditions, c. andersoni grew and proliferated rapidly with the completion of the entire life cycle within 72h post-infection. the developmental stages of c. andersoni are ...200212464418
host adaptation and host-parasite co-evolution in cryptosporidium: implications for taxonomy and public health.to assess the genetic diversity and evolution of cryptosporidium parasites, the partial ssrrna, actin, and 70kda heat shock protein (hsp70) genes of 15 new cryptosporidium parasites were sequenced. sequence data were analysed together with those previously obtained from other cryptosporidium parasites (10 cryptosporidium spp. and eight cryptosporidium genotypes). results of this multi-locus genetic characterisation indicate that host adaptation is a general phenomenon in the genus cryptosporidiu ...200212464424
inhibitory effect of selenium on cryptosporidium parvum infection in vitro and in vivo.the anticryptosporidial effect of sodium selenite (selenium) was evaluated in a bovine fallopian tube epithelial (bfre) cell culture system and an immunosuppressed c57bl/6n adult mouse model. parasite numbers in cell culture were significantly reduced (p<0.01) following treatment with selenium (se) at concentrations of 6, 9, and 12 microm at 48 h postinoculation (pi) and at 1.5, 3, and 6 microm at 96 h pi. parasite reduction was greater than 50% at 48 h pi when 9 and 12 microm se was used, and a ...200212666840
comparison of in vitro cell culture and a mouse assay for measuring infectivity of cryptosporidium parvum.in vitro cell cultures were compared to neonatal mice for measuring the infectivity of five genotype 2 isolates of cryptosporidium parvum. oocyst doses were enumerated by flow cytometry and delivered to animals and cell monolayers by using standardized procedures. each dose of oocysts was inoculated into up to nine replicates of 9 to 12 mice or 6 to 10 cell culture wells. infections were detected by hematoxylin and eosin staining in cd-1 mice, by reverse transcriptase pcr in hct-8 and caco-2 cel ...200212147476
cryptosporidium andersoni from a danish cattle herd: identification and preliminary characterisation.in november 1997, cryptosporidium andersoni, for the first time, was isolated from a danish heifer. the isolate was characterised morphologically, molecularly, and furthermore inoculated into mice and one calf. data on the distribution of cryptosporidia in the herd of origin were obtained at two separate visits in december 1997 and april 1998. c. andersoni was detected in 27 (19.0%) of 142 cattle examined at the first visit, whereas c. parvum was found in six (4.2%). at the following visit 42 (2 ...200212072212
a multiplex allele specific polymerase chain reaction (mas-pcr) on the dihydrofolate reductase gene for the detection of cryptosporidium parvum genotypes 1 and 2.a multiplex allele specific polymerase chain reaction (mas-pcr) based on the cryptosporidium parvum dihydrofolate reductase (dhfr) gene sequence differentiates genotype 1 ('human') from 2 ('cattle') in a 1-step reaction. the mas-pcr was validated on a panel of 34 microscopically positive c. parvum faecal samples of human and animal origin in comparison with 2 published pcr-restriction fragment length polymorphism (rflp) methods targeting dhfr and the oocyst wall protein (cowp) genes. a validatio ...200212166518
prevalence of giardia and cryptosporidium and characterization of cryptosporidium spp. isolated from wildlife, human, and agricultural sources in the north saskatchewan river basin in alberta, canada.the environmental distribution of giardia spp. and cryptosporidium spp. is dependent upon human, agricultural, and wildlife sources. the significance of each source with regard to the presence of parasites in the environment is unknown. this 2-year study examined parasite prevalence in human sewage influent, wildlife, and agricultural sources associated with the north saskatchewan river basin in alberta, canada. fecal samples were collected from cow-calf, dairy, and hog operations in the watersh ...200212166680
serological detection of exposure to cryptosporidium parvum in cattle by elisa and its evaluation in relation to coprological tests.we evaluated serum examination as an alternative to fecal analysis for the diagnosis of exposure to cryptosporidium parvum in cattle. the accuracy of the serum elisa was compared to the combined results of concentration flotation microscopy and fecal enzyme immunoassay. the expected performance of the serum elisa at different levels of infection with c. parvum was evaluated using the predicative values positive and negative. optimal conditions for the serum elisa can be achieved by diluting the ...200212172810
