Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
differentiation between human and animal isolates of cryptosporidium parvum using molecular and biological markers.isolates of cryptosporidium parvum obtained from infected humans, calves and lambs were typed using arbitrary primed polymerase chain reaction (ap-pcr) and isoenzyme electrophoresis. all animal isolates tested (n = 17) showed similar profiles in ap-pcr and isoenzyme typing. in ap-pcr assays, 9 out of 15 human isolates showed a distinct "human" profile while the remaining 6 isolates showed the "animal" profile. in isoenzyme typing, 5 human isolates which had shown "human" profiles in ap-pcr demon ...19989569095
cryptosporidiosis in young alpacas. 19989569489
lack of activity of an association of detergent and germicidal agents on the infectivity of cryptosporidium parvum oocysts. 19989570672
sensitive and rapid detection of viable giardia cysts and cryptosporidium parvum oocysts in large-volume water samples with wound fiberglass cartridge filters and reverse transcription-pcr.we recently described a reverse transcription-pcr (rt-pcr) for detecting low numbers of viable cryptosporidium parvum oocysts spiked into clarified environmental water concentrates. we have now modified the assay for direct analysis of primary sample concentrates with simultaneous detection of viable c. parvum oocysts, giardia cysts, and a novel type of internal positive control (ipc). the ipc was designed to assess both efficiency of mrna isolation and potential rt-pcr inhibition. sensitivity t ...19989572946
differentiation of cryptosporidium parvum isolates by a simplified randomly amplified polymorphic dna technique.genomic dna was isolated from cryptosporidium parvum oocysts by a specific immunomagnetic separation-in vitro excystation procedure and subjected to randomly amplified polymorphic dna analysis using sequence-independent primers. an estuary c. parvum isolate was easily differentiated from several bovine isolates, while five bovine isolates of the same origin were indistinguishable from each other.19989572980
cryptosporidium parvum infection of human intestinal xenografts in scid mice induces production of human tumor necrosis factor alpha and interleukin-8.the protozoan parasite cryptosporidium parvum invades intestinal epithelial cells and can cause life-threatening diarrhea in immunocompromised individuals. despite the clinical importance of this organism, much remains to be learned about the pathogenesis of c. parvum-induced diarrhea. to explore the role of the intestinal inflammatory response in c. parvum disease, using c. parvum oocysts we infected human intestinal xenografts in severe combined immunodeficient (scid) mice. seven days after in ...19989573136
intestinal parasitic infections in human immunodeficiency virus (hiv)-positive and hiv-negative individuals in san pedro sula, honduras.honduras has at least five-times more human immunodeficiency virus (hiv)-infected individuals than any other country in central america. the relationship between hiv status and the presence of intestinal parasites in this part of the world is unknown. this study presents the results from a prospective, comparative study for the presence of parasites in 52 hiv-positive and 48 hiv-negative persons in san pedro sula, honduras. infection with hiv was determined by microagglutination and confirmed by ...19989574787
molecular cloning and expression analysis of a cryptosporidium parvum gene encoding a new member of the thrombospondin family.the apicomplexan parasite cryptosporidium parvum invades and multiplies primarily in the brush border cells of the intestinal mucosa causing in aids patients a severe diarrhoea that represents a significant contributing factor leading to death. morphological analysis indicates that the invasion machinery of c. parvum is similar to the apical complex of other parasites of the phylum apicomplexa. we provide here evidence indicating that c. parvum also shares with these parasites a molecule crucial ...19989574918
failure to differentiate cryptosporidium parvum from c. meleagridis based on pcr amplification of eight dna sequences.in order to determine the specificities of pcr-based assays used for detecting cryptosporidium parvum dna, eight pairs of previously described pcr primers targeting six distinct regions of the cryptosporidium genome were evaluated for the detection of c. parvum, the agent of human cryptosporidiosis, and c. muris, c. baileyi, and c. meleagridis, three cryptosporidium species that infect birds or mammals but are not considered to be human pathogens. the four cryptosporidium species were divided in ...19989575132
hydrogen peroxide gas plasma sterilization is effective against cryptosporidium parvum oocysts.the aim of this work was to evaluate in an immunosuppressed rat cryptosporidiosis model a new method that combines vacuum and low-temperature hydrogen peroxide gas plasma for sterilization of endoscopic material contaminated by cryptosporidium parvum. rats were challenged with oocysts either air-dried or air-dried and treated with vacuum alone or associated with gas plasma. no rat was found infected after gas plasma exposure of oocysts, whereas vacuum or air-drying alone resulted only in a decre ...19989584807
direct isolation of dna from patient stools for polymerase chain reaction detection of cryptosporidium parvum.although polymerase chain reaction (pcr) can sensitively detect parasitic or other infections, its use with fecal samples is extremely limited, primarily because of the presence of substances that inhibit dna extension. here an improved protocol is reported for directly isolating dna from aged or fresh formalin-fixed stools, which can then be used to detect cryptosporidium parvum by nested pcr. this method is highly reproducible, sensitive, and specific. it detects <1 pg of c. parvum dna in huma ...19989593044
hypoxanthine, guanine, xanthine phosphoribosyltransferase activity in cryptosporidium parvum.all parasitic protozoa examined to date are incapable of de novo synthesis of purine nucleotides and rely on salvage mechanisms for survival. we have identified hypoxanthine, guanine, xanthine phosphoribosyl-transferase activities in crude cell-free extracts of cryptosporidium sporulated oocysts utilizing radiolabeled substrates. guanine, hypoxanthine, and xanthine were converted to their corresponding mononucleotides with specific activities of 346, 280, and 108 nmol/min/mg protein, respectivel ...19989603483
