Publications

TitleAbstractYear
Filter
PMID
Filter
growth-inhibitory effects of interferon-gamma on neospora caninum in murine macrophages by a nitric oxide mechanism.to clarify the effector pathway of neospora caninum growth-inhibitory activity induced by interferon-gamma (ifn-gamma) in murine macrophages we examined the relationship between ifn-gamma and nitric oxide (no). production of no was enhanced in cultures of macrophages supplemented with ifn-gamma, and dose-dependent growth inhibition was observed. these findings suggest that the inhibitory activity induced in macrophages by ifn-gamma is mediated no molecules. a competitive inhibitor of the l-argin ...200011002987
evidence of point-source exposure to neospora caninum and protective immunity in a herd of beef cows.to determine whether cows with evidence of previous infection with neospora caninum were less likely to abort or give birth prematurely during an outbreak of neosporosis, compared with herdmates with evidence of primary infection.200010997162
comparison of the ifat and iscom-elisa response in bovine foetuses with neospora caninum infection.the study was carried out to evaluate the efficacy of foetal serology in the diagnosis of neospora-associated bovine abortions. fluids from 14 foetuses of cows with confirmed neosporosis (group a), seven foetuses with confirmed bovine viral diarrhoea virus (bvd infection) (group b) and 11 aborted foetuses without demonstrable infection (group c) were examined. the age of the foetuses ranged from 4.5 months to 9 months. albumin concentration (measured by rocket immunoelectrophoresis) was not sign ...199910576568
spatial associations among density of cattle, abundance of wild canids, and seroprevalence to neospora caninum in a population of beef calves.to determine the epidemiologic plausibility of a sylvatic transmission cycle for neospora caninum between wild canids and beef cattle.200011061391
[clinical neosporosis in the dog: a review].neospora caninum is an intracellular protozoan parasite that was first recognized in dogs in 1988. n. caninum may cause neuromuscular disease in dogs. later, it was discovered that n. caninum has a wide host range and is an important cause of abortion in cattle. in this article, the literature on n. caninum in the dog is reviewed, with emphasis on clinical signs, pathology, diagnosis, treatment, and prognosis.200011060927
the antigenic composition of neospora caninum.neospora caninum is an apicomplexan parasite which causes neosporosis, namely stillbirth and abortion in cattle, and neuromuscular disease in dogs. although n. caninum is phylogenetically and biologically closely related to toxoplasma gondii, it is antigenically clearly distinct. in analogy to t. gondii, three stages have been identified. these are: (i) asexually proliferating tachyzoites; (ii) tissue cysts harbouring slowly dividing bradyzoites; and (iii) oocysts containing sporozoites. the sex ...199910576569
association of serologic status for neospora caninum with postweaning weight gain and carcass measurements in beef calves.to determine the seroprevalence for neospora caninum in a population of beef calves in a feedlot and the association of serologic status with postweaning weight gain and carcass measurements.200011061390
[the role of the dog in the epidemiology of neosporosis in cattle].neospora caninum is an intracellular protozoan parasite that was discovered in a dog in 1988. since then, n. caninum has been demonstrated in a variety of animal species and it has been recognized as an important cause of abortion in cattle. an infection with n. caninum can be maintained in cattle herds for several generations by transplacental transmission from cow to calf. recently, it was demonstrated that dogs can act as definitive hosts of n. caninum and therefore may be a source of infecti ...200011060928
immunization of balb/c mice with killed neospora caninum tachyzoite antigen induces a type 2 immune response and exacerbates encephalitis and neurological disease.balb/c mice were immunized subcutaneously with soluble neospora caninum tachyzoite antigen (nso) entrapped in nonionic surfactant vesicles (nisvs) or administered with freund's complete adjuvant (fca). following virulent parasite challenge, groups of mice immunized with nso and either nisvs or fca had clinical neurological disease and increased numbers of brain lesions compared to groups of mice inoculated with fca, nisvs, or phosphate-buffered saline (pbs) alone. increased numbers of brain lesi ...200011063494
significance of neospora caninum in british dairy cattle determined by estimation of seroprevalence in normally calving cattle and aborting cattle.a case control study was conducted to evaluate the significance of neospora caninum infections in cattle in england and wales. the prevalence of n. caninum in normally calving cattle (the control group; n = 418) and aborting cattle (n = 633) was estimated using a commercial antibody-detection elisa. prevalence estimates for bovine virus diarrhoea virus, infectious bovine rhinotracheitis virus and leptospira hardjo were also obtained by serology. the prevalence of n. caninum was significantly hig ...199910576570
delivery of neospora caninum surface protein, ncsrs2 (nc-p43), to mouse using recombinant vaccinia virus.in order to develop a vaccine against neospora caninum in dogs and cattle, we constructed a recombinant vaccinia virus expressing the n. caninum surface protein, ncsrs2 (nc-p43). monoclonal antibodies to ncsrs2 and anti-n. caninum tachyzoite mouse serum recognized the ncsrs2 expressed by the recombinant vaccinia virus. in addition, recombinant ncsrs2 was transported to the cell surface. mice infected with the recombinant virus predominantly produced igg1 antibody (ab) to n. caninum, rather than ...200011097303
neospora caninum-associated abortion in cattle: the time of experimentally-induced parasitaemia during gestation determines foetal survival.the parasite, neospora caninum is an important cause of abortion in cattle. it is transmitted vertically or horizontally and infection may result in abortion or the birth of a live, healthy but infected calf at full-term. only a proportion of infected cattle abort and the pathogenesis of abortion is not understood. groups of cattle were infected with 10(7) n. caninum tachyzoites intravenously at different times relative to gestation. intravenous inoculation was chosen to reproduce the putative h ...200011072897
serological investigation of an outbreak of neospora caninum-associated abortion in a dairy herd in southeastern united states.an outbreak of neospora caninum-associated abortion occurred in a south carolina dairy wherein greater than 10% of the herd aborted over a 4-month period. of the total number of cows at mid-late gestation, nearly 40% (28/71) aborted while the remaining 60% (43/71) gave birth to normal calves. immunohistochemical examination of brain tissue from a subset of aborted fetuses confirmed n. caninum as the causative agent of abortion in these animals. a variety of serological assays, including indirect ...200011078940
