Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
effect of lot variability on ultraviolet radiation inactivation kinetics of cryptosporidium parvum oocysts.numerous studies have demonstrated the efficiency of ultraviolet (uv) radiation for the inactivation of oocysts of cryptosporidium parvum. in these studies inactivation is measured as reduction in oocysts. a primary goal is to estimate the uv radiation required to achieve a high degree of inactivation. different lots of cryptosporidium parvum oocysts are used in these studies, and the inactivation rate may vary depending on the lot of oocysts used. the goal of this paper is to account for the er ...200515984796
development of a ct equation taking into consideration the effect of lot variability on the inactivation of cryptosporidium parvum oocysts with ozone.cryptosporidium parvum oocysts are prevalent in surface water and ground water under the influence of surface water, and are difficult to inactivate using free chlorine, the most common disinfectant currently used for treating drinking water. in contrast, it has been shown that ozone is a more effective disinfectant than chlorine. us epa is currently evaluating a treatment rule, which addresses the control of c. parvum oocysts in drinking water. the use of ct (average disinfectant concentration ...200515963550
unique endemicity of cryptosporidiosis in children in kuwait.to understand the transmission of cryptosporidium infection in children, fecal specimens from 62 kuwaiti children with gastrointestinal symptoms found to be positive by microscopy were genotyped and subtyped with a small subunit rrna-based pcr-restriction fragment length polymorphism analysis and a 60-kda glycoprotein-based dna sequencing tool. the median age of infected children was 4.5 years, and 77% of infections occurred during the cool season of november to april. fifty-eight of the childre ...200515956401
development and test for long-term stability of a synthetic standard for a quantitative cryptosporidium parvum lightcycler pcr assay.a recently described quantitative rapid cycle real time pcr (lightcycler) assay detects cryptosporidium parvum after in vitro excystation, which is a surrogate marker for the viability of the organisms. in the original assay the quantification standard is a dilution series of c. parvum oocysts with a microscopically determined excystation rate. the need to keep suspensions of viable oocysts in stock and to continuously monitor their excystation rate, however, renders the assay impracticable for ...200515952449
spatial distributions of cryptosporidium oocysts in porous media: evidence for dual mode deposition.spatial distributions of cryptosporidium parvum oocysts in columns packed with uniform glass-bead collectors were measured over a broad range of physicochemical conditions. oocyst deposition behavior is shown to deviate from predictions based on classical colloid filtration theory (cft) in the presence of repulsive (unfavorable) colloidal interactions. specifically, cft tends to predict greater removal of oocysts (less transport) than that observed in controlled laboratory experiments. compariso ...200515952366
a histological study of the transit of cryptosporidium parvum oocysts through clams (tapes decussatus).a histological study was carried out to investigate the transit of cryptosporidium parvum oocysts through the clam tapes decussatus. spat of approximately 5-7 mm shell length were maintained in a tank of natural sea water contaminated with purified c. parvum oocysts. the experiment lasted 240 h and, every 24 h, five specimens were killed, placed in bouin's fixative, and processed routinely for histological examination. sections (3 mum) cut from the all body tissues were stained with modified gom ...200515925002
detection of cryptosporidium parvum oocysts on fresh vegetables and 1 herbs using antibodies specific for a cryptosporidium parvum viral antigen.the purpose of this study was to determine if the viral symbiont of cryptosporidium parvum (cpv) sporozoites could be used as a target for sensitive detection of the parasite in food samples. polyclonal sera specific to the recombinant viral capsid protein (rcpv40) was used in a dot blot hybridization assay to detect oocysts recovered from green onions and cilantro. small batches of chopped green onions and cilantro leaves were artificially contaminated with three different concentrations of ooc ...200515895749
effect of halofuginone lactate on the occurrence of cryptosporidium parvum and growth of neonatal dairy calves.thirty-one holstein bull calves were purchased at birth from 3 dairy farms in eastern ontario. each calf was assigned at random to oral treatment with either 5 mg of halofuginone lactate in 10.0 ml of aqueous carrier solution (halocur, base comprised 10 mg of benzoic acid, 100 mg of lactic acid, and 0.3 mg of tartrazine) or 10 ml of placebo (halocur base minus the active ingredient, halofuginone lactate) administered 15 to 30 min after morning milk feeding for the first 7 d of life. intakes of m ...200515829673
mucosal cytokine and antigen-specific responses to cryptosporidium parvum in il-12p40 ko mice.studies of cellular immune responses to cryptosporidium parvum have been limited in part by lack of suitable animal models. il-12p40(-/-)mice are susceptible to initial infection with c. parvum but recover within 2 weeks, rendering the animals resistant to reinfection. because the host responses that determine duration and severity of primary infection are not yet understood, we studied the cellular immune response to primary infection with c. parvum in il-12p40(-/-)mice and also explored possib ...200515813719
application of quantitative real-time reverse transcription-pcr in assessing drug efficacy against the intracellular pathogen cryptosporidium parvum in vitro.we report here on a quantitative real-time reverse transcription-pcr (qrt-pcr) assay for assessing drug efficacy against the intracellular pathogen cryptosporidium parvum. the qrt-pcr assay detects 18s rrna transcripts from both parasites, that is, the cycle threshold for 18s rrna from parasites (c(t)([p18s])) and host cells (c(t)([h18s])), and evaluates the relative expression between parasite and host rrna levels (i.e., deltac(t) = c(t)([p18s]) - c(t)([h18s])) to minimize experimental and oper ...200516251280
inhibitory activities of epidermal growth factor receptor tyrosine kinase-targeted dihydroxyisoflavone and trihydroxydeoxybenzoin derivatives on sarcocystis neurona, neospora caninum, and cryptosporidium parvum development.several gene sequences of parasitic protozoa belonging to protein kinase gene families and epidermal growth factor (egf)-like peptides, which act via binding to receptor tyrosine kinases of the egf receptor (egfr) family, appear to mediate host-protozoan interactions. as a clue to egfr protein tyrosine kinase (ptk) mediation and a novel approach for identifying anticoccidial agents, activities against sarcocystis neurona, neospora caninum, and cryptosporidium parvum grown in bm and hct-8 cell cu ...200516251305