randomly amplified polymorphic dna pcr analysis of bovine cryptosporidium parvum strains isolated from the watershed of the red river of the north.cryptosporidium parvum is a protozoan parasite that causes the disease cryptosporidiosis in a variety of mammals, including neonatal calves and humans. millions of oocysts are shed during acute cryptosporidiosis, and zoonotic transmission is inferred, though not proven, to be a general phenomenon. very little is known about the degree of strain variation exhibited by bovine and human isolates, though such knowledge would enable the amount of bovine-to-human transmission to be more precisely anal ...19989603845
method detection limits of pcr and immunofluorescence assay for cryptosporidium parvum in soil.we determined and compared the method detection limits (mdlalpha) of a pcr and an immunofluorescence assay (ifa) for detection of cryptosporidium parvum oocysts in soils. based on the mdlalpha and the quantitative nature and stability of the ifa, pcr analysis is not a useful screening step for soil studies of oocyst transport.19989603851
attachment of cryptosporidium parvum sporozoites to human intestinal epithelial cells.an enzyme-linked immunosorbent assay-based attachment model using the human intestinal cell line caco-2a was developed to study attachment of cryptosporidium parvum sporozoites in vitro and to assess potential inhibitors of sporozoite binding. in this system, attachment was related to sporozoite dose, incubation time, and host cell differentiation status. polyclonal antibodies to c. parvum as well as glycoprotein inhibitors of a sporozoite lectin reduced attachment. this model will be a valuable ...19989632617
high-temperature inducible cell-free transcription and replication of double-stranded rnas within the parasitic protozoan cryptosporidium parvum.sporozoites of the protozoan parasite, cryptosporidium parvum, were found to contain free, full-size plus strands transcribed from two extrachromosomal, cytoplasmic, virus-like double-stranded rnas (dsrnas). cell-free transcription and replication of both dsrnas were observed in crude sporozoite lysates. rna polymerase activity was found to be dependent upon addition of mg2+ or mn2+, as well as the four ribonucleoside triphosphates, and was insensitive to inhibitors of cellular dna-dependent rna ...19989636372
prophylactic effect of bovine anti-cryptosporidium hyperimmune colostrum immunoglobulin in healthy volunteers challenged with cryptosporidium parvum.bovine hyperimmune anti-cryptosporidium colostrum immunoglobulin (baci) decreases the intensity of cryptosporidium parvum infection in vitro. we investigated the prophylactic effect of baci in healthy adults challenged with c. parvum. after we established an oocyst dose that resulted in 100% infection in four volunteers (baseline group), 16 volunteers were randomized to receive (1) baci prior to c. parvum challenge (baci group) and a nonfat milk placebo 30 minutes later, (2) baci prior to and 30 ...19989636857
cryptosporidium and other parasites in ethiopian aids patients with chronic diarrhoea.previous studies in other african countries have shown high prevalences of isospora belli and cryptosporidium parvum infections in acquired immunodeficiency syndrome (aids) patients with chronic diarrhoea. however, there is lack of information regarding these infectious agents in ethiopian aids patients. thus, this investigation has been aimed at determining the prevalence of cryptosporidium and other related gastrointestinal parasites in aids patients with diarrhoea in seven addis ababa hospita ...19989640833
giardia sp. cysts and infectious cryptosporidium parvum oocysts in the feces of migratory canada geese (branta canadensis).fecal droppings of migratory canada geese, branta canadensis, collected from nine sites near the chesapeake bay (maryland), were examined for the presence of cryptosporidium parvum and giardia spp. cryptosporidium sp. oocysts were found in feces at seven of nine sites, and giardia cysts were found at all nine sites. the oocysts from three sites were infectious for mice and molecularly identified as the zoonotic genotype of cryptosporidium parvum. waterfowl can disseminate infectious c. parvum oo ...19989647860
determination of immuno-cross-reactivity between cryptosporidium parvum and eimeria spp.immuno-cross-reactivity between cryptosporidium parvum and eimeria spp. was studied by the indirect fluorescent antibody test (ifat) and western blot procedure. thirty-seven sera from asymptomatic (non-diarrheic) cattle, with known coprological (presence-absence of coccidia) and serological data respecting c. parvum, were tested by ifat using eimeria oocysts as antigen. most sera (54%) displayed immunofluorescence around the surface of the eimeria oocysts. simultaneously, serum samples from rabb ...19989653985
evidence for the shikimate pathway in apicomplexan parasites.parasites of the phylum apicomplexa cause substantial morbidity, mortality and economic losses, and new medicines to treat them are needed urgently. the shikimate pathway is an attractive target for herbicides and antimicrobial agents because it is essential in algae, higher plants, bacteria and fungi, but absent from mammals. here we present biochemical, genetic and chemotherapeutic evidence for the presence of enzymes of the shikimate pathway in apicomplexan parasites. in vitro growth of toxop ...19989655396
persistent diarrhea in the returned traveler.in conclusion, the causes of chronic diarrhea in the returned traveler are protean. careful evaluation requires an understanding of where the traveler has been, when they were there, the type of diarrheal illness, medications taken, and knowledge of the patients' other medical problems. protozoa, particularly g. lamblia, c. parvum, and c. cayatenensis, are among the more commonly identified agents. if the patient is immunocompromised, microsporidia and isospora become more likely, and a prior hi ...19989658255
infection by cryptosporidium parvum in renal patients submitted to renal transplant or hemodialysis.the frequency of infection by cryptosporidium parvum was determined in two groups of renal patients submitted to immunosuppression. one group consisted of 23 renal transplanted individuals, and the other consisted of 32 patients with chronic renal insufficiency, periodically submitted to hemodialysis. a third group of 27 patients with systemic arterial hypertension, not immunosuppressed, was used as control. during a period of 18 months all the patients were submitted to faecal examination to de ...19989662959
