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susceptibility of b-cell deficient c57bl/6 (micromt) mice to neospora caninum infection.neospora caninum is a coccidian parasite of veterinary importance by causing abortion or stillbirth in cattle among other problems in diverse animal species. we assessed an experimental murine model for its suitability to study the immune response to n. caninum infection. thus, wild-type (wt) c57bl/6 mice and b-cell (and consequently antibody)-deficient micromt mice were infected with n. caninum tachyzoites and sacrificed at days 10, 24 and 29-44 post infection (dpi). various organs were collect ...199910320620
the efficiency of vertical transmission of neospora caninum in dairy cattle analysed by serological techniques.the association of neospora caninum infections with cattle families was examined in a dairy cattle herd with sporadic abortions using three different serological tests. cattle seropositive for n. caninum clustered in six families, three of which encountered abortions. in absence of age-related differences in the n. caninum seroprevalence, the family association of n. caninum infection indicated that congenital infection represented the predominant route of transmission in this herd. fourteen (93 ...19989870361
comparison of the biological characteristics of two isolates of neospora caninum.this study compared the biological and genetic properties of a bovine (nc-sweb1) and a canine (nc-liverpool) isolate of neospora caninum. a mouse model for cns infection demonstrated marked differences in pathogenicity between the isolates. nc-liverpool induced severe clinical signs of neosporosis in 57/58 mice including discoordinated movement, hindlimb paralysis and coat ruffling with severe weight loss. in contrast nc-sweb1 induced similar but less severe symptoms in a much smaller proportion ...199910340326
oral neospora caninum inoculation of neonatal calves.four calves born to cows seronegative for neospora caninum were dosed orally within 6 h after birth with tachyzoites of the bovine n. caninum nc-sweb1 isolate added to colostrum. two of the calves were dosed via stomach tube and two by feeding bottle. the latter two calves showed transient fever and passed blood-stained diarrhoea 1-2 weeks after inoculation. from 5 weeks after inoculation they developed a significant antibody response which remained high until the calves were euthanised and necr ...19989770634
dogs are definitive hosts of neospora caninum.dogs were investigated to determine if they are definitive hosts of neospora caninum. four dogs were fed n. caninum tissue cysts in infected mouse tissue, and two negative control dogs were fed uninfected mouse tissue. dog faeces were examined daily for 30 days using a sucrose flotation technique. three challenged dogs shed spherical to subspherical unsporulated oocysts, measuring 10 to 11 microns in diameter. oocysts sporulated within 3 days and contained two sporocysts, each with four sporozoi ...19989770635
neospora caninum-associated abortion in a dairy herd in argentina. 19989770768
a multiple antigen elisa to detect neospora-specific antibodies in bovine sera, bovine foetal fluids, ovine and caprine sera.neospora caninum is a cyst-forming coccidian parasite recently identified as a cause of abortion in cattle. the epidemiology of neosporosis is poorly understood, partly because accurate diagnosis of infection is difficult. in this paper we describe the development of a multiple antigen-based enzyme-linked immunosorbent assay (elisa) to detect antibodies to n. caninum in sera from cattle, sheep and goats as well as from bovine foetal fluids. a water-soluble fraction (wsf) of sonicated nc-1 strain ...19989777723
bovine abortion associated with neospora caninum in northern spain.during 1996, aborted bovine fetuses from dairy herds in norther spain were examined by histopathological, immunohistochemical and serological methods for evidence of infection by neospora caninum. microscopical brain changes consistent with those of neosporosis were detected in 36 of 81 fetuses and specific antibodies (ifat titres > or = 1/16) in 32 of 63. eight fetuses with neurological lesions were seronegative, and eight without lesions were seropositive. in 25 of 34 fetal brains with lesions ...199910074662
pathological and immunological findings of athymic nude and congenic wild type balb/c mice experimentally infected with neospora caninum.neospora is a cyst-forming coccidian parasite that causes abortions and neuromuscular disorders in a wide variety of mammals. japanese bovine isolate jpa1 was inoculated intraperitoneally into balb/c nu/ nu (athymic nude) and balb/c (congenic wild type) female mice to examine the distribution of parasites and resistance mechanisms to neospora infection. all the athymic nude mice died within 28 days after intraperitoneal injection of 2 x 10(5) jpa1 tachyzoites, whereas all the congenic wild type ...199910421099
