| extensive polymorphism in cryptosporidium parvum identified by multilocus microsatellite analysis. | restriction fragment length polymorphism and dna sequence analysis discern two main types of cryptosporidium parvum. we present a survey of length polymorphism at several microsatellite loci for type 1 and type 2 isolates. a total of 14 microsatellite loci were identified from c. parvum dna sequences deposited in public databases. all repeats were mono-, di-, and trinucleotide repeats of a, at, and aat, reflecting the high at content of the c. parvum genome. several of these loci showed signific ... | 2000 | 10919789 |
| evaluation of immunomagnetic separation for recovery of cryptosporidium parvum and giardia duodenalis from high-iron matrices. | in this study we examined the recovery of cryptosporidium parvum and giardia duodenalis from matrices containing various concentrations of dissolved iron. the organisms were recovered by using the immunomagnetic separation-immunofluorescent assay method, and the levels of recovery were compared to the dissolved iron concentrations. the levels of recovery of c. parvum decreased sharply at dissolved iron concentrations greater than 4 mg/liter, while the levels of recovery of g. duodenalis decrease ... | 2000 | 10919831 |
| outbreak of gastroenteritis associated with an interactive water fountain at a beachside park--florida, 1999. | since 1989, approximately 170 outbreaks associated with recreational water venues (e.g., swimming pools, waterparks, fountains, hot tubs and spas, lakes, rivers, and oceans) have been reported, with almost half resulting in gastrointestinal illness (1-5). this report summarizes the investigation of an outbreak of gastroenteritis in florida during 1999. the findings indicated that shigella sonnei and cryptosporidium parvum infections caused illness in persons exposed to an "interactive" water fou ... | 2000 | 10921495 |
| the identification and characterisation of an unusual genotype of cryptosporidium from human faeces as cryptosporidium meleagridis. | an unusual genotype of cryptosporidium was identified in the faeces of six human patients by pcr/rflp analysis of the cryptosporidium oocyst wall protein (cowp) gene. conventional microscopy showed oocysts indistinguishable in size from those of cryptosporidium parvum, which reacted with two different commercially available anti-oocyst monoclonal antibodies. the isolates were further characterised by pcr/rflp analysis of the thrombospondin-related adhesive protein of cryptosporidium-1 (trap-c1) ... | 2000 | 10930736 |
| absence of cd40-cd40 ligand interactions in x-linked hyper-igm syndrome does not affect differentiation of t helper cell subsets. | the aim of this study was to investigate the effect of absent cd40-cd40 ligand interactions in patients with x-linked hyper-igm syndrome (xhigm) on the generation of th1 and th2 immunity. whole blood from patients and sex- and age-matched controls was stimulated with phorbol myristate acetate (pma) and calcium ionophore a23187 in the presence of brefeldin a. after 5 h, cellular production of interferon-gamma, il-4, tumour necrosis factor-alpha and il-2 was measured by intracellular cytokine stai ... | 2000 | 10931152 |
| [a new trichromic safranin stain for the detection of cryptosporidium parvum, cyclospora cayetanensis, species of microsporidia and isospora belli in fecal material]. | cryptosporidium parvum, isospora belli, cyclospora cayetanensis and microsporidia are frequent pathogens in the immunodeficient host, which may cause multiple infections. the above mentioned parasites are found in feces by the application of different specific tintorial techniques. the objective of this work was the development of a stain for the simultaneous detection of these parasites, reducing costs as well as the time taken to make the diagnosis. the safranin-trichrome stain is simple, chip ... | 1999 | 10932763 |
| recovery and viability of cryptosporidium parvum oocysts and giardia intestinalis cysts using the membrane dissolution procedure. | previously, the cellulose acetate membrane filter dissolution method was reported to yield cryptosporidium parvum oocyst recoveries of 70.5%, with recovered oocysts retaining their infectivity. in contrast, high spike doses (approximately 1 x 10(5) cryptosporidium parvum oocysts and giardia intestinalis cysts) yielded recoveries ranging from 0.4% to 83.9%, and 3.2% to 90.3%, respectively, in this study. recoveries with low spike doses (approximately 100 (oo)cysts) continued to demonstrate high v ... | 2000 | 10941515 |
| laboratory diagnosis of cryptosporidium parvum infection. | | 2000 | 10943506 |
| clinical aspects of human cryptosporidiosis. | | 2000 | 10943507 |
| host immune responses against cryptosporidium. | | 2000 | 10943508 |
| gene discovery in cryptosporidium parvum: expressed sequence tags and genome survey sequences. | | 2000 | 10943509 |
| epidemiology and strain variation of cryptosporidium parvum. | | 2000 | 10943510 |
| detection of cryptosporidia and cryptosporidium parvum oocysts in environmental water samples by immunomagnetic separation-polymerase chain reaction. | cryptosporidium parvum has emerged as one of the most important new contaminants found in drinking water. current protocols for the detection of cryptosporidia are time-consuming and rather inefficient. we recently described an immunomagnetic separation-polymerase chain reaction (ims-pcr) assay permitting highly sensitive detection of c. parvum oocysts in drinking water samples. in this study, a second ims-pcr assay to detect all cryptosporidial oocysts was developed, and both ims-pcr assays wer ... | 2000 | 10945772 |
| fecal antibodies to cryptosporidium parvum in healthy volunteers. | this study examined the intestinal antibody response in 26 healthy volunteers challenged with cryptosporidium parvum oocysts. fecal extracts were assayed for total secretory immunoglobulin a (iga) and c. parvum-specific iga reactivity. specific iga reactivity was standardized to iga concentration and expressed as a reactivity index (ri). anti-c. parvum fecal iga (figa) increased significantly in 17 of 26 (65.4%) following oocyst ingestion. of those with detectable responses, 59, 76.5, and 94.1% ... | 2000 | 10948127 |
| mediation of cryptosporidium parvum infection in vitro by mucin-like glycoproteins defined by a neutralizing monoclonal antibody. | the protozoan parasite cryptosporidium parvum is a significant cause of diarrheal disease worldwide. attachment to and invasion of host intestinal epithelial cells by c. parvum sporozoites are crucial steps in the pathogenesis of cryptosporidiosis. the molecular basis of these initial interactions is unknown. in order to identify putative c. parvum adhesion- and invasion-specific proteins, we raised monoclonal antibodies (mabs) to sporozoites and evaluated them for inhibition of attachment and i ... | 2000 | 10948140 |