paromomycin and geneticin inhibit intracellular cryptosporidium parvum without trafficking through the host cell cytoplasm: implications for drug delivery.cryptosporidium parvum, which causes intractable diarrhea and lethal wasting in people with aids, occupies an unusual intracellular but extracytoplasmic niche. no reliable therapy for cryptosporidiosis exists, though the aminoglycoside paromomycin is somewhat effective. we report that paromomycin and the related compound geneticin manifest their major in vitro anti-c. parvum activity against intracellular parasites via a mechanism that does not require drug trafficking through the host cell cyto ...19989673275
acute pancreatitis associated with cryptosporidium parvum enteritis in an immunocompetent man. 19989675489
pulmonary cryptosporidiosis in patients with acquired immunodeficiency syndrome.several reports have showed cryptosporidium species as a cause of intractable diarrhea and malabsorption in patients with acquired immunodeficiency syndrome (hiv). a case of chronic diarrhea in a drug addict woman associated with a symptomatic interstitial pulmonary infection due to cryptosporidium parvum is described. this unusual c. parvum spread into the bronchial tree is underlined and a survey of the literature is made.19989676183
the epidemiology of cryptosporidiosis: application of experimental sub-typing and antibody detection systems to the investigation of water-borne outbreaks.a technique based on the analysis of banding patterns obtained by sds-page western-blotting of an oocyst wall antigen obtained from faeces has been evaluated to subtype cryptosporidium parvum tyzzer, 1912. this technique appears to have sufficient stability to recognise multiple types of this parasite. a similar western-blotting technique has also been used to assess antibody responses to cryptosporidial antigens in human sera. two systems were developed: one against three antigens of apparent m ...19989684318
cryptosporidium parvum infection in experimentally infected mice: infection dynamics and effect of immunosuppression.the effect of mouse strain, age, sex, and the size of infective dose on the susceptibility to infection with the coccidium cryptosporidium parvum tyzzer, 1912 was determined using several murine models. mice were infected with c. parvum oocysts originally of cervine origin, maintained by repeat passage in calves. all mice in the experimental groups proved susceptible to infection, though this resulted asymptomatic in all cases. c. parvum infection in balb/c and porton mice exhibited some variati ...19989684319
viability of cryptosporidium parvum oocysts in natural waters.water-borne transmission of the coccidium cryptosporidium parvum tyzzer, 1912 is frequently responsible for outbreaks of human cryptosporidiosis. one of the most important was reported in 1993 in milwaukee in the united states, where 403,000 cases were recorded. the determination of the percentage of oocysts excystated is the first step in evaluating their viability, but it alone is not sufficient. this percentage depended on the conditions of storage and also the presence of oxidant or disinfec ...19989684321
clinical features of diarrhoea in children caused by cryptosporidium parvum. 19989684327
the role of wild rodents in ecology of cryptosporidiosis in poland. 19989684328
efficacy of nitazoxanide against cryptosporidium parvum in cell culture and in animal models.nitazoxanide (ntz), a drug currently being tested in human clinical trials for efficacy against chronic cryptosporidiosis, was assessed in cell culture and in two animal models. the inhibitory activity of ntz was compared with that of paromomycin (prm), a drug that is partially effective against cryptosporidium parvum. a concentration of 10 microg of ntz/ml (32 microm) consistently reduced parasite growth in cell culture by more than 90% with little evidence of drug-associated cytotoxicity, in c ...19989687390
control of the immune response by dhea and its metabolites.the 17 keto steroid, dehydroepiandrosterone (5-androsten-3 beta-17-one, dhea) has been shown to protect mice from a variety of lethal infections. this includes, but is not limited to, infection with viruses (herpesvirus type 2, coxsackievirus b4-cvb4),bacteria (enterococcus faecalis, pseudomonas aeruginosa), and a parasite (cryptosporidium parvum). we have reported that androstenediol (5-androsten-3 beta-17 beta-diol, beta aed), which is derived from dhea, is at least 100x more effective in up-r ...19989691759
molecular characterization of cryptosporidium from various hosts.a 298 bp region of the cryptosporidium parvum 18s rdna and a 390 bp region of the acetyl-coa synthetase gene were sequenced for a range of human and animal isolates of cryptosporidium from different geographical areas. a distinct genotype is common to isolates from cattle, sheep and goats and also an alpaca from peru and is referred to here as the 'calf'-derived cryptosporidium genotype. another genotype of 'human'-derived isolates also appears to be conserved amongst human isolates although hum ...19989695098
the gamma interferon gene knockout mouse: a highly sensitive model for evaluation of therapeutic agents against cryptosporidium parvum.cryptosporidiosis is a serious disease in malnourished children and in people with malignancies or aids. current rodent models for evaluating drug therapy against cryptosporidiosis have many limitations, including the need for a high inoculum, the absence of symptoms resembling those seen in humans, and the need to maintain exogenous immunosuppression. we have developed a gamma interferon knockout (gko) mouse model with which to evaluate therapies against c. parvum and have used paromomycin for ...19989705383
detection of cryptosporidia in different water sources in alexandria by monoclonal antibody test and modified ziehl neelsen stain.cryptosporidium paruum has become one of the most important contaminant found in drinking water and is associated with high risk of waterborne diseases particularly for the immunocompromised. in the present study, cryptosporidium was found in uncovered water tanks, nearby the shore in el noubareya and el mahmoudeya canals and in one swimming pool. direct flourescence monoclonal antibody was more sensitive in detecting the organism. ziehl-neelsen although less sensitive, yet it has the advantage ...19989707677
decreased prevalence of intestinal cryptosporidiosis in hiv-infected patients concomitant to the widespread use of protease inhibitors. 19989708424