pathogenesis of human and bovine cryptosporidium parvum in gnotobiotic pigs.to compare the pathogenesis of human genotype 1 (hug1) and bovine genotype 2 (bog2) cryptosporidium parvum, neonatal gnotobiotic pigs were given 1-10 hug1 or bog2 oocysts. the prepatent and patent periods were significantly longer for hug1 than for bog2 c. parvum (prepatent, 8.6 vs. 5.6 days; patent, 16.6 vs. 10.3 days). bog2-infected pigs developed significantly more severe disease than did hug1-infected pigs. bog2 parasites were seen microscopically throughout the intestines during the prepate ...200212195362
survival of cryptosporidium parvum oocysts recovered from experimentally contaminated oysters (ostrea edulis) and clams (tapes decussatus).samples of two species of shellfish that form part of the human food chain (the oyster ostrea edulis and the marine clam tapes decussatus) were experimentally contaminated with cryptosporidium parvum oocysts. changes in the viability of oocysts subsequently recovered from the shellfish were evaluated by means of an immunofluorescent antibody technique (ifat) and inclusion/exclusion of the fluorogenic vital dye propidium iodide. there was a sharp decrease in oocyst viability during the first 4 da ...200211936501
cryptosporidium virulence determinants--are we there yet?exposure to cryptosporidium parvum in healthy individuals results in transient infection that may be asymptomatic or can result in self-limited diarrhoea. in contrast, acquired immune deficiency syndrome patients with cryptosporidiosis can experience severe manifestations of disease. volunteer studies have demonstrated that as few as 10 oocysts can cause infection in otherwise healthy adults and that isolates from geographically diverse regions differ in infectivity and, perhaps, virulence. vari ...200211943224
specific bovine antibody response against a new recombinant cryptosporidium parvum antigen containing 4 zinc-finger motifs.a cryptosporidium parvum sporozoite and oocyst lambda gt11 cdna library was screened with a hyperimmune rabbit serum that was developed against insoluble fragments of ultrasonicated oocysts. a clone named cp22.4.1 encoding a protein of 231 amino acids with 4 zinc-finger domains characterized by a cys-x2-cys-x4-his-x4-cys motif was isolated and characterized. there was a complete match between the sequencing data of the coding region of cp22.4.1 and the corresponding gene at chromosomal level. cl ...200211949214
sources and species of cryptosporidium oocysts in the wachusett reservoir watershed.understanding the behavior of cryptosporidium oocysts in the environment is critical to developing improved watershed management practices for protection of the public from waterborne cryptosporidiosis. analytical methods of improved specificity and sensitivity are essential to this task. we developed a nested pcr-restriction fragment length polymorphism assay that allows detection of a single oocyst in environmental samples and differentiates the human pathogen cryptosporidium parvum from other ...200211823192
treatment with neurokinin-1 receptor antagonist reduces severity of inflammatory bowel disease induced by cryptosporidium parvum.inflammatory bowel disease (ibd) is a chronic, debilitating disorder of uncertain and perhaps multiple etiologies. it is believed to be due in part to disregulation of the immune system. neuroimmune interactions may be involved in induction or maintenance of ibd. in the present study, we examined the potential role of a neurotransmitter, substance p, in a mouse model of ibd. we found that binding sites for substance p, and more specifically, neurokinin-1 receptors, were upregulated in intestinal ...200211874873
role of murine intestinal intraepithelial lymphocytes and lamina propria lymphocytes against primary and challenge infections with cryptosporidium parvum.to investigate the role of intestinal lamina propria lymphocytes (lpl) and intraepithelial lymphocytes (iel) in controlling cryptosporidium parvum infection, changes in their phenotypes and functional properties were studied after induction of primary and challenge infections in immunocompetent mice. as shown by oocyst-shedding patterns, the challenge-infected group recovered more rapidly from infection than did the primary-infected group. in lpl, proportions of activated cd4+, cd25+, igg1+, iga ...200312760640
