The pathogenesis of experimental neosporosis in pregnant sheep

Buxton, D.; Maley, S.W.; Wright, Stephen E.; Thomson, K.M.; Rae, A.G.; Innes, Elisabeth A.

doi:10.1016/s0021-9975(07)80003-x

Cited by 188 publications

(135 citation statements)

References 24 publications

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“…Afterwards, inoculated mice were examined daily and killed with CO 2 gas at 20 weeks post-inoculation. At necropsy, brain was removed aseptically and examined by a nested-PCR procedure [7].…”

Section: Bioassay In Balb/c Nu/nu Mice and Heifersmentioning

confidence: 99%

Effects of re-infection with Neospora caninum in bulls on parasite detection in semen and blood and immunological responses

et al. 2008

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Three bulls with experimentally induced primary infection with Neospora caninum were re-infected intravenously with 10 8 live N. caninum tachyzoites of the NC-1 isolate at 300 days post-infection to investigate the presence of N. caninum in semen and blood, and the associated immune responses. In parallel, three bulls with experimentally induced primary infection with N. caninum and three noninfected bulls were also monitored. Re-infected and infected bulls showed an intermittent presence of N. caninum DNA in semen with a parasite load ranging from 0.1 to 15.6 (mean 4.4) and 0.1 to 11.1 (mean 4.1) parasites/ml, respectively. Re-infected bulls showed significant and persistent serum-specific IgM and IgG antibody responses. Specific IgG levels were detected in seminal plasma of all infected bulls, but the magnitude of the response was significantly higher in re-infected rather than in chronically infected animals. The mean specific IFN-g levels in re-infected bulls were significantly increased as early as 3 and 7 days after experimental infection when compared to bulls in other groups. This study showed that the intermittent presence and parasite load of N. caninum in the semen of reinfected bulls is very similar to that reported in chronically infected animals. The protozoa could not be isolated from BALB/c nu/nu mice inoculated with PCR-positive semen samples and inseminated heifers with pooled semen samples did not show seroconversion. Plasma IFN-g level seems to be a good indicator of a recent N. caninum infection.

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Section: Bioassay In Balb/c Nu/nu Mice and Heifersmentioning

confidence: 99%

Effects of re-infection with Neospora caninum in bulls on parasite detection in semen and blood and immunological responses

et al. 2008

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“…Nested-PCR was carried out using four oligonucleotides, as previously described by Buxton et al [9]. Briefly, DNA amplification was performed in 25 ml total volume and after the primary amplification, 5 ml of PCR product was used as template in the secondary amplification reaction mixture.…”

Section: Pcr Proceduresmentioning

confidence: 99%

Experimental neosporosis in bulls: Parasite detection in semen and blood and specific antibody and interferon-gamma responses

et al. 2007

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Aim: To investigate the presence of Neospora caninum in semen and blood, and the development of specific antibody and interferon-gamma (IFN-g) responses in experimentally infected bulls. Methods: Eight bulls were intravenously infected with 10 8 live N. caninum tachyzoites of NC-1 isolate. The presence of N. caninum in semen and blood was assessed using a nested-PCR procedure. PCR-positive semen samples were bioassayed using a BALB/c nu/nu mouse model. Specific anti-N. caninum antibody and IFN-g responses were also examined. In parallel, eight seronegative bulls were studied as non-infected controls. All bulls were monitored for 26 weeks. Results: All eight experimentally infected bulls showed N. caninum DNA in their semen and/or blood samples at some time during the course of the study. Parasite load in semen ranged from 0.1 to 14.5 parasites/ml (mean 6.0). N. caninum could not be detected in BALB/c nu/nu mice inoculated with PCR-positive semen samples. A significant increase in mean serum specific IgM antibody response to N. caninum was detected between 10 and 28 days post-infection (p.i.). Serum specific IgG, IgG1, and IgG2 antibody levels in experimentally infected bulls were significantly different after 21, 10, and 14 days p.i. as compared to controls, respectively. Specific anti-N. caninum IgG were detected in seminal plasma from infected bulls and values obtained were different from controls after 25 days p.i. Mean specific IFN-g responses in experimentally infected bulls were significantly higher than controls 3 days p.i. Conclusions: This is the first study to report the presence of N. caninum DNA in the semen and blood of experimentally infected bulls. Our observations indicate an intermittent presence of N. caninum in low numbers in semen and associated with chronic stage of the infection. This study is also the first to report the detection of anti-N. caninum IgG in seminal plasma of experimentally infected bulls. #

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“…DNA extraction from samples of fresh brain, lung tissue and abomasum content of the fetuses was performed on proteinase K buffer, followed by phenol and chloroform treatment (Sambrook & Russel 2001). Brucella abortus (field strains), N. caninum and T. gondii were detected by PCR as described Bricker & Halling (1995), Burg et al (1989) and Buxton et al (1998) positive control was 50ng of genomic DNA from parasites or bacteria culture. Serum samples from dams of fetuses collected during the visit to the farm were tested by the indirect immunoϐluorescen-ce assay (IFA) using Toxoplasma gondii (RH strain) cultivated in Vero cells, with 1:64 dilution as cut-off value (Opel et al 1991).…”

Section: Methodsmentioning

confidence: 99%