| transforming growth factor beta1 is expressed in the jejunum after experimental cryptosporidium parvum infection in humans. | biopsies from volunteers challenged with cryptosporidium parvum were examined for transforming growth factor beta1 (tgf-beta1). none of the prechallenge biopsies exhibited tgf-beta. seven of 12 volunteers with oocyst shedding expressed tgf-beta versus 2 of 13 volunteers without detected oocysts. the association of tgf-beta expression with oocyst excretion and the timing of symptoms suggests that tgf-beta mediates intestinal healing. | 2000 | 10948171 |
| from the centers for disease control and prevention. outbreak of gastroenteritis associated with an interactive water fountain at a beachside park--florida, 1999. | | 2000 | 10950662 |
| interferon-gamma is required for innate immunity to cryptosporidium parvum in mice. | although cd4 t cells are required for recovery from cryptosporidial infection, mice with severe combined immunodeficiency (scid) remain infected for long periods without ill effect. in contrast, mice whose ability to use interferon(ifn)-gamma is impaired, by neutralization or gene knockout, experience heavy cryptosporidial infection that may lead to death. to determine whether the innate immunity of scid mice to cryptosporidium parvum (cp) requires ifn-gamma, doubly immunodeficient c57bl/6 scid- ... | 2000 | 10950807 |
| the initiation translation factor eif-4a of cryptosporidium parvum is encoded by two distinct mrna forms and shows dna sequence polymorphism distinguishing genotype 1 and 2 isolates. | the eukaryotic translation initiation factor eif-4a is an atp-dependent rna helicase involved in ribosome attachment to the 5' end of mrnas. employing as a probe a cryptosporidium parvum genomic amplicon encoding a partial polypeptide related to eif-4a, we screened a c. parvum sporozoite cdna library to clone the full length of the gene. two complete cdnas were characterized, cp.f6 and cp.f10, which consisted of 1,900 and 1,418 bp, respectively. the overlapping portions of the sequences shared 1 ... | 2000 | 10958456 |
| dna fingerprinting of cryptosporidium parvum isolates using amplified fragment length polymorphism (aflp). | the genetic variability of 10 cryptosporidium parvum isolates of human and animal origin was investigated using amplified fragment length polymorphism (aflp). analysis of fluorescent dye-labeled amplified products was carried out using an abi prisms 377 dna sequencer and abi prisms genescan software. one-hundred and twelve primer combinations were evaluated using a single c. parvum isolate. the patterns generated were highly reproducible. for subsequent study, a subset of 9 primer pairs that yie ... | 2000 | 10958466 |
| infection of immunosuppressed c57bl/6n adult mice with a single oocyst of cryptosporidium parvum. | the present study was designed to determine the minimum number of cryptosporidium parvum oocysts capable of producing patent infections in immunosuppressed c57bl/6n adult mice. sixty-four female mice were divided into 6 groups of 8 mice each, except group 1 that contained 24 mice. mice in groups 1-3 were immunosuppressed with dexamethasone and inoculated with 1, 5, and 10 oocysts per mouse, respectively. the accuracy of the inoculum size was microscopically confirmed. mice in groups 4-6 served a ... | 2000 | 10958482 |
| identification and characterisation of three antigenic proteins from cryptosporidium parvum sporozoites using a dna library expressing poly-histidine tagged peptides. | to identify antigenic peptides of the parasite cryptosporidium parvum, an expression library that allows for the production of chimeric proteins fused with a 6-histidine tag was made. the library was screened with c. parvum sporozoite rabbit anti-serum, and three positive clones (sa20, sa35, and sa40) were identified. the corresponding recombinant proteins (sa20, sa35, and sa40) were expressed in escherichia coli and purified by metal-affinity chromatography. the sequence of sa20 and sa35 clones ... | 1999 | 10961848 |
| cryptosporidium parvum: oocysts purification using potassium bromide discontinuous gradient. | cryptosporidium parvum oocysts were purified using a discontinuous potassium bromide density gradient, composed by three solutions of 6, 16 and 28% (w/v) kbr in tris-edta buffer. fecal samples containing oocysts were washed to diminish interfering lipids and applied to the gradient. after centrifugation, oocysts can be easily aspirated from a clear band, diluted and washed by centrifugation in phosphate buffer to remove residual kbr. this method allows the purification of large amounts of highly ... | 2000 | 10962159 |
| detection and speciation of cryptosporidium spp. in environmental water samples by immunomagnetic separation, pcr and endonuclease restriction. | current methods for the detection of cryptosporidium oocysts in water samples are both time-consuming and subject to variation in sensitivity. a genus-specific pcr assay was designed for the specific amplification of a 552-bp region of the 18s rrna gene. postamplification endonuclease restriction generated unique digest patterns that enabled differentiation between the three species, c. muris, c. baileyi and c. parvum, the major human pathogen. theoretical restriction profiles for other cryptosp ... | 2000 | 10966225 |
| [prevalence of cryptosporidium parvum among children of less than 5 years of age in the urban zone of campo grande, mato grosso do sul state, brazil, 1996]. | the purpose of this study was to establish the prevalence of cryptosporidium parvum among infants of less than 5 years of age, resident in the urban area of campo grande, mato grosso do sul state, brazil, 1996/97, through parasitological examinations and epidemiological analysis of the diagnosed cases. it was a transverse study with domiciliary inquiry and we evaluated 1051 fecal samples processed by the blagg method, and a modified ziehl-neelsen staining was used for research of oocysts of c. p ... | 2000 | 10967597 |
| detection of giardia lamblia, entamoeba histolytica/entamoeba dispar, and cryptosporidium parvum antigens in human fecal specimens using the triage parasite panel enzyme immunoassay. | the triage parasite panel (biosite diagnostics, san diego, calif.) is a new qualitative enzyme immunoassay (eia) panel for the detection of giardia lamblia, entamoeba histolytica/e. dispar, and cryptosporidium parvum in fresh or fresh, frozen, unfixed human fecal specimens. by using specific antibodies, antigens specific for these organisms are captured and immobilized on a membrane. panel performance was evaluated with known positive and negative stool specimens (a total of 444 specimens) that ... | 2000 | 10970380 |