antibody reaction of human anti-toxoplasma gondii positive and negative sera with neospora caninum antigens.anti-neospora caninum antibody was detected in anti-toxoplasma gondii positive and negative human sera by elisa, western blot and immunofluorescence assay (ifa). twelve cases out of 172 (6.7%) toxoplasma-positive sera cross-reacted with both t. gondii and n. caninum antigens, and one out of 110 toxoplasma-negative sera reacted with n. caninum antigen by elisa. by western blot, all 12 sera reacted with t. gondii antigens with various banding patterns but specifically at 30 kda (sag1) and 22 kda ( ...19989868893
the major 36 kda neospora caninum tachyzoite surface protein is closely related to the major toxoplasma gondii surface antigen.the tachyzoites and the tissue cysts containing bradyzoites of neospora caninum and toxoplasma gondii, respectively, are difficult to distinguish morphologically. specific antigens have been identified in t. gondii tachyzoites and bradyzoites, some of which are stage-specifically expressed, and different functions have been attributed to some of them. a tachyzoite stage-specifically expressed surface protein is the major surface antigen 1 (sag1) which has been shown to be involved in host cell a ...19989879890
[molecular and immunodiagnostic studies of bovine neosporosis in switzerland].cyst-forming coccidia may cause significant losses in livestock, primarily due to abortion, loss of young animals and neuromuscular diseases. rather recently, neospora caninum has been recognized as one of the major protozoal abortion-inducing parasites in cattle. the present study addressed the performance of different diagnostic tools (in vitro-cultivation; histology; immunohistochemistry; serology; pcr) suitable for the direct or indirect detection of n. caninum. by pcr, neospora-dna was dete ...199910028228
characterization of temperature-sensitive strains of neospora caninum in mice.temperature-sensitive (ts) strains of the neospora caninum tachyzoites were selected by chemical mutagenesis and selection for growth at 32 c. three ts strains and the parental, n. caninum wild-type strain, nc-1, were examined in the present study for their ability to cause disease in inbred balb/c mice, outbred icr mice, and chemically immunosuppressed icr mice. in balb/c mice, all 3 strains failed to induce clinical disease, whereas infection with the nc-1 strain caused central nervous system ...199910207365
neospora caninum: tachyzoites express a potent type-i nucleoside triphosphate hydrolase.we have identified type i nucleoside triphosphate hydrolase (ntpase; ec 3.6. 1.3) activity, previously thought to be restricted to the virulent strains of toxoplasma gondii, in the cell extracts of neospora caninum tachyzoites. sequence analysis of a complete cdna from nc-1 strain indicated that n. caninum ntpases shared approximately 69% identity to the ntpases of t. gondii and are most similar to the ntpase-i isozyme. southern blot analysis of genomic dna and sequence analysis of two independe ...19989806873
an igg avidity elisa to discriminate between recent and chronic neospora caninum infection.the avidity of igg antibodies directed to neospora caninum was measured using an igg avidity enzyme-linked immunosorbent assay (elisa) employing n. caninum proteins incorporated into immunostimulating complexes as antigen. in this elisa, low-affinity antibodies were eluted by adding an incubation step with urea after the serum incubation. the antibody titers obtained with and without incubation with urea were then used to calculate the igg avidity values. analysis of sequential sera collected fr ...19999925210
predictive values of fetal histopathology and immunoperoxidase staining in diagnosing bovine abortion caused by neospora caninum in a dairy herd. 19999925219
cellular immune responses in cattle experimentally infected with neospora caninum.neospora caninum has recently been identified as an important cause of infectious abortion in cattle. the parasite is closely related to toxoplasma gondii, but the two species are antigenically distinct. to examine cell proliferative responses and the induction of ifn-gamma in experimentally infected cattle, four 2-4 months old calves were subcutaneously inoculated with n. caninum tachyzoites. peripheral blood mononuclear cells were collected regularly and stimulated in vitro with a crude lysate ...19989988308
