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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
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
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
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
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
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
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
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
prevalence of antibodies to neospora caninum in horses in france. 200111266072
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
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
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
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
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
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
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
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
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
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
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
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
do cows protect fetuses from neospora caninum transmission? 200111137733
histopathological survey of aborted bovine fetuses in scotland with special reference to neospora caninum. 200011132675
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
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
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
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
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
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
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
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
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
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
[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
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
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
use of purified tachyzoite surface antigen p38 in an elisa to diagnose bovine neosporosis.affinity-purified 38 kda surface antigen of neospora caninum tachyzoites was used to develop an enzyme-linked immunosorbent assay (elisa) to diagnose n. caninum-associated abortion in cattle. the specificity of this antigen was demonstrated by using sera from cattle experimentally infected with other apicomplexan parasites. in a panel of field sera, serological differences could be demonstrated between herds with epidemic and endemic abortions. optimal elisa cut-offs were determined for the dete ...200010996331
toxoplasmosis as a suspected cause of abortion in a greenland muskox (ovibos moshatus wardi).toxoplasma gondii tachyzoites were seen in the placenta of a late-term aborted greenland muskox (ovibos moschatus wardi) fetus in a captive herd at the san francisco zoo. the organism stained with anti-t. gondii polyclonal rabbit serum but not with anti-neospora caninum serum. the dam had a toxoplasma titer of > or =1:3,200 at the time of abortion and in each of the previous 3 yr (modified agglutination test). the muskox is a new host record for t. gondii.200010982143
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
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
neospora hughesi: experimental infections in mice, gerbils, and dogs.neospora hughesi is a recently described cause of equine protozoal myeloencephalitis (epm). a rodent model for pathogenicity would facilitate development of therapies to be used in horses. in the present study, we examined the susceptibility of balb/c gamma-interferon gene knockout (gamma-infko), balb/c, cd-1, and c57bl/6 strains of mice and gerbils to infection with tachyzoites of the nh-a1 strain of n. hughesi isolated from a horse from al, usa. only the gamma-ifnko mice developed severe clini ...200010946135
a european perspective on neospora caninum.since the identification of neospora caninum in 1984 as a parasite separate from toxoplasma gondii by bjerkas et al., and its subsequent characterization and classification in 1988 by dubey and co-workers, this parasite has attracted increasing attention, primarily as an important causative agent of abortion in cattle and neuromuscular disease in dogs, but also as a complementary model system to t. gondii for investigating the basic biology of intracellular parasitism. during november 11-14, 199 ...200010927081
neosporosis in water buffalo (bubalus bubalis) in southern italy.a study was carried on 1377 water buffalo serum samples from 50 farms in southern italy to test the presence of neospora caninum antibodies by indirect fluorescence antibody test (ifat). rabbit anti-buffalo immunoglobulins conjugated to fluorescein were used in the test. fluorescence in sera dilutions above 1:200 was considered as indicative of the presence of n. caninum antibodies. the overall prevalence of infection in the animals was 34.6%. the prevalence increased in relation to the age of s ...200010889356
seroprevalence of neospora caninum infection in domestic dogs in turkey. 200010872789