| an immunoglobulin g1 monoclonal antibody highly specific to the wall of cryptosporidium oocysts. | the detection of cryptosporidium oocysts in drinking water is critically dependent on the quality of immunofluorescent reagents. experiments were performed to develop a method for producing highly specific antibodies to cryptosporidium oocysts that can be used for water testing. balb/c mice were immunized with six different antigen preparations and monitored for immunoglobulin g (igg) and igm responses to the surface of cryptosporidium oocysts. one group of mice received purified oocyst walls, a ... | 2000 | 10973448 |
| emerging public health concerns regarding cryptosporidiosis. | | 2000 | 10976295 |
| foodborne infections vectored by molluscan shellfish. | foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5000 deaths each year in the united states. the authors present and analyze information derived from epidemiologic investigations and surveillance systems on foodborne infections caused by consumption of molluscan shellfish. this review focuses on the bias in reporting of shellfish-vectored illness, prevention and control of such infections, the origin of recognized viral and bacterial etiologic agents, an ... | 2000 | 10981028 |
| effect of high hydrostatic pressure on cryptosporidium parvum infectivity. | the incidence of foodborne disease outbreaks caused by contaminated low-ph fruit juices is increasing. with recent mandatory pasteurization of apple juice and the industry's concerns of food safety, fruit juice processors are showing more interest in alternative nonthermal technologies that can kill >99.99% of microbial pathogens present in foods. the association of the coccidian protozoan, cryptosporidium, with diarrheal disease outbreaks from contaminated tap water and fruit juice raises a saf ... | 2000 | 10983803 |
| [parasitologic diagnosis. cryptosporidiosis]. | | 2000 | 10986899 |
| water and health: precaution must be guided for the health of the public. | | 2000 | 10990472 |
| [(1)n,(12)n]bis(ethyl)-cis-6,7-dehydrospermine: a new drug for treatment and prevention of cryptosporidium parvum infection of mice deficient in t-cell receptor alpha. | cryptosporidium parvum infection of t-cell receptor alpha (tcr-alpha)-deficient mice results in a persistent infection. in this study, treatment with a polyamine analogue (sl-11047) prevented c. parvum infection in suckling tcr-alpha-deficient mice and cleared an existing infection in older mice. treatment with putrescine, while capable of preventing infection, did not clear c. parvum from previously infected mice. these findings provide further evidence that polyamine metabolic pathways are tar ... | 2000 | 10991882 |
| transforming growth factor beta1 ameliorates intestinal epithelial barrier disruption by cryptosporidium parvum in vitro in the absence of mucosal t lymphocytes. | exposure to oocysts of the protozoan cryptosporidium parvum causes intestinal epithelial cell dysfunction in vivo and in vitro, but effective means by which mucosal injury might be prevented remain unclear. we examined the ability of transforming growth factor beta1 (tgf-beta1)-a cytokine synthesized and released by cells in the intestine-to preserve the barrier function of human colonic epithelia when challenged with c. parvum oocysts and then studied the mechanisms involved. epithelial barrier ... | 2000 | 10992464 |
| the occurrence of cryptosporidium parvum and c. muris in wild rodents and insectivores in spain. | five rodent and two insectivore species were investigated for cryptosporidium at seven sites in north-eastern spain. of the 442 animals studied, 82 apodemus sylvaticus, 1 a. flavicollis, 5 mus spretus, 1 rattus rattus, 8 clethrionomys glareolus and 13 crocidura russula were infected with only c. parvum. eleven a. sylvaticus and 2 c. glareolus were infected with only c. muris and 16 a. sylvaticus, 1 m. spretus and 2 c. glareolus showed mixed infections. both cryptosporidial species were found in ... | 2000 | 10996736 |
| cryptosporidiosis of the gastrointestinal tract associated with sclerosing cholangitis in the absence of documented immunodeficiency: cryptosporidium parvum and sclerosing cholangitis in an immunocompetent child. | | 2000 | 10997381 |
| quantitative flow cytometric evaluation of maximal cryptosporidium parvum oocyst infectivity in a neonate mouse model. | the importance of waterborne transmission of cryptosporidium parvum to humans has been highlighted by recent outbreaks of cryptosporidiosis. the first step in a survey of contaminated water currently consists of counting c. parvum oocysts. data suggest that an accurate risk evaluation should include a determination of viability and infectivity of counted oocysts in water. in this study, oocyst infectivity was addressed by using a suckling mouse model. four-day-old nmri (naval medical research in ... | 2000 | 11010875 |
| implications and importance of genotyping cryptosporidium. | | 2000 | 11014024 |
| microbiological safety of drinking water. | emerging pathogens in drinking water have become increasingly important during the decade. these include newly-recognized pathogens from fecal sources such as cryptosporidium parvum, campylobacter spp., and rotavirus, as well as pathogens that are able to grow in water distribution systems, like legionella spp., mycobacteria, and aeromonads. to perform a risk analysis for the pathogens in drinking water, it is necessary to understand the ecology of these organisms. the ecology of the drinking-wa ... | 2000 | 11018125 |
| how safe is our drinking water? | | 2000 | 11021256 |
| prevalence of giardia sp. cryptosporidium parvum and cryptosporidium andersoni (syn. c. muris) [correction of cryptosporidium parvum and cryptosporidium muris (c. andersoni)] in 109 dairy herds in five counties of southeastern new york. | a cross-sectional study was undertaken to determine the prevalence of giardia sp. (g. duodenalis group), cryptosporidium parvum and cryptosporidium andersoni (c. muris) [corrected] in dairy cattle in three different age groups, and to evaluate the association of age and season with prevalence. one hundred and nine dairy farms, from a total of 212 farms, in five counties of southeastern new york volunteered to participate. on these farms, 2943 fecal samples were collected from three defined age g ... | 2000 | 11027856 |