il-4 protects adult c57bl/6 mice from prolonged cryptosporidium parvum infection: analysis of cd4+alpha beta+ifn-gamma+ and cd4+alpha beta+il-4+ lymphocytes in gut-associated lymphoid tissue during resolution of infection.resistance of adult c57bl/6 mice to severe cryptosporidium parvum infection is dependent on cd4+alpha beta+ tcr lymphocytes. in this study, we demonstrated that treatment with anti-ifn-gamma mab extended oocyst excretion 18 days longer, and anti-il-4 mab extended oocyst excretion at least 11 days longer than isotype control mab treatment. analysis of the specific activity of anti-ifn-gamma mab present in treated mouse sera suggested that ifn-gamma may have a limited role in the resolution phase ...19989712058
role of immunoglobulin a monoclonal antibodies against p23 in controlling murine cryptosporidium parvum infection.cryptosporidium parvum is an important diarrhea-causing protozoan parasite of immunocompetent and immunocompromised hosts. immunoglobulin a (iga) has been implicated in resistance to mucosal infections with bacteria, viruses, and parasites, but little is known about the role of iga in the control of c. parvum infection. we assessed the role of iga during c. parvum infection in neonatal mice. iga-secreting hybridomas were developed by using peyer's patch lymphocytes from balb/c mice which had bee ...19989712802
dicationic furans inhibit development of cryptosporidium parvum in hsd/icr suckling swiss mice.the efficacy of dicationic diarylfurans was evaluated against cryptosporidium parvum by a suckling murine model. candidate drugs were solubilized or suspended in deionized water and administered orally at a constant dose rate on days 0-5 (treatment day 0) to suckling icr swiss mice experimentally inoculated with oocysts of c. parvum. efficacy was based on numbers of oocysts recovered from the intestinal tracts of mice subjected to necropsy examination on day 6. numerous candidate furans signific ...19989714224
[clinical profile of cryptosporidiosis in a pediatric hospital environment in burkina faso].data concerning cryptosporidium parvum infection in black africa are highly fragmentary. a 12-month study was carried out on 1392 stool specimens from children under 36 months of age with (n = 756) or without diarrhea (n = 629) in the pediatric department of bobo dioulasso hospital in burkina faso. in 558 children hiv blood tests were also performed. the phenicated fuchsin technique was used to identify cryptosporidia oocysts. results were positive in 72 of the 1392 stool specimens tested (5.2%) ...19989718555
bovine t cell responses to cryptosporidium parvum infection.to better understand the immune mechanisms important for clearing of the primary infection and the subsequent development of resistance to cryptosporidium parvum infection, several groups have recently characterised changes within the lymphoid cell population of the intestinal mucosa and associated lymphoid tissue in calves with cryptosporidiosis. in naive animals, infection results in a significant increase in the number of cd4+ and cd8+ t cells present within the intraepithelial lymphocyte pop ...19989724879
the signature 10-hydroxy stearic acid thought to correlate with infectivity in oocysts of cryptosporidium species is an artifact.heating or freezing leads to loss in infectivity of oocysts of cryptosporidium parvum toward neonatal balb/c mice and is reflected in the profile of the polar lipid fatty acids. upon loss of infectivity, the ratio of polar lipid to neutral lipid fatty acid decreased and the relative proportions of 18:1n-9 also decreased; proportions of 18:2n-6 and 20:5n-6 increased, whereas the proportions of 16:0 remained constant with freezing. during these investigations, a novel fatty acid, 10-oh 18:0, was d ...19989727616
the antibody response to 27-, 17-, and 15-kda cryptosporidium antigens following experimental infection in humans.previous studies have suggested that persons infected with cryptosporidium parvum develop antibody responses to 27-, 17-, and 15-kda c. parvum antigens. studies of volunteers infected with cryptosporidium species provided an opportunity to evaluate the relationship between antibody reactivity to these antigens and infection outcome. as monitored by immunoblot, increases in specific antibody reactivity were more prevalent among volunteers who developed signs and symptoms of cryptosporidiosis (n = ...19989728553
genotypic and phenotypic characterization of cryptosporidium parvum isolates from people with aids.genotypic analysis of cryptosporidium parvum has demonstrated the presence of two subgroups within the species, whereas biochemical and antigenic characterization have shown more heterogeneity. the clinical relevance of these observations is unknown. c. parvum isolates from people with aids were studied with respect to parasite genotypes and virulence in cell monolayers and laboratory animals. ten of 13 oocyst samples had a characteristic human-associated (h) genotype; 3 had a genotype typical o ...19989728554
identification and cloning of a developmentally regulated cryptosporidium parvum gene by differential mrna display pcr.to identify cryptosporidium parvum genes expressed during intracellular development, differential mrna display was used to detect differences in gene expression between mock-infected and c. parvum-infected human epithelial cells. a reproducible band present only in c. parvum-infected cells, ddhc-23, was isolated and cloned. southern blot analysis demonstrated that ddhc-23 represented a c. parvum gene. rt-pcr revealed that hc-23 mrna levels decreased from 6 to 12h post-infection (pi), were maxima ...19989729442
evaluation of periparturient dairy cows and contact surfaces as a reservoir of cryptosporidium parvum for calfhood infection.to determine whether periparturient cows or contact surfaces to which newborn calves are exposed are reservoirs of cryptosporidium parvum oocysts.19989736387
effects of cryptosporidium parvum infection in peruvian children: growth faltering and subsequent catch-up growth.the authors conducted a 2-year (1989-1991) community-based longitudinal study in a shantytown in lima, peru, to examine the effect of cryptosporidium parvum infection on child growth during the year following the onset of infection. a cohort of children, aged 0-3 months at recruitment, was followed monthly for anthropometrics, weekly for stool samples, and daily for diarrheal status. data from 185 children in the cohort permitted a comparison of growth in c. parvum-infected and noninfected child ...19989737562
telomeric sequences of cryptosporidium parvum. 19989747979