towards evaluating the economic impact of bovine neosporosis.in spite of the global importance of neosporosis as a cause of bovine abortion, there is very little information about its economic consequences. the economic costs are a product of estimations of the quantity of the effects attributable to neospora infection, and the particular unit costs of those effects. in this brief review, which arose from a workshop on the economics of coccidiosis held at the cost 820 meeting, toledo 1998, we discuss the possible effects of neosporosis which are of econom ...199910576571
do cows protect fetuses from neospora caninum transmission? 200111137733
seroprevalence of neospora caninum infection in dairy and beef cattle in spain.in recent years, neosporosis has been identified as a major cause of abortion in dairy and beef cattle. although the disease has been described worldwide, there is a jack of information concerning the prevalence of this infection in different cattle production systems. the aim of this study was to investigate the seroprevalence of neospora caninum infection in a representative area of beef and dairy cattle production in spain. a cross-sectional study was undertaken in which herds constituted the ...199910576572
development and validation of species-specific nested pcrs for diagnosis of acute sarcocystiosis in sheep.sheep may be infected by four species of sarcocystis. two of these species, sarcocystis tenella and sarcocystis arieticanis, are pathogenic. they may cause abortion or acute disease during the early phase of infection, and chronic disease during the late phase of infection. thus far, diagnosis of sarcocystiosis in sheep has been limited, because traditional diagnostic tests based on the detection of sarcocystis-specific antibodies are only genus-specific and, thus, cannot differentiate between p ...199910576582
vertical and horizontal transmission of neospora caninum in dairy herds in québec.neospora caninum is an important cause of abortion in dairy cattle. the objective of this observational study was to estimate the rate of vertical transmission of n. caninum in dairy herds in québec and to investigate horizontal transmission in the same herds. the genealogy of cows from 23 dairy herds were examined. prevalence of seropositive animals in herds studied varied from 4.3% to 61.8% (average, 21.9%). the overall rate of vertical transmission was estimated to be 44.4%, varying from 0% t ...200010857030
neospora then and now: prevalence of neospora caninum in maritime canada in 1979, 1989, and 1998.the seroprevalence of neospora caninum was compared among new brunswick, nova scotia, and prince edward island in 1998, 1989, and 1979. in 1998, the seroprevalence was lowest in prince edward island, where it was the same as in 1989. neospora caninum was present in 1979, but at a lower prevalence.200011126492
neospora caninum in cattle. m. mcallister et al. (2000) evidence of point-source exposure to neospora caninum and protective immunity in a herd of beef cows. j. am. vet. med. assoc. 217, 881-887 200011121844
prevention of vertical transmission of neospora caninum in balb/c mice by recombinant vaccinia virus carrying ncsrs2 gene.neospora caninum infection is the major cause of bovine abortion. to develop a vaccine against n. caninum infection, recombinant vaccinia viruses carrying ncsrs2 and ncsag1 genes (vv/nc-p43 and vv/nc-p36, respectively) were constructed and were tested in a mouse model. vaccination of dams with vv/nc-p43 appeared to confer effective protection against vertical transmission to offspring, though that with vv/nc-p36 only provided partial protection. moreover, the vv/nc-p43 vaccination provoked cellu ...200111166895
isolation of neospora caninum genes detected during a chronic murine infection.in order to isolate genes coding for antigens of neospora caninum which are recognised by the host immune system during a chronic murine infection, a cdna library was immunoscreened with pooled sera from mice which survived three independent infections by n. caninum. two new genes from n. caninum were isolated and expressed in escherichia coli. the genes identified include one homologous to gra1 of toxoplasma gondii, plus another (ncp20) previously unknown in any taxon. both genes encode small p ...200111165273
canine neosporosis: clinical and pathological findings and first isolation of neospora caninum in germany.neosporosis was diagnosed in an 11-week-old puppy of the breed kleiner münsterländer with progressive hindlimb paresis. pathohistological and immunohistological examinations revealed a disseminated infection with neospora caninum. parasitic stages were demonstrated in the brain, spinal cord, retina, muscles, thymus, heart, liver, kidney, stomach, adrenal gland, and skin. immunohistochemistry investigations were carried out using polyclonal rabbit antisera developed against n. caninum tachyzoites ...200010669128
a random amplified polymorphic dna polymerase chain reaction technique that differentiates between neospora species.neospora caninum is a recently described coccidial parasite that was first isolated from a dog in 1988 and has subsequently been shown to infect a wide range of mammals. neospora hughesi, a new species of this genus, has recently been isolated from the spinal cord of horses showing clinical signs of equine protozoal myeloencephalitis. the random amplified polymorphic dna polymerase chain reaction technique is capable of differentiating between n. caninum and n. hughesi.200011191920
gerbils (meriones unguiculatus) are highly susceptible to oral infection with neospora caninum oocysts.laboratory-reared gerbils (meriones unguiculatus) were found to be highly susceptible to oral infection with neospora caninum (nc-liv strain) oocysts. gerbils fed approximately 1000 oocysts became sick or died at 6-13 days post feeding of oocysts (pfo). n. caninum was isolated in cell culture and from gamma-interferon-knockout mice inoculated with homogenates of mesenteric lymph nodes of gerbils examined as early as 1 day pfo. numerous n. caninum tachyzoites were found in ulcerative lesions in t ...200010685849
neospora caninum: is it really different from hammondia heydorni or is it a strain of toxoplasma gondii? an opinion.the published data concerning toxoplasma gondii, hammondia hammondi, h. heydorni and neospora caninum on one side and between t. gondii on the other were neglected by most authors. as conclusion we are convinced that there are only two valid species: isospora (toxoplasma) gondii and hammondia heydorni. the first includes as a strain h. hammondi and the latter n. caninum. in any case there is absolutely no reason (with respect to general zoological nomenclature) to create new genera!200010685850
evidence of post-natal transmission of neospora caninum in dutch dairy herds.eighteen dairy herds with neosporosis-associated abortions were analysed for antibodies against neospora caninum. blood samples of all cows, heifers and calves were collected on the same day for each farm. a total of 2430 heads of cattle were examined. for each herd, the seropositive and seronegative animals were plotted against month of birth. analysis of seroprevalence in relation to age showed an equal distribution of seropositives in all age-groups in 10 herds. in contrast, in eight herds an ...200111239942