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 caninum infected the alimentary tract of nude mice and was transmitted to other mice by intraperitoneal inoculation with the intestinal contents.neospora caninum (bt-2 strain) that originated from the brain of a holstein calf was serially passaged through 10 generations of balb/c nude mice by intraperitoneal inoculation. histological examination of the mice revealed that numerous clusters of tachyzoites appeared in the pancreas, stomach and small intestine as well as in the central nervous system (cns) and skeletal muscles. intestinal contents of the infected mice were inoculated intraperitoneally into uninfected nude mice and 3 of the 1 ...200010852403
[neospora caninum and neosporosis--basic science at the institute of parasitology and possible implications]. 200010850161
neosporosis in cattle.during the past decade, neospora caninum infection has emerged as an important reproductive disease in cattle throughout the world. abortion, occurring during the middle of gestation, is the primary clinical sign of the infection in cattle. surveys in several countries from three continents have identified n. caninum infection as the major diagnosed cause of bovine abortion. both endemic and epidemic patterns of abortion may occur in herds. an important feature of this disease is that the protoz ...200010844212
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
the role of cd4(+) or cd8(+) t cells in the protective immune response of balb/c mice to neospora caninum infection.the role of cd4(+) or cd8(+) t cells in the immune response of balb/c mice against neospora caninum infection was examined by using anti-cd4 and/or anti-cd8 monoclonal antibodies (mabs). mice were intraperitoneally inoculated with anti-cd4 and/or anti-cd8 mabs before and after infection with n. caninum and observed for 30 days after infection. most of the anti-cd4 mab-treated mice and all of the anti-cd4 and anti-cd8 mabs-treated mice died within 30 days post-infection (p.i.). in contrast, 100% ...200010841998
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
seroprevalence of neospora caninum infection following an abortion outbreak in a dairy cattle herd.to investigate the seroprevalence of neospora caninum infection in a commercial dairy cattle herd, 15 months after detection of an abortion outbreak.200010840574
neospora caninum infections in australia and new zealand.to review the current state of knowledge of neospora caninum infections with particular reference to australia and new zealand.200010840573
in vitro isolation and characterization of bovine neospora caninum in korea.the brains of nine aborted bovine fetuses and two newborn calves born from dams suspected to be infected with neospora caninum were homogenized and inoculated into vero cells. all fetuses and calves were from cows determined as seropositive to n. caninum by an ifa test. sera and thoracic fluids of all fetuses and calves also revealed high antibody titer to n. caninum by ifat ranging from 1:800 to 1:3200. n. caninum was isolated from the brains of one aborted fetus and one newborn calf when the b ...200010828521
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
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
isolation, characterization and expression of a gra2 homologue from neospora caninum.a cdna library derived from mrna of tachyzoites of neospora caninum (nc-liverpool strain) was screened with antisera from a cow naturally infected with n. caninum. the dna sequence of 1 recombinant isolated predicted a significant protein sequence homology of the gene product to the 28 kda (gra2) antigen of toxoplasma gondii. studies on the n. caninum gene coding for this antigen demonstrated the presence of a single intron flanked by 2 exons; the gene was also highly expressed in culture-derive ...200010811279
molecular characterization of a novel microneme antigen in neospora caninum.the apical complex of the parasites belonging to the phylum sporozoa is believed to be critically involved in the events leading to host cell invasion. the characterization of the components of this subcellular structure is therefore an important step towards understanding how these parasites achieve host cell entry. affinity-purification of an anti-neospora caninum antiserum on a reactive protein band of approximately 40 kda following triton-x-114 extraction of parasite proteins, sds-page and w ...200010802317
diagnosis and epidemiology of bovine neosporosis: a review.neospora caninum is a protozoan parasite that was first described in dogs in 1988. subsequently the parasite has been associated with abortion in cattle. evidence is accumulating that neosporosis is a major cause of reproductive failure in cattle all over the world. recent knowledge of neosporosis is reviewed with emphasis on the diagnosis and epidemiology of the disease in cattle. in addition, attention is paid to strategies for disease control and prevention.200010789513
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
neutralization of maternal il-4 modulates congenital protozoal transmission: comparison of innate versus acquired immune responses.il-4 levels were modulated in mice to test the hypothesis that induction of a maternal type 1 response would decrease the frequency of congenital neospora caninum transmission. this hypothesis tested the relationship between il-4 and both innate and adaptive immunity utilizing two basic experimental designs. in the first, maternal il-4 was neutralized with mab during pregnancy in naive mice concomitant with initial, virulent infection. in the second, maternal il-4 was neutralized before pregnanc ...200010779783
biological characterisation of sarcocystis neurona isolated from a southern sea otter (enhydra lutris nereis).sarcocystis neurona was isolated from the brain of a juvenile, male southern sea otter (enhydra lutris nereis) suffering from cns disease. schizonts and merozoites in tissue sections of the otter's brain reacted with anti-s. neurona antiserum immunohistochemically. development in cell culture was by endopolyogeny and mature schizonts were first observed at 3 days postinoculation. pcr of merozoite dna using primer pairs jnb33/jnb54 and restriction enzyme digestion of the 1100 bp product with dra ...200010779575
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
[the occurrence of toxoplasma gondii and neospora caninum as regards meat hygiene].toxoplasma gondii and neospora caninum are phenotypically and phylogenetically closely related cyst-forming coccidia, both of which may cause abortion in livestock animals. t. gondii exhibits also zoonotic potential by causing diaplacental infections in the human fetus and harmful infections in immunosuppressed individuals. humans get infected either by consuming inappropriately prepared cyst-containing meat or by ingesting oocysts originating from cat feces. therefore, in order to assess infect ...200010748708
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
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
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
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
molecular characterization of a thrombospondin-related anonymous protein homologue in neospora caninum.thrombospondin-related anonymous protein (trap) family members participate in attachment and invasion of host cells by apicomplexan parasites. a trap homologue in neospora caninum strain nc-1 (ncmic2) was cloned, sequenced and found to be 61% identical (75% similar) at the amino acid level to toxoplasma gondii mic2 (tgmic2). similar to tgmic2, the predicted amino acid sequence of ncmic2 contains one integrin-like domain (i or a domain), five thrombospondin (tsp) repeats, a putative transmembrane ...200010717300
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
determination of the activity of diclazuril against sarcocystis neurona and sarcocystis falcatula in cell cultures.diclazuril is a benzeneacetonitril anticoccidial that has excellent activity against the extraintestinal stages of toxoplasma gondii and neospora caninum. it also is highly active against intestinal coccidia of poultry. the present study examined the efficacy of diclazuril in inhibiting merozoite production of sarcocystis neurona and sarcocystis falcatula in bovine turbinate cell cultures. diclazuril inhibited merozoite production by more than 80% in cultures of s. neurona or s. falcatula treate ...200010701584
progress in the serodiagnosis of neospora caninum infections of cattle.neospora caninum is an apicomplexan protozoan that has become the focus of significant research attention worldwide. this organism infects a range of host species, including dogs, from which it was originally reported in 1984, but it is most important as a major cause of bovine abortion. as a result of the global importance of n. caninum, researchers have developed a number of serological tests to investigate the epidemiology of infection and disease. in this article, robert atkinson, peter harp ...200010689330
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
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
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
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
prevention of vertical transfer of neospora caninum in balb/c mice by vaccination.neosporosis is an important cause of abortion and neonatal morbidity in dairy cattle. the disease is caused by neospora caninum, an intracellular protozoan parasite. in this report, we describe the use of a mouse model in the preliminary evaluation of vaccination as a means to prevent vertical transfer of n. caninum. parasites present in the tissues of the offspring were detected using an n. caninum-specific polymerase chain reaction assay. immunization of dams with a single inoculation of a cru ...199910647039
structural analysis of free and protein-bound glycosyl-phosphatidylinositols of neospora caninum. 200010613708
growth of and competition between neospora caninum and toxoplasma gondii in vitro.competitive interactions between neospora caninum and toxoplasma gondii were studied because both species appear to have identical ecological niches in vitro. tachyzoites of n. caninum (nc-1 isolate) and t. gondii (rh isolate) were compared in three in vitro studies: (1) rate of penetration of host cells; (2) generation time; and (3) competition between the two species when grown together in the same flask and allowed to compete for space. when tachyzoites of the two species were inoculated onto ...199910608460
the in vitro development of neospora caninum bradyzoites.neospora caninum is a recently identified apicomplexan protozoan parasite that is closely related to toxoplasma gondii. neospora caninum is of significant economic importance as it causes neurological disease and abortion in numerous animals. antibodies to bag1/hsp30 (also known as bag5), a t. gondii bradyzoite-specific protein, have been demonstrated to react with n. caninum tissue cysts in vivo. bradyzoite differentiation of n. caninum in vitro was investigated using culture conditions previou ...199910608459
high prevalence of antibodies to neospora caninum in white-tailed deer (odocoileus virginianus).serum samples of 400 white-tailed deer (odocoileus virginianus) from 16 preserves in northeastern illinois were tested for neospora caninum antibodies in the n. caninum agglutination test using mouse-derived n. caninum tachyzoites and mercaptoethanol. antibodies were found in 162 deer with titres of 1:40 (47 deer), 1:80 (32 deer), 1:160 (17 deer), 1:200 (eight deer), 1:400 (19 deer), 1:800 (17 deer) and > or = 1:1600 (22 deer). there were no significant differences in prevalence between age or s ...199910608458
neospora caninum infections in bovine foetuses and dairy cows with abortions in argentina.antibodies to neospora caninum were measured in bovine foetuses, dairy cows and beef cows in argentina using the ifat, the n. caninum agglutination test, and the recombinant ncdg1 and ncdg2 elisa. serum antibodies (ifat titre 1:80) were found in 20 of 82 (24.4%) dairy cow foetuses and one of 22 (4.5%) beef cow foetuses. microscopic lesions suggestive of neosporosis were seen in brains of seven of eight foetuses with ifat titres of 1:80. antibodies (ifat) were found in 122 of 189 (64.5%) dairy co ...199910608457
mathematical models of neospora caninum infection in dairy cattle: transmission and options for control.the transmission and control of neospora caninum infection in dairy cattle was examined using deterministic and stochastic models. parameter estimates were derived from recent studies conducted in the uk and from the published literature. three routes of transmission were considered: maternal vertical transmission with a high probability (0.95), horizontal transmission from infected cattle within the herd, and horizontal transmission from an independent external source. putative infection via po ...199910608456
estimation of vertical and horizontal transmission parameters of neospora caninum infections in dairy cattle.transmission parameters of neospora caninum infections in dairy cattle were determined in six herds with a history of neospora-associated abortions, using an antibody-detection elisa to detect evidence of infection. a total of 124 seropositive dams and their calves were tested at calving to estimate vertical transmission, and 154 seronegative heifers were monitored prospectively from birth for evidence of post-natal infection. the probability of vertical transmission was very high; 95.2% (95% co ...199910608455
seroepidemiological evidence for a relationship between neospora caninum infections in dogs and cattle.dogs from dairy farms with a known prevalence of neospora caninum antibodies in the cattle were examined for the presence of n. caninum antibodies using an elisa. data of farm dogs were compared with those of dogs examined at a university clinic, which originated mainly in urban areas. of the 152 farm dogs, 36 (23.6%) were seropositive to n. caninum, which was significantly higher than the proportion of seropositives in the clinic dog population (19 of 344, 5.5%). seroprevalence was significantl ...199910608454
postnatal neospora caninum transmission and transient serologic responses in two dairies.cattle on two typically managed drylot dairies were serologically monitored from birth through year 1 to year 4 of life to characterise congenital and postnatal neospora caninum transmission. of the 456 calves enrolled, 284 were classified as n. caninum negative and 172 were classified as n. caninum positive. ninety-six percent of congenitally infected calves were seropositive for all samples tested. seven (4%) of the 172 congenitally infected animals had a period that persisted for 9 to 18 mont ...199910608453
bovine neosporosis: comparison of serological methods using outbreak sera from a dairy herd in new zealand.serological methods developed to detect neospora caninum specific bovine antibodies were compared using sera from an abortion outbreak on a dairy farm in new zealand. these methods included four elisas, ifat and immunoblot. the abortions (n = 16) on the farm were restricted to one of two groups of the herd which consisted of 194 adult dairy cows. all elisas, ifat and immunoblot (applying stringent cut-off levels) revealed a statistically significant association between seropositivity and abortio ...199910608452
oral infection of calves with neospora caninum oocysts from dogs: humoral and cellular immune responses.neospora caninum has been identified as a major cause of abortion in cattle in a number of countries throughout the world. until the recent demonstration that dogs can serve as a definitive host of this parasite, it was not possible to study the infection in cattle orally exposed to oocysts. the aim of this study was to investigate the potential of n. caninum oocysts to infect calves, and to define initial immune responses that arise after oral infection. seven calves were fed approximately 10(4 ...199910608451