cryptosporidiosis in urban zambian children: an analysis of risk factors.in four crowded townships of lusaka, zambia, the prevalence of cryptosporidiosis in 222 children with diarrhea was 18%, with marked temporal and geographic variation over the course of one rainy season. using data on the finding of oocysts of cryptosporidium parvum in urban water supplies, the areas under study were categorized as high or low risk. prevalence of cryptosporidiosis in children with diarrhea was higher in high risk areas after stratification by early/late stage of the rains (mantel ...19989749640
the use of a ribosomal rna targeted oligonucleotide probe for fluorescent labelling of viable cryptosporidium parvum oocysts.a fluorescence in situ hybridization (fish) technique has been developed for the fluorescent labelling of cryptosporidium parvum oocysts in water samples. the fish technique employs a fluorescently labelled oligonucleotide probe (cry1 probe) targeting a specific sequence in the 18s ribosomal rna (rrna) of c. parvum. hybridization with the cry1 probe resulted in fluorescence of sporozoites within oocysts that were capable of excystation, while oocysts that were dead prior to fixation did not fluo ...19989750273
cryptosporidium parvum is cytopathic for cultured human biliary epithelia via an apoptotic mechanism.while the clinical features of sclerosing cholangitis secondary to opportunistic infections of the biliary tree in patients with acquired immunodeficiency syndrome (aids) are well known, the mechanisms by which microbial pathogens such as cryptosporidium parvum associated with this syndrome actually cause disease are obscure. we established an in vitro model of biliary cryptosporidiosis employing a human biliary epithelial cell line. using morphological and biochemical techniques, we examined th ...19989755224
new perspectives on the pathogenesis of cryptosporidium biliary disease. 19989755257
establishing the cryptosporidium parvum karyotype by noti and sfii restriction analysis and southern hybridization.the molecular karyotype of the coccidian parasite cryptosporidium parvum has proven difficult to study because chromosomes of similar sizes migrate together when submitted to pulsed-field gel electrophoresis (pfge). in the present work, the karyotype was studied by restriction of chromosome-sized dna with the rare-cutting enzymes noti and sfii, followed by pfge separation of the restriction fragments and southern hybridization. these experiments showed that the c. parvum karyotype is formed by e ...19989757000
viable cryptosporidium parvum oocysts exposed to chlorine or other oxidising conditions may lack identifying epitopes.the intestinal protozoan parasite cryptosporidium parvum is a known cause of water-borne disease in humans. the detection of cryptosporidium oocysts in water samples relies upon the use of fluorescently labelled antibodies, preferably using flow cytometry and epifluorescence microscopy. here we demonstrate that four commercially available antibodies recognise a similar set of immunodominant epitopes on the oocyst wall. these epitopes appear to be carbohydrate in nature and are labile to chlorine ...19989762566
prevalence of and risk factors for shedding of cryptosporidium parvum in holstein freisian dairy calves in central méxico.a total of 31 dairy farms from three states in central méxico were selected for this study in order to determine the prevalence of and risk factors for cryptosporidium parvum shedding in young holstein freisian calves. fecal samples were obtained once from each calf for acid-fast staining for detection of c. parvum oocysts. information on each calf and on each dairy's management practices regarding the maternity pen, calf hutches and calf feeding was obtained by personal interview using a standa ...19989762732
characterisation of a cryptosporidium parvum-specific cdna clone and detection of parasite dna in mucosal scrapings of infected mice.a cdna library was constructed using total rna extracted from oocysts and sporozoites of the protozoan parasite cryptosporidium parvum. the expression library was screened with an anti-c. parvum antiserum and a clone, cp3.4, with a 2043 bp insert, was extracted. southern blot analysis demonstrated a single copy gene that was located on a 1.6 mb chromosome. the gene was found to be c. parvum specific as cp3.4 did not cross-hybridise with chromosomal dna from three other apicomplexan parasites. th ...19989763286
construction and characterisation of a genomic pac library of the intestinal parasite cryptosporidium parvum. 19989763297
cryptosporidium parvum: pcr-rflp analysis of the trap-c1 (thrombospondin-related adhesive protein of cryptosporidium-1) gene discriminates between two alleles differentially associated with parasite isolates of animal and human origin. 19989769250
declining prevalence of cryptosporidiosis in san francisco. 19989770178
cyclosporiasis in a traveler returning from south america.cyclospora is a coccidian, previously referred to as a cyanobacterium-like body, with an epidemiology similar to that of cryptosporidium parvum. in recent years, several studies have shown that cyclospora is not a rare opportunistic pathogen but rather is the cause of common, worldwide intestinal infections in healthy adults and children. previous reports of diarrhea resulting from cyclospora sp. have been linked to travelers and immunocompromised patients. the species has a worldwide distributi ...19989772334
multilocus genotypic analysis of cryptosporidium parvum isolates from different hosts and geographical origins.the genetic analysis of oocysts recovered from the stools of humans and animals infected with cryptosporidium parvum has consistently shown the existence of two distinct genotypes. one of the genotypes is found exclusively in some human infections, whereas the other genotype is found in human as well as in animal infections. on the basis of these observations and the results of published epidemiological studies with single polymorphic markers, the existence of two separate transmission cycles ha ...19989774575
genotyping reference service for cryptosporidium parvum: request for faecal specimens. 19989780486
cryptosporidiosis in indonesia: a hospital-based study and a community-based survey.hospital-based and community-based studies were conducted to understand the prevalence and mode of transmission of cryptosporidium parvum infection in surabaya, indonesia. in both studies people with and without diarrhea were examined for oocysts. a community-based survey included questionnaires to a community and stool examination of cats. questionnaires covered demographic information, health status, and hygienic indicators. in the hospital, c. parvum oocysts were found in 26 (2.8%) of 917 pat ...19989790442