prevalence of neospora hughesi and sarcocystis neurona antibodies in horses from various geographical locations.parasite-specific antibody responses to neospora antigens were detected using the immunofluorescent antibody test (ifat) and immunoblot analysis in select equine populations. for comparison, a naturally infected neospora hughesi horse and an experimentally inoculated neospora caninum horse were used. in addition, all samples were tested for antibodies to sarcocystis neurona by immunoblot analysis. a total of 208 samples was evaluated. the equine populations were derived from five distinct geogra ...200111223207
prevalence of antibodies to neospora caninum in horses in france. 200111266072
neospora caninum and bovine virus diarrhoea virus infections in swedish dairy cows in relation to abortion.the protozoan parasite neospora caninum and bovine virus diarrhoea virus (bvdv) are recognized as important causes of bovine abortion and congenital disease worldwide. in this study, serological investigations were performed to estimate the prevalence of n. caninum infection in swedish dairy cattle, to assess to what extent it may affect abortion rates, and to determine possible effects of coinfection with bvdv. the overall n. caninum seroprevalence in swedish dairy cows was estimated at 2% (16/ ...200010712809
molecular comparison of the dense granule proteins gra6 and gra7 of neospora hughesi and neospora caninum.neospora hughesi is a recently described apicomplexan parasite that has been associated with several cases of equine protozoal myeloencephalitis. the biology of this new parasite is just beginning to be defined. towards this understanding, we report important differences between the nucleotide and deduced amino acid sequences of the dense granule proteins gra6 and gra7 of n. hughesi and neospora caninum. this information can be used to differentiate the two species and contribute to further unde ...200111226451
increased risk of abortion following neospora caninum abortion outbreaks: a retrospective and prospective cohort study in four dairy herds.explosive abortion outbreaks in 4 dutch dairy herds during 1992 to 1994 are reported. in 50 of 51 fetuses submitted during the first 3 wk of the outbreaks characteristic histological lesions compatible for infection with neospora caninum were seen. diagnosis of infection was confirmed by immunohistochemistry in 40 fetuses (78%). no evidence for other abortifacients was found. the abortion risk of the herds was investigated in a prospective and retrospective cohort study. the prospective study sh ...199810732067
seroprevalence of neospora caninum in beef cattle in northern alberta.blood samples were collected from 1806 pregnancy-tested cows from 174 herds at a northern alberta auction mart in the fall of 1998. one hundred sixty-two (9.0%) of these samples were positive for antibodies to n. caninum. thirty-five of 260 samples (13.5%) collected from the same region in the 1980s were also serologically positive for n. caninum.200111272457
the inhibitory effect of interferon gamma and tumor necrosis factor alpha on intracellular multiplication of neospora caninum in primary bovine brain cells.primary culture of bovine brain cells was examined for its susceptibility to neospora caninum infections, and this model was used to investigate the effects of bovine interferon gamma (ifn-gamma) and tumor necrosis factors alpha (tnf-alpha) on tachyzoite growth. tachyzoites of n. caninum grew well in this culture, and tachyzoite growth in astroglia and microglia were confirmed by immunocytochemical staining. ifn-gamma inhibited the tachyzoite growth, and this inhibition was not reversed by the a ...200010770613
characterization of the oregon isolate of neospora hughesi from a horse.neospora hughesi was isolated in cell cultures inoculated with homogenate of spinal cord from a horse in oregon. tachyzoites of this oregon isolate of n. hughesi were maintained continuously by cell culture passage and tachyzoites were infective to immunosuppressed mice. gamma interferon gene knockout (ko) mice injected with tachyzoites developed fatal myocarditis and numerous tachyzoites were seen in lesions. gerbils (meriones unguiculatus) inoculated with tachyzoites developed antibodies (> or ...200111318565
a stochastic model for disease transmission in a managed herd, motivated by neospora caninum amongst dairy cattle.a stochastic model for the spread of neospora caninum infection within a herd of dairy cattle is studied, in particular the long-term (equilibrium) behaviour of the model. the model incorporates the interesting feature that total herd size is constrained to lie within a fairly small interval, but not held exactly constant. approximations for the joint distribution of numbers of susceptible and infected individuals present in equilibrium are derived based upon a diffusion approximation to the inf ...200111292494
intergenic spacer (igs) polymorphism: a new genetic marker for differentiation of toxoplasma gondii strains and neospora caninum.the region between the 28s and 18s rrna genes, including the intergenic spacer (igs) region and the 5s rrna gene, from 32 strains of toxoplasma gondii and the nc1 strain of neospora caninum was amplified and used for dna sequencing and/or restriction fragment length polymorphism (rflp) analysis. the 5s rdna sequences from 20 strains of t. gondii were identical. the igs region between the 5s and 18s rrna genes (nontranscribed spacer 2 or nts 2) showed 10 nucleotide variations. six of the 10 varia ...200010958446
naturally-occurring neospora caninum infection in an adult sheep and her twin fetuses.neospora caninum tissue cysts were found in the brains of surgically delivered twin fetuses at 119 days of gestation. in the brains of both fetuses, there was an inflammatory reaction involving perivascular cuffings of mononuclear cells, glial nodules. the dam of these fetuses died because of metritis. histopathological examination of the ewe revealed n. caninum tissue cysts and focal gliosis with mononuclear cell cuffings. a n. caninum-specific dna fragment was detected in a brain homogenate of ...200111318580
monoclonal antibody inhibition of neospora caninum tachyzoite invasion into host cells.monoclonal antibodies were produced against neospora caninum tachyzoites to identify antigens which may play a role during invasion of host cells. confocal laser microscopy showed that most antigens recognised by the mab were located on the surface, but one mab, 1a5, reacted to the apical end of the parasite. some mabs, which recognised 70, 42 and 36kda parasite proteins, significantly inhibited the invasion of the parasite in vitro. the mabs which recognised 42 and 36kda parasite protein, react ...200010675744
effects of sequence alignment and structural domains of ribosomal dna on phylogeny reconstruction for the protozoan family sarcocystidae.finding correct species relationships using phylogeny reconstruction based on molecular data is dependent on several empirical and technical factors. these include the choice of dna sequence from which phylogeny is to be inferred, the establishment of character homology within a sequence alignment, and the phylogeny algorithm used. nevertheless, sequencing and phylogeny tools provide a way of testing certain hypotheses regarding the relationship among the organisms for which phenotypic character ...200011110900
abortion risk in progeny of cows after a neospora caninum epidemic.a study was done of the descendants of cows from 4 dairy herds in which there had been n. caninum abortion outbreaks. precolostral antibodies to n. caninum were demonstrated in 34 of 50 (68%) f1 calves and in 14 of 17 (82%) f2 calves from cows that aborted during the outbreaks. in 214 f1 progeny, n. caninum seroprevalence was nearly 50%, and there was a significant association between serostatus of the offspring and serostatus of dams. these observations indicated that congenital infection was a ...199810732068
characteristics of neospora caninum-associated abortion storms in diary herds in the netherlands (1995 to 1997).abortion storms in 50 dairy herds in the netherlands were reported in which there was a strong association with neospora caninum-infection. the duration of the abortion storms ranged from 6 to 65 d (mean 41.5 d). the cumulative proportion of aborting cows ranged from 0.11 to 0.57 (mean 0.26) of the animals at risk. an apparent seasonal influence was noted as most abortion storms occurred during the summer and early autumn. the prevalence of antibodies to n. caninum in 50 herds which had had an a ...199910734391
risk factors for neospora caninum-associated abortion storms in dairy herds in the netherlands (1995 to 1997).a 2 to 1 matched case control study design was used to analyze herd level risk factors for neospora caninum-associated abortion storms in 47 dairy herds. data were obtained using a questionnaire regarding the state of affairs at the farms over the 2 years prior to the abortion storm. the questionnaire included 120 variables considered to be potential risk factors for either introduction of infection or recrudescence of chronic infection. the relationship between risk factors and case control pai ...199910734392
postnatal neosporosis in dairy cattle in northeast thailand.a total of 83 dairy cows in loei province (muang) and nong bua lamphu (nbl) province, northeast thailand were sampled three times within 6 months in 1998 and their sera were examined for antibodies to neospora caninum at a dilution of 1:100 in the indirect fluorescent antibody test (ifat). in muang the seroprevalence of n. caninum was 37.5% (june), 60% (august), and 62.5% (november). in nbl the prevalence was 50% (august) and 70% (november). in both areas abortions were observed between 1 and 3 ...200111113552
experimental studies on the transmission of neospora caninum between cattle.three studies were conducted to investigate the transmission of neospora caninum between cattle by the oral route. in the first study, six calves were dosed with 10(7)n caninum tachyzoites (nc livb1) in colostrum and/or milk replacer on four occasions. in the second study, two calves and two cows were fed placental tissues from n caninum -infected cows, and, in the third study, seven uninfected calves were fostered onto n caninum -infected dams. in the first study, all six calves developed antib ...200111356096
bovine abortion associated with neospora caninum in hungary.the authors report the first case of bovine neosporosis in hungary based on investigations made on an aborted fetus. the diagnostic methods included traditional as well as molecular techniques. this record extends further the geographic range of the disease.200111402646
protective efficacy of vaccination by recombinant vaccinia virus against neospora caninum infection.the recombinant vaccinia viruses expressing the surface protein of neospora caninum tachyzoite, ncsag1 or ncsrs2, were constructed. the vaccination with these recombinant viruses could protect effectively the parasite invasion in a mouse model system. the vaccine efficacy of ncsrs2 was higher than that of ncsag1. the present study indicated that a high level of igg1 ab production to parasite is important for clearance of parasite at the early stage of infection and that t cell response has a cru ...200111163660
neospora caninum infection in a clinically healthy calf: parasitological study and serological follow-up.in this study a case of congenital infection in a clinically healthy calf is reported. the mother showed high antibody levels (ifat) at 230 days of gestation (igg titres > or = 1:1600, igm titres > or = 1:320) and the parasite was isolated from placental cotyledonary villi at calving. the igm values are indicative of a recent infection in the third trimester of gestation. the calf was monitored serologically for igm and igg from birth until slaughtering, at 8 months of age. igm titre showed a pe ...200010780172
dogs shed neospora caninum oocysts after ingestion of naturally infected bovine placenta but not after ingestion of colostrum spiked with neospora caninum tachyzoites.an experiment was carried out to determine whether bovine colostrum or placenta could be a source of infection of neospora caninum for dogs. for this purpose, two dogs were fed bovine colostrum to which culture-derived n. caninum tachyzoites were added and two other dogs were fed placental cotyledonary tissue from n. caninum seropositive cows. one dog served as a negative control during the start of the experiment but this control dog was fed cotyledonary tissue later on. none of the dogs did pr ...200111403764
in the absence of endogenous gamma interferon, mice acutely infected with neospora caninum succumb to a lethal immune response characterized by inactivation of peritoneal macrophages.following infection with neospora caninum, balb/c mice were shown to be resistant to an acute infection but developed a latent chronic infection. however, balb/c background gamma interferon (ifn-gamma)-deficient mice were sensitive to the acute infection. since the immune response in ifn-gamma-deficient mice is scantly known, we examined the function of macrophages, major histocompatibility complex (mhc) class ii expression, t-cell responses, and serum cytokine levels in the mice. all ifn-gamma- ...200111427432
reproductive performance of a cow-calf herd following a neospora caninum-associated abortion epidemic.this study examines the long-term impact of a neospora caninum-associated abortion outbreak in a large cow-calf herd in northern alberta. blood samples were collected 4 times from all bred females and heifer calves born during the spring before the outbreak: (1) at the time of the outbreak, (2) the following spring, (3) the subsequent fall, and, finally, (4) the second spring after the outbreak. the samples were analyzed using a commercially available enzyme-linked immunosorbent assay for n. can ...200111360856
