The Veterinary Record, Vol 138, Issue 8, 184-186
Copyright © 1996 by British Veterinary Association

Tissue culture-propagated orf virus vaccine protects lambs from orf virus challenge

¹ Moredun Research Institute, 408 Gilmerton Road, Edinburgh, EH17 7JH
² Moredun Animal Health, 408 Gilmerton Road, Edinburgh, EH17 7JH
³ Grampian Pharmaceuticals, MFM Laboratories, 4 Warner Drive, Springwood Industrial Estate, Rayne Road, Braintree, Essex CM7 7YW

Twenty, eight-day-old specific pathogen-free (SPF) lambs were vaccinated by a single scarification approximately 4 cm in length on the inner right thigh with a double-pronged applicator. The titre of live virus in the vaccine was 10^7·2 TCID₅₀/ml and the estimated dose per lamb was 0·04 ml. Three months and six months later 10 of the vaccinated lambs and five age-matched unvaccinated control specific pathogen free lambs were challenged by a single scarification with virulent virus on the inner left thigh in the same way. After the vaccination all 20 lambs developed lesions characteristic of orf virus infection that had largely resolved four weeks later, when they all had reciprocal ELISA antibody titres 3200 that persisted in all but one of them until they were challenged. After the challenge, the development of lesions in the vaccinated and unvaccinated sheep was compared daily for four weