This thesis covers three main areas of research. The first is a longitudinal sero-epidemiological study of a dairy herd which suffered an abortion storm linked to infection with <I>N. caninum</I> during August/September 1995. The main aims were to study the long term antibody response in cattle which have suffered <I>N. caninum</I> associated abortion, and to assess the rates of congenital infection, abortion and repeat abortion on the farm during the subsequent 3 year period. The second area of study investigated <I>Neospora</I> antigens recognised by <I>Neospora</I> antibody positive sera using western blot. Diagnosis of infection with <I>N. caninum</I> depends on detection of anti-<I>N.caninum</I> antibody in serum, but animals which have previously aborted due to neosporosis can become sero-negative by <I>Neospora </I>IFAT and ELISA several months post-abortion. The third area investigates cell mediated immune responses to <I>N. caninum </I>and the antigens involved in induction of T cell responses. <I>N. caninum</I> can induce repeat abortion in some individuals unlike the closely related coccidian parasite <I>Toxoplasma gondii</I> which induces life long protective immunity after primary infection. Cellular immune responses are important in the development of immunity to <I>T.gondii</I> and therefore are likely to be important in preventing repeat abortions in 95% of the cattle which abort due to neosporosis. This study showed that experimental infection of calves with <I>N. caninum</I> NC1 tachyzoites stimulated a cell mediated response detectable in peripheral blood using a simple proliferation assay. This response was characterised by the production of the T cell cytokine IFNγ which is produced by CD4+, CD8+ and natural killer cells and is known to be important for protection against other intracellular parasites.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:657323 |
| Date | January 1999 |
| Creators | Marks, Joanne |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/15265 |
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