increase of th1 type cytokine mrna expression in peripheral blood lymphocytes of calves experimentally infected with cryptosporidium parvum.the expression of the messenger rna of interleukin-12 (il-12), interferon-gamma, interleukin-4, interleukin-6, and interleukin-10 was examined by reverse-transcriptase polymerase chain reaction in peripheral blood lymphocytes of calves that were orally inoculated with cryptosporidium parvum oocysts. in all of the calves, gene expression of interleukin-12, interleukin-6, and interferon-gamma was observed at delivery and this expression was repressed within the next 24h. in calves inoculated with ...200312719145
recovery and enumeration of cryptosporidium parvum from animal fecal matrices.accurate quantification of cryptosporidium parvum oocysts in animal fecal deposits on land is an essential starting point for estimating watershed c. parvum loads. due to the general poor performance and variable recovery efficiency of existing enumeration methods, protocols were devised based on initial dispersion of oocysts from feces by vortexing in 2 mm tetrasodium pyrophosphate, followed by immunomagnetic separation. the protocols were validated by using an internal control seed preparation ...200312732556
aids-associated diarrhea and wasting in northeast brazil is associated with subtherapeutic plasma levels of antiretroviral medications and with both bovine and human subtypes of cryptosporidium parvum.advanced hiv infection is frequently complicated by diarrhea, disruption of bowel structure and function, and malnutrition. resulting malabsorption of or pharmacokinetic changes in antiretroviral agents might lead to subtherapeutic drug dosing and treatment failure in individual patients, and could require dose adjustment and/or dietary supplements during periods of diarrheal illness. we determined the plasma levels of antiretroviral medications in patients that had already been started on medic ...200312807688
viability and infectivity of cryptosporidium parvum oocysts detected in river water in hokkaido, japan.the viability and infectivity of cryptosporidium parvum (c. parvum) oocysts, detected in water samples collected from river water in hokkaido, were investigated using severe combined immunodeficient (scid) mice. the water samples collected from september 27 through october 10, 2001 by filtration using cuno cartridge filters were purified and concentrated by the discontinuous centrifugal flotation method. from 1.2 x 10 (5) liters of the raw river water, approximately 2 x 10(4) oocysts were obtain ...200312808210
intra-isolate variation of cryptosporidium parvum small subunit ribosomal rna genes from human hosts in england.cryptosporidium parvum is a protozoan parasite responsible for a number of water-borne outbreaks of human gastrointestinal infection. the importance of this parasite for human health has led to several investigations into its epidemiology. in the present study, sequence and pcr-rflp analyses were performed on cloned ssu rrna genes from human and bovine c. parvum isolates. each cloned gene was assigned a genotype using asei restriction digestion profiles. although sequence heterogeneity was obser ...200312764612
influence of surface characteristics on the stability of cryptosporidium parvum oocysts.microelectrophoresis is a common technique for probing the surface chemistry of the cryptosporidium parvum oocyst. results of previous studies of the electrophoretic mobility of c. parvum oocysts in which microelectrophoresis was used are incongruent. in this work we demonstrated that capillary electrophoresis may also be used to probe the surface characteristics of c. parvum oocysts, and we related the surface chemistry of c. parvum oocysts to their stability in water. capillary electrophoresis ...200312839749
cyclooxygenase blockade and exogenous glutamine enhance sodium absorption in infected bovine ileum.we have previously shown that prostanoids inhibit electroneutral sodium absorption in cryptosporidium parvum-infected porcine ileum, whereas glutamine stimulates electroneutral sodium absorption. we postulated that glutamine would stimulate sodium absorption via a cyclooxygenase (cox)-dependent pathway. we tested this hypothesis in c. parvum-infected calves, which are the natural hosts of cryptosporidiosis. tissues from healthy and infected calves were studied in ussing chambers and analyzed via ...200312466144
comparison of tests for viable and infectious cryptosporidium parvum oocysts.the purpose of this study was to compare different assays for viable cryptosporidium parvum incubated in water at a temperature commonly found in the environment. c. parvum oocysts were stored in sterile water for 9 months at 15 degrees c. a sample was removed monthly and analyzed by five different assays to determine oocyst viability. mouse infection and cell culture showed that c. parvum oocysts remained viable and infectious when stored for 7 months at this temperature. fluorescence in situ h ...200312474036
population structures and the role of genetic exchange in the zoonotic pathogen cryptosporidium parvum.apicomplexan protozoan parasites include some of the most globally important human and animal pathogens, all of which have obligatory sexual cycles in their definitive hosts. despite their importance and the relevance of understanding the population genetic structure and role of genetic exchange in generating diversity, population genetic analysis has largely been restricted to plasmodium spp. and toxoplasma gondii. these species show a considerable diversity of population structure suggesting d ...200312664161
cryptosporidium parvum and giardia intestinalis in calf diarrhoea in sweden.the objective of this study conducted in 75 herds was to investigate the presence and significance of criptosporidium parvum and giardia intestinalis in swedish dairy calves in comparison with rotavirus, coronavirus and escherichia coli k99+. the farmers were asked to collect faecal samples from each heifer calf that had diarrhoea between birth and 90 days of age, and also from a healthy calf of the same age. in total, 270 samples were collected and analysed. c. parvum, either alone or together ...200315074627
rapid displacement of cryptosporidium parvum type 1 by type 2 in mixed infections in piglets.genotypes 1 and 2 of cryptosporidium parvum are the primary types associated with infections in humans, with type 1 being by far the predominant genotype. the frequency of mixed infection with both genotypes in humans is relatively rare, while type 1, which experimentally infects other mammals, has been found to naturally infect almost exclusively humans. one possible explanation for the absence of type 1 in other mammals and the low frequency of mixed infections in humans is the inability of ty ...200314500498
long-term study of cryptosporidium prevalence on a lowland farm in the united kingdom.a longitudinal sample survey testing for cryptosporidium in livestock and small wild mammals conducted over 6 years (1992-1997) on a lowland farm in warwickshire, england, has shown the parasite to be endemic and persistently present in all mammalian categories. faecal samples were taken throughout the year and oocysts concentrated by a formal ether sedimentation method for detection by immunofluorescence staining using a commercially available genus specific monoclonal antibody. cryptosporidium ...200314519315
comparison of method 1623 and cell culture-pcr for detection of cryptosporidium spp. in source waters.analysis of cryptosporidium occurrence in six watersheds by method 1623 and the integrated cell culture-pcr (cc-pcr) technique provided an opportunity to evaluate these two methods. the average recovery efficiencies were 58.5% for the cc-pcr technique and 72% for method 1623, but the values were not significantly different (p = 0.06). cryptosporidium oocysts were detected in 60 of 593 samples (10.1%) by method 1623. infectious oocysts were detected in 22 of 560 samples (3.9%) by the cc-pcr techn ...200312571019
multilocus genotyping of cryptosporidium parvum type 2: population genetics and sub-structuring.cryptosporidium parvum is an intracellular protozoan parasite that infects the gastrointestinal tract of humans and other mammals. it has significant economic importance as a pathogen of livestock and, as there is no effective treatment or vaccine available, understanding transmission routes and identifying sources of infection is key to preventing future outbreaks and controlling this disease. in this study we have determined the multilocus genotype (mlg) of 240 c. parvum type 2 (bovine) isolat ...200314522184
contamination of atlantic coast commercial shellfish with cryptosporidium.shellfish (oysters and/or clams) were obtained from 37 commercial harvesting sites in 13 atlantic coast states from maine to florida and one site in new brunswick, canada. gill washings from each of 25 shellfish at each site were examined by immunofluorescence microscopy (ifa) for oocysts of cryptosporidium. gill washings from another 25 shellfish at each site were grouped into five pools of five shellfish each. dna from each pool was utilized for pcr and genotyping. oocysts were found in 3.7% o ...200312489014
utility of the cryptosporidium oocyst wall protein (cowp) gene in a nested pcr approach for detection infection in cattle.a preliminary molecular epidemiological study was carried out to investigate the utility of the cryptosporidium oocyst wall protein (cowp) gene in the detection of cryptosporidium oocysts in fecal samples. a nested polymerase chain reaction (pcr) approach using cowp gene primers was adopted for this purpose. fecal samples were spiked with each of 1, 10, and 100 oocysts of c. parvum, four samples for each number, and the dna was extracted from each sample using a glassbead method. the presence of ...200312531291
foot and mouth disease and cryptosporidiosis: possible interaction between two emerging infectious diseases.during 2001, a large outbreak of foot and mouth disease occurred in the united kingdom, during which approximately 2,030 confirmed cases of the disease were reported, >6 million animals were slaughtered, and strict restrictions on access to the countryside were imposed. we report a dramatic decline in the reported incidence of human cryptosporidiosis in northwest england during weeks 13-38 in 2001, compared with the previous 11 years. this decline coincided with the period of foot and mouth rest ...200312533291
identification and genetic characterisation of giardia and cryptosporidium strains in humans and dairy cattle in the waikato region of new zealand.giardia intestinalis and cryptosporidium parvum are commonly acquired waterborne parasites but little is known about their transmission cycles with regard to humans and animals. faecal samples were collected over two time periods within the waikato region of new zealand from dairy cattle and humans and all positive isolates were genotyped. of the 724 faecal specimens examined (354 cows, 304 calves and 66 humans), 16 cows, 32 calves and 5 humans were positive for g. intestinalis. phylogenetic gro ...200312639000
detection of cryptosporidium parvum and giardia lamblia carried by synanthropic flies by combined fluorescent in situ hybridization and a monoclonal antibody.wild-caught synanthropic flies were tested for the presence of cryptosporidium parvum and giardia lamblia on their exoskeletons and in their digestive tracks by fluorescent in situ hybridization and fluorescein isothiocyanate (fitc)-conjugated monoclonal antibody (mab) against cryptosporidium and giardia cell wall epitopes. the levels of c. parvum were positively correlated with the levels of g. lamblia, indicating a common source of contamination. the majority of oocysts and cysts were potentia ...200312641416
pathogenicity of cryptosporidium parvum--evaluation of an animal infection model.with the intention of developing a standardised method for assessment of pathogenicity of cryptosporidium parvum, the cpb-0 isolate was studied by propagation in 1-day-old calves followed by inoculation into specific pathogen free (spf) piglets. the experiment was repeated. diarrhoea and shedding of oocysts were seen in all animals infected with the cpb-0 isolate. clinical signs included depression, inappetence, vomiting (exclusively in the piglets), and death. histological examination at 17 and ...200312651216
characterization of cryptosporidium meleagridis of human origin passaged through different host species.cryptosporidium meleagridis, a protozoon first observed in turkeys, has been linked by several investigators to cryptosporidiosis in humans. c. meleagridis is the only known cryptosporidium species that infects both avian and mammalian species. we describe the successful propagation of c. meleagridis (isolate tu1867), originally purified from a patient with diarrhea, in laboratory animals including chickens, mice, piglets, and calves. tu1867 was readily transmitted from one animal host to anothe ...200312654797
seasonal change in the number of cryptosporidium parvum oocysts in water samples from the rivers in hokkaido, japan, detected by the ferric sulfate flocculation method.an epidemiological study was carried out in natural water supplies of hokkaido, one of the largest dairy prefectures in japan. to investigate the prevalence of cryptosporidium parvum (c. parvum) oocysts water samples were collected from three rivers in the eastern area of hokkaido from august 1999 to october 2001, and c. parvum oocysts were collected and purified by the ferric sulfate flocculation method. the oocysts were detected using the immunofluorescent assay test (ifat) and 4', 6-diamidino ...200312576717
cryptosporidium infection of cattle in the tokachi district, hokkaido.the prevalence of cryptosporidium infection was examined in 480 healthy cattle (0-39 months old) in the tokachi district in hokkaido during the period from june to september in 2000 and from june to july in 2001. c. parvum oocysts were detected in 6 of 50 cattle (0-2 months old) in 2001; while c. muris was detected in 2 of 56 cattle (6-8 months old) in 2001, in 1 of 15 cattle (9-11 months old) in 2001, in 1 of 88 cattle (15-17 months old) in 2000, in 4 of 89 cattle (18-21 months old) in 2000 and ...200312576718
efficacy of glutaraldehyde disinfectant against cryptosporidium parvum in the presence of various organic soils.the opportunistic protozoan cryptosporidium parvum is highly resistant to disinfectants, including those specifically used for processing reused medical equipment in hospitals. c. parvum oocysts were dried onto glass and steel grooved penicylinders and challenged with 2.5% glutaraldehyde solution in the presence of 3 types of soil with exposures at 10 min, 90 min, and 10 h. the influence of organic soils on disinfection was measured with 5% fetal bovine serum (fbs), 10% fbs, and 5 mg mucin/ml. a ...200312607746
cryptosporidiosis associated with animal contacts.transmission of cryptosporidium sp. within the general public was studied. we were looking for a possible risk of infection associated with animal contacts. investigation of the animal contacts of affected individuals led to the formulation of the hypothesis that animals are a source of cryptosporidiosis. the research was done in the region of ljubljana, an area with 587,000 inhabitants during a period of three years. stool specimens of 338 persons with acute enteric diseases were positive for c ...200312674690
molecular analysis of the 18s rrna gene of cryptosporidium parasites from patients with or without human immunodeficiency virus infections living in kenya, malawi, brazil, the united kingdom, and vietnam.an 840-bp fragment of the 18s rrna gene was used to identify cryptosporidium spp. recovered from human immunodeficiency virus (hiv)-infected and -uninfected patients from kenya, malawi, brazil, the united kingdom, and vietnam. initial identification was by ziehl-neelsen acid-fast staining. confirmation was by nested pcr, targeting the most polymorphic region of the 18s rrna gene. genotyping was by restriction endonuclease digestion of the pcr product followed by nucleotide sequencing. among 63 i ...200312682130
recombinant bovine herpesvirus-1 expressing p23 protein of cryptosporidium parvum induces neutralizing antibodies in rabbits.in order to develop a vaccine against cryptosporidiosis in cattle, we constructed a recombinant bovine herpesvirus-1 (bhv-1) expressing an immunodominant surface protein, p23, of cryptosporidium parvum sporozoites. in the recombinant virus, the p23 gene under the control of a cag promoter and a gene coding for an enhanced green fluorescent protein were integrated into the gg gene of bhv-1. despite a low frequency of homologous recombination, cloning of the recombinants was easy because of the sp ...200312760641
a novel multiplex polymerase chain reaction approach for detection of four human infective cryptosporidium isolates: cryptosporidium parvum, types h and c, cryptosporidium canis, and cryptosporidium felis in fecal and soil samples.a nested multiplex polymerase chain reaction (pcr) approach was adopted for the simultaneous detection of 4 human infective genotypes of the protozoan parasite cryptosporidium. specific pcr primers were designed for the heat shock protein 70 gene of 2 genotypes of cryptosporidium parvum (human and bovine types), cryptosporidium canis, and cryptosporidium felis. these 4 genotypes have all been found in human fecal samples. the primers amplified dna fragments of specific sizes, each representing a ...200312735348
cryptosporidium and host resistance: historical perspective and some novel approaches.cryptosporidium parvum is recognized as a major cause of diarrheal disease in neonatal bovine calves. in addition, this protozoan parasite has emerged as an important cause of disease in both immunocompromised and immunocompetent humans. despite years of research, no consistently effective means of prevention or treatment are readily available for cryptosporidiosis in any species. infection through ingestion of contaminated water has been widely documented; c. parvum was reported to be responsib ...200312885209
improved quantitative estimates of low environmental loading and sporadic periparturient shedding of cryptosporidium parvum in adult beef cattle.our primary goal was to generate an accurate estimate of the daily environmental loading rate of cryptosporidium parvum oocysts for adult beef cattle, using immunomagnetic separation coupled with direct immunofluorescence microscopy for a highly sensitive diagnostic assay. an additional goal was to measure the prevalence and intensity of fecal shedding of c. parvum oocysts in pre- and postparturient cows as an indicator of their potential to infect young calves. this diagnostic method could dete ...200312902248
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