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Thrombotic meningoencephalitis associated with Histophilus ovis infection in lambs in Europe
  1. J. P. Cassidy, MVB, MRCVS1,
  2. S. W. J. McDowell, BVM&S, MRCVS1,
  3. G. A. C. Reilly, BVM&S, MRCVS1,1,
  4. W. J. McConnell, BA1,
  5. F. Forster, BSc1 and
  6. D. Lawler, MVB, MRCVS2,2
  1. 1 Veterinary Sciences Division, Department of Agriculture for Northern Ireland, Stoney Road, Stormont, Belfast BT4 3SD
  2. 2 Jubilee Veterinary Centre, 3 Jubilee Road, Newtonards, County Down BT22 4YH


Thrombotic meningoencephalitis is an acute, usually fatal disease of cattle caused by Haemophilus somnus. Although it has been widely recognised in cattle there have been only two previous reports of the condition in sheep, in Australia and Canada, where the causal organisms were identified as Histophilus ovis and an H somnus-like organism, respectively. This paper describes the clinical, pathological and microbiological features of the disease in two lambs from a flock in Northern Ireland. In both lambs the clinical signs and histological lesions were similar to those previously described in sheep and cattle, and H ovis was isolated from the brain tissue of both of them. The authors believe this to be the first report of thrombotic meningoencephalitis in sheep in Europe.

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  • Mr Reilly's present address is Cedarmount Veterinary Clinic, 67 Bryansburn Road, Bangor, County Down BT20 3SD

  • Ms Lawler's present address is Department of Veterinary Clinical Studies, Royal (Dick) School of Veterinary Studies, Veterinary Field Station, Easter Bush, Roslin, Midlothian EH25 9RG

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