interferon-gamma and interleukin-12 mediate protection to acute neospora caninum infection in balb/c mice.the type of immune response required to protect mice against clinical disease during acute neospora caninum challenge was investigated in balb/c mice. groups of female balb/c mice were infected i.p. with n. caninum tachyzoites concomitant with either: (1) antibody to interferon-gamma; (2) recombinant murine interleukin-12; or (3) recombinant murine interleukin-12 plus antibody to interferon-gamma. mice treated with anti-interferon-gamma alone had increased morbidity/mortality, decreased body wei ...199910608450
phenotypic characterisation of a neospora caninum temperature-sensitive strain in normal and immunodeficient mice.the in vivo persistence, immunogenicity and pathogenicity of a recently described temperature-sensitive (ts) strain from neospora caninum, ncts-8, was investigated in normal and immunodeficient mice. groups of balb/c and scid/bg mice were infected s.c. with 5 x 10(6) wild-type nc-1, control ncts-8 (pass 0) or ncts-8 tachyzoites prepared at four in vitro passage levels (pass 7, 13, 21 and 28). for persistence and immunogenicity studies, balb/c mice were bled and sacrificed at 4, 6 or 8 weeks p.i. ...199910608449
immunogenicity of a killed whole neospora caninum tachyzoite preparation formulated with different adjuvants.a killed whole neospora caninum tachyzoite preparation was formulated with various adjuvants and tested for its immunogenicity in cattle. the adjuvants used were: havlogen, a polymer of acrylic acid cross-linked with polyallylsucrose; polygen, a non-particulate copolymer; a mixture of havlogen and bay r-1005, which is a preparation of free base synthetic glycolipids; and montanide isa 773, a water-in-oil emulsion made with a mixture of metabolisable and mineral oils. immune responses in immunise ...199910608448
detection of surface-associated and intracellular glycoconjugates and glycoproteins in neospora caninum tachyzoites.the surface-associated molecules of the invasive stages of apicomplexan parasites such as neospora caninum and toxoplasma gondii are most likely crucially involved in mediating the interaction between the parasite and its host cell. in n. caninum, several antigens have recently been identified which could participate in host cell adhesion and/or invasion. these are antigens which are either constitutively expressed on the outer plasma membrane, or antigens which are only transiently localised on ...199910608447
development of a single tube nested polymerase chain reaction assay for the detection of neospora caninum dna.sensitive detection techniques are required to study the life cycle of neospora caninum and to diagnose infections. in this study, we describe the development of a pcr assay for n. caninum based on two successive amplification steps within a single tube. this technique, called single tube nested pcr, was sensitive to a single copy of target sequence, and able to amplify parasite dna from biological specimens such as formalin-fixed, paraffin-embedded tissues of naturally infected dogs and cattle. ...199910608446
a competitive pcr assay for quantitative detection of neospora caninum.a quantitative-competitive pcr (qc-pcr) assay was developed for measurement of neospora caninum levels in the tissues of infected animals. a molecule was synthesised for use in pcr as a competitor to the target neospora-specific nc5 genomic sequence. the assay was used to evaluate the relative level of parasites in the brain and lungs of mouse pups in a model of vertical transmission of n. caninum. infection on day 11 of gestation resulted in similar levels of parasites in all offspring. the ass ...199910608445
differentiation of neospora hughesi from neospora caninum based on their immunodominant surface antigen, sag1 and srs2.neospora hughesi is a newly recognised parasite that is closely related to neospora caninum, and is a cause of equine protozoal myeloencephalitis. we have characterised two n. hughesi immunodominant tachyzoite antigens which exhibit antigenic and molecular differences from the homologous tachyzoite antigens on n. caninum. these antigens on n. hughesi are referred to as nhsag1 and nhsrs2, using the same mnemonics as used for the n. caninum antigens (ncsag1 and ncsrs2), and are homologous to toxop ...199910608444
physical characterisation of the plastid dna in neospora caninum.the physical characteristics of the plastid dna in neospora caninum were investigated using pulsed-field gel electrophoresis and tem. in a comparison of contour-clamped homogenous electric field and field inversion gel electrophoresis, the latter proved the more successful technique for studying the plastid molecules. in most cases, restriction or modifying enzymes were required to enable the plastid dna molecules to enter the gel from the well area. the unit length of the plastid of n. caninum ...199910608443
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