| frequency of cryptosporidium spp. as cause of human gastrointestinal disease in switzerland and possible sources of infection. | detection of cryptosporidium parvum is not routinely done in laboratories of clinical microbiology and there is no obligation to communicate isolations of this pathogen to health authorities. for these reasons, frequency of cryptosporidiosis and sources of infection are only poorly known in switzerland. to obtain more concise information in this field, feces from 5179 hospitalized and 1256 ambulatory patients with suspected gastrointestinal infections were screened for cryptosporidium spp. over ... | 2000 | 11028268 |
| intestinal parasitic infections, with a special emphasis on cryptosporidiosis, in amerindians from western venezuela. | the prevalences of intestinal parasites and intensities of helminth infections were studied in two amerindian villages in venezuela. single stool specimens were collected from 303 individuals from saimadoyi and 130 from campo rosario. wet mounts, iron-hematoxylin-stained smears, and formalin-ether concentrates were examined for the presence of parasites; modified ziehl-neelsen carbol-fuchsin staining of 10% formalin-preserved stool was used to identify cryptosporidium parvum. helminth ova counts ... | 2000 | 11037776 |
| active, multisite, laboratory-based surveillance for cryptosporidium parvum. | cryptosporidium parvum leaped to the attention of the united states following the 1993 outbreak in milwaukee, wisconsin, which sickened 400,000 people. other outbreaks in the united states have been associated with drinking and recreational water, consumption of contaminated foods, contact with animals, and childcare attendance. despite its public health importance, the number of people who become infected each year is not known. in 1997, active surveillance for c. parvum was added to the foodbo ... | 2000 | 11037779 |
| a 23-kda recombinant antigen of cryptosporidium parvum induces a cellular immune response on in vitro stimulated spleen and mesenteric lymph node cells from infected mice. | in the present study, we focused on a 23-kda antigen, cp23, which has been shown to be a major target of humoral immune responses in cryptosporidium parvum infections and is present in both the sporozoite and merozoite stages. recombinant cp23 antigen was shown to stimulate a specific proliferative response by splenocytes and mesenteric lymph node cells from infected interferon gamma knockout balb/c mice. cp23 stimulation also induced tnf-alpha, il-2, and il-5 mrna production by spleen cells fro ... | 2000 | 11038318 |
| excretion patterns of mucosally delivered antibodies to p23 in cryptosporidium parvum infected calves. | fecal samples obtained at intervals from six calves with acute cryptosporidiosis contained antibodies of multiple isotypes to p23. igm-, iga-, and igg(1)-isotype anti-p23 appeared before igg(2)-isotype antibodies. all anti-p23 antibodies had declined by 2 months after infection. one calf that failed to shed oocysts following initial exposure developed igg(1)-isotype anti-p23 antibodies. one calf that died following exposure to cryptosporidium parvum oocysts lacked detectable anti-p23 antibodies. ... | 2000 | 11044562 |
| enumeration of cryptosporidium spp. in water with us epa method 1622, usa. | the occurrence of cryptosporidium parvum or other pathogenic cryptosporidium species in water must be known in order to assess risk and determine the treatment needed to reduce cryptosporidium oocysts to acceptable levels in finished drinking water. because cryptosporidium oocyst occurrence may be sparse, methods must concentrate a large volume of water and correctly identify oocysts in the concentrate. the u.s. environmental protection agency information collection rule (icr) protozoan method g ... | 2000 | 11048851 |
| risk of cryptosporidium parvum transmission between hospital roommates. | patients with active diarrhea caused by infection with cryptosporidium parvum can potentially contaminate the environment, which could serve as a risk for transmission to other patients in a hospital setting. a retrospective cohort study was performed to quantify the risk of nosocomial roommate-to-roommate transmission of cryptosporidium and to evaluate the need for isolation of cryptosporidium-infected patients. thirty-seven human immunodeficiency virus (hiv)-infected roommates of 21 index pati ... | 2000 | 11049775 |
| paromomycin: no more effective than placebo for treatment of cryptosporidiosis in patients with advanced human immunodeficiency virus infection. aids clinical trial group. | to evaluate the efficacy of paromomycin for the treatment of symptomatic cryptosporidial enteritis in human immunodeficiency virus-infected adults, we conducted a prospective, randomized, double-blind, placebo-controlled trial before the widespread introduction of highly active antiretroviral therapy (haart). seven units under the auspices of the aids clinical trials group enrolled 35 adults with cd4 cell counts of < or = 150/mm(3). initially, 17 patients received paromomycin (500 mg 4 times dai ... | 2000 | 11049793 |
| mannose-binding lectin is a component of innate mucosal defense against cryptosporidium parvum in aids. | nonimmune mechanisms of mucosal defense seem to be biologically important and might explain the observed variability in the course of enteric infection in immunodeficiency. mannose-binding lectin (mbl) deficiency is associated with persistent diarrhea in children. we found that genetic determinants of mbl deficiency appear to predispose to cryptosporidiosis in patients with the acquired immunodeficiency syndrome (aids), and went on to study interactions of mbl and complement on cryptosporidium p ... | 2000 | 11054381 |
| characterization of cryptosporidium parvum by matrix-assisted laser desorption ionization-time of flight mass spectrometry. | matrix-assisted laser desorption ionization-time of flight mass spectrometry (maldi-tof ms) was used to investigate whole and freeze-thawed cryptosporidium parvum oocysts. whole oocysts revealed some mass spectral features. reproducible patterns of spectral markers and increased sensitivity were obtained after the oocysts were lysed with a freeze-thaw procedure. spectral-marker patterns for c. parvum were distinguishable from those obtained for cryptosporidium muris. one spectral marker appears ... | 2000 | 11055915 |
