| increased susceptibility of beta7-integrin-deficient neonatal mice in the early stage of cryptosporidium parvum infection. | numerous inflammatory cells are recruited in response to cryptosporidium parvum infection. these cells include interferon gamma-producing t lymphocytes, which are of major importance for the resolution of infection. here, we show that beta7 integrin is not essential for the control of infection in mice but that beta7-deficient neonatal mice are more susceptible during the early stages of infection. | 2004 | 15155674 |
| genotyping of cryptosporidium parvum with microsatellite markers. | recent outbreaks of cryptosporidiosis caused by cryptosporidium parvum in the united states and other countries, as well as the emergence of cryptosporidiosis as a frequent cause of morbidity and mortality in immunodeficient individuals, have raised the interest of the research community in this parasite. the genus cryptosporidium, phylum apicomplexa, comprises an undefined number of species, of which only c. parvum is of public health concern. cryptosporidiosis is contracted through the ingesti ... | 2004 | 15156029 |
| immunomagnetic separation of pathogenic organisms from environmental matrices. | one of the most difficult challenges in the analysis of environmental samples is to separate the organism of interest from a sample that is high in background debris. immunomagnetic separation (ims) is one technique that has been developed to accomplish this in a rapid and reliable assay. immunomagnetic separation (or biomagnetic separation) involves a superparamag-netic, monodispersed, polystyrene microsphere that is coated with a specific ligand. when added to a heterogeneous target suspension ... | 2004 | 15156030 |
| equine cryptosporidium parvum infections in western poland. | a total of 564 fecal specimens from 318 horses used for recreational riding, child hippotherapy, and racing at ten commercial and government-run stables in western poland were tested for cryptosporidium parvum oocysts by microscopic examination of ziehl-neelsen stained smears, enzyme immunoassay, and combined direct immunofluorescent antibody and fluorescent in situ hybridization. also, seven stool specimens from five personnel who had repeated contact with these horses were tested for c. parvum ... | 2004 | 15156396 |
| complete development of cryptosporidium parvum in host cell-free culture. | the present study describes the complete in vitro development of cryptosporidium parvum (cattle genotype) in rpmi-1640 maintenance medium devoid of host cells. this represents the first report in which cryptosporidium is shown to multiply, develop and complete its life cycle without the need for host cells. furthermore, cultivation of cryptosporidium in diphasic medium consisting of a coagulated new born calf serum base overlaid with maintenance medium greatly increased the total number of crypt ... | 2004 | 15157759 |
| complete development of cryptosporidium parvum in rabbit chondrocytes (veli cells). | cryptosporidium parvum is an intracellular protozoan parasite that causes severe infection in humans and animals. the great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. the aim of this study was to demonstrate that c. parvum can complete its entire life cycle-from sporozoite to infective oocyst-in veli cells (a line derived from primary culture of rabbit auricular chondrocytes). successful infections w ... | 2004 | 15158190 |
| cryptosporidium parvum attachment to and internalization by human biliary epithelia in vitro: a morphologic study. | to explore the mechanisms by which cryptosporidium parvum infects epithelial cells, we performed a detailed morphological study by serial electron microscopy to assess attachment to and internalization of biliary epithelial cells by c. parvum in an in vitro model of human biliary cryptosporidiosis. when c. parvum sporozoites initially attach to the host cell membrane, the rhoptry of the sporozoite extends to the attachment site; both micronemes and dense granules are recruited to the apical comp ... | 2004 | 15165040 |
| detection of cryptosporidium antibodies in sera and oral fluids using multiplex bead assay. | for the first time, a multiplex bead assay (mba) was used to assay oral fluid and serum specimens for immunoglobulin g (igg) antibodies to specific cryptosporidium parvum antigens that were coupled to polystyrene beads. recombinant c. parvum 17- and 27-kda antigens (r17 and r27, respectively) both linked with glutathione-s-transferase (gst) fusion proteins, native 17-kda antigen, and gst alone were each coupled to microspheres that could be differentiated based on variable amounts of internally ... | 2004 | 15165066 |
| the humoral and cellular immune responses in mice induced by dna vaccine expressing the sporozoite surface protein of cryptosporidium parvum. | cryptosporidiosis, a protozoan disease, is caused by cryptosporidium parvum in animals and humans. to study the humoral and cellular immune responses induced by dna vaccine expressing the sporozoite surface protein, cp15/60, of cryptosporidium parvum, the recombinant plasmid containing the cp15/60 gene was injected into tibialis a interior muscle of balb/c mice. the mice were subsequently given booster doses twice at 3-week intervals. the humoral and cellular immune responses were detected at di ... | 2004 | 15169612 |
| cryptosporidium parvum: effect of multi-drug reversing agents on the expression and function of atp-binding cassette transporters. | in the present study, the gene expression of three multidrug resistance (mdr) and resistance-associated protein (mrp) transport proteins or efflux pumps was characterized and the phenotypic evidence for such pumps was demonstrated in cultured madin-darby canine kidney (mdck) cells. a gradient for the fluorescent probe calcein was established between parasite and host cell suggestive of a parasite extrusion pump at the parasite-host interface. this gradient was decreased in a glucose-free medium ... | 2004 | 15172220 |
| [cell response of rat liver parenchyma to the infection by the intestinal protozoan pathogen cryptosporidium parvum (sporozoa, coccidia)]. | in the present work, the authors' previous studies of a "distant action", exerted by an intestinal pathogen (cryptosporidium parvum) on the liver of experimentally infected baby rats, were extended to include shifts in the quantity of glycogen, protein and nuclear dna in the host liver at different degrees of infection. one of the outcomes of this work is the discovery of a very quick response of hepatocytes and a high sensitivity of rat liver to parasitic invasion even at a weak intensity of in ... | 2004 | 15174350 |
| mechanisms underlying the evolution and maintenance of functionally heterogeneous 18s rrna genes in apicomplexans. | in many species of the protist phylum apicomplexa, ribosomal rna (rrna) gene copies are structurally and functionally heterogeneous, owing to distinct requirements for rrna-expression patterns at different developmental stages. the genomic mechanisms underlying the maintenance of this system over long-term evolutionary history are unclear. therefore, the aim of this study was to investigate what processes underlie the long-term evolution of apicomplexan 18s genes in representative species. the r ... | 2004 | 15175411 |
| prevalence and age-related variation of cryptosporidium species and genotypes in dairy calves. | fifteen dairy farms in seven states on the east coast of the us were each visited on two consecutive years to determinate the prevalence of cryptosporidium species in pre-weaned (5 days to 2 months) and post-weaned calves (3-11 months), respectively. after each of 971 fecal specimens collected directly from each calf was sieved and subjected to density gradient centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy, and polymerase chain ... | 2004 | 15177715 |
| genotype and animal infectivity of a human isolate of cryptosporidium parvum in the republic of korea. | cryptosporidium parvum oocysts were isolated from a child suffering from acute gastroenteritis and successfully passaged in a calf and mice (designated hereafter snu-h1) in the republic of korea; its molecular genotype has been analyzed. the gag microsatellite region was amplified by a polymerase chain reaction (pcr), with a 238 base pair product, which is commonly displayed in c. parvum. the isolate was shown to be a mixture of the genotypes 1 (anthroponotic) and 2 (zoonotic). to study its infe ... | 2004 | 15181350 |
| cryptosporidium parvum and giardia lamblia recovered from flies on a cattle farm and in a landfill. | filth flies associated with a cattle barn and a municipal landfill were tested positive by combined immunofluorescent antibody and fluorescent in situ hybridization for cryptosporidium parvum and giardia lamblia on their exoskeletons and in their guts. more pathogens were carried by flies from the cattle barn than from the landfill; 81% of c. parvum and 84% of g. lamblia pathogens were presumptively viable. | 2004 | 15184182 |
| a multidomain adhesion protein family expressed in plasmodium falciparum is essential for transmission to the mosquito. | the recent sequencing of several apicomplexan genomes has provided the opportunity to characterize novel antigens essential for the parasite life cycle that might lead to the development of new diagnostic and therapeutic markers. here we have screened the plasmodium falciparum genome sequence for genes encoding extracellular multidomain putative adhesive proteins. three of these identified genes, named pfccp1, pfccp2, and pfccp3, have multiple adhesive modules including a common limulus coagulat ... | 2004 | 15184503 |
| predictive population dose-response assessment for cryptosporidium parvum: infection endpoint. | data validation of safe doses of pathogens in drinking water consistent with public health goals is not possible due to the number of subjects that would be needed at each dose. because of this problem, together with the difficulty in extrapolating pathogenic response between species, and the ability of microbes to adapt rapidly, confidence-level-dependent assessments of cryptosporidium parvum dose-response have been developed. however, these results, even on a relative basis, are dependent on c ... | 2004 | 15192860 |
| emerging waterborne pathogens: can we kill them all? | the rapid emergence of cryptosporidium parvum and escherichia coli 0157:h7 have created a threat to the drinking water industry and there is a growing need to develop a strategy for recognizing potential emerging waterborne pathogens. globalization of trade, changing population demographics and changes in treatment technology have been driving factors in the emergence of these new pathogens. an understanding of disinfectant action and microbial resistance to treatment processes is needed to bett ... | 2004 | 15193323 |
| kinetics of spleen and peyer's patch lymphocyte populations during gut parasite clearing in cryptosporidium parvum infected suckling mice. | data from experimental and human cryptosporidiosis have established a major role of specific immunity in the control of cryptosporidium parvum infection. in this work, alterations in spleen and peyer's patch (pp) lymphocytes were investigated in the course of a spontaneously resolutive gut cryptosporidiosis in four-day-old suckling nmri mice infected with either 4 x 10(5) or 30 viable oocysts. oocysts from entire small intestines, and spleen and pp lymphocytes were examined using flow cytometry ... | 2004 | 15198640 |
| sporadic cryptosporidiosis, north cumbria, england, 1996-2000. | risk factors for sporadic cryptosporidiosis were determined in 152 patients and 466 unmatched controls who resided in two local government districts in north cumbria, north west england, from march 1, 1996, to february 29, 2000. risk was associated with the usual daily volume of cold unboiled tap water drunk (odds ratio [or] 1.40, 95% confidence intervals [ci] 1.14 to 1.71 per pint consumed per day [p = 0.001]) and short visits to farms (or 2.02, 95% ci 1.04 to 3.90, p = 0.04). fifty-six (84%) o ... | 2004 | 15207050 |
| a generic sandwich-type biosensor with nanomolar detection limits. | a quantitative and highly sensitive, yet simple and rapid, biosensor system was developed for the detection of nucleic acid sequences that can also be adapted to the detection of antigens. a dipstick-type biosensor with liposome amplification, based on a sandwich assay format with optical detection, was combined with a simple coupling reaction that allows the transformation of the generic biosensor components to target specific ones by a mere incubation step. this biosensor platform system was d ... | 2004 | 15214421 |
| human waterborne parasites in zebra mussels ( dreissena polymorpha) from the shannon river drainage area, ireland. | zebra mussels ( dreissena polymorpha) from throughout the shannon river drainage area in ireland were tested for the anthropozoonotic waterborne parasites cryptosporidium parvum, giardia lamblia, encephalitozoon intestinalis, e. hellem, and enterocytozoon bieneusi, by the multiplexed combined direct immunofluorescent antibody and fluorescent in situ hybridization method, and pcr. parasite transmission stages were found at 75% of sites, with the highest mean concentration of 16, nine, and eight c ... | 2004 | 15221465 |
| uv disinfection of indigenous aerobic spores: implications for uv reactor validation in unfiltered waters. | conventional validation testing of uv reactors use cultured microorganisms spiked into test water flowing through a reactor. these tests are limited by the microbe titer it is possible to grow, thus limiting the size of the reactor it is possible to validate. the goal of this study was to examine the uv inactivation of indigenous aerobic spores naturally occurring in raw/unfiltered water supplies and to assess their use as an alternative indicator for validation testing of uv reactor performance ... | 2004 | 15223284 |
| immunolocalization of an enterotoxic glycoprotein exoantigen on the secretory organelles of cryptosporidium parvum sporozoites. | in this study, the fine ultrastructures of the secretory organelles of c. parvum sporozoites were demonstrated using transmission electron microscopy (tem). meanwhile, a previously identified enterotoxic 18-20 kda copro-antigen (18-20 kda cca), associated with cryptosporidiosis in both human and calves, was isolated and immunolocalized on c. parvum sporozoites. using immunoelectron microscopy and anti-18-20 kda monospecific antibody demonstrated marked existence of the 18-20 kda cca on the apica ... | 2004 | 15224585 |
| overland and near-surface transport of cryptosporidium parvum from vegetated and nonvegetated surfaces. | understanding microbial pathogen transport patterns in overland flow is important for developing best management practices for limiting microbial transport to water resources. knowledge about the effectiveness of vegetative filter strips (vfs) to reduce pathogen transport from livestock confinement areas is limited. in this study, overland and near-surface transport of cryptosporidium parvum has been investigated. effects of land slopes, vegetation, and rainfall intensities on oocyst transport w ... | 2004 | 15224935 |
| infection with cryptosporidium hominis and reinfection with cryptosporidium parvum in a transplanted ileum. | a transplanted ileum was found to be infected with cryptosporidium hominis 6 days after transplantation. although the infection resolved, the ileum was later found to be infected with cryptosporidium parvum. the presence of the parasite was not always correlated with diarrhea. no other gastrointestinal symptom was ever detected. treatment with azithromycin and paromomycin apparently failed. | 2004 | 15233648 |
| characterization and potential use of a cryptosporidium parvum virus (cpv) antigen for detecting c. parvum oocysts. | the purpose of this study was to characterize the viral symbiont (cpv) of cryptosporidium parvum sporozoites and evaluate the cpv capsid protein (cpv40) as a target for sensitive detection of the parasite. recombinant cpv40 was produced in escherichia coli, purified by affinity chromatography, and used to prepare polyclonal rabbit sera specific for the viral capsid protein. anti-rcpv40 recognized a 40 kda and a 30 kda protein in c. parvum oocysts and appeared to localize to the apical end of the ... | 2004 | 15234516 |
| host-adapted cryptosporidium spp. in canada geese (branta canadensis). | the prevalence and distribution of cryptosporidium spp. in the fecal droppings of the free-living waterfowl canada geese were examined at 13 sites in ohio and illinois. on the basis of the analysis of the small-subunit rrna gene by pcr, followed by restriction fragment length polymorphism analysis and dna sequencing, 49 (23.4%) of 209 fecal specimens collected from 10 sites (76.9%) were positive for cryptosporidium spp. the following five cryptosporidium species and genotypes were identified: cr ... | 2004 | 15240303 |
| genotyping of cryptosporidium isolates from chamelea gallina clams in italy. | chamelea gallina clams collected from the mouths of rivers along the adriatic sea (central italy) were found to harbor cryptosporidium parvum (genotype 2), which is the lineage involved in zoonotic transmission. the clams were collected from the mouths of rivers near whose banks ruminants are brought to graze. this paper reports the environmental spread of c. parvum in italy and highlights the fact that genotyping of seaborne cryptosporidium isolates is a powerful tool with which to investigate ... | 2004 | 15240321 |
| evaluation of cryptosporidium parvum oocyst recovery efficiencies from various filtration cartridges by electrochemiluminescence assays. | to evaluate four types of filtration cartridges for their capacities, efficiency for capture and release of cryptosporidium parvum oocysts for detection. | 2004 | 15242454 |
| levels of zoonotic agents in british livestock manures. | to determine the prevalence and levels of zoonotic agents in livestock wastes. | 2004 | 15242463 |
| detection and genotyping of entamoeba histolytica, entamoeba dispar, giardia lamblia, and cryptosporidium parvum by oligonucleotide microarray. | entamoeba histolytica, giardia lamblia, and cryptosporidium parvum are the most frequently identified protozoan parasites causing waterborne disease outbreaks. the morbidity and mortality associated with these intestinal parasitic infections warrant the development of rapid and accurate detection and genotyping methods to aid public health efforts aimed at preventing and controlling outbreaks. in this study, we describe the development of an oligonucleotide microarray capable of detecting and di ... | 2004 | 15243091 |
| [chronic diarrhea induced by cryptosporidium parvum in an immunocompetent adult: difficult diagnosis and unsatisfactory treatment]. | | 2004 | 15243331 |
| genomics meets transgenics in search of the elusive cryptosporidium drug target. | cryptosporidium is an important pathogen of humans, and a challenging model for the laboratory. the parasite genome sequence, accessible through a comprehensive database, now provides exciting opportunities for urgently needed advances. comparative genomics, combined with the genetic system in the related parasite toxoplasma gondii, outlines a detailed cryptosporidium parvum metabolic map and facilitates cell biological analyses. new targets for cryptosporidium drug and vaccine development can b ... | 2004 | 15246316 |
| release of cryptosporidium and giardia from dairy cattle manure: physical factors. | various physical factors affecting the release rate of naturally occurring cryptosporidium parvum oocysts and giardia duodenalis cysts from dairy manure disks to sprinkled water were studied. the investigated factors included temperature (5 or 23 degrees c), manure type (calf manure, a 50% calf and 50% cow manure mixture, and a 10% calf and 90% cow manure mixture), and water application method (mist or drip) and flow rate. effluent concentrations of manure and (oo)cysts were always several order ... | 2004 | 15254132 |
| adhesion of cryptosporidium parvum and giardia lamblia to solid surfaces: the role of surface charge and hydrophobicity. | adhesion of cryptosporidium parvum and giardia lamblia to four materials of different surface charge and hydrophobicity was investigated. glass beads were used with and without three polymer coatings: aminosilines (a0750), fluorosilines (t2494), an amino cationic polymer. surface charge density and hydrophobicity of the beads were characterized by measuring the zeta potential (zp) and the contact angle, respectively. adhesion was derived from batch experiments where negatively charged (oo)cysts ... | 2004 | 15261066 |
| molecular epidemiology of giardia and cryptosporidium infections in dairy calves originating from three sources in western australia. | a longitudinal study was undertaken to determine the spread of naturally acquired giardia and cryptosporidium in dairy cattle in western australia. samples were collected weekly from birth to weaning, and only calves that were sampled four or more times were included in the analysis. it was found that calves rapidly acquire infections with cryptosporidium parvum and giardia, with cryptosporidium being the first to appear within 1-3 weeks after birth whereas giardia was most prevalent in calves 4 ... | 2004 | 15265565 |
| prevalence of cryptosporidium for foreign workers in taiwan. | | 2004 | 15267060 |
| characterization of a mitochondrion-like organelle in cryptosporidium parvum. | cryptosporidium parvum is a protozoan parasite that causes widespread diarrhoeal disease in humans and other animals and is responsible for large waterborne outbreaks of cryptosporidiosis. unlike many organisms belonging to the phylum apicomplexa, such as plasmodium spp. and toxoplasma gondii, there is no clinically proven drug treatment against this parasite. aspects of the basic biology of c. parvum remain poorly understood, including a detailed knowledge of key metabolic pathways, its genome ... | 2004 | 15267107 |
| cryptosporidium parvum imp dehydrogenase: identification of functional, structural, and dynamic properties that can be exploited for drug design. | the protozoan parasite cryptosporidium parvum causes severe enteritis with substantial morbidity and mortality among aids patients and young children. no fully effective treatment is available. c. parvum relies on inosine 5'-monophosphate dehydrogenase (impdh) to produce guanine nucleotides and is highly susceptible to impdh inhibition. furthermore, c. parvum obtained its impdh gene by lateral transfer from an epsilon-proteobacterium, suggesting that the parasite enzyme might have very different ... | 2004 | 15269207 |
| [microbiological risk associated with consumption of drinking water in developed countries]. | this article provides an overview of the waterborne disease (wbd) issue in developed countries (usa, canada, uk and other european countries). the factors involved in the epidemiology of waterborne infection are analysed (microbial, social, environmental, etc.) and the main wbd etiological agents are described with particular interest to emerging pathogens (i.e. cryptosporidium parvum, legionella and calicivirus). microorganism characteristics related to water contamination risk are described an ... | 2004 | 15269459 |
| filter-based microfluidic device as a platform for immunofluorescent assay of microbial cells. | a filter-based microfluidic device was combined with immunofluorescent labeling as a platform to rapidly detect microbial cells. the coin-sized device consisted of micro-chambers, micro-channels and filter weirs (gap = 1-2 microm), and was demonstrated to effectively trap and concentrate microbial cells (i.e., cryptosporidium parvum and giardia lamblia), which were larger in size than the weir gap. after sample injection, a staining solution containing fluorescently-labeled antibodies was contin ... | 2004 | 15269801 |
| point prevalence of cryptosporidium, cyclospora, and isospora infections in patients being evaluated for diarrhea. | from march to september 2001, 315 specimens from "nonrepeat" patients that were submitted for ova and parasite examination were stained using the kinyoun modified acid-fast stain to detect the intestinal coccidians. four patients (1.3%) were infected with coccidians, 2 with cryptosporidium parvum and 2 with cyclospora cayetanensis. no infections with isospora belli were detected. in comparison, 15 patients (4.8%) had infections with one or more intestinal parasites detected by routine trichrome ... | 2004 | 15272527 |
| zoonotic transmission of cryptosporidium parvum: implications for water-borne cryptosporidiosis. | the emergence of cryptosporidium parvum-associated cryptosporidiosis as a worldwide zoonosis has stimulated interest in the modes of pathogen transmission. here, thaddeus graczyk, ronald fayer and michael cranfield discuss the complex epidemiology of c. parvum, emphasizing the crosstransmission potential of the pathogen, mechanical vectors involved in water-borne transmission of the oocysts, and factors contributing to contamination of pristine waters with cryptosporidium. they also outline the ... | 1997 | 15275048 |
| rhoptry organelles of the apicomplexa: their role in host cell invasion and intracellular survival. | members of the phylum apicomplexa are obligate intracellular parasites that invade erythrocytes, lymphocytes, macrophages or cells of the alimentary canal in various vertebrate species. organelles within the apical complex of invasive stages facilitate host cell invasion. parasites in this phylum cause some of the most debilitating diseases of medical and veterinary importance. these include malaria, toxoplasmosis, babesiosis, theileriosis (east coast fever), and coccidiosis in poultry and lives ... | 1996 | 15275182 |
| water-borne cryptosporidium: a perspective from the usa. | in the usa, cryptosporidium parvum has attracted considerable interest due to recent outbreaks of cryptosporidiosis attributed to water supplies contaminated with oocysts. because of its unprecedented magnitude, the outbreak which occurred in milwaukee in april 1993 was widely publicized and studied. information collected during this and other recent outbreaks is being evaluated by regulatory agencies and the water industry with the aim of designing cost-effective measures that will reduce the r ... | 1996 | 15275195 |
| the pathogenesis of cryptosporidiosis. | human infection with the protozoan parasite cryptosporidium parvum has recently emerged as a global public health problem. although infection is unrelenting in patients classically regarded as immunocompromised, a tantalizing observation is that infection with this parasite results in both acute self-limited as well as chronic diarrhea in young children. recent data have begun to elucidate multiple potential mechanisms by which parasitism of the intestinal epithelium may yield an intestinal secr ... | 1996 | 15275201 |
| cryptosporidium and cryptosporidiosis. | the tiny, iodine- and chlorine-resistant protozoan oocysts of cryptosporidium parvum, long recognized by veterinarians, have become increasingly noted as a cause of watery diarrhea in developed and developing countries throughout the world. for immunocompromised patients, particularly those with aids, this diarrhea can be severe and life-threatening. clovis martins and richard guerrant here discuss the increasing recognition of this important pathogen in immunocompetent patients as well, and out ... | 1995 | 15275395 |
| a non-biological surrogate for sequential disinfection processes. | an evaluation of fluorescent yg-microspheres (polysciences inc.) was performed to simulate cryptosporidium parvum (c. parvum) oocysts inactivation in treatment systems that utilize multiple disinfectants. experiments were conducted in batch reactors that included an ozone primary stage and a secondary free chlorine treatment stage. a flow cytometer was used to track changes in the fluorescence intensity distribution due to exposure to the chemical disinfectant. microsphere 'survival ratios' (n/n ... | 2004 | 15276757 |
| improvement of recoveries for the determination of protozoa cryptosporidium and giardia in water using method 1623. | the u.s. environmental protection agency has developed method 1623 for simultaneous detection of cryptosporidium oocysts and giardia cysts in water. method 1623 includes four major steps: filtration, immunomagnetic separation (ims), fluorescent antibody (fa) staining and microscopic examination. it was noted that the recovery levels following ims-fa and fa staining were high, averaging more than 92.0% and 89.0% for c. parvum oocysts and g. lamblia cysts, respectively. in contrast, when the filtr ... | 2004 | 15279936 |
| quantitative and qualitative comparison of density-based purification methods for detection of cryptosporidium oocysts in turbid environmental matrices. | purification methods for cryptosporidium oocysts are usually selected on the basis of recovery yield, but the amount of particulate debris in environmental matrices could limit efficiency of oocyst detection by microscopic examination or pcr detection. previous studies have shown that the standard immunomagnetic separation (ims) procedure would not be the most suitable method for oocyst purification from turbid matrices. we compared the capacity of percoll-sucrose flotation and six other density ... | 2004 | 15279942 |
| molecular characterization of cryptosporidium parvum isolates obtained from humans. | fifty stool specimens collected from severe diarrheic patients attending misr university hospital, were examined microscopically for protozoan parasites mainly, cryptosporidium parvum. stool examination revealed 22 cases with c. parvum, 8 with e. histolytica, 14 with g. intestinalis and six were parasite-free. the results were compared with the established nested pcr assay to detect dna directly from stool specimens. after the extraction of dna from stool, a 402-bp fragment of c. parvum dna was ... | 2004 | 15287169 |
| an improved 'cold sscp' method for the genotypic and subgenotypic characterization of cryptosporidium. | a simple, non-isotopic pcr-based single-strand conformation polymorphism ('cold sscp') method is described which allows the efficient detection of genetic variation among and within genotypes of cryptosporidium parvum. this low cost approach has important advantages over other 'genotyping' methods and is applicable to a wide range of genetic loci and organisms. | 2004 | 15294321 |
| protection against the early acute phase of cryptosporidium parvum infection conferred by interleukin-4-induced expression of t helper 1 cytokines. | immunity to cryptosporidium parvum infection involves a t helper (th) 1 response with interferon (ifn)- gamma and interleukin (il)-12 activity, but the role of th2 cytokines, such as il-4, is unclear. around the peak of infection, production of oocysts in il-4-deficient and il-4 receptor alpha -deficient neonatal balb/c mice was greater than that in wild-type (wt) mice. susceptibility to infection was increased or decreased, respectively, in wt mice treated with anti-il-4 neutralizing antibodies ... | 2004 | 15295711 |
| [highly active antiretroviral therapy and cryptosporidiosis]. | in hiv infected persons, cryptosporidium parvum causes chronic diarrhoea, which can be life-threatening in persons with aids and with a low cd4+ t cell count. however, a specific and effective therapy for this opportunistic infection does not yet exist. since the use of a combination therapy with a highly active antiretroviral therapy (haart), the prevalence of c. parvum infection in persons with aids has been strongly reduced. this favorable outcome was usually attributed to the recovery of the ... | 2004 | 15305695 |
| [cryptosporidium oocyst viability and infectivity evaluation by flow cytometry]. | evaluating waterborne cryptosporidium sp. oocyst infectivity is presently a major issue for the estimation of environmental risks. the aim of this presentation, was to describe a new model suitable for determining in vivo oocyst infectivity. in this model, infection was assessed in suckling mice seven days after oocyst ingestion by measuring the number of gut oocysts using flow cytometry. four days old mice were orally infected by serially diluted c. parvum oocyst suspensions. this model was fou ... | 2004 | 15314578 |
| inactivation of enteric microbes in water by electro-chemical oxidant from brine (nacl) and free chlorine. | oxidant solutions of mostly free chlorine can be electrochemically produced on-site from brine (nacl) solution and used to disinfect water at the household or community level. in this study electrochemical oxidant (eco) from brine and free chlorine were evaluated under laboratory conditions for inactivation of test microbes. purified suspensions of escherichia coli, the rugose strain of vibrio cholerae, clostridium perfringens spores, ms2 coliphage and cryptosporidium parvum oocysts were treated ... | 2004 | 15318500 |
| using ultraviolet light for disinfection of finished water. | ultraviolet light is now recognised to be very effective for inactivation of cryptosporidium parvum oocysts; however, its application for disinfection of finished water necessitates validation of uv reactors prior to their installation. although reactor performance will likely be assessed using non-pathogenic microorganisms as biodosimetry surrogates, it would be prudent for the water industry to simultaneously measure cryptosporidium oocysts inactivation in controlled bench-scale studies using ... | 2004 | 15318505 |
| evaluation of the purification capacity of nine portable, small-scale water purification devices. | a test was performed to evaluate the microbial and chemical purification capacity of nine portable, small-scale water purification filter devices with production capacity less than 100 l/h. the devices were tested for simultaneous removal capacity of bacteria (cultured escherichia coli, clostridium perfringens, klebsiella pneumoniae and enterobacter cloacae), enteric protozoans (formalin-stored cryptosporidium parvum oocysts), viral markers (f-rna bacteriophages) and microcystins produced by tox ... | 2004 | 15318506 |
| giardia and cryptosporidium in source waters of são paulo state, brazil. | giardia lamblia and cryptosporidium parvum are two protozoan intestinal parasites responsible for many drinking-water-related disease outbreaks in recent years. they are very resistant to conventional water treatment processes, can persist for long times in the environment and are, therefore, of great concern for public health. this work aimed to evaluate the presence of giardia and cryptosporidium in water sources from são paulo state, brazil, as part of the "evaluation of inland waters from sã ... | 2004 | 15318516 |
| sporadic cryptosporidiosis case-control study with genotyping. | we report a case-control study of sporadic cryptosporidiosis with genotyping of isolates from case-patients. a postal questionnaire was completed by 427 patients and 427 controls. we obtained genotyping data on isolates from 191 patients; 115 were cryptosporidium hominis, and 76 were c. parvum. when all cryptosporidiosis cases were analyzed, three variables were strongly associated with illness: travel outside the united kingdom, contact with another person with diarrhea, and touching cattle. ea ... | 2004 | 15324544 |
| liver disease in children with primary immunodeficiencies. | to investigate clinical features and to establish optimal management in children with primary immunodeficiency (pid) and liver disease. study design a retrospective analysis of medical records of 147 children with pid who presented with abnormal liver tests to a tertiary center. | 2004 | 15343186 |
| current progress in the fatty acid metabolism in cryptosporidium parvum. | cryptosporidium parvum is one of the apicomplexans that can cause severe diarrhea in humans and animals. the slow development of anti-cryptosporidiosis chemotherapy is primarily due to the poor understanding on the basic metabolic pathways in this parasite. many well-defined or promising drug targets found in other apicomplexans are either absent or highly divergent in c. parvum. the recently discovered apicoplast and its associated type ii fatty acid synthetic enzymes in plasmodium, toxoplasma, ... | 2004 | 15352319 |
| removal effect of the water purifier for home use against cryptosporidium parvum oocysts. | the removal effects of the faucet mounted type water purifier for home use were examined against cryptosporidium parvum oocysts. the water purifier is composed of a layer of granular activated carbon and the hollow fiber membrane filter. the cartridges were unused, 25%, 50% and 75% flow down by arizona-dust of u. s. a. two respective cartridges were used of the examination. the faucet and the water purifier were connected by anti-pressure tube, and 3.0 x 10(7) oocysts of cryptosporidium parvum w ... | 2004 | 15353844 |
| cryptosporidiosis: an update in molecular epidemiology. | molecular tools have been developed to detect and differentiate cryptosporidium at the species/genotype and subtype levels. these tools have been increasingly used in the characterization of the transmission of cryptosporidium spp. this review addresses the most recent developments in molecular epidemiology of cryptosporidiosis. | 2004 | 15353969 |
| health sequelae of human cryptosporidiosis in immunocompetent patients. | there have been no systematic studies following up the longer term health effects of cases of cryptosporidiosis for which genotype data exist. | 2004 | 15356813 |
| cryptosporidium suis n. sp. (apicomplexa: cryptosporidiidae) in pigs (sus scrofa). | molecular and biological characteristics of a new species of cryptosporidium from the feces of pigs (sus scrofa) is described. oocysts are structurally indistinguishable from those of cryptosporidium parvum; they are passed fully sporulated, lack sporocysts, and measure 4.9-4.4 microm (mean = 4.6 microm) x 4.0-4.3 microm (mean = 4.2 microm); length to width ratio 1.1 (n = 50). cryptosporidium suis is not transmissible to nude mice and is poorly infectious for cattle. molecular and phylogenetic a ... | 2004 | 15357067 |
| effect of hydrogen peroxide and other protease inhibitors on cryptosporidium parvum excystation and in vitro development. | this study was undertaken to observe the effects of hydrogen peroxide on cryptosporidium parvum oocysts with respect to protease activity in comparison to known protease inhibitors. in assessing the possible mechanisms of action of hydrogen peroxide, treatment effectiveness was analyzed using 3 assays and the potential roles of proteases and cations were considered. treatment of c. parvum oocysts with hydrogen peroxide inhibited protease activity up to 50% compared with untreated controls. treat ... | 2004 | 15357093 |
| indigenous bacterial spores as indicators of cryptosporidium inactivation using chlorine dioxide. | this objective of this study was to explore the practicality of monitoring naturally occurring organisms to predict drinking water treatment plant performance, in this case for the reduction of cryptosporidium. surface and ground water from seven drinking water treatment plants across north america that use chlorine dioxide were surveyed for aerobic and anaerobic bacterial spore concentrations. the concentrations of total spores were usually high enough in both raw and treated water to allow 4- ... | 2003 | 15382738 |
| confirmed detection of cyclospora cayetanesis, encephalitozoon intestinalis and cryptosporidium parvum in water used for drinking. | human enteropathogenic microsporidia (hem), cryptosporidium parvum, cyclospora cayetanesis, and giardia lamblia are associated with gastrointestinal disease in humans. to date, the mode of transmission and environmental occurrence of hem (encephalitozoon intestinalis and enterocytozoon bieneusi) and cyclospora cayetanesis have not been fully elucidated due to lack of sensitive and specific environmental screening methods. the present study was undertaken with recently developed methods, to scree ... | 2003 | 15384722 |
| prevalence of cryptosporidium parvum in private drinking water cisterns in bani-kenanah district, northern jordan. | due to water scarcity in jordan, the water authority only pump the water once or twice a week to the population. thus people in rural areas, including the bani-kenanah district, make the most of their water resources by storing rainwater in private reservoirs for use during periods of water shortage. these reservoirs include; underground cisterns and concrete or metal tanks. the water collected in these reservoirs is at risk of contamination. during the period march-july 2002, the three types of ... | 2004 | 15385214 |
| cryptosporidium parvum at different developmental stages modulates host cell apoptosis in vitro. | we studied apoptosis in a human ileocecal adenocarcinoma tumor cell line (hct-8) infected with cryptosporidium parvum, from 2 to 72 h postinfection (h.p.i.). at 2 h.p.i., the percentage of annexin v-positive cells in the cell culture had increased to 10% compared to 2.5% in noninfected control culture; sorted infected cells expressed mrna of fasl, the active form of caspase 3, and high caspase 3 activity, whereas the noninfected neighboring cells sorted from the same culture showed no signs of a ... | 2004 | 15385510 |
| host cell tropism underlies species restriction of human and bovine cryptosporidium parvum genotypes. | it has been recognized recently that human cryptosporidiosis is usually caused by cryptosporidium parvum genotype i ("human" c. parvum), which is not found in animals. compared to c. parvum genotype ii, little is known of the biology of invasion of the human-restricted c. parvum genotype i. the aims of the present study were (i) to explore and compare with genotype ii the pathogenesis of c. parvum genotype i infection by using an established in vitro model of infection and (ii) to examine the po ... | 2004 | 15385517 |
| cryptosporidiosis: pathogenesis and immunology. | cryptosporidium parvum is an increasingly recognized agent of intestinal infection in normal and immunocompromised humans, and in many other animals. the intraepithelial cell infection results in villous atrophy, mild submucosal inflammation, reduction of brush-border enzymes and a characteristic persistent watery diarrhea. the infection is self-limiting in immunocompetent hosts, probably because of specific acquired immunity; specific serum and secretory antibody responses develop that may be r ... | 1992 | 15463522 |
| cellular biology of cryptosporidium parvum. | with the emergence of cryptosporidium parvum as a major pathogen encountered in human and veterinary clinical practice, a need for increased knowledge of the cellular- and immuno-biology of this apicomplexan parasite has developed. initial work has used paradigms taken from other apicomplexans, especially plasmodium, toxoplasma and eimeria, as a starting point. in this article, carolyn petersen discusses the observation that in these organisms, molecular targets of antibodies (which have protect ... | 1993 | 15463717 |
| cases from the osler medical service at johns hopkins university. cryptosporidium parvum. | | 2004 | 15464711 |
| use of semiconductor quantum dots for photostable immunofluorescence labeling of cryptosporidium parvum. | cryptosporidium parvum is a waterborne pathogen that poses potential risk to drinking water consumers. the detection of cryptosporidium oocysts, its transmissive stage, is used in the latest u.s. environmental protection agency method 1622, which utilizes organic fluorophores such as fluorescein isothiocyanate (fitc) to label the oocysts by conjugation with anti-cryptosporidium sp. monoclonal antibody (mab). however, fitc exhibits low resistance to photodegradation. this property will inevitably ... | 2004 | 15466507 |
| a review of chemotherapeutic approaches to the treatment of cryptosporidiosis. | this review focuses on chemotherapies used against the parasite, cryptosporidium parvum, the causative agent of cryptosporidiosis. populations at risk from severe morbidity or mortality from cryptosporidiosis are discussed with particular reference to those infected with hiv. the review then examines chemotherapies used in the clinical setting, as well as a number of in vitro and in vivo experimental studies. it begins with a discussion of the targets within cryptosporidium that have been the fo ... | 2003 | 15482125 |
| molecular genetic characterization and subcellular localization of a putative theileria annulata membrane protein. | a theileria annulata protein (tad) exhibiting an n-terminal signal sequence for endoplasmic reticulum membrane translocation and a conserved cysteine-rich region was isolated by screening the mrna of a t. annulata-infected bovine lymphoblastoid cell line with degenerated primers directed against t. annulata-targeting sequences. the tad-coding sequence was found to be most closely related to the genomic dna sequence of t. parva (tigr database, 72%) and the amino acid sequence of plasmodium falcip ... | 2004 | 15490238 |
| characterisation of benzimidazole binding with recombinant tubulin from giardia duodenalis, encephalitozoon intestinalis, and cryptosporidium parvum. | the binding kinetics of several benzimidazole compounds were determined with recombinant tubulin from benzimidazole-sensitive and -insensitive organisms. this study utilised the naturally occurring high efficacy of the benzimidazoles for the parasitic protozoa giardia duodenalis and encephalitozoon intestinalis, and low efficacy with cryptosporidium parvum. direct kinetic analysis of the benzimidazole-beta-tubulin interaction was performed using a fluorescence-based quenching method to determine ... | 2004 | 15500920 |
| the genome of cryptosporidium hominis. | cryptosporidium species cause acute gastroenteritis and diarrhoea worldwide. they are members of the apicomplexa--protozoan pathogens that invade host cells by using a specialized apical complex and are usually transmitted by an invertebrate vector or intermediate host. in contrast to other apicomplexans, cryptosporidium is transmitted by ingestion of oocysts and completes its life cycle in a single host. no therapy is available, and control focuses on eliminating oocysts in water supplies. two ... | 2004 | 15510150 |
| evaluation of two rapid assays for detecting cryptosporidium parvum in calf feces. | to evaluate 2 rapid, patient-side assays for detection of cryptosporidium parvum in feces from neonatal calves with diarrhea. | 2004 | 15515989 |
| structural analysis of cryptosporidium parvum. | cryptosporidium parvum (apicomplexa, formerly sporozoa) is the causative agent of cryptosporidiosis, an enteric disease of substantial medical and veterinary importance. c. parvum shows a number of unique features that differ from the rest of the class of coccidea in which it is currently grouped taxonomically. differences occur in the overall structure of the transmission form and the invasive stages of the parasite, its intracellular location, the presence of recently described additional extr ... | 2004 | 15525433 |
| seasonal shedding of multiple cryptosporidium genotypes in california ground squirrels (spermophilus beecheyi). | twelve percent of 853 california ground squirrels (spermophilus beecheyi) from six different geographic locations in kern county, calif., were found to be shedding on average 44,482 oocysts g of feces(-1). the mean annual environmental loading rate of cryptosporidium oocysts was 57,882 oocysts squirrel(-1) day(-1), with seasonal patterns of fecal shedding ranging from <10,000 oocysts squirrel(-1) day(-1) in fall, winter, and spring to levels of 2 x 10(5) oocysts squirrel(-1) day(-1) in summer. j ... | 2004 | 15528541 |
| effect of egg yolk antibody on experimental cryptosporidium parvum infection in scid mice. | in this study the effect of chicken egg yolk antibody (igy) against cryptosporidium parvum infection was examined. igy sample was prepared from eggs of chickens immunized with c. parvum oocyst antigens. in vitro, antibody-treated sporozoites showed reduced binding to caco-2 cells and lost vitality. these phenomena were not observed with a control igy sample prepared from eggs of non-immunized chickens. scid mice orally administered with the antibody demonstrated partial reduction in oocyst shedd ... | 2004 | 15531042 |
| phylogenomic evidence supports past endosymbiosis, intracellular and horizontal gene transfer in cryptosporidium parvum. | the apicomplexan parasite cryptosporidium parvum is an emerging pathogen capable of causing illness in humans and other animals and death in immunocompromised individuals. no effective treatment is available and the genome sequence has recently been completed. this parasite differs from other apicomplexans in its lack of a plastid organelle, the apicoplast. gene transfer, either intracellular from an endosymbiont/donor organelle or horizontal from another organism, can provide evidence of a prev ... | 2004 | 15535864 |
| re-use of wastewater: preventing the recovery of pathogens by using medium-pressure uv lamp technology. | ultraviolet (uv) light has become widely accepted as an alternative to chlorination or ozonation for wastewater disinfection. there are now over 2,000 wastewater treatment plants worldwide using either low- or medium-pressure uv technology. recent studies investigating uv lamp technology, configuration, cleaning requirements and ageing, as well as long-term performance tests, have demonstrated beyond any doubt the effectiveness of uv in inactivating pathogens in wastewater. research has also sho ... | 2004 | 15537023 |
| irreversible uv inactivation of cryptosporidium spp. despite the presence of uv repair genes. | ultraviolet light is being considered as a disinfectant by the water industry because it appears to be very effective for inactivating pathogens, including cryptosporidium parvum. however, many organisms have mechanisms for repairing ultraviolet light-induced dna damage, which may limit the utility of this disinfection technology. inactivation of c. parvum was assessed by measuring infectivity in cells of the human ileocecal adenocarcinoma hct-8 cell line, with an assay targeting a heat shock pr ... | 2004 | 15537090 |