molecular epidemiology of human cryptosporidiosis.species within the genus cryptosporidium are protozoan parasites that infect a wide range of vertebrates, and represent a significant cause of morbidity and mortality in those animals. in humans, cryptosporidiosis is a common cause of diarrhoeal disease with a global distribution. unravelling the epidemiology of human infection has proven to be difficult, due to the existence of multiple transmission routes (person-to-person, animal-to-person, waterborne, foodborne and airborne transmission), an ...200516252472
the unusual architecture and predicted function of the mitochondrion organelle in cryptosporidium parvum and hominis species: the strong paradigm of the structure-function relationship.cryptosporidium spp. is a protozoan parasite that causes widespread diarrhoeal disease in humans and other animals and is responsible for large waterborne outbreaks of cryptosporidiosis. unlike many organisms belonging to the phylum apicomplexa, such as plasmodium spp. and toxoplasma gondii, there is no clinically proven drug treatment against this parasite. some aspects of the basic biology of cryptosporidium spp. such as the understanding of key metabolic pathways or the full description of th ...200516252476
stimulation of innate immunity in newborn kids against cryptosporidium parvum infection-challenge by intranasal/per-oral administration of liposomal formulation of n-l18-norabu-gmdp adjuvant.the effects of a liposomal preparation of lipophilic immunomodulator beta-d-glcnstearoyl-(1-4)-normurnac-l-abu-d-isogln (n-l18-norabu-gmdp) were investigated on resistance to cryptosporidium parvum infection in neonatal kids. the liposomal preparation was administered subcutaneously or intranasally/orally (i.n./p.o.) twice at doses of 100 microg, 200 microg, or 1000 microg per kid pre-infection challenge. the treatment schemes were (i) 72 and 24 h pre-infection challenge, (ii) 24 h pre-infection ...200516255818
[a case of chronic diarrhea and hypoproteinemia associated with cryptosporidium parvum and cyclospora cayetanenis]. 200516255869
identification and determination of the viability of giardia lamblia cysts and cryptosporidium parvum and cryptosporidium hominis oocysts in human fecal and water supply samples by fluorescent in situ hybridization (fish) and monoclonal antibodies.in the present study, fluorescent in situ hybridization (fish) and monoclonal antibodies (mabs) were evaluated for species-specific detection and viability determination of giardia lamblia, cryptosporidium parvum, and cryptosporidium hominis in human fecal and water supply samples. a total of 50 fecal human samples positive for g. lamblia cysts, 38 positive for c. parvum, and 23 positive for c. hominis were studied. also, 18 water supply samples positive for giardia spp. and cryptosporidium spp. ...200516261356
detection of infectious cryptosporidium oocysts by cell culture immunofluorescence assay: applicability to environmental samples.in the past few years many waterborne outbreaks related to cryptosporidium have been described. current methods for detection of cryptosporidium in water for the most part rely on viability assays which are not informative concerning the infectivity of oocysts. however, for estimation of the risk of infection with cryptosporidium this information is required. for environmental samples the oocyst counts are often low, and the oocysts have been exposed to unfavorable conditions. therefore, determi ...200516269711
development of a rapid method for simultaneous recovery of diverse microbes in drinking water by ultrafiltration with sodium polyphosphate and surfactants.the ability to simultaneously concentrate diverse microbes is an important consideration for sample collection methods that are used for emergency response and environmental monitoring when drinking water may be contaminated with an array of unknown microbes. this study focused on developing a concentration method using ultrafilters and different combinations of a chemical dispersant (sodium polyphosphate [napp]) and surfactants. tap water samples were seeded with bacteriophage ms2, escherichia ...200516269722
aerobic spore-forming bacteria for assessing quality of drinking water produced from surface water.cryptosporidium and giardia represent a major microbiological issue for drinking water production from surface water. as their monitoring through a treatment process is rather tedious and as low-concentration goals should be reached for drinking water, aerobic spore-forming bacteria (asfb) have been studied as an indicator microorganism for a drinking water treatment plant using surface water. the results reveal that monitoring naturally occurring asfb better highlights daily achievable performa ...200516280148
giardia duodenalis and cryptosporidium parvum infections in adult goats and their implications for neonatal kids.during the kidding season between january and april 2003, 10 farms were selected and divided into two groups of five. the farms in group a had had serious diarrhoeal illness and losses in neonatal kids the previous year, and there were cryptosporidium parvum infections in kids associated with diarrhoea during the survey. on the farms in group b, there was no history of diarrhoeal disease the previous year and neither c parvum oocysts nor diarrhoea were detected in neonatal kids during the survey ...200516284331
new genotypes and factors associated with cryptosporidium detection in mussels (mytilus spp.) along the california coast.a 3 year study was conducted to evaluate mussels as bioindicators of faecal contamination in coastal ecosystems of california. haemolymph samples from 4680 mussels (mytilus spp.) were tested for cryptosporidium genotypes using pcr amplification and dna sequence analysis. our hypotheses were that mussels collected from sites near livestock runoff or human sewage outflow would be more likely to contain the faecal pathogen cryptosporidium than mussels collected distant to these sites, and that the ...200515993883
cryptosporidium infection in livestock and first identification of cryptosporidium parvum genotype in cattle feces in taiwan.fecal survey by modified ziehl-neelsen (mzn) method and immunofluorescence assay (ifa) of cryptosporidium infection in cattle and goats in taiwan showed a prevalence of 37.6% (173/460) and 35.8% (44/123), respectively. in addition to the calves, adult cattle were also found to be shedding cryptosporidium oocyst. no significant difference was observed between diarrheic and non-diarrheic cattle feces with regard to the presence of cryptosporidium oocyst. two groups of oocysts with different diamet ...200515997405
[opportunistic protozoa--the problem in immunodeficient patients].protozoan infections with a mild or asymptomatic course in immunocompetent individuals, in the case of immunocompromised patients could cause severe syndromes or fatal outcome. the different clinical course is possible to diagnose only with specific laboratory methods. actual settlements on the most often diagnosed in human opportunistic protozoan infections pathogenesis and diagnostics are presented.200515997648