neospora caninum: identification of 19-, 38-, and 40-kda surface antigens and a 33-kda dense granule antigen using monoclonal antibodies.neospora caninum, a coccidian parasite closely related to toxoplasma gondii, can infect a broad host range and is regarded as an important cause of bovine abortion worldwide. in the present study, four antigens of n. caninum were partially characterized using monoclonal antibodies. immunofluorescence of viable tachyzoites as well as the immunoprecipitation of antigens extracted from tachyzoites previously labeled by surface biotinylation revealed that three of these antigens with apparent molecu ...199910366536
uncovering the biology and epidemiology of neospora caninum. 199910366825
herd-specific and age-specific seroprevalence of neospora caninum in 14 british dairy herds.all the cattle in 14 dairy herds in england were tested for neospora caninum-specific antibodies with a commercial elisa. three of the herds had had sporadic abortions, eight had had endemic abortions and three had had epidemic abortions associated with n caninum before the study. of 4295 cattle tested, 17.1 per cent were seropositive and the herd-specific prevalence ranged from 7.3 per cent to 44.8 per cent. no significant effect of either herd size (p = 0.988), endemic (p = 0.869) or epidemic ...199910371011
[diagnosis and epidemiology of neospora caninum-associated abortions in cattle].neospora caninum, a recently discovered protozoan parasite closely related to toxoplasma gondii, has world-wide been recognized as an important cause of bovine abortion. n. caninum possesses a wide host range. the dog can be a definitive host for n. caninum. in cattle, the infection is transmitted transplacentally with high efficiency, while the majority of congenitally infected calves is clinically normal at birth and thereafter. whether horizontal transmission occurs in cattle and whether this ...199910384703
bovine abortion, neospora caninum and dogs. 19989795406
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
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
prevalence of antibodies to sarcocystis neurona, toxoplasma gondii and neospora caninum in horses from argentina.sera from 76 horses from argentina were examined for antibodies to sarcocystis neurona, toxoplasma gondii and neospora caninum. antibodies to s. neurona were found in 27 (35.5%) of 76 horses using immunoblots with culture derived merozoites as antigen. antibodies to t. gondii were found in 10 (13.1%) of 76 horses by using the modified agglutination test with formalin-fixed tachyzoites and mercaptoethanol; titers were 1:25 (two horses), 1:50 (six horses), 1:100 (two horses), and 1:200 (one horse) ...199910489203
vertical transmission of neospora caninum in balb/c mice determined by polymerase chain reaction detection.vertical transmission of neospora caninum was evaluated in balb/c mice using an n. caninum-specific polymerase chain reaction (pcr) assay as a means of detecting parasite transmission to offspring. balb/c mice were infected with the nc-1 isolate of n. caninum during pregnancy (days 8-15 gestation). transmission of parasite, detected by pcr, was determined in 2- to 23-day-old offspring. when dams were infected on days 13-15 of gestation, transfer of parasites was detected in only a proportion of ...199910386452
absence of serological evidence for human neospora caninum infection. 199910404607
associations of neospora caninum seropositivity with gestation number and pregnancy outcome in danish dairy herds.the prevalence and distribution of seropositivity towards the protozoan parasite neospora caninum were studied in single blood samples from 1561 cows from 31 danish dairy herds. blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test. seroprevalence in 15 herds with previous abortions assigned to neosporosis ranged from 1% to 58%, with a mean frequency of 22%. in eight out of 16 herds without a history of n.caninum related abortions, no sero ...199910423771
repetitive abortion in neospora-infected ewes.pregnant ewes inoculated with cultured neospora caninum tachyzoites in 1995, 1996, or 1995 and 1996 aborted or delivered weak or clinically normal lambs in 1996. nine of 11 ewes in the study had previously produced infected lambs or fetuses after being experimentally infected in 1995. fetuses and lambs produced in 1996 showed histologic lesions and zoites indicative of neospora. serologic responses and production of infected fetuses/lambs indicated systemic neosporosis in the ewes during gestati ...199910348105
recent advances in neospora and neosporosis.neospora caninum has emerged as a major cause of abortion in cattle in many countries. this paper reviews recent advances in the life cycle and biology of neospora with the emphasis on bovine neosporosis. the role of the recently discovered oocyst stage of n. caninum in the epidemiology of neosporosis is discussed. progress made in serologic diagnosis of n. caninum infection is discussed. there is no vaccine for preventing neospora-induced abortions in cattle or to prevent oocyst shedding in dog ...199910456423
seroprevalence of neospora caninum and abortion in dairy cows in northern spain.the seroprevalence of neospora caninum infection was estimated from a sample of 889 cattle from 43 dairy herds in three counties in the asturias region of spain. the true prevalence of infection was estimated to be 30.6 per cent (95 per cent confidence interval (ci) 27.6 to 33.6). seropositivity was associated with abortion during the previous year (odds ratio (or)=3.31, p<0.001) and was slightly higher among purchased cattle (37.6 per cent), than among cattle raised on the farm (29.1 per cent) ...199910460027
seroprevalence of neospora caninum in dairy cattle in bahia, brazil.sera collected from 447 dairy cattle on 14 dairy farms were tested for neospora caninum antibodies by use of an immunofluorescent antibody technique. positive reactions with titres > or =1:200 were found in 63 (14.09%) of animals. neospora positive sera were also tested for toxoplasma gondii antibodies by using a commercial latex agglutination test. antibodies to t. gondii were detected in 3 (4.76%) of 63 n. caninum positive sera. these results indicate that n. caninum infection is widespread am ...199910489205
seroprevalence of antibodies to neospora caninum and associated abortion in dairy cattle from central thailand.a total of 904 sera from dairy cattle in 11 provinces of central thailand were tested for antibodies to neospora caninum employing the indirect fluorescent antibody test (ifat). fifty four (6%) cattle were positive in ifat, titres of 1:200 (16 cattle), 1:400 (9 cattle), 1:800 (14 cattle), 1:1600 (7 cattle), 1:3200 (6 cattle) and two positives. no significant difference was observed among the provinces. the seropositivity for toxoplasma gondii by a commercial latex agglutination test was 4% (2 ou ...199910489202
confirmation that the dog is a definitive host for neospora caninum.two mixed-breed littermate dogs were fed mouse brains containing tissue cysts of the nc-beef isolate of neospora caninum. both dogs excreted n. caninum oocysts in their feces. dog 1 which was given methylprednisolone acetate (mpa) prior to ingesting tissue cysts, excreted oocysts on days 5 to 10 inclusive and on day 17 after ingesting tissue cysts. dog 1 had a serum antibody titer of 1:200 in the indirect fluorescent antibody test (ifat) 35 days after it was fed tissue cysts. dog 2, which was no ...199910384909
serological evidence of human infection with the protozoan neospora caninum.neospora caninum is a protozoan parasite that is closely related to toxoplasma gondii. dogs are a definitive host. prior to its discovery in 1988, n. caninum infection in animals was often mistakenly diagnosed as toxoplasmosis. neosporosis in animals is characterized by encephalitis, abortion, and other conditions that clinically and pathologically resemble toxoplasmosis. the potential of n. caninum to infect humans is unknown. therefore, evidence of human exposure to this parasite was sought by ...199910473533
seroprevalences of neospora caninum and toxoplasma gondii in nondomestic felids from southern africa.sera from 68 nondomestic captive and free-ranging felids from southern africa were tested for antibodies to neospora caninum and toxoplasma gondii by the indirect fluorescent antibody test. four of the 68 (5.9%) serum samples were positive for antibodies to n. caninum, with titers ranging from 1:50 to 1:200. all other animals were negative for antibodies to n. caninum at a dilution of 1:50. fifty of the 68 (74%) serum samples tested positive for antibodies to t. gondii, with titers ranging from ...199910484140
in vitro isolation of neospora caninum from a stillborn calf in the uk.neospora caninum was isolated in vero cell culture from the brain of a stillborn calf. this isolate (designated nc-livb1) is the first to be obtained from cattle in the united kingdom and was confirmed as n. caninum by immunofluorescence with specific antibodies and by internal transcribed spacer 1 (its1) sequence analysis. differences were found between nc-livb1, other bovine isolates and canine isolates of n. caninum and closely related protozoal parasites, using random amplified polymorphic d ...199910425249
neospora caninum continues to be implicated in bovine abortion cases. 199910452389
serum antibody profile and reproductive performance during two consecutive pregnancies of cows naturally infected with neospora caninum.the objective of this study was to record how the antibody levels change over time during pregnancy in dairy cows naturally infected with the protozoan parasite neospora caninum, and relate this to the reproductive performance. eighteen cows with antibodies to n. caninum were serum sampled monthly during their first pregnancy and 13 of them were also followed for a second pregnancy. in all, five pregnancies ended in abortion and two in stillbirth. antibodies to n. caninum in serum were demonstra ...199910488725
serological differences in neospora caninum-associated epidemic and endemic abortions.a sandwich enzyme-linked immunosorbent assay (elisa) for the sensitive and specific detection of bovine antibodies to neospora caninum was developed and evaluated using sera from cattle experimentally infected with n. caninum, toxoplasma gondii, sarcocystis cruzi, sarcocystis hominis, sarcocystis hirsuta, eimeria bovis, cryptosporidium parvum, babesia divergens, and field sera from naturally exposed animals. field sera were classified using a gold standard that included the results from an indir ...199910461950
prevalence of antibodies to neospora caninum in dogs.serum samples from 1077 dogs suspected of having neospora caninum infections from 35 states in the united states and 3 provinces in canada were tested for n. caninum igg antibodies by the indirect fluorescent antibody test. antibodies to n. caninum were found in 75 of 1077 (7%) of the samples. twenty of the positive dogs were females, 17 were males and the sex was not recorded on 38 dogs. chi square analysis indicated no differences (p > 0.05) based on sex were present. dogs from the southeast a ...199910488735
the relationship of hammondia hammondi and sarcocystis mucosa to other heteroxenous cyst-forming coccidia as inferred by phylogenetic analysis of the 18s ssu ribosomal dna sequence.the complete sequence of the 18s small subunit (ssu) ribosomal dna of hammondia hammondi and sarcocystis mucosa was obtained and compared to ssu rdna sequences of neospora caninum, toxoplasma gondii, besnoitia besnoiti, 2 species of frenkelia, 3 species of isospora, and 13 species of sarcocystis. analyses showed that h. hammondi and t. gondii are monophyletic and that these taxa shared a common ancestor with n. caninum and b. besnoiti. the weight of evidence shows that s. mucosa, s. neurona, and ...199910466120
characterization of a cdna encoding a subtilisin-like serine protease (nc-p65) of neospora caninum.the nc-p65 cdna is the first protease sequence cloned and described for neospora caninum. the full length cdna was isolated by 5'- and 3'-rapid amplification of cdna ends (race). nc-p65 was composed of 865 amino acids with a predicted signal sequence, a proposed pro-domain, and an internal region of conserved repeats. analysis of the deduced amino acid sequence revealed that this protein had homology to the serine proteases of the subtilisin-like superfamily (subtilases) and had a predicted acti ...199910551364
detection by pcr of neospora caninum in fetal tissues from spontaneous bovine abortions.the routine diagnosis of neospora caninum abortion is based upon histopathologic changes in fetal tissues and identification of tissue parasites by immunohistochemistry. confirmation of n. caninum infection by immunohistochemistry has low sensitivity. in the present study, we examined the utility of pcr in detecting n. caninum infection in fetal tissues from spontaneous bovine abortion. dna was obtained from fresh and formalin-fixed tissues from 61 bovine fetuses submitted for abortion diagnosis ...199910565932
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
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
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
comparative ultrastructure of tachyzoites, bradyzoites, and tissue cysts of neospora caninum and toxoplasma gondii.the ultrastructure of tachyzoites, bradyzoites and tissue cysts of the nc-1, nc-5 and nc-liverpool strains of neospora caninum are reviewed and compared with those of the veg and me-49 strains of toxoplasma gondii. while each stage of n. caninum and t. gondii shared many ultrastructural characteristics, each parasite stage also had certain features or organelles that could be used to distinguish the two parasites. some of the most prominent ultrastructural differences occurred in the number, app ...199910608436
hepatic sarcocystosis in a horse.hepatic sarcocystosis was diagnosed in a horse in association with refractory bacterial osteomyelitis and plasma cell tumor of the maxilla and hepatic salmonellosis. gross lesions included pleural, pericardial, and peritoneal effusions, hepatomegaly, gastric ulceration, colonic edema, and proliferative tissues filling 2 maxillary dental alveoli. histologically, liver was characterized by severe suppurative, necrotizing, periportal hepatitis, and severe periacinar necrosis. hepatocytes frequently ...199910577737