neospora caninum seroprevalence and associated risk factors in beef cattle in the northwestern united states.a neospora caninum seroprevalence and risk factor survey of 2585 cows was conducted in 55 beef cow-calf herds located in five northwestern states of the usa. blood samples were collected by private veterinary practitioners and management practices were surveyed using a mail questionnaire. producers were randomly selected from those that employed these veterinarians to perform annual herd pregnancy examinations. questions were asked about animal management, grazing and feeding, immunization and r ...200010828508
evaluation of the embryo transfer procedure proposed by the international embryo transfer society as a method of controlling vertical transmission of neospora caninum in cattle.to evaluate efficacy of embryo transfer into seronegative recipients, using the procedure proposed by the international embryo transfer society (iets), for preventing vertical transmission of neospora caninum in cattle.200111394835
serological survey and first finding of neospora caninum in taiwan, and the detection of its antibodies in various body fluids of cattle.a serological survey for antibodies against neospora caninum in cattle, goats and farm dogs in taiwan was carried out. sera of 613 cattle from 25 dairy farms, 24 goats from six goat farms and 13 dogs from six dairy cattle farms were tested for antibodies against n. caninum using indirect fluorescence antibody test (ifat). the same sera were also tested for antibodies against toxoplasma gondii using latex agglutination test. of the 613 cattle sera, 44.9% (275/613) were found to have antibodies ag ...200010828511
serologic survey of neospora caninum infection in a closed dairy cattle herd in maryland: risk of serologic reactivity by production groups.prevalence of antibodies to neospora caninum was determined in a cross-sectional consensus survey of 1029 bovines in a dairy herd with endemic neospora-induced abortion. sera were screened by indirect fluorescent antibody test (ifat). the prevalence of n. caninum antibody in the ifat was 17.9% in 107 neonates, 26.2% in 233 yearling heifers and steers, 39.07% in 218 mature heifers, and 26.9% in 465 milking cows. serologic reactivity was associated with production grouping on the farm with the gre ...200010841997
immunization of dogs with a canine herpesvirus vector expressing neospora caninum surface protein, ncsrs2.in order to develop a vaccine against neospora caninum in dogs, we constructed recombinant canine herpesvirus (chv) expressing n. caninum surface protein, ncsrs2. indirect immunofluorescence indicated that the antigenic structure of the recombinant ncsrs2 was similar to the authentic parasite protein. the dogs immunised with recombinant virus produced igg antibody to n. caninum, and their sera recognised the parasite protein on western blot. the dogs inoculated with recombinant virus showed no c ...200011027782
prevalence of neospora caninum antibodies in wild ruminants from the italian alps. 200111442237
isolation of neospora caninum from the brain of a naturally infected adult dairy cow.neospora caninum was isolated from the brain of a 2-year-old dairy cow that had aborted confirmed n. caninum-infected fetuses on two occasions. the cow had an indirect fluorescent antibody titer of 1:1600 to n. caninum. the cow was killed 24 days after its second abortion and the brain was bioassayed for n. caninum in nude mice. multifocal areas of perivascular cuffing and glial nodules were observed in the cerebrum and mesencephalon of the cow, but n. caninum was not identified in histological ...200010842005
first isolation of neospora caninum from the feces of a naturally infected dog.neospora caninum is a major cause of abortion in cattle worldwide. cattle become infected with n. caninum by ingesting oocysts from the environment or transplacentally from dam to fetus. experimentally, dogs can act as definitive hosts, but dogs excrete few oocysts after ingesting tissue cysts. a natural definitive host was unknown until now. in the present study, n. caninum was isolated from the feces of a dog. gerbils (meriones unguiculatus) fed feces from the dog developed antibodies to n. ca ...200111426726
seroprevalence of neospora caninum in female water buffaloes (bubalus bubalis) from the southeastern region of brazil.antibodies to neospora caninum were assayed in sera of 222 female water buffaloes from ribeira valley of são paulo state, brazil, using an indirect fluorescent antibody test (ifat) and neospora agglutination test (nat). ifat antibodies were found in 64% of buffaloes with titers of 1:25 (42 buffaloes), 1:50 (53 buffaloes), 1:100 (31 buffaloes), 1:200 (10 buffaloes), 1:400 (3 buffaloes), or > or =1:800 (3 buffaloes). nat antibodies were found in 53% of buffaloes; in titers of 1:40 in 52 buffaloes, ...200111511420
cutaneous neosporosis in two adult dogs on chronic immunosuppressive therapy.antemortem diagnosis of generalized ulcerative and pyogranulomatous dermatitis with numerous intralesional tachyzoites was made from skin biopsy specimens from 2 adult dogs on chronic immunosuppressive therapy. a 9-year-old italian greyhound was on long-term corticosteroid therapy for the treatment of a lupus-like systemic autoimmune disorder, and a 7-year-old labrador retriever had received several months of chemotherapy for lymphosarcoma. the tachyzoites were identified as neospora caninum by ...200111482605
detection of igg antibody against neospora caninum in cattle in korea.a total of 492 cattle sera was screened by igg-elisa against neospora caninum (nc-1 strain and a korean isolate, kba-2) and toxoplasma gondii. out of 492, 113 sera (23.0%) reacted positively to either nc-1 or kba-2 strains of n. caninum. among the 113 positive sera, 92 sera (81.4%) reacted with antigens of both strains, but 6 sera (5.3%) with nc-1 and 15 sera (13.3%) with kba-2 strain only. and with t. gondii antigen, 6 sera (1.2%) were positive but all reacted with n. caninum antigen also. west ...200011138317
neospora caninum infection associated with stillbirths in captive antelopes (tragelaphus imberbis).neosporosis was diagnosed in full-term stillborn twin calves of captive antelopes (tragelaphus imberbis) in a german zoo. in both calves a multifocal non-suppurative encephalitis was present and infection with neospora (n.) caninum was confirmed by foetal serology and pcr. n. caninum-dna was detected in brain, heart, lung, liver and spleen of a third full-term stillborn calf. histopathological lesions were absent in this calf and antibodies against n. caninum were not detected in pleural fluid. ...200111358631
prevalence of antibodies to neospora caninum and toxoplasma gondii in gray foxes (urocyon cinereoargenteus) from south carolina.little is known about the epidemiology of neospora caninum in wild mammal populations. it has been suggested that a sylvatic cycle exists for n. caninum. dogs and potentially other canids are a definitive host for n. caninum. the present study was done to determine the prevalence of antibodies to n. caninum in a population of gray foxes (urocyon cinereoargenteus) from a nonagricultural setting in south carolina. we also determined the prevalence of antibodies to toxoplasma gondii in these animal ...200111358632
failure of dogs to shed oocysts after being fed bovine fetuses naturally infected by neospora caninum.neospora caninum is a protozoan that causes abortion in cattle. the dog has recently been identified as a definitive host for n. caninum. to verify if bovine fetuses can infect dogs, nine 2-4-month-old dogs were fed bovine fetuses naturally infected by n. caninum. none of the dogs excreted oocysts, seroconverted, had clinical signs or lesions compatible with n. caninum infection. additional studies will be necessary to determine the natural mode of infection of dogs by n. caninum.200111358630
neosporosis. aspects of epidemiology and host immune response.neospora caninum is a recently recognized protozoan parasite which has been described as causing a neuromuscular paralysis in dogs and is emerging as a major cause of bovine infertility and abortion worldwide. the parasite is known to infect a range of warm blooded animals but the disease predominates in dogs and cattle. it is not yet known if n. caninum can infect and cause disease in people. the dog has recently been identified as the definitive host and the parasite may be transmitted through ...200011193706
efficacy of toltrazuril and ponazuril against experimental neospora caninum infection in mice.neosporosis is a disease affecting predominantly fetal development in cattle and dog hosts; and it may cause neuromuscular disfunction in infected newborn calves and pups. predispositions--including, e.g. transient immunosuppression during pregnancy--may result in an increased dissemination of the parasite within the host or its offspring. chemotherapeutic treatment of neosporosis may be an issue, provided that an appropriate drug is made available. in this respect, we describe the use of a mous ...200111199848
isolation and characterization of two parasitic protozoa from a pacific harbor seal (phoca vitulina richardsi) with meningoencephalomyelitis.two species of protozoans were isolated from a harbor seal with fatal meninogoencephalitis. serologic reactivity was detected to both sarcocystis neurona and toxoplasma gondii. parasites associated with brain inflammation and necrosis reacted only with immunohistochemical stains utilizing polyclonal antisera raised against sarcocystis neurona. however, 2 distinct parasites were observed in cell cultures derived from the seal's brain tissue. these parasites were separated by mouse passage and lim ...200111534647
serological evidence for naturally occurring transmission of neospora caninum among foxes (vulpes vulpes).the study describes the time course of the neospora caninum-specific antibody response in experimentally infected foxes, in naturally n. caninum-seropositive vixens and their litters. an immunofluorescence test, a tachyzoite surface antigen based elisa and an immunoblot assay were established for this purpose. the immunoblot patterns of naturally seropositive and experimentally infected foxes revealed a high degree of similarity and resembled those reported for other intermediate host species. r ...200111306121
serological analysis of calves experimentally infected with neospora caninum: a 1-year study.a serological study was conducted with calves experimentally infected with the protozoan parasite neospora caninum. the animals were inoculated with either a low or high dose of n. caninum tachyzoites and temperature responses monitored daily for the first 2 weeks after inoculation. blood samples were collected before inoculation, and at regular intervals thereafter for 1 year. serological analysis was achieved using an indirect fluorescent antibody test (ifat), an enzyme-linked immunosorbent as ...200111182233
isolation of neospora caninum from the brain of a naturally infected dog, and production of encysted bradyzoites in gerbils.neospora caninum was isolated from the brain of an adult dog in brazil. cerebral tissue from the dog was inoculated into mongolian gerbils. gerbils were euthanized 3-4 months later and bradyzoite-containing tissue cysts were observed in their brains. n. caninum (designated nc-bahia) was isolated in cell culture after inoculation with tissue cysts from the gerbils. the identity of the parasite was confirmed by immunohistochemical examination and polymerase chain reaction (pcr). gerbils may be a u ...200111587828
prevalence of neospora caninum infection in dogs from beef-cattle farms, dairy farms, and from urban areas of argentina.prevalence of anti-neospora caninum antibodies was determined in sera of 320 dogs from argentina using the indirect fluorescent antibody test (ifat). antibodies to n. caninum were found in 121 of 320 (37.8%) sera with titers of 1:50 (21 dogs), 1:100 (23 dogs), 1:200 (23 dogs), 1:400 (17 dogs), 1:800 (23 dogs), and > or = 1:1.600 (14 dogs). the seropositivity (ifat, > or = 1:50) was higher in dogs from dairy (48% of 125) and beef (54.2% of 35) farms than in dogs from urban areas (26.2% of 160). p ...200111534656
characterization of neospora caninum surface protein ncsrs2 based on baculovirus expression system and its application for serodiagnosis of neospora infection.the baculovirus expression system has proved to be a useful tool for the production of recombinant proteins. here we have characterized the neospora caninum surface protein ncsrs2 produced by two types of the recombinant virus and also have developed an enzyme-linked immunosorbent assay (elisa) using recombinant ncsrs2 for the serologic diagnosis of neospora infection. western blot analysis showed two major protein bands that were detectable in insect cells infected with each recombinant baculov ...200111682519
tgm2ap participates in toxoplasma gondii invasion of host cells and is tightly associated with the adhesive protein tgmic2.like other members of the medically important phylum apicomplexa, toxoplasma gondii is an obligate intracellular parasite that secretes several classes of proteins involved in the active invasion of target host cells. proteins in apical secretory organelles known as micronemes have been strongly implicated in parasite attachment to host cells. tgmic2 is a microneme protein with multiple adhesive domains that bind target cells and is mobilized onto the parasite surface during parasite attachment. ...200111532123
determination of antigenic domain in gst fused major surface protein (nc-p43) of neospora caninum.the antigenic domain of the major surface protein (nc-p43) of neospora caninum was examined by polymerase chain reaction of its gene fragments and recombinant expression as gst fusion proteins. the fragments of nc-p43 were as follow: a total open reading frame (ofr), t; ofr without signal sequence and c-terminal hydrophobic sequence, s; n-terminal 2/3 parts of s, a; c-terminal 2/3 parts, p; n-terminal 1/3 part, x; middle 1/3 part, y; and c-terminal 1/3 part, z, respectively. the dna fragments we ...200111590914
oocyst excretion in dogs fed mouse brains containing tissue cysts of a cloned line of neospora caninum.neospora caninum is an apicomplexan parasite that causes neonatal neuromuscular disease in dogs and abortions in cattle. bovine neosporosis is a major production problem worldwide. the parasite is transmitted to cattle via oocysts excreted by dogs or by transplacental transmission. dogs are the only proven definitive host for n. caninum. one of 3 dogs fed mouse brains containing tissue cysts of a wild-type n. caninum strain ck0160sc3b (cko) excreted oocysts in its feces. two of 3 dogs fed mouse ...200111534658
small-subunit rdna sequencing of the italian bovine neospora caninum isolate (nc-pv1 strain).the small-subunit (ssu) rdna of the neospora sp. nc-pv1 strain isolated in italy from cattle has been sequenced and compared to the other five n. caninum strains ssu rdna sequences deposited in the data bases. the nc-pv1 strain sequence is identical to three published sequences. minor differences, respectively four nucleotide bases and one nucleotide base, have been found when comparing the nc-pv1 sequence with two other available sequences of n. caninum. according to these results, the neospora ...200011686077
neospora caninum in persistently infected, pregnant cows: spontaneous transplacental infection is associated with an acute increase in maternal antibody.nine cows which were naturally and persistently infected with neospora caninum were housed and observed intensively throughout pregnancy. no recrudescence of a latent infection was detected by pcr tests on maternal blood but fetal infection, implying a recrudescence of maternal parasitosis, was associated with a marked increase in maternal antibody. the increase occurred in the second half of pregnancy in five cows which infected their calves, and before mid-pregnancy in one cow which aborted. t ...200111688746
neospora caninum microneme protein ncmic3: secretion, subcellular localization, and functional involvement in host cell interaction.in apicomplexan parasites, host cell adhesion and subsequent invasion involve the sequential release of molecules originating from secretory organelles named micronemes, rhoptries, and dense granules. microneme proteins have been shown to be released at the onset of the initial contact between the parasite and the host cell and thus mediate and establish the physical interaction between the parasite and the host cell surface. this interaction most likely involves adhesive domains found within th ...200111553593
association between exposure to neospora caninum and milk production in dairy cows.to determine association between exposure to neospora caninum and milk production in dairy cows.200111549092
comparative molecular investigation of nc5-pcr amplicons from neospora caninum nc-1 and hammondia heydorni-berlin-1996.the clinical relevance of neospora caninum as a cyst-forming coccidian parasite is increasingly acknowledged within veterinary medicine, although the pathways of transmission are far from being solved. the parasite is well known for causing diaplacental infections in cows associated with abortion and/or severe damage of the fetus. in addition, it may cause neuromuscular disease in dogs, which thus apparently act as intermediate hosts as well as final hosts. in our previous studies, we have demon ...200111688897
comparison of the growth inhibitory effects of canine ifn-alpha, -beta and -gamma on canine cells infected with neospora caninum tachyzoites.the growth inhibitory effects of recombinant canine interferon alpha (ifn-alpha), beta (ifn-beta) and gamma (ifn-gamma) were examined on madin-darby canine kidney cells infected with neospora caninum tachyzoites. the parasite growth was inhibited by all ifns in a dose-dependent manner. ifn-gamma inhibited the parasite growth with greater efficacy than ifn-alpha or ifn-beta. moreover, the effect of ifns on n. caninum growth associated with the suppression of the host cell viability. the present s ...200111346181
serodiagnosis of toxoplasma gondii infection in cats by enzyme-linked immunosorbent assay using recombinant sag1.the gene encoding surface antigen 1 (sag1, p30) of toxoplasma gondii (t. gondii) was cloned into the plasmid pgex-4t-3 and subsequently expressed in escherichia coli (e. coli) as a glutathione-s-transferase (gst) fusion protein. the recombinant sag1 (rsag1) was refolded using 8m urea solution followed by dialysis and thereafter evaluated in an enzyme-linked immunosorbent assay (elisa) for serological diagnosis of toxoplasmosis. the test sera were adsorbed with gst to block non-specific reactivit ...200111705650
leishmania infantum and neospora caninum simultaneous skin infection in a young dog in italy.leishmania infantum, the agent of canine leishmaniasis in mediterranean countries, and neospora caninum, a recently recognized protozoal pathogen in dogs, were diagnosed in a 9-month-old argentine dogo dog. both skin lesions and neurological signs were present. histopathology of cutaneous lesions revealed a suppurative, diffuse dermatitis with numerous intracellular protozoa. serology was positive for both l. infantum (1:640) and n. caninum (1:800). double-label immunohistochemical staining of s ...200111705654
immunity to experimental neosporosis in pregnant sheep.neospora caninum is an important cause of fetal loss in cattle but has also infrequently been shown to cause disease in sheep and goats. experimental infection of pregnant sheep with n. caninum causes clinical and pathological changes very similar to those of neosporosis in cattle. an experiment in sheep was undertaken to examine whether infection with n. caninum before pregnancy conferred immunity to subsequent challenge with the parasite during pregnancy. primary inoculation of nc1 tachyzoites ...200111240899
association of serologic status for neospora caninum and postweaning feed efficiency in beef steers.to determine the effects of serologic status for neospora caninum on short-term weight gain, feed intake, and feed efficiency (feed intake/gain).200111697371
a previous infection with toxoplasma gondii does not protect against a challenge with neospora caninum in pregnant sheep.sheep immunized with toxoplasma gondii (toxovax) prior to pregnancy were tested for their ability to withstand a challenge at 90 days gestation with 107 neospora caninum (nc1) tachyzoites. the antibody responses in sheep following immunization with t. gondii were specific for t. gondii whereas peripheral blood mononuclear cells responded to both t. gondii and n. caninum antigen in vitro. this suggested that there was induction of crossreactive immune recognition in the sheep, at least at the cel ...200111240903
neospora caninum: its oocysts and its identity: an opinion.a recently published opinion that hammondia heydorni, neospora caninum, and n. hughesi are a single species is not supported by genetic comparisons. furthermore, the suggestion that oocysts shed by dogs after experimental infection with n. caninum might have been of another organism is not consistent with the finding that these oocysts induced n. caninum infections in mice.200011068821