| national surveillance for infection with cryptosporidium parvum, 1995-1998: what have we learned? | infection with cryptosporidium parvum generally causes a self-limiting diarrheal illness. symptoms can, however, last for weeks and can be severe, especially in immunocompromised individuals. in 1994, the council of state and territorial epidemiologists (cste) recommended that cryptosporidiosis be a nationally notifiable disease. forty-seven states have made infection with c. parvum notifiable to the centers for disease control and prevention (cdc), and laboratories in the three remaining states ... | 2000 | 11059430 |
| control of cryptosporidium in water systems using cartridge filtration. | | 2000 | 11066357 |
| prevalence of cryptosporidium parvum infection and pattern of oocyst shedding in calves in japan. | cryptosporidium parvum infection and the pattern of oocyst shedding were observed in calves. a total of 480 fecal samples were collected from 30 calves (age, < or =30 days) over a period of 10 months from june 1998 to march 1999. a sucrose centrifugal flotation technique revealed 28/30 (93%) calves were passing cryptosporidium oocysts. oocyst shedding was first detected on the sixth day after birth, with 8% of the calves testing positive. this rate increased day by day and reached approximately ... | 2000 | 11078941 |
| short-term exposure to membrane-active antibiotics inhibits cryptosporidium parvum infection in cell culture. | a cell culture system and double fluorogenic staining were used to study the susceptibility of cryptosporidium parvum to membrane-active antibiotics. buforin ii and magainin ii exerted a cytotoxic effect on sporozoites but did not consistently affect oocyst viability. lasalocid and nigericin demonstrated less activity against sporozoites but reduced the infectivity of oocysts. | 2000 | 11083662 |
| cloning and molecular characterization of a gene encoding a cryptosporidium parvum putative 20s proteasome beta1-type subunit. | a dna sequence composed of 1281 nucleotides (nt) consisting of a single open reading frame (orf) encoding a putative 20s proteasome beta1-type subunit was isolated from clones derived from genomic libraries constructed from the ksu-1 isolate of cryptosporidium parvum. southern blot analysis suggested that the sequenced dna exists in the c. parvum genome as a single copy; transcription was verified through reverse transcription-polymerase chain reaction (rt-pcr) performed on total rna isolated fr ... | 2000 | 11092745 |
| adoptive transfer of immunity with intraepithelial lymphocytes in cryptosporidium parvum-infected severe combined immunodeficient mice. | intestinal infections with the protozoan parasite cryptosporidium parvum are prevalent in both immunocompetent and immunocompromised hosts. although c parvum is an important cause of outbreaks and opportunistic infections worldwide, little is known about protective mucosal immune responses. this is in part because animal models of infection are limited to those with genetic or induced immunodeficiencies. | 2000 | 11093682 |
| eradication of cryptosporidia and microsporidia following successful antiretroviral therapy. | incidence of opportunistic protozoal infections causing diarrheal illnesses in patients with hiv has decreased since the introduction of highly active antiretroviral therapy (haart). the objective of this study was to determine whether the parasites, cryptosporidia, and microsporidia were effectively eradicated or only suppressed following treatment. | 2000 | 11103042 |
| emerging pathogens associated with infectious diarrhea. | in recent years, emerging microbial pathogens associated with infectious diarrhea have caused significant morbidity and mortality. although sporadic cases of infectious diarrhea have occurred worldwide in the past, recent outbreaks in the united states traced to contaminated water or food have raised concerns about the safety of the water supply and the adequacy of surveillance of the food supply and foodborne diseases. in 1993, cryptosporidium parvum, an important cause of unrelenting diarrhea ... | 1997 | 11105133 |
| epidemiology of cryptosporidium: transmission, detection and identification. | there are 10 valid species of cryptosporidium and perhaps other cryptic species hidden under the umbrella of cryptosporidium parvum. the oocyst stage is of primary importance for the dispersal, survival, and infectivity of the parasite and is of major importance for detection and identification. because most oocysts measure 4-6 microm, appear nearly spherical, and have obscure internal structures, there are few or no morphometric features to differentiate species and in vitro cultivation does no ... | 2000 | 11113257 |
| detection of cryptosporidium oocysts in soil samples by enzyme-linked immunoassay. | an elisa protocol was adapted for detection of cryptosporidium parvum oocysts in soil samples and the limit of detection of the test was determined. a modified indirect antigen capture elisa protocol was developed using monoclonal antibodies against the oocyst outer wall. the accuracy of the elisa was compared to spiked soil samples and measured in terms of sensitivity and specificity of the test. the performance of the elisa was evaluated in field soil samples and measured using the kappa-stati ... | 2001 | 11113547 |
| 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 ... | 2001 | 11120964 |
| estimating viability of cryptosporidium parvum oocysts using reverse transcriptase-polymerase chain reaction (rt-pcr) directed at mrna encoding amyloglucosidase. | the purpose of the present study was to determine if reverse transcriptase-polymerase chain reaction (rt-pcr) directed at mrna encoding the enzyme amyloglucosidase (cpag) could serve as a indicator for c. parvum oocyst viability. oocysts were stored for 1-11 months in the refrigerator and at monthly intervals extracted for total rna for rt-pcr analysis. an aliquot of these c. parvum oocysts was inoculated into neonatal mice which were necropsied 4 days later for ileal tissue that was analyzed by ... | 2000 | 11121608 |
| b cells are required for the induction of intestinal inflammatory lesions in tcralpha-deficient mice persistently infected with cryptosporidium parvum. | mice with targeted disruptions in the t-cell receptor alpha gene (tcralpha-/-) spontaneously develop inflammatory intestinal lesions with extensive b-cell lamina propria infiltrates. cryptosporidium parvum infection accelerates intestinal lesion formation in tcralpha-/- mice. in the present study, tcralpha-/- mice were crossed with jh-/- (b-cell-deficient) mice and challenged with c. parvum to determine if b cells are required for intestinal lesion development. tcralpha-/- x jh-/- mice challenge ... | 2000 | 11128483 |