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
prevalence of antibodies to neospora caninum in horses in north america.serum samples from 296 horses slaughtered for food in the united states were tested for antibodies to neospora caninum by the neospora-agglutination test (nat). antibodies were found in 69 (23.3%) horses with titers of 1:40 (19 horses), 1:80 (19 horses), 1:100 (3 horses), 1:200 (7 horses), 1:400 (4 horses), and 1:800 (17 horses). this is the first serologic survey for n. caninum antibodies in horses.199910577738
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
a structural study of the neospora caninum oocyst.oocysts of neospora caninum were collected from the faeces of a dog fed mouse brains containing tissue cysts of the nc-beef strain of n. caninum. sporulated oocysts were spherical to subspherical, and were 11.7x11.3 microm. the length/width ratio was 1.04. no micropyle or oocyst residuum was present. polar granules were not present, although occasionally tiny refractile granules were seen among sporocysts. sporocysts were ellipsoidal, did not contain a stieda body, and were 8.4x6.1 microm. the l ...199910608437
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
experimental inoculation of domestic pigeons (columbia livia) and zebra finches (poephila guttata) with neospora caninum tachyzoites.dogs are a definitive host of neospora caninum and cattle are intermediate hosts. alternative life-cycles have not been investigated. foxes are frequently seropositive, but may not commonly prey upon cattle; therefore, other intermediate hosts may exist that are frequent prey of foxes. three domestic pigeons (columbia livia) and three zebra finches (poephila guttata) were inoculated with n. caninum tachyzoites, to determine if they could serve as intermediate hosts. tissue culture, pcr, serology ...199910608438
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
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
outbreak of abortion associated with neospora caninum infection in a beef herd.abortion outbreaks caused by infection with neospora caninum in beef cattle have not been well documented. neospora caninum infection was confirmed in 4 fetuses that were aborted by cattle in a 350-head beef herd; an additional 58 cattle aborted during the next 2.5 months. overall, 44.4% (157/354) of the cattle in the herd did not become pregnant or experienced fetal loss during this period. initially, 81.3% (282/347) of the herd was seropositive for antibodies to n caninum, and seropositive cow ...199910579048
ingestion of neospora caninum tissue cysts by mustela species.dogs are a definitive host of neospora caninum, a protozoal parasite that causes abortion in cattle. mustelids were tested to determine if they could also be definitive hosts. the procedures used were the same as those previously used to test dogs. ermine (mustela erminea), weasels (mustela frenata) and ferrets (mustela putorius) were fed n. caninum-infected mice. neospora caninum oocysts were not observed. mustelid faeces were fed to mice. the mice did not seroconvert and n. caninum was not det ...199910608439
phylogenetic analysis based on full-length large subunit ribosomal rna gene sequence comparison reveals that neospora caninum is more closely related to hammondia heydorni than to toxoplasma gondii.since its first description in the late 1980s, neospora caninum has been recognised as a prominent tissue cyst-forming parasite due to its ability to induce congenital disease and abortion in animals, especially cattle. it is found worldwide and is a cause of significant economic losses for the livestock industry. however, its place within the family sarcocystidae, like that of several other taxa, remains unresolved. neospora caninum shares several morphological and life cycle characters with ha ...199910608441
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
evaluation of a commercial elisa for detecting serum antibody to neospora caninum in cattle.a commercially available serum antibody detection enzyme-linked immunosorbent assay for neospora caninum in cattle was evaluated against an immunofluorescent antibody test (ifat) by applying it to 397 sera from normal adult cattle, 352 sera from cattle which had recently aborted, and 422 sera from two herds which had a history of n caninum-associated abortions. it was evaluated in two laboratories and showed high reproducibility, repeatability and almost perfect or substantial agreement with the ...199910606017
neosporosis--the first decade of research.this paper reviews the history of neospora caninum for the past decade, and provides a prospective for research for the next decade.199910608433