a polygen-adjuvanted killed neospora caninum tachyzoite preparation failed to prevent foetal infection in pregnant cattle following i.v./i.m. experimental tachyzoite challenge.cattle immunised with a polygen-adjuvanted killed neospora caninum tachyzoite preparation were previously shown to produce interferon (ifn)-gamma at levels similar to those of tachyzoite-infected cattle. in view of the critical role of ifn-gamma in resistance of mice to n. caninum infection, these results prompted us to test the polygen-adjuvanted preparation in pregnant cattle to determine whether it will be able to prevent foetal infection following an experimental tachyzoite challenge. seven ...200010980287
specific detection of neospora caninum oocysts in fecal samples from experimentally-infected dogs using the polymerase chain reaction.neospora caninum oocysts, passed in the feces of a definitive host (dog), were isolated, and genomic dna was extracted. a polymerase cahin reaction (pcr) targeting the n. caninum-specific nc 5 genomic sequence was performed using the isolated dna. a synthesized competitor molecule containing part of the nc 5 sequence was included in the assay as a check against false-negative pcr results and to quantify n. caninum oocyst dna in fecal samples. a standard curve of the ratio of fluorescence intensi ...200111318571
myosin diversity in apicomplexa.a polymerase chain reaction (pcr) screen was used to examine the diversity of myosins in 7 apicomplexan parasites: toxoplasma gondii, plasmodium falciparum, neospora caninum, eimeria tenella, sarcocystis muris, babesia bovis, and cryptosporidium parvum. using degenerate pcr primers compatible with the majority of known myosin classes, putative myosin sequences were obtained from all of these species. all of the sequences obtained showed greatest similarity to previously identified apicomplexan m ...200111318578
detection of igg antibodies to neospora caninum and toxoplasma gondii in dogs examined in a veterinary hospital from brazil.a total of 163 dogs with neuromuscular, respiratory and/or gastrointestinal disorders, was admitted at the veterinary hospital, federal university of uberlândia, brazil, and submitted to serology for toxoplasma gondii and neospora caninum. assays for t. gondii included indirect haemagglutination (iha), indirect fluorescent antibody (ifat-tg), immunoenzymatic (elisa), and immunoblotting (ib-tg). assays for n. caninum included ifat-nc and immunoprecipitation (ip-nc). based on concordant results by ...200111423182
rare detection of neospora caninum in placentas from seropositive dams giving birth to full-term calves.neospora caninum is thought to be transmitted to cattle by dogs, the only known definitive host. although aborted fetuses seem the most likely source of infective material for dogs, placentas from seropositive dams appear also as a potential source of infective material. the objective of the study was to evaluate the presence of n. caninum organisms in placentas of full-term calves born to seropositive cows. sixteen placentas, 11 from neospora-seropositive cows, were examined histologically and ...200111289218
histopathological survey of aborted bovine fetuses in scotland with special reference to neospora caninum. 200011132675
toxoplasma gondii: molecular cloning and characterization of a novel 18-kda secretory antigen, tgmic10.hoff, e. f., cook, s. h., sherman, g. d., harper, j. m., ferguson, d. j. p., dubremetz, j. f., and carruthers, v. b. 2001. toxoplasma gondii: molecular cloning and characterization of a novel 18-kda secretory antigen, tgmic10. experimental parasitology, 97, 77-88. during host cell invasion, toxoplasma gondii secretes proteins from specialized organelles (micronemes and rhoptries) located at the apical end of the parasite. the contents of the micronemes appear to be crucial to t. gondii invasion, ...200111281704
neosporosis in mexican dairy herds: lesions and immunohistochemical detection of neospora caninum in fetuses.of 211 aborted bovine fetuses collected from mexican dairy herds between january 1996 and march 1999, 73 showed microscopical lesions consistent with neosporosis. of these 73 fetuses, 58 (79%) showed lymphocytic myocarditis, 39 (53%) showed microgliosis and multifocal necrosis in the brain, 39 (53%) showed lymphocytic hepatitis, and 19 (26%) showed lymphocytic myositis. immunohistochemical examination of brain, myocardium and liver from 53 of the same 73 fetuses demonstrated neospora caninum ant ...200111437517
genetic and biological diversity among isolates of neospora caninum.neospora caninum is a protozoan parasite that causes bovine abortion. the epidemiology of n. caninum is poorly understood and little is known about the genetic diversity of the parasite, or whether individual isolates differ in virulence. such diversity may, among other factors, underlie the range of pathologies seen in cattle. in this study we analysed biological and genetic variation in 6 isolates of n. caninum originating from canine and bovine hosts by measurement of growth rate in vitro, we ...200111467779
interferon-gamma-induced apoptosis in host cells infected with neospora caninum.interferon-gamma (ifn-gamma) has a crucial role for host defence against parasite infection. it is not clear, however, how ifn-gamma affects the parasite-infected host cells. the effect of ifn-gamma on neospora caninum-infected cells was investigated in murine fibroblasts and canine kidney cells in vitro. in the presence of ifn-gamma, the viability of the infected host cell was decreased and apoptotic cell death occurred, as analysed by dna stainings with propidium iodide and a terminal deoxy-nu ...200111467780
immunohistochemical and ultrastructural evidence for neospora caninum tissue cysts in skeletal muscles of naturally infected dogs and cattle.protozoan stages were detected in the skeletal muscles of four dogs suffering from neosporosis and two neonatal calves with confirmed neospora caninum- infection which could be immunohistochemically labelled by an antiserum against the bradyzoite-specific antigen bag-5. in one calf, a tissue cyst was labelled by an antiserum against the n. caninum isolate nc-1. ultrastructurally, a 0.3-1 microm-thick cyst wall surrounded the labelled parasites. the cysts were located within myofibres and contain ...200111429181
protease activity and host cell binding of the 42-kda rhoptry protein from toxoplasma gondii after secretion.three proteases were identified in the excretory/secretory proteins (esp) from toxoplasma gondii by the gelatin acrylamide gel electrophoresis (gage), of which the molecular masses were 80, 70, and 42 kda. one of the proteases with 42 kda was reactive to a monoclonal antibody (mab), tg786 clone, which was localized in the rhoptry of t. gondii by immunohistochemistry. the protease was maximally active at the ph range between 7.5 and 8.5, and was sensitive to inhibition by tpck and egta. the gelat ...200111563841
Displaying items 301 - 400 of 1864