actin-dependent motility in cryptosporidium parvum sporozoites.the present study investigated the role of actin polymerization and myosin motor protein activity in the gliding motility of cryptosporidium parvum sporozoites. short motility trails were detected using an indirect immunofluorescent assay (ifa) with a polyclonal antisporozoite antibody following incubation of sporozoites on poly-l-lysine-coated glass slides. sporozoite motility was blocked following exposure to cytochalasin d, a myosin light-chain kinase inhibitor 1-(5-iodonaphthalene-1-sulfonyl ...19989794629
cryptosporidium parvum: an attempt at experimental infection in rainbow trout oncorhynchus mykiss.a study was carried out on rainbow trout oncorhynchus mykiss fed with a commercial feed contaminated with bovine-isolated cryptosporidium parvum oocysts whose viability and infectivity were previously tested by inoculation of oocysts to neonatal swiss cd-1 mice. histological examination of hematoxylin-eosin-stained gastrointestinal sections from control and c. parvum-exposed fish revealed no life-cycle stages of cryptosporidium in any part of the apical border of the digestive tract. however, se ...19989794634
detection of cryptosporidium oocysts and giardia cysts in the tissues of eastern oysters (crassostrea virginica) carrying principal oyster infectious diseases.the potential cross-reactivity of the combined cryptosporidium/giardia direct immunofluorescence antibodies (ifa) of merifluor and hydrofluor-combo tests was examined against tissues containing known developmental stages of 12 pathogens causing the principal infectious diseases in oysters. spores of haplosporidium nelsoni and haplosporidium costale produced positive acid-fast stain (afs) reactions similar in intensity to cryptosporidium parvum oocysts. hexamia nelsoni trophozoites produced posit ...19989794651
susceptibility differences to cryptosporidium parvum infection in two strains of gamma interferon knockout mice.differences in susceptibility to cryptosporidial infections were investigated between 2 strains of gamma interferon knockout (gko) mice. male c57bl/6j-ifg and balb/c-ifg (gko) mice, ages 8-10 wk, were inoculated with infectious oocysts at various doses. c57bl/6j-ifg mice developed overwhelming infections and died 9-12 days after infection. low inoculum doses (1 x 10(3)) did not increase the survival time significantly. the infection intensity in c57bl/6j-ifg mice inoculated with 1 x 10(5) oocyst ...19989794653
comparative efficacy evaluation of dicationic carbazole compounds, nitazoxanide, and paromomycin against cryptosporidium parvum infections in a neonatal mouse model.the efficacies of dicationic carbazole compounds, nitazoxanide (ntz), and paromomycin were evaluated against the aucp1 isolate of cryptosporidium parvum by using a neonatal mouse model. compounds were solubilized or suspended in deionized water and administered orally by gavage to neonatal mice at a constant dose rate on days 0 to 5 (treatment started on day 0). dose rates varied for individual carbazole compounds but ranged from 0.65 to 20 mg/kg of body weight. ntz was tested at 100 and 150 mg/ ...19989797219
influence of pretreatment and experimental conditions on electrophoretic mobility and hydrophobicity of cryptosporidium parvum oocysts.surface properties of cryptosporidium parvum oocysts were investigated by using electrophoretic mobility and hydrophobicity measurements. oocysts purified from calf feces by several sucrose flotation steps and deionized water (di) washes (dis method) had an electrophoretic mobility (neutral surface charge) near 0.0 m2 v-1 s-1 over a ph range of 2 to 10. the mean electrophoretic mobility of oocysts stored in di containing a mixture of antibiotics had a lower standard deviation (sigma = 0.36) than ...19989797304
sedimentation of free and attached cryptosporidium oocysts and giardia cysts in water.experimental analysis of the sedimentation velocity of cryptosporidium parvum oocysts and giardia lamblia cysts was compared with mathematical description of their sedimentation velocities by using measurements of (oo)cyst size and density and the density and viscosity of the sedimentation medium to determine if the sedimentation kinetics of freely suspended oocysts of c. parvum and cysts of g. lamblia can be described by stokes' law. the theoretically calculated sedimentation kinetics showed a ...19989797307
sequence polymorphism in the beta-tubulin gene reveals heterogeneous and variable population structures in cryptosporidium parvum.restriction fragment length polymorphism (rflp) analysis of isolates of cryptosporidium parvum has revealed two subgroups, termed h and c. the limited resolution of the rflp method precludes an in-depth study of the genetic structure of c. parvum populations. published c. parvum restriction polymorphisms lie within protein-coding regions known to be more homogeneous than noncoding sequences. to better assess the degrees of heterogeneity between and within c. parvum isolates, sequence polymorphis ...19989797309
immunomagnetic separation of cryptosporidium parvum from source water samples of various turbidities.immunomagnetic separation (ims) procedures which specifically capture cryptosporidium oocysts and have the potential to isolate oocysts from debris have become commercially available. we compared two ims kits (kit db [dynabeads anti-cryptosporidium; product no. 730.01; dynal a.s., oslo, norway] and kit ic1 [crypto scan ims; product no. r10; clearwater diagnostics company, llc, portland, maine]) and a modification of kit ic1 (kit ic2 [crypto scan ims; product no. r10; clearwater diagnostics compa ...19989797313
persistent diarrhea in a cohort of israeli bedouin infants: role of enteric pathogens and family and environmental factors.this study examined the role of enteric pathogens and infant, family, and household characteristics in persistent diarrhea. bedouin infants from southern israel were followed from birth to age 18-23 months. during monthly home visits, stool samples were obtained, and feeding practices and history of diarrhea were determined, and at age 3 months, an environmental assessment was done. diarrhea surveillance was either via a network covering all community health care facilities or via weekly intervi ...19989806038
prevalence of and risk factors for fecal shedding of cryptosporidium parvum oocysts in horses.to determine prevalence of and risk factors for fecal shedding of cryptosporidium parvum oocysts among 3 populations of horses.19989810386
efficacy of select antivirals against cryptosporidium parvum in vitro.cryptosporidium parvum is an intestinal pathogen associated with diarrheal disease in both humans and animals. currently, no effective therapy exists to eliminate the parasite in the absence of a healthy, intact immune system. we used an in situ, enzyme-linked immunosorbent assay (elisa) as a primary screen to examine the effects of 13 antivirals on the development of c. parvum in human ileocecal adenocarcinoma (hct-8) cells in vitro. six of the compounds displayed some efficacy, and dose-respon ...19989812363
gastric involvement in aids associated cryptosporidiosis.cryptosporidiosis has been shown to be a common cause of diarrhoea in both immunocompetent and immunosuppressed individuals. there are very few data on the distribution of cryptosporidium parvum along the gastrointestinal tract.19989824572
rapid method for fluorescent in situ ribosomal rna labelling of cryptosporidium parvum.a method for fluorescence in situ hybridization (fish) is described that requires less than 1 h duration. oocysts were resuspended in 50% ethanol and incubated at 80 degrees c for 10 min for simultaneous fixation and permeabilization. samples were than incubated with the oligonucleotide probe at 48 degrees c for more than 30 min. the rrna binding specificity of the optimized protocol was confirmed. fish was found to be valuable as a second label for oocysts presumptively identified immunofluores ...19989830116
a study of cryptosporidium parvum genotypes and population structure.genetic evidence for the occurrence of two cryptosporidium parvum subgroups is presented. this evidence is based on restriction fragment length polymorphism analysis of several independent loci. sequence analysis of the beta-tubulin intron revealed additional polymorphism. the stability of the genetic profiles following passage of c. parvum isolates between different hosts was investigated.19989830538
variable distribution of cryptosporidium parvum in the intestine of aids patients revealed by polymerase chain reaction.cryptosporidium parvum is associated with persistent diarrhoea and malnutrition in children, with large waterborne outbreaks and with the diarrhoea-wasting syndrome in aids. however, pathophysiology of infection remains to be defined and the reasons for the variability of clinical features are uncertain. the polymerase chain reaction (pcr) is valuable for the analysis of infections with non-culturable organisms because of its high sensitivity, so we compared pcr and microscopy as tools for the a ...19989831408
cryptosporidiosis in bovine and human health.cryptosporidiosis, which is caused by cryptosporidium parvum and was discovered in mice at the turn of the century, emerged as a frequently reported intestinal disease of animals and humans in the 1980s when its zoonotic potential was recognized. in recent years, the public has become aware of severe cryptosporidiosis because of its incidence in aids patients and because of massive outbreaks of cryptosporidial enteritis among the general populace worldwide from contaminated drinking water. lives ...19989839243
viability of cryptosporidium parvum oocysts: assessment by the dye permeability assay. 19989841633
cryptosporidium parvum initiates inflammatory bowel disease in germfree t cell receptor-alpha-deficient mice.flora-bearing mice with targeted disruption of t cell receptor (tcr)-alpha or -beta genes spontaneously develop intestinal inflammation with features similar to ulcerative colitis in humans. tcr-alpha-deficient mice maintained germfree or colonized with a limited number of intestinal bacteria failed to develop inflammatory bowel disease (ibd)-like lesions. evidently, inflammation in these mice does not develop spontaneously or result from a generalized antigenic stimulation, but rather requires ...19989846962
a novel multi-domain mucin-like glycoprotein of cryptosporidium parvum mediates invasion.cryptosporidium parvum is a protozoan parasite which produces self-limited disease in immunocompetent hosts and devastating, persistent diarrhea in immunocompromised individuals. there is no effective treatment for cryptosporidiosis and little is known about the basic biology of the organism. cloning and sequence analysis of the gene encoding gp900, a previously identified > 900 kda glycoprotein, predicts a mucin-like glycoprotein composed of distal cysteine-rich domains separated by polythreoni ...19989851610
a case control study of potential enteric pathogens for calves raised in cow-calf herds.a matched case control study was performed to describe the epidemiological features of potential enteric pathogens for calves reared in 53 cow-calf herds located in western switzerland. a total of 106 diarrhoeic calves and 126 healthy control calves were collected, all calves were less than 4 months old. faecal samples were analysed for presence of infectious agents related to calf diarrhoea including enterotoxigenic e. coli, verotoxin producing e. coli (vtec), campylobacter sp., yersinia sp., s ...19989852767
molecular characterisation of cryptosporidium parvum from two large suspected waterborne outbreaks. outbreak control team south and west devon 1995, incident management team and further epidemiological and microbiological studies subgroup north thames 1997.polymerase chain reaction/restriction fragment length polymorphism (pcr/rflp) analysis of the cryptosporidium parvum outer wall protein (cowp) gene was applied to specimens collected from 95 patients with cryptosporidiosis associated with two suspected waterborne outbreaks, 46 sporadic human cases and 62 infected livestock from other areas, and 12 patients infected with other gastrointestinal parasites. ninety-six per cent of c. parvum isolates from patients linked to the two suspected waterborn ...19989854879
investigation of an outbreak of cryptosporidiosis associated with treated surface water finds limits to the value of case control studies.fifty-two cases of cryptosporidiosis satisfied the case definition employed in investigation of an outbreak in spring 1996 among residents of the wirral peninsula supplied by a single water treatment plant using river water. the attack rate among those whose water was supplied solely from the plant was 1.42 per 10,000, compared with 0.42/10,000 among those having some but less than 50% supplied from it. single oocysts were detected in treated water from this plant on four occasions during the in ...19989854880
waterborne cryptosporidiosis. 19989854897