| unexpected activity of beta-cyclodextrin against experimental infection by cryptosporidium parvum. | an unexpected activity of beta-cyclodextrin, an excipient used in pharmaceutical technology, was observed against cryptosporidium parvum. the viability and infectivity of purified oocysts, exposed for 24 hr to beta-cyclodextrin (2.5% suspension), were evaluated by inclusion/exclusion of 2 fluorogenic vital dyes and a suckling murine model, respectively. results of the viability assay showed a high proportion of nonviable oocysts (81.5%). the intensity of experimental infection, determined 7 days ... | 2000 | 11128490 |
| molecular characterization of a cryptosporidium isolate from a black bear. | to further validate the observation of the existence of host-adapted strains of cryptosporidium parvum, we genetically characterized an isolate of cryptosporidium parasite from a black bear. sequence analysis of the ribosomal rna small subunit and the 70-kda heat shock protein (hsp70) showed that this parasite represents a new genotype of c. parvum and is related to the c. parvum dog genotype. this finding is helpful for clarifying cryptosporidium taxonomy. | 2000 | 11128505 |
| host cell apoptosis impairs cryptosporidium parvum development in vitro. | the absence of a self-sustaining in vitro propagation method for cryptosporidium parvum is a major obstacle for research on this parasite. conventional cell monolayers are unsuitable for long-term parasite propagation because the level of infection decreases over time and few oocysts, if any, are produced. the interaction between parasite and host cell was studied to identify factors limiting parasite development in vitro. loss of substrate adherence and death of parasitized host cells was obser ... | 2000 | 11128511 |
| a factor derived from adult rat and cow small intestine reduces cryptosporidium parvum infection in infant rats. | cryptosporidium parvum is an intracellular protozoan parasite of the mammalian intestine. in rats, c. parvum infection is age related; infants are susceptible, whereas adults are resistant. the transition from susceptibility to resistance usually takes place around the age of weaning. in the present study, infant rats were orally inoculated with a preparation of intestinal scrapings taken from adult rats or cows. infant rats received the scrapings daily from 3 to 14 days of age, were inoculated ... | 2000 | 11128521 |
| antibody reactivity to cryptosporidium parvum in saliva of calves after experimental infection. | antibodies against cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. salivary anti-c. parvum iga antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. salivary anti-c. parvum igg antibody levels showed a gradual increase along with the change in iga antibody levels during the infection. in c ... | 2000 | 11129874 |
| enteropathogenicity of plesiomonas shigelloides and aeromonas spp. in experimental mono- and coinfection with cryptosporidium parvum in the intestine of neonatal balb/c mice. | enteropathogenicity of plesiomonas shigelloides, aeromonas hydrophila, a. caviae and a. sobria was studied both in monoinfections and in coinfections with coccidium cryptosporidium parvum in neonatal balb/c mice. in monoinfection experiments, neonatal balb/c mice were orally infected with 7 x 10(7) or 7 x 10(8) cfu, respectively, of a strain of p. shigelloides or a strain of an aeromonas spp. in coinfection experiments, the neonatal mice were, in addition to being orally infected with one of the ... | 2001 | 11131040 |
| cryptosporidium parvum infection stimulates the secretion of tgf-beta, il-8 and rantes by caco-2 cell line. | cryptosporidium parvum is a common cause of diarrhea in humans. although mild inflammatory mucosal infiltrate is usually observed, limited information is currently available on the pathogenic mechanisms involved in this phenomenon. the aim of this work was to investigate in vitro the influence of c. parvum infection on the secretion of lymphocyte-targeted chemokines (rantes. mip-1alpha, mip-1beta, il-8), proinflammatory cytokines (tnf-alpha, gm-csf and il-6) and tgf-beta by human enterocytic cac ... | 2000 | 11133108 |
| 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 ... | 2001 | 11133382 |
| the salivary apyrase of the blood-sucking sand fly phlebotomus papatasi belongs to the novel cimex family of apyrases. | apyrases are enzymes that hydrolyze nucleotide di- and triphosphates to orthophosphate and mononucleotides. at least two families of enzymes, belonging to the 5'-nucleotidase and to the actin/heat shock 70/sugar kinase superfamily, have evolved independently to serve the apyrase reaction. both families require either ca(2+) or mg(2+) for their action. a novel apyrase enzyme sequence, with no homology to any other known protein sequence, was found recently in the salivary glands of the hematophag ... | 2001 | 11136609 |
| multiyear prospective study of intestinal parasitism in a cohort of peace corps volunteers in guatemala. | we conducted a prospective, longitudinal study in a cohort of 36 peace corps volunteers (pcvs) in guatemala to study the incidence and natural history of intestinal parasitic infections during the pcvs' >2-year overseas stay. pcvs collected stool specimens at least monthly and when ill with gastrointestinal symptoms. of the 1,168 specimens tested, 453 (38.8%) were positive for at least one parasite and 48 (4.1%) were positive for a pathogenic parasite. a median interval of 187 days (range, 14 to ... | 2001 | 11136744 |
| evaluation of the triage micro parasite panel for detection of giardia lamblia, entamoeba histolytica/entamoeba dispar, and cryptosporidium parvum in patient stool specimens. | a study comparing the triage micro parasite panel (biosite diagnostics, inc., san diego, calif.) to conventional o&p examination (o&p) was performed using patient fecal specimens. five hundred twenty-three stool samples were compared. nineteen specimens were found to be positive by triage, and 29 were found to be positive by o&p. seven specimens were positive for giardia lamblia, four were positive for entamoeba histolytica/e. dispar, and three were positive for cryptosporidium parvum as determi ... | 2001 | 11136793 |
| extraction and genotyping of cryptosporidium parvum dna from fecal smears on glass slides stained conventionally for direct microscope examination. | a method was developed for extracting cryptosporidial dna from stained fecal smears on glass microscope slides. the correct genotype of cryptosporidium parvum was amplified by pcr from 89 (85%) of 105 smears following conventional staining but not from negative controls. this technique may have applications for analysis of other infectious agents. | 2001 | 11136813 |