synergistic inactivation of cryptosporidium parvum using ozone followed by monochloramine in two natural waters.the effect of sequential exposure to ozone followed by monochloramine on inactivation of cryptosporidium parvum oocysts suspended in untreated natural surface water from two different sources was studied in bench-scale batch reactors. animal infectivity using neonatal cd-1 mice was used to measure oocyst inactivation. a statistically significant synergistic effect on oocyst inactivation was measured in both natural water samples studied. the magnitude of the effect measured in the natural water ...200516000207
environmental temperature controls cryptosporidium oocyst metabolic rate and associated retention of infectivity.cryptosporidium is a significant cause of water-borne enteric disease throughout the world and represents a challenge to the water industry and a threat to public health. in this study we report the use of a cell culture-taqman pcr assay to measure oocyst inactivation rates in reagent-grade and environmental waters over a range of temperatures. while oocysts incubated at 4 degrees c and 15 degrees c remained infective over the 12-week holding period, we observed a 4 log(10) reduction in infectiv ...200516000797
functional characterization of an evolutionarily distinct phosphopantetheinyl transferase in the apicomplexan cryptosporidium parvum.recently, two types of fatty acid synthases (fass) have been discovered from apicomplexan parasites. although significant progress has been made in characterizing these apicomplexan fass, virtually nothing was previously known about the activation and regulation of these enzymes. in this study, we report the discovery and characterization of two distinct types of phosphopantetheinyl transferase (pptase) that are responsible for synthesizing holo-acyl carrier protein (acp) from three apicomplexan ...200516002647
pulmonary cryptosporidiosis in an aids patient: successful treatment with paromomycin plus azithromycin.extra-intestinal cryptosporidiosis, especially of the biliary and respiratory tract, is likely in the course of an intestinal involvement, whereas it is rare without such a localization. we report a case of pulmonary cryptosporidiosis without apparent intestinal involvement in an aids patient, with favourable outcome after antimicrobial combination therapy with paromomycin plus azithromycin. the successful response to antimicrobial treatment was subsequently maintained by effective highly active ...200516004637
use of nitazoxanide as a new therapeutic option for persistent diarrhea: a pediatric perspective.despite advances in the management of diarrheal disorders, diarrhea is the second most frequent illness in the world. persistent diarrhea, common in community pediatrics, is often caused by organisms such as giardia lamblia, cryptosporidium parvum and, less frequently, cyclospora, isospora belli, and clostridium difficile. identifying the causative organism is often challenging, and diagnostic tests may be inaccurate and expensive and, thus, of limited benefit. consequently, carefully chosen emp ...200516004666
treatment of cryptosporidiosis in immunocompromised hosts.the most important species of cryptosporidium in humans, c. parvum and c. hominis, cause severe and chronic life-threatening gastroenteritis in immunocompromised patients. despite a certain efficacy shown by passive immunotherapy or by some chemotherapeutic agents (e.g. paromomycin and nitazoxanide), no significant benefit has been demonstrated. the use of highly active antiretroviral therapy (haart) in persons with the acquired immunodeficiency syndrome drastically reduces the prevalence of cry ...200516006765
the protozoan parasite cryptosporidium parvum possesses two functionally and evolutionarily divergent replication protein a large subunits.very little is known about protozoan replication protein a (rpa), a heterotrimeric complex critical for dna replication and repair. we have discovered that in medically and economically important apicomplexan parasites, two unique rpa complexes may exist based on two different types of large subunit rpa1. in this study, we characterized the single-stranded dna binding features of two distinct types (i.e. short and long) of rpa1 subunits from cryptosporidium parvum (cprpa1a and cprpa1b). these tw ...200516014411
[cryptosporidiosis in newborn calves in ankara region: clinical, haematological findings and treatment with lasalocid-na].in the first part of the present study, a total of 109 faeces samples collected from calves suffering from diarrhoea were examined for cryptosporidium parvum oocytes and 39 (35.8%) of them were found to be positive. on the basis of oocyte counts, 14 (36%) samples were assessed as mildly infected and 25 (64%) samples as heavily infected. the occurrence of the disease was more common in winter (56.4%) than during other seasons (autuma 0%, summer 15.4% spring 28.2%. in the present study, the ionoph ...200516028484
a dance teacher with kidney-pancreas transplant and diarrhoea: what is the cause? 200516033769
recombinant proteins of cryptosporidium parvum induce proliferation of mesenteric lymph node cells in infected mice.recombinant antigens of cryptosporidium parvum, cp900 and cp40 but not cp15, stimulated c. parvum-specific proliferative immune responses of mesenteric lymph node cells in c57bl/6j mice infected with different isolates (md, gch1, ucp, and iowa) of c. parvum, indicating that both cp900 and cp40 are immunodominant targets of cellular immune responses during c. parvum infection.200516041049
infectivity of cryptosporidium hominis and cryptosporidium parvum genotype 2 isolates in immunosuppressed mongolian gerbils.one-month-old dexamethasone-immunosuppressed mongolian gerbils were challenged with 1 oocyst to 2 x 10(5) oocysts from two isolates genotyped as cryptosporidium hominis and c. parvum (genotype 2), respectively. a similar dose-dependent gut infection was obtained, and the initial genotype maintained for 21 to 22 days. the data suggest that immunosuppressed gerbils provide a reliable rodent model of persistent c. hominis infection.200516041051
prediction of the general transcription factors associated with rna polymerase ii in plasmodium falciparum: conserved features and differences relative to other eukaryotes.to date, only a few transcription factors have been identified in the genome of the parasite plasmodium falciparum, the causative agent of malaria. moreover, no detailed molecular analysis of its basal transcription machinery, which is otherwise well-conserved in the crown group of eukaryotes, has yet been reported. in this study, we have used a combination of sensitive sequence analysis methods to predict the existence of several parasite encoded general transcription factors associated with rn ...200516042788
seasonal temperature fluctuations induces rapid inactivation of cryptosporidium parvum.this study measured the inactivation rate of bovine genotype a cryptosporidium parvum oocysts attributable to diurnal oscillations of ambient temperature and solar radiation typical of california rangelands and dairies from spring through autumn. we first measured the relationship between air temperature and the internal temperature of bovine feces exposed to sunlight on commercial operations throughout california. once maximum air temperature exceeded the mid 20 degrees c, diurnal thermal regim ...200516047784
localization of polyketide synthase encoding genes to the toxic dinoflagellate karenia brevis.karenia brevis is a toxic marine dinoflagellate endemic to the gulf of mexico. blooms of this harmful alga cause fish kills, marine mammal mortalities and neurotoxic shellfish poisonings. these harmful effects are attributed to a suite of polyketide secondary metabolites known as the brevetoxins. the carbon framework of all polyketides is assembled by a polyketide synthase (pks). previously, pks encoding genes were amplified from k. brevis culture and their similarity to a pks gene from the clos ...200516051286
kinetics of cryptosporidium parvum-specific cytokine responses in healing and nonhealing murine models of c. parvum infection.susceptibility or resistance to infection with cryptosporidium parvum correlates with the ability of mice to produce characteristic panels of cytokines in response to infection. both adult healing and nonhealing mouse models of cryptosporidiosis were used to study the cell-mediated immune response during the course of c. parvum infection. mesenteric lymph node (mln) lymphocytes from both mouse models were proliferated after ex vivo re-stimulation with c. parvum sporozoite antigen. study of the c ...200516052360
quantification of the infectivity of cryptosporidium parvum by monitoring the oocyst discharge from scid mice.doses of 1-10(5) oocysts of cryptosporidium parvum hnj-1 were inoculated into severe combined immunodeficient (scid) mice, and the discharge of oocysts was monitored for 30 days post inoculation. none of the mice discharged any oocysts after oral inoculation of one oocyst. only one of five scid mice discharged oocysts after oral inoculation of 10 oocysts, and the prepatent period was 17 days. the other four mice did not discharge any oocysts. all the scid mice discharged oocysts after oral inocu ...200516076530
enzyme immunoassay of cryptosporidium-specific immunoglobulin g antibodies to assess longitudinal infection trends in six communities in british columbia, canada.a newly developed enzyme-linked immunosorbent assay (elisa) that detects immunoglobulin g antibodies to the 27-kda cryptosporidium parvum sporozoite surface antigen was used to test 4,097 sera collected from pregnant women in 6 communities in british columbia, canada, between january 1996, and december 1997. waterborne outbreaks of cryptosporidiosis occurred in two of the study communities during the period of follow-up, and elisa seropositivity was high in all six communities during the study p ...200516103592
oral administration of hyperimmune anti-cryptosporidium parvum ovine colostral whey confers a high level of protection against cryptosporidiosis in newborn nmri mice.hyperimmune anti-cryptosporidium parvum ovine colostral whey (hocw) was tested to determine whether it conferred passive immunity to newborn nmri mice. three hocws (groups iv-vi), 2 nonimmune colostral wheys (groups ii and iii), and pbs (group i) were administered once (experiment a) and 3 times (experiment b) daily from -1 to 15 days postinfection (pi). mice in groups i-vi were inoculated with 5 x 10(5) oocysts (day 0 pi), and group vii mice acted as controls. the percentage and intensity of in ...200516108564
gliding motility leads to active cellular invasion by cryptosporidium parvum sporozoites.we examined gliding motility and cell invasion by an early-branching apicomplexan, cryptosporidium parvum, which causes diarrheal disease in humans and animals. real-time video microscopy demonstrated that c. parvum sporozoites undergo circular and helical gliding, two of the three stereotypical movements exhibited by toxoplasma gondii tachyzoites. c. parvum sporozoites moved more rapidly than t. gondii sporozoites, which showed the same rates of motility as tachyzoites. motility by c. parvum sp ...200516113253
multiattribute evaluation of two simple tests for the detection of cryptosporidium parvum in calf faeces.there is a need for simple and inexpensive diagnostic and screening tests for the detection of cryptosporidium parvum infection in calves. a sucrose wet mount test and a lateral immunochromatography test were evaluated for epidemiological sensitivity and specificity, cost per test, simplicity, test time and ease of batching. polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) of the cryptosporidium oocyst wall protein (cowp) gene locus, with gel electrophoresis, was use ...200516115735
cryptosporidiumparvum oocysts in seawater clams (chameleagallina) in italy.bivalves filter large volumes of water and can concentrate organisms which are pathogenic for humans and animals. our aim was to evaluate the presence of cryptosporidium spp. in clams from the adriatic coast (abruzzo region) and genetically characterize the oocysts isolated from the clams. from march to july 2003, 960 specimens of clams (chamelea gallina) present in nature were collected at 500 m from the tordino, tronto, vibrata and vomano river mouths on the adriatic sea. the haemolymph and ti ...200515907570
extracellular like-gregarine stages of cryptosporidium parvum.the present study confirms the existence of extracellular stages of cryptosporidiumparvum during in vitro culture on mdck, hct 8 and vero cells as well as alveolar macrophages, by optic, nomarski and transmission electron microscopy images. extracellular trophozoite/gamont, stages in syzygy, zygotes and spores with eight sporozoites were seen in the supernatant of the cultures. the first ultrastructural images of extracellular stages of c. parvum are shown in this study. the morphology of these ...200515907779
significance of cryptosporidium parvum in horses. 200515908503
[intestinal parasitosis during aids diarrhoea].the main goal of this work was to study the parasitic infections during aids diarrhoea. a longitudinal study was carried out from october 2000 to november 2001 in the hepato-gastro-enterology department of gabriel toure hospital and in the department of epidemiology and parasitic infections of faculty of medicine, pharmacy and odonto-stomatology of bamako (mali), concerning hiv positive patients suffering from diarrhoea. detecting microbes in stools has been done through direct microscopic exami ...200515915971
cryptosporidium infection impairs growth and muscular protein synthesis in suckling rats.this study aimed to explore the metabolic consequences of cryptosporidiosis in an acute experimental model both at the peak of infection and after parasite clearance. four-day-old suckling rats were infected with 10(6) oocysts of cryptosporidium parvum. at the peak of infection (day 8 pi), c. parvum resulted in a dramatic reduction both in nutrient intake (-50%) and body weight (16.3+/-5.2 vs 27.3+/-1.0 g, p<0.01) with a decrease in both lean body mass and adipose tissue. muscular fractional and ...200515924222
characterisation of a cryptosporidium isolate from water buffalo (bubalus bubalis) by sequencing of a fragment of the cryptosporidium oocyst wall protein gene (cowp).cryptosporidium oocysts were detected using a direct immunofluorescence antibody test in the faeces of an asymptomatic water buffalo (bubalus bubalis) heifer from a dairy farm close to santiago de compostela (nw spain). oocysts were morphologically indistinguishable from cryptosporidium parvum. using dna extracted from this sample and a pcr-rflp analysis of a 341 base pairs fragment of the cryptosporidium oocyst wall protein (cowp) gene, a previously undescribed fragment pattern was generated. t ...200515935559
prevalence of cryptosporidium parvum infection in southwestern ontario and its association with diarrhea in neonatal dairy calves.cryptosporidium parvum infection was detected in 203 (40.6%) of 500 ontario dairy calves aged 7 to 21 d, on a convenience sample of 51 farms with a history of calf diarrhea. within-farm prevalence ranged from 0% to 70%, and both shedding and intensity of shedding were significantly associated with diarrhea. this parasite appears to be common in ontario dairy calves and important as a cause of dairy calf scours in the province.200515943123
molecular characterization of cryptosporidium species and genotypes in chile.knowledge of species and genotypes on cryptosporidium involved in human transmission is fundamental in studying the epidemiology of cryptosporidiosis. this is the first study in molecular epidemiology of cryptosporidiosis that has been made in chile. cryptosporidium parvum species and genotypes involved in human and bovine cryptosporidiosis were determined by pcr-rflp. low prevalence of cryptosporidium was found in humans and cattle. of the 127 cattle studied, only in one was c. parvum detected ...200515952040
serological responses to cryptosporidium antigens among women using riverbank-filtered water, conventionally filtered surface water and groundwater in hungary.we compared serological responses to cryptosporidium parvum antigens using surplus sera from females undergoing routine screening for pregnancy from three counties in hungary where bank-filtered surface water, conventionally filtered and disinfected surface water, and groundwater from either a karst or confined aquifer are commonly used for drinking water. the primary purpose was to determine whether the prevalence and intensity of serological responses, indicators of prior cryptosporidium infec ...200515952455
crystallization of three key glycolytic enzymes of the opportunistic pathogen cryptosporidium parvum.cryptosporidium parvum is one of the major causes of waterborne diseases worldwide. this protozoan parasite depends mainly on the anaerobic oxidation of glucose for energy production. in order to identify the differences in the three-dimensional structure of key glycolytic enzymes of c. parvum and its human host, we have expressed, purified and crystallized recombinant versions of three important glycolytic enzymes of the parasite, namely, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinas ...200515953771
incidence of cryptosporidium parvum in the dairy cattle population in a new york city watershed.a longitudinal study of 2-year duration was conducted to determine the risk, as measured by incidence rate, of cryptosporidium parvum infection among dairy cattle in the catskill/delaware watershed of new york city (nyc), and the factors that predispose animals to the likelihood of infection. a proportional sampling scheme with follow up at quarterly farm visits was employed for heifers and cows. additionally, all calves born on the 39 study farms were sampled once during the first four weeks of ...200515955631
declines of zoonotic agents in liquid livestock wastes stored in batches on-farm.to measure the decline rates of zoonotic agents introduced into liquid livestock wastes in on-farm storage tanks.200515960665
local peroxynitrite formation contributes to early control of cryptosporidium parvum infection.in intestinal inflammation, mucosal injury is often exacerbated by the reaction of no with neutrophil-derived superoxide to form the potent oxidant peroxynitrite. peroxynitrite also has antimicrobial properties that aid in the killing mechanism of macrophages and neutrophils. cryptosporidium parvum parasitizes intestinal epithelium, resulting in loss of epithelial cells and mucosal inflammation. synthesis of no is significantly increased and arises from the induced expression of inducible nitric ...200515972479
endoparasites in calves of beef cattle herds: management systems dependent and genetic influences.prevalences and intensities of excretion of faecal stages of giardia duodenalis, cryptosporidium parvum, eimeria spp., strongyloides papillosus and strongyles were determined in a german upland area in german angus (ga) and german simmental (gs) suckler of beef cattle herds covering two winter housing periods and the grazing season between them. influences of the housing systems applied (maintenance on deep litter with (dl+) and without run-out (dl--), on slatted floor (sf) or by winter run-out ...200515979802
expression of p23 of cryptosporidium parvum in toxoplasma gondii and evaluation of its protective effects.in this study, p23 of cryptosporidium parvum sporozoites, an immunodominant surface protein, was stably expressed in toxoplasma gondii (tg/p23) and its protective effects were evaluated in a mouse model. the molecular weight and antigenic property of p23 expressed by tg/p23 were similar to those of the native p23. mice immunized with lysed tg/p23 tachyzoites produced specific neutralizing antibodies against c. parvum. these findings indicate that the t. gondii vector may provide a new tool for t ...200515986633
cryptosporidium excystation and invasion: getting to the guts of the matter.cryptosporidium parvum excystation and host cell invasion have been characterized in some detail ultrastructurally. however, until recently, the biochemical and molecular basis of host-parasite interactions and parasite- and host-specific molecules involved in excystation, motility and host cell invasion have been poorly understood. this article describes our understanding of cryptosporidium excystation and the events leading to host cell invasion, and draws from information available about thes ...200515734661
prevalence and characterisation of cryptosporidium species in cattle faeces and on beef carcases at slaughter.cattle are known reservoirs and asymptomatic excretors of cryptosporidium, a protozoan parasite that causes severe and protracted diarrhoea in people. the incidence of cryptosporidium was investigated in 288 matched samples taken from beef carcases of 1 g samples of faeces retrieved immediately after de-legging, 25 cm2 samples of beef excised from the rump of uneviscerated carcases, and 25 cm2 samples of beef excised from the brisket area of eviscerated carcases. cryptosporidium species were det ...200515736696
development of procedures for direct extraction of cryptosporidium dna from water concentrates and for relief of pcr inhibitors.extraction of high-quality dna is a key step in pcr detection of cryptosporidium and other pathogens in environmental samples. currently, cryptosporidium oocysts in water samples have to be purified from water concentrates before dna is extracted. this study compared the effectiveness of six dna extraction methods (dna extraction with the qiaamp dna minikit after oocyst purification with immunomagnetic separation and direct dna extraction methods using the fastdna spin kit for soil, qiaamp dna s ...200515746310
quantitative-pcr assessment of cryptosporidium parvum cell culture infection.a quantitative taqman pcr method was developed for assessing the cryptosporidium parvum infection of in vitro cultivated human ileocecal adenocarcinoma (hct-8) cell cultures. this method, termed cell culture quantitative sequence detection (cc-qsd), has numerous applications, several of which are presented. cc-qsd was used to investigate parasite infection in cell culture over time, the effects of oocyst treatment on infectivity and infectivity assessment of different c. parvum isolates. cc-qsd ...200515746352
effect of batch-process solar disinfection on survival of cryptosporidium parvum oocysts in drinking water.the results of batch-process solar disinfection (sodis) of cryptosporidium parvum oocysts in water are reported. oocyst suspensions were exposed to simulated sunlight (830 w m(-2)) at 40 degrees c. viability assays (4',6'-diamidino-2-phenylindole [dapi]/propidium iodide and excystation) and infectivity tests (swiss cd-1 suckling mice) were performed. sodis exposures of 6 and 12 h reduced oocyst infectivity from 100% to 7.5% (standard deviation = 2.3) and 0% (standard deviation = 0.0), respective ...200515746372
detection of cryptosporidium and identification to the species level by nested pcr and restriction fragment length polymorphism.cryptosporidiosis is an emerging protozoan disease associated with large waterborne outbreaks. diagnosis relies on microscopic examination of stools, but this method cannot identify the infecting species of cryptosporidium. we have developed a test based on nested pcr and restriction fragment length polymorphism (rflp) that offers simple identification of cryptosporidium hominis, cryptosporidium parvum, and most other human infective species in stool samples. purified c. parvum oocysts were used ...200515750054
a new apicomplexa-specific protein kinase family: multiple members in plasmodium falciparum, all with an export signature.malaria caused by protozoan parasites of the genus plasmodium spp. is a major health burden in tropical countries. the development of new control tools, including vaccines and drugs, is urgently needed. the availability of genome sequences from several malaria parasite species provides a basis on which to identify new potential intervention targets. database mining for orthologs to the plasmodium falciparum trophozoite protein r45, a vaccine candidate, led us identify a new gene family.200515752424
sporadic cryptosporidiosis decline after membrane filtration of public water supplies, england, 1996-2002.the incidence of sporadic cryptosporidiosis among 106,000 residents of 2 local government districts in northwest england before and after installation of membrane filtration of public water supplies was compared to that of 59,700 residents whose public water supplies remained unchanged. a national outbreak of foot and mouth disease in livestock during 2001 was associated with a decline in sporadic human cryptosporidiosis in all regions of the united kingdom. in a poisson regression model, membra ...200515752443
straining, attachment, and detachment of cryptosporidium oocysts in saturated porous media.accurate knowledge of the transport and deposition behavior for pathogenic cryptosporidium parvum oocysts is needed to assess contamination and protect water resources. experimental and modeling studies were undertaken to examine the roles of attachment, detachment, and straining on oocyst transport and retention. saturated column studies were conducted using ottawa aquifer sands (u.s. silica, ottawa, il) with median grain sizes of 710, 360, and 150 microm. decreasing the median sand size tended ...200515758099
prevalence of giardia and cryptosporidium in beef cows in southern ontario and in beef calves in southern british columbia.in 1998 and 1999, fecal samples were collected from 669 beef cows on 39 farms located within 10 counties of ontario. overall prevalences of giardia, cryptosporidium muris, and cryptosporidium parvum in cows were 8.7%, 10.6%, and 18.4%, respectively. of the 39 farms sampled, giardia was detected on 64%, cr. muris on 72%, and cr. parvum on 90%. cryptosporidium parvum was detected in 28% of the cows in 1998 and in 5.2% in 1999. differences between the 2 y were attributed to sampling during calving ...200515759828
capture of water-borne colloids in granular beds using external electric fields: improving removal of cryptosporidium parvum.suboptimal coagulation in water treatment plants often results in reduced removal efficiency of cryptosporidium parvum oocysts by several orders of magnitude (j. awwa 94(6) (2002) 97, j. awwa 93(12) (2001) 64). the effect of external electric field on removal of c. parvum oocysts in packed granular beds was studied experimentally. a cylindrical configuration of electrodes, with granular media in the annular space was used. a negative dc potential was applied to the central electrode. no coagulan ...200515766959
direct comparison of selected methods for genetic categorisation of cryptosporidium parvum and cryptosporidium hominis species.a study was undertaken to compare the performance of five different molecular methods (available in four different laboratories) for the identification of cryptosporidium parvum and cryptosporidium hominis and the detection of genetic variation within each of these species. the same panel of oocyst dna samples derived from faeces (n=54; coded blindly) was sent for analysis by: (i) dna sequence analysis of a fragment of the hsp70 gene; (ii) dna sequence analysis and the ssrrna gene in laboratory ...200515777916
parasitic infections in hiv-infected patients who visited seoul national university hospital during the period 1995-2003.the prevalence of parasitic infections was investigated in human immunodeficiency virus (hiv)-infected patients (n = 105) who visited seoul national university hospital, seoul, korea, during the period from 1995 to 2003. fecal samples were collected from 67 patients for intestinal parasite examinations, and sputum or bronchoalveolar lavage samples from 60 patients for examination of pneumocystis carinii. both samples were obtained from 22 patients. thirty-three (31.4%) of the 105 were found to h ...200515793352
immuno-capture of cryptosporidium parvum using micro-well array.a glass slide and micro-well array chip on which anti-cryptosporidium parvum antibody was immobilized were used for the rapid capture and detection of c. parvum. biotinylated anti-c. parvum antibodies were spotted onto the streptavidin-coated glass slides. c. parvum oocysts were captured specifically on the spot when more than 73 ng of anti-c. parvum antibody was applied onto the glass slide. however, c. parvum oocysts captured on the glass slide were detached by repeating washing steps. to impr ...200515797326
electron tomographic and ultrastructural analysis of the cryptosporidium parvum relict mitochondrion, its associated membranes, and organelles.sporozoites of the apicomplexan cryptosporidium parvum possess a small, membranous organelle sandwiched between the nucleus and crystalloid body. based upon immunolabelling data, this organelle was identified as a relict mitochondrion. transmission electron microscopy and tomographic reconstruction reveal the complex arrangement of membranes in the vicinity of this organelle, as well as its internal organization. the mitochondrion is enveloped by multiple segments of rough endoplasmic reticulum ...200515817118
immunization protocols against cryptosporidium parvum in ovines: protection in suckling lambs.ovine colostrum and milk from immunized ewes were tested for their ability to prevent cryptosporidiosis in the lambs experimentally infected with 10(6) oocysts of cryptosporidium parvum at 36-48 h of age (day 0 post-infection). all lambs became infected and developed clinical cryptosporidiosis. however, lambs fed by immunized dams have shown shedding involved, significantly, fewer oocysts and lasted for a shorter period than in control lambs. in addition, diarrhoea was less severe. the best resu ...200515817197
risk of infection with cryptosporidium parvum and cryptosporidium hominis in dairy cattle in the new york city watershed.to determine the risk posed by cryptosporidium parvum and cryptosporidium hominis from dairy cattle in the new york city watershed (nycw).200515822584
frequency and characteristics of selected enteropathogens in fecal and rectal specimens from childhood diarrhea in trinidad, 1998-2000.to determine the prevalence and characteristics of selected enteric pathogens in diarrheic children in six counties of the island of trinidad.200515826396
parasitic zoonoses in papua new guinea.relatively few species of zoonotic parasites have been recorded in humans in papua new guinea. a greater number of potentially zoonotic species, mostly nematodes, occur in animals but are yet to be reported from humans. protozoa is the best represented group of those infecting man, with giardia duodenalis, cryptosporidium parvum, cyclospora cayetanesis, toxoplasma gondii, sarcocystis spp., entamoeba polecki, balantidium coli and, possibly, blastocystis hominis. the only zoonotic helminths infect ...200515831107
diarrhea associated with cryptosporidium parvum among young children of the nile river delta in egypt.over a 2-year period, the prevalence and clinical characteristics of cryptosporidium-associated diarrhea in the nile river delta of egypt was studied. a stool sample was obtained from children with diarrhea attending one of two study hospitals and of the 1275 children evaluated, 214 (17%) were found to be infected with cryptosporidium. younger age was a risk factor for developing cryptosporidium-associated diarrhea. children <12 months of age were 2.4 times more likely to be infected with crypto ...200515831665
cryptosporidium infection in renal transplant patients.cryptosporidium parvum, an intracellular protozoan parasite, is a significant cause of gastrointestinal disease worldwide. transmission can occur from an infected person, animal or fecally contaminated environment. the clinical manifestations of cryptosporidiosis are dependent on the immunologic state of the host. infection among immunocompetent hosts results in diarrhea that is typically self-limited. in immunocompromised hosts, however, the infection may be protracted and life-threatening with ...200515847259
how clean must our drinking water be: the importance of protective immunity.cryptosporidium parvum is an important cause of epidemic diarrhea. few studies have assessed whether serological evidence of prior infection in adults is related to a reduced occurrence of enteric illness.200515688300
fate of pathogens present in livestock wastes spread onto fescue plots.fecal wastes from a variety of farmed livestock were inoculated with livestock isolates of escherichia coli o157, listeria monocytogenes, salmonella, campylobacter jejuni, and cryptosporidium parvum oocysts at levels representative of the levels found in naturally contaminated wastes. the wastes were subsequently spread onto a grass pasture, and the decline of each of the zoonotic agents was monitored over time. there were no significant differences among the decimal reduction times for the bact ...200515691918
detection and discrimination of cryptosporidium parvum and c. hominis in water samples by immunomagnetic separation-pcr.cryptosporidium parvum and c. hominis have been the cause of large and serious outbreaks of waterborne cryptosporidiosis. a specific and sensitive recovery-detection method is required for control of this pathogen in drinking water. in the present study, nested pcr-restriction fragment length polymorphism (rflp), which targets the divergent cpgp40/15 gene, was developed. this nested pcr detected only the gene derived from c. parvum and c. hominis strains, and rflp was able to discriminate betwee ...200515691946
association of cryptosporidium parvum with suspended particles: impact on oocyst sedimentation.the association of cryptosporidium parvum oocysts with suspended particles can alter the oocysts' effective physical properties and influence their transport in aquatic systems. to assess this behavior, c. parvum oocysts were mixed with various suspended sediments under a variety of water chemical conditions, and the resulting settling of the oocysts was observed. direct microscopic observations showed that oocysts attached to suspended sediments. settling column and batch experiments demonstrat ...200515691968
chronic diarrhea. 200515629902
use of artificial neural networks to accurately identify cryptosporidium oocyst and giardia cyst images.cryptosporidium parvum and giardia lamblia are protozoa capable of causing gastrointestinal diseases. currently, these organisms are identified using immunofluorescent antibody (ifa)-based microscopy, and identification requires trained individuals for final confirmation. since artificial neural networks (ann) can provide an automated means of identification, thereby reducing human errors related to misidentification, ann were developed to identify cryptosporidium oocyst and giardia cyst images. ...200515640173
role of surface proteins in the deposition kinetics of cryptosporidium parvum oocysts.a radial stagnation point flow system was used to investigate the influence of cryptosporidium parvum surface properties on oocyst deposition kinetics onto solid surfaces. to determine the role of oocyst surface proteins in adhesion, the deposition kinetics of viable oocysts were compared with the deposition kinetics of oocysts treated (inactivated) with either heat or formalin. results showed a significantly higher deposition rate with formalin and heat-treated oocysts compared to viable oocyst ...200515641844
the detection of cryptosporidium parvum and escherichia coli o157 in uk bivalve shellfish.optimised immunomagnetic separation methods to detect cryptosporidium parvum and escherichia coli o157 in uk shellfish are described. whole tissue homogenates gave the best recoveries for c. parvum oocysts compared with gill or haemolymph extracts. the sensitivity of recovery from spiked samples was comparable to that achieved when processing water and varied from 12-34% in mussels, 48-69.5% in oysters and 30-65% in scallops. maximum recovery of e. coli o157 was achieved by enriching in buffered ...200515649541
land application of treated sewage sludge: quantifying pathogen risks from consumption of crops.to predict the number of humans in the uk infected through consumption of root crops grown on agricultural land to which treated sewage sludge has been applied in accordance with the current regulations and guidance (safe sludge matrix).200515659193
the unusual mitochondrial compartment of cryptosporidium parvum.recent studies, including the cryptosporidium parvum genome project, have provided evidence for a mitochondrial-derived compartment in this parasite. this organelle appears to lack a genome, and thus must be entirely dependent on nuclear-encoded proteins. here, we review the evidence for such an organelle in c. parvum and its probable function. there is no adequate treatment for infection by this parasite and so the elucidation of the role of this organelle and the effective targeting of its fun ...200515664529
the response of cryptosporidium parvum to uv light.ultraviolet (uv) light is being considered as a disinfectant by the water industry because it appears to be very effective for controlling potential waterborne pathogens, including cryptosporidium parvum. however, many organisms have mechanisms such as nucleotide excision repair and photolyase enzymes for repairing uv-induced dna damage and regaining preirradiation levels of infectivity or population density. genes encoding uv repair proteins exist in c. parvum, so the parasite should be able to ...200515664531
identification of cryptosporidium parvum genotype 2 in domestic horses. 200515675524
nf-kappab-mediated expression of inos promotes epithelial defense against infection by cryptosporidium parvum in neonatal piglets.cryptosporidium sp. parasitizes intestinal epithelium, resulting in enterocyte loss, villous atrophy, and malabsorptive diarrhea. we have shown that mucosal expression of inducible nitric oxide (no) synthase (inos) is increased in infected piglets and that inhibition of inos in vitro has no short-term effect on barrier function. no exerts inhibitory effects on a variety of pathogens; nevertheless, the specific sites of inos expression, pathways of inos induction, and mechanism of no action in cr ...200616123198
obtaining hyperimmune anti-cryptosporidium parvum ovine colostrum. a study of the humoral immune response in immunized sheep.three ewes were immunized five times over a 2-month period prior to giving birth by intramuscular injection, oral administration and intramammary infusion of antigen and viable or freeze-dried cryptosporidium parvum oocyst solution emulsified with freund's complete and incomplete adjuvant. two animals served as controls and another two as adjuvant controls. serum was collected at first immunization and thereafter every 2 to 4 weeks. colostrum and milk were collected as well. all samples were ass ...200616292678
recombinant bovine interleukin-12 stimulates a gut immune response but does not provide resistance to cryptosporidium parvum infection in neonatal calves.this study was undertaken to determine if administration of recombinant bovine interleukin-12 (rboil-12) could stimulate a cellular immune response that protected calves from an oral challenge inoculation with cryptosporidium parvum oocysts. in a first experiment, rboil-12 intraperitoneally administered as a single dose 1 day before challenge inoculation, did not alter the course of infection. the percentage of immune competent cells and levels of cytokine gene expression in the ileo-cecal mucos ...200616386849
environmental load of cryptosporidium parvum oocysts from cattle manure in feedlots from the central and western united states.the first step in assessing the risk of water contamination by cryptosporidium parvum oocysts from feedlot cattle (bos taurus) production systems is to quantify the number of c. parvum oocysts present in the fecal material deposited by feedlot cattle. our primary objective for this project was to estimate the daily environmental load of c. parvum oocysts in fecal material deposited by feedlot cattle from across the central and western usa. our secondary goal was to genotype isolates of c. parvum ...200616391291
prevalence of intestinal parasites including microsporidia in human immunodeficiency virus-infected adults in cameroon: a cross-sectional study.to assess the prevalence of intestinal parasites in a cohort of human immunodeficiency virus (hiv)-infected adults in cameroon, a cross-sectional study was conducted. detection of parasites was performed in 181 stool samples from 154 hiv-infected patients with a mean cd4 cell count of 238 cells/mm(3). only 35 patients (22%) were receiving antiretroviral therapy at the time of stool sampling, and 46 (29%) had diarrhea. opportunistic protozoa were found in 15 patients (9.7%), 8 of whom (53%) had d ...200616407362
[high prevalence of cyclospora cayetanensis among indigenous people in bolivar state, venezuela].the intestinal coccidioses caused by cryptosporidium parvum, isospora belli, and cyclospora cayetanensis are parasitoses of major medical importance, but many epidemiological aspects of these infections are still unknown in bolívar state, venezuela. to determine the prevalence of intestinal parasites and especially of intestinal coccidiosis, an indigenous population in san antonio de morichal was evaluated from july 2003 to april 2004. stool samples obtained by spontaneous evacuation were preser ...200616410862
[prevalence of cryptosporidium sp. in institutionalized dogs in the city of são paulo, brazil].dogs play an important role as infection source of human cryptosporidiosis. the objective of the study was to determine the prevalence of cryptosporidium sp. in dogs as well as to compare two techniques of fecal analysis.200616410992
cryptosporidium parvum bovine genotype oocysts in the respiratory samples of an aids patient: efficacy of treatment with a combination of azithromycin and paromomycin.cryptosporidium has been recognized as an emerging zoonotic agent of intestinal cryptosporidiosis leading to diarrhea, malabsorption syndrome, and weight loss in aids patients. in the present case, oocysts of zoonotic cryptosporidium parvum were detected in the sputum and stool samples of an aids patient with a 3-month history of intestinal cryptosporidiosis. the oocysts were detected by modified ziehl-neelsen staining; confirmation was achieved by nested polymerase chain reaction (pcr), targeti ...200616416289
potential sources of microbial contamination in unpasteurized apple cider.a study was conducted to identify possible sources of microbial contamination and to assess the effect of good cleaning and sanitation practices on the microbial quality and safety of unpasteurized apple cider. raw unwashed apples, washed apples, cleaning water, fresh cider, and finished cider samples were collected from five ontario producers over 4 months and microbiologically tested. total coliforms were found in 31, 71 and 38% of the unwashed apple, water, and washed apple samples, respectiv ...200616416911
Refresh
firstprev
...11121314151617181920...
nextlast
Displaying items 1901 - 2000 of 3503