[intestinal parasitic infections and leishmaniasis in patients with hiv infection].intestinal parasite infections are very frequent in hiv patients with severe immunodeficiency (cd4 < 100/mm3) causing chronic diarrhea and malabsorption in the majority of cases. the most frequent microorganisms are microsporidia and cryptosporidium parvum while cyclospora cayetanensis and isospora belli are more prevalent in subtropical and tropical areas and rare in industrialized areas. the diagnosis can be obtained by stool examination (differences in size and form of cysts), although micros ...19989859620
surveillance for waterborne-disease outbreaks--united states, 1995-1996.since 1971, cdc and the u.s. environmental protection agency have maintained a collaborative surveillance system for collecting and periodically reporting data that relate to occurrences and causes of waterborne-disease outbreaks (wbdos).19989859954
calves as a potential reservoir of cryptosporidium parvum and giardia sp.studies on cryptosporidiosis and giardiosis were carried out between march and april 1997 on 75 calves from 9 selected farms of wielkopolska macroregion. faecal specimens from calves, 3-13 days old, were screened for oocysts of c. parvum using ziehl-neelsen staining and both for oocysts of c. parvum and cysts of giardia sp. using direct immunofluorescent (merifluor cryptosporidium/giardia) assay. the oocysts of c. parvum assessed by ziehl-neelsen staining were revealed on 6 (67%) of 9 farms exam ...19989860815
differentiating human from animal isolates of cryptosporidium parvum.we analyzed 92 cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. used as a molecular marker, this method can differentiate between the two genotypes of c. parvum and elucidate the transmission of infection to humans.19989866750
evaluation of fluorochromes for flow cytometric detection of cryptosporidium parvum oocysts labelled by fluorescent in situ hybridization.oligonucleotide probes specific to cryptosporidium parvum (cry1) were conjugated with a range of fluorochromes. the fluorescence after in situ hybridization (fish) labelling of oocysts and controls was assessed. the objective was to determine the most suitable conjugate for fish labelling, followed by analysis with a 488 nm laser flow cytometer. the most promising candidate was fluorescein isothiocyanate but only when linked to the cry1 probe via an 18-carbon spacer arm consisting of six ethylen ...19989871354
a happy map of cryptosporidium parvum.we have constructed a happy map of the apicomplexan parasite cryptosporidium parvum. we have placed 204 markers on the 10.4-mb genome, giving an average marker spacing of approximately 50 kb, with an effective resolution of approximately 40 kb. happy mapping (an in vitro linkage technique based on screening approximately haploid amounts of dna by the polymerase chain reaction) is fast and accurate and is not subject to the distortions inherent in cloning, meiotic recombination, or hybrid cell fo ...19989872984
characterization of experimental cryptosporidium parvum infection in ifn-gamma knockout mice.severe cryptosporidial infections were produced in gamma interferon (ifn-gamma) knockout mice. mean oocyst shedding increased from 332 to 30,717 oocysts/100 microliters of faecal suspension between day 4 and 9 after administration of 1 x 10(5) oocysts/mouse. no significant differences in oocyst shedding were observed in mice after being inoculated with 1 x 10(5), 1 x 10(4) or 1 x 10(3) oocysts/mouse (p > 0.05). infected mouse weights decreased an average 3-4 g before death or euthanization. hist ...19989881376
ultrastructural analysis of the sporozoite of cryptosporidium parvum.cryopreparation of live sporozoites and oocysts of the apicomplexan parasite cryptosporidium parvum, followed by transmission electron microscopy, was undertaken to show the 3d arrangement of organelles, their number and distribution. profiles of parasites obtained from energy-filtering transmission electron microscopy of serial sections provided 3d reconstructions from which morphometric data and stereo images were derived. the results suggest that sporozoites have a single rhoptry containing a ...19989884216
detection of cryptosporidium parvum and c. muris oocysts in spiked backwash water using three pcr-based protocols.cryptosporidium parvum is an important protozoan that was shown in recent years to be responsible for a number of water-borne outbreaks of diarrhoea. in this study, ways to improve the extraction of dna from purified c. parvum oocysts and from backwash water (a heavily contaminated by-product of sand filtration), for use in the polymerase chain reaction (pcr), were investigated. the use of a commercial dna purification kit reduced overall assay time as did the inclusion of an excystation step. i ...199823196162
flow cytometric analysis of microsporidia belonging to the genus encephalitozoon.flow cytometry was used in the identification of human microsporidia belonging to the genus encephalitozoon. microsporidian spores of encephalitozoon hellem, e. cuniculi, and e. intestinalis were propagated in axenic cultures of monkey kidney e6 cells, purified with percoll, and exposed to homologous and heterologous rabbit antiserum and monoclonal antibody prepared against e. hellem spores. after reaction to goat anti-rabbit immunoglobulin g (igg) or goat anti-mouse igg conjugated to fluorescei ...19999889221
detection of cryptosporidium parvum in horses: thresholds of acid-fast stain, immunofluorescence assay, and flow cytometry.feces collected from three asymptomatic horses and seeded with cryptosporidium parvum oocysts (10(1) to 10(6)/g of feces) were evaluated by acid-fast staining (af), an immunofluorescent antibody (ifa) technique, and flow cytometry. the thresholds of detection were 5 x 10(5) oocysts/g of feces for the ifa and af techniques and 5 x 10(4) oocysts/g for flow cytometry.19999889243
receptor/ligand interactions between cryptosporidium parvum and the surface of the host cell.the ability of membrane antigens on sporozoites of the intestinal pathogen, cryptosporidium parvum, to bind host cell surface antigens was investigated. a novel membrane-associated protein of approximately 47 kda, designated cp47, was found to possess significant binding affinity for the surface of both human and animal ileal cells. this protein was purified by a combination of anion-exchange chromatography on fplc and immunoaffinity chromatography. purified cp47 demonstrated competitive binding ...199910381561
Refresh
firstprev
12345678910...
nextlast
Displaying items 701 - 800 of 3503