| efficacy of vegetated buffer strips for retaining cryptosporidium parvum. | overland and shallow subsurface hydrologic transport of pathogenic cryptosporidium parvum oocysts from cattle feces into surface drinking water supplies is a major concern on annual grasslands in california's central and southern sierra nevada foothills. soil boxes (0.5 m wide x 1.1 m long x 0.3 m deep) were used to evaluate the ability of grass vegetated buffer strips to retain 2 x 10(8) spiked c. parvum oocysts in 200-g fecal deposits during simulated rainfall intensities of 30 to 47.5 mm/h ov ... | 2004 | 15537947 |
| apical organelle discharge by cryptosporidium parvum is temperature, cytoskeleton, and intracellular calcium dependent and required for host cell invasion. | the apical organelles in apicomplexan parasites are characteristic secretory vesicles containing complex mixtures of molecules. while apical organelle discharge has been demonstrated to be involved in the cellular invasion of some apicomplexan parasites, including toxoplasma gondii and plasmodium spp., the mechanisms of apical organelle discharge by cryptosporidium parvum sporozoites and its role in host cell invasion are unclear. here we show that the discharge of c. parvum apical organelles oc ... | 2004 | 15557601 |
| microbial adhesion of cryptosporidium parvum sporozoites: purification of an inhibitory lipid from bovine mucosa. | cryptosporidium parvum is a protozoan pathogen of humans and livestock worldwide. its ability to infect a wide range of species raises questions as to the involvement of a specific host cell receptor for parasite-host recognition. to investigate the mechanism of parasite-host cell recognition, we have developed an in vitro cell suspension binding assay to investigate adhesion of c. parvum sporozoites to host cells. morphologic features of binding events observed with this assay were identical to ... | 2004 | 15562596 |
| ingestion of cryptosporidium oocysts by caenorhabditis elegans. | cryptosporidium parvum has been associated with outbreaks of human illness by consumption of contaminated water, fresh fruits, and vegetables. free-living nematodes may play a role in pathogen transmission in the environment. caenorhabditis elegans is a free-living soil nematode that has been extensively studied and serves as a good model to study possible transmission of c. parvum oocysts that may come into contact with produce before harvest. the objective of this study was to determine whethe ... | 2004 | 15562624 |
| protection of calves against cryptosporiosis by oral inoculation with gamma-irradiated cryptosporidium parvum oocysts. | the purpose of this study was to determine whether gamma-irradiated cryptosporidium parvum oocysts could elicit protective immunity against cryptosporidiosis in dairy calves. cryptosporidium parvum iowa strain oocysts (1 x 10(6) per inoculation) were exposed to various levels of gamma irradiation (350-500 gy) and inoculated into 1-day-old dairy calves. the calves were examined daily for clinical signs of cryptosporidiosis, and fecal samples were processed for the presence of c. parvum oocysts. a ... | 2004 | 15562625 |
| a study of risk factors associated with the prevalence of cryptosporidium in villages around lake atitlan, guatemala. | cryptosporidium parvum is an endemic, zoonotic coccidian parasitosis that is highly prevalent in third-world countries where waterborne fecal contamination of food and drink or person-to-person contact with oocysts are the most common methods of transmission of the enteric protozoan. this type of transmission of the parasite made the villages around lake atitlan, guatemala a unique site to compare environmental risk factors with the level of cryptosporidium infections in the local residents. the ... | 2004 | 15565263 |
| cryptosporidium: a water-borne zoonotic parasite. | of 155 species of mammals reported to be infected with cryptosporidium parvum or c. parvum-like organisms most animals are found in the orders artiodactyla, primates, and rodentia. because cryptosporidium from most of these animals have been identified by oocyst morphology alone with little or no host specificity and/or molecular data to support identification it is not known how many of the reported isolates are actually c. parvum or other species. cryptosporidiosis is a cause of morbidity and ... | 2004 | 15567578 |
| cyclospora cayetanensis, a food- and waterborne coccidian parasite. | food- and waterborne coccidia including cryptosporidium parvum, cyclospora cayetanensis, sarcocystis hominis and sarcocystis suihominis, and isospora belli are cyst-forming apicomplexan protozoa that cause intracellular infections, predominantly in the epithelial cells of the intestine. they are transmitted by oocysts from person-to-person by the fecal-oral route or via contaminated water or food. the most common symptom of infection is diarrhea, however, asymptomatic infections occur. infection ... | 2004 | 15567580 |
| drinking water treatment processes for removal of cryptosporidium and giardia. | major waterborne cryptosporidiosis and giardiasis outbreaks associated with contaminated drinking water have been linked to evidence of suboptimal treatment. cryptosporidium parvum oocysts are particularly more resistant than giardia lamblia cysts to removal and inactivation by conventional water treatment (coagulation, sedimentation, filtration and chlorine disinfection); therefore, extensive research has been focused on the optimization of treatment processes and application of new technologie ... | 2004 | 15567586 |
| epidemiologic and environmental investigation of a recreational water outbreak caused by two genotypes of cryptosporidium parvum in ohio in 2000. | in august 2000, the ohio department of health requested assistance to investigate a cryptosporidiosis outbreak with more than 700 clinical case-patients. an epidemiologic and environmental investigation was conducted. stool specimens, pool water, and sand filter samples were analyzed. a community-based case-control study showed that the main risk factor was swimming in pool a (odds ratio [or] = 42, 95% confidence interval [ci] = 12.3-144.9). this was supported by results of polymerase chain reac ... | 2004 | 15569788 |
| transport of cryptosporidium oocysts in porous media: role of straining and physicochemical filtration. | the transport and filtration behavior of cryptosporidium parvum oocysts in columns packed with quartz sand was systematically examined under repulsive electrostatic conditions. an increase in solution ionic strength resulted in greater oocyst deposition rates despite theoretical predictions of a significant electrostatic energy barrier to deposition. relatively high deposition rates obtained with both oocysts and polystyrene latex particles of comparable size at low ionic strength (1 mm) suggest ... | 2004 | 15573591 |
| particles in filter effluent: the roles of deposition and detachment. | particles in the effluent of granular media filters can be classified as influent particles that were never removed or as particles that detached after prior deposition. to determine the effects of particle size, filter media depth and filter run duration on the relative fraction of each class, laboratory experiments were performed using suspensions of four sizes of polystyrene particles (0.2, 1.2, 2.5, and 4.0 microm diameters) that were destabilized with 0.04 m calcium chloride and continuousl ... | 2004 | 15573617 |