sequence evidence for an altered genetic code in the neospora caninum plastid.the plastid dna of neospora caninum encodes a homologue of the rpob gene, which is believed to encode a subunit of a bacterial or chloroplast-like rna polymerase. the predicted protein product of the n. caninum rpob gene has three in-frame uga codons which appear to encode tryptophan residues rather than act as stop codons. based on the nucleotide sequence of a portion of the ssrrna gene of the n. caninum plastid, a model for suppression of uga termination in this plastid is presented.199910608442
comparison of the major antigens of neospora caninum and toxoplasma gondii.the apicomplexa are a diverse group of parasitic protozoa with very ancient phylogenetic roots. consistent with their phylogeny, the extant species share conserved proteins and traits that were found in their apicomplexan progenitor, but at the same time they have diverged to occupy different biological niches (e.g. host-range and cell type). characterisation of gene and protein diversity is important for distinguishing between related parasites, for determining their phylogeny, and for providin ...199910608434
serologic prevalence of sarcocystis neurona, toxoplasma gondii, and neospora caninum in horses in brazil.to determine serologic prevalence of sarcocystis neurona, toxoplasma gondii, and neospora caninum in horses in brazil.199910511862
estimation of neospora caninum seroprevalence in dairy cattle from normandy, france.an epidemiological study was conducted in orne (france) on randomly selected dairy herds (42 herds including 1,924 cows and heifers, which were at least 15 months old). the aim was primarily to estimate the seroprevalence of neospora caninum infection from two blood samples per cow, using an enzyme-linked immunosorbent assay (elisa) for n. caninum (one positive result indicating infection). the second aim was to test the association between some individual and herd factors and n. caninum seropos ...199910543387
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
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
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
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
serological diagnosis of neospora caninum infection.since the first isolation of the apicomplexan parasite neospora caninum, a range of serological assays have been developed for use in dogs, cattle and a variety of other potential host species. the tests include the indirect fluorescent antibody test, the direct agglutination test and different enzyme-linked immunosorbent assays. this article reviews the principles and properties of the available tests which are discussed in relation to different applications.199910608435
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
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
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
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
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
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
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
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
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
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
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
structural analysis of free and protein-bound glycosyl-phosphatidylinositols of neospora caninum. 200010613708
effect of polyclonal antisera developed against dense granule-associated neospora caninum proteins on cell invasion and development in vitro by n. caninum tachyzoites.the effects of polyclonal antisera to 2 recombinant dense granule (dg) antigens of neospora caninum on invasion and development by n. caninum tachyzoites in baby hamster kidney cell cultures were examined. in immunofluorescent antibody tests, the anti-dg sera, at dilutions of 1:100 to 1:500, reacted intensely with individual intracellular tachyzoites and groups of tachyzoites enclosed in parasitophorous vacuoles at 2 and 52 h p.i., respectively. tachyzoites suspended in diluted anti-dg sera and ...199910599076
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
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
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
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
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
seroprevalence of neospora caninum infection in domestic dogs in turkey. 200010872789
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
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
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
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
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
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
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