| infections by protozoa in immunocompromised hosts. | protozoa are among the most important pathogens that can cause infection in immunocompromised patients. they infect particularly individuals with impaired cell immunity, such as those with hematologic neoplasias, those submitted to transplant of solid organs, those under high-dose corticosteroid therapy, and carriers of the human immunodeficiency virus. among the protozoa that most commonly cause disease in immunocompromised individuals are toxoplasma gondii, trypanosoma cruzi, cryptosporidium p ... | 2000 | 11142706 |
| activity of buforin ii alone and in combination with azithromycin and minocycline against cryptosporidium parvum in cell culture. | the in vitro anti-cryptosporidial activity of buforin ii alone and in combination with azithromycin and minocycline was investigated. buforin ii showed moderate activity, which increased with increasing concentration to 55.7% suppression of growth at 20 microm. moreover, its activity was enhanced when it was combined with either azithromycin or minocycline with >90% parasite reduction at the highest concentration tested. buforin ii may be active in inhibiting cryptosporidium parvum growth in vit ... | 2001 | 11152438 |
| rifabutin but not clarithromycin prevents cryptosporidiosis in persons with advanced hiv infection. | macrolides have been reported to be effective for the prevention of cryptosporidiosis in persons with hiv infection. | 2000 | 11153670 |
| [cryptosporidium spp. in farms in the eastern region of venezuela]. | cryptosporidiosis is caused by the coccidian protozoa cryptosporidium. it is the most worldwide prevalent pathogen associated with diarrhea in young cattle and usually is caused by c. parvum which is also responsible of infections in humans, specially in immunocompromised patients. faecal samples from 75 young cattle aged between 2 to 20 weeks, were collected in four western dairy farms of venezuela and screened for the presence of cryptosporidium oocysts. positive samples were detected in 22 an ... | 2000 | 11155766 |
| cryptosporidium infection in bedouin infants assessed by prospective evaluation of anticryptosporidial antibodies and stool examination. | an enzyme-linked immunosorbent assay system using oocyst lysate as antigen was used to detect serum- specific antibody responses to cryptosporidium parvum between 1989 and 1994 in consecutive sera obtained at birth, and at the age of 6, 12, and 23 months, from 52 infants living in a bedouin town located in the south of israel. the serologic tests revealed high levels of immunoglobulin g anti-cryptosporidium at birth that dropped significantly by the age of 6 months and then rose continuously to ... | 2001 | 11159166 |
| expression of tumor necrosis factor alpha and interleukin 1 beta in jejuna of volunteers after experimental challenge with cryptosporidium parvum correlates with exposure but not with symptoms. | jejunal biopsies from volunteers challenged with cryptosporidium parvum were examined for tumor necrosis factor alpha (tnf-alpha) and interleukin (il)-1 beta mrna. postchallenge biopsies from 15 of 28 (54%) volunteers expressed tnf-alpha; 14% expressed il-1 beta. cytokine expression did not correlate with enteric symptoms, suggesting that tnf-alpha and il-1 beta are not key mediators of diarrhea in human cryptosporidiosis. | 2001 | 11160015 |
| cryptosporidium parvum: functional complementation of a parasite transcriptional coactivator cpmbf1 in yeast. | we report here the identification of a novel multiprotein bridging factor type 1 from the apicomplexan cryptosporidium parvum (cpmbf1), one of the opportunistic pathogens in aids patients. in slime molds, insects, and humans, mbf1-regulated systems have been associated with cell differentiation, which indicates that cpmbf1 could be responsible for the activation of similar systems in c. parvum during its complex life cycle. because of the difficulties and high cost in obtaining sufficient and pu ... | 2000 | 11162372 |
| marrow-derived cd40-positive cells are required for mice to clear cryptosporidium parvum infection. | to clear a cryptosporidium parvum infection, mice need cd4+ t cells, major histocompatibility complex class ii, and an intact cd40-cd154 signaling pathway. cd40 is constitutively expressed on marrow-derived cells such as dendritic cells and b lymphocytes and is induced by gamma interferon (ifn-gamma) on most somatic cells. to determine whether the cd40 needed to clear a c. parvum infection has to be on marrow-derived mononuclear cells or on the epithelial cells that normally harbor the parasite, ... | 2001 | 11179337 |
| cryptosporidium parvum-specific mucosal immune response in c57bl/6 neonatal and gamma interferon-deficient mice: role of tumor necrosis factor alpha in protection. | both neonatal and c57bl/6 gamma interferon (ifn-gamma) knockout (c57bl/6-gko) mice are susceptible to cryptosporidium parvum, but the course of infection is different. neonatal mice are able to clear the parasite within 3 weeks, whereas c57bl/6-gko mice, depending on age, die rapidly or remain chronically infected. the mechanism by which ifn-gamma leads to a protective immunity is yet poorly understood. in order to investigate the effect of ifn-gamma on other cytokines expressed in the intestina ... | 2001 | 11179338 |
| characterization of an intestinal epithelial cell receptor recognized by the cryptosporidium parvum sporozoite ligand csl. | the protozoan parasite cryptosporidium parvum is a leading cause of diarrhea in humans and neonatal calves. the absence of approved parasite-specific drugs, vaccines, and immunotherapies for cryptosporidiosis relates in part to limited knowledge on the pathogenesis of zoite attachment and invasion. we recently reported that the c. parvum apical complex glycoprotein csl contains a zoite ligand for intestinal epithelial cells which is defined by monoclonal antibody (mab) 3e2. in the present study, ... | 2001 | 11179341 |
| morphologic, host specificity, and genetic characterization of a european cryptosporidium andersoni isolate. | this study was undertaken in order to characterize a cryptosporidium muris-like parasite isolated from cattle in hungary and to compare this strain with other cryptosporidium species. to date, the large-type oocysts isolated from cattle were considered as c. muris described from several mammals. the size, form, and structure of the oocysts of the hungarian strain were identical with those described by others from cattle. an apparent difference between the morphometric data of c. muris-like paras ... | 2000 | 11191899 |
| detection of the cryptosporidium parvum "human" genotype in a dugong (dugong dugon). | the cryptosporidium "human" genotype was identified in a paraffin-embedded tissue section from a dugong (dugong dugon) by 2 independent laboratories. dna sequencing and polymerase chain reaction/restriction fragment length polymorphism analysis of the 18s ribosomal rna gene and the acetyl coa synthethase gene clearly identified the genotype as that of the cryptosporidium variant that infects humans. this is the first report of the human cryptosporidium genotype in a nonprimate host. | 2000 | 11191916 |
| detection of mucosally delivered antibody to cryptosporidium parvum p23 in infected calves. | we have developed an assay to detect mucosally delivered antibody to cryptosporidium parvum sporozoite antigens. we absorbed a recombinant 23-kd sporozoite protein to polystyrene microspheres, and used flow cytometry to detect, titer, and determine the isotype of antibody to p23 that was shed in the feces of experimentally infected calves. noninoculated calves have low levels of mucosal antibody to p23, with igg1 as the predominant isotype. antibody titers rise in inoculated calves as the animal ... | 2000 | 11193650 |
| the effect of ivermectin on cryptosporidium parvum in experimentally infected rat. | ivermectin, (=ivomec) a broad spectrum antiparasitic agent has become a promising drug for treating wide range of parasitic infection and infestation. this study was carried out to investigate its activity against cryptosporidiosis in a rat model. the results showed that ivermectin is effective at a dose of 200 mg/kg. | 2000 | 11198372 |
| interferon gamma induces enterocyte resistance against infection by the intracellular pathogen cryptosporidium parvum. | interferon (ifn)-gamma plays an important role in the immunologic control of infection by the protozoan enteropathogen cryptosporidium parvum. we tested the hypothesis that ifn-gamma may directly inhibit infection of enterocytes by this pathogen. | 2001 | 11208718 |
| [cryptosporidiosis in the andean region of colombia: seroprevalence and recognition of antigens]. | the objective of this study was to investigate, for the first time, the seroprevalence of cryptosporidiosis among urban and rural inhabitants in several departments of the andean region of colombia. the antigen recognition of cryptosporidium parvum was also studied with sera. between june 1996 and october 1998 1,778 serum samples were collected from people selected through convenience sampling. the detection of anti-c. parvum antibodies (igm, iga, and igg) was carried out with enzyme-linked immu ... | 2000 | 11209249 |
| [outbreak of cryptosporidiosis in guadarrama (autonomous community of madrid)]. | in spring of 1998, an acute gastroenteritis outbreak, which mainly affected preschool children, took place in guadarrama (community of madrid, spain). | 2000 | 11217242 |
| immunoassay for viable cryptosporidium parvum oocysts in turbid environmental water samples. | cryptosporidium parvum oocysts in drinking water have been implicated in outbreaks of diarrheal disease. current methods for monitoring environmental exposures to c. parvum only account for total number of oocysts without regard for the viability of the parasite. measurement of oocyst viability, as indicated by an oocyst's ability to excyst, is useful because over time oocysts lose the ability to excyst and become noninfective. thus, correlating the number of viable oocysts in drinking water wit ... | 2001 | 11227892 |
| treatment with agmatine inhibits cryptosporidium parvum infection in infant mice. | cryptosporidium parvum is an intracellular protozoan parasite that causes enteric infection and diarrhea in a wide range of mammalian hosts, including humans and economically important livestock species. there are no effective vaccines or drug treatments available for cryptosporidiosis. cryptosporidium parvum utilizes a unique metabolic pathway for the synthesis of polyamines, forming agmatine as an intermediary metabolite. we treated infant mice with oral doses of agmatine for 2 days before, th ... | 2001 | 11227893 |
| relevance of cryptosporidium parvum hsp70 mrna amplification as a tool to discriminate between viable and dead oocysts. | two mrna extraction methods were compared in this study to clarify the discrepancies found between authors regarding the presence of mrna in inactivated cryptosporidium parvum oocysts. cryptosporidium parvum heat shock protein 70 (hsp70) mrna extraction was performed by using oligo(dt)20-labeled magnetic beads or by incubating oocyst lysates with dnase i. significant differences in mrna recovery rates between these 2 techniques were observed when working on inactivated oocysts. we consistently d ... | 2001 | 11227898 |
| evidence for the emergence of a type-1-like immune response in intestinal mucosa of calves recovering from cryptosporidiosis. | this study was undertaken to characterize the mucosal response to cryptosporidium parvum in infected calves that had recovered from diarrhea. flow cytometric surface phenotypes of lamina propria lymphocyte (lpl) suspensions from infected calves and age-matched controls revealed the presence of a significantly larger proportion of cd25+ lpl in infected calves than in controls. freshly isolated lpl from infected calves expressed more inos and interferon (ifn)-gamma than did controls. infected calv ... | 2001 | 11227908 |
| concentration and detection of cryptosporidium oocysts in surface water samples by method 1622 using ultrafiltration and capsule filtration. | the protozoan parasite cryptosporidium parvum is known to occur widely in both source and drinking water and has caused waterborne outbreaks of gastroenteritis. to improve monitoring, the u.s. environmental protection agency developed method 1622 for isolation and detection of cryptosporidium oocysts in water. method 1622 is performance based and involves filtration, concentration, immunomagnetic separation, fluorescent-antibody staining and 4',6-diamidino-2-phenylindole (dapi) counterstaining, ... | 2001 | 11229901 |
| 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 ... | 2001 | 11229905 |
| identification of enteropathogenic escherichia coli in simian immunodeficiency virus-infected infant and adult rhesus macaques. | enteropathogenic escherichia coli (epec) was recognized as a common opportunistic pathogen of simian immunodeficiency virus-infected rhesus macaques (macaca mulatta) with aids. retrospective analysis revealed that 27 of 96 (28.1%) animals with aids had features of epec infection, and epec was the most frequent pathogen of the gastrointestinal tract identified morphologically. in 7.3% of animals dying with aids, epec represented the sole opportunistic agent of the gastrointestinal tract at death. ... | 2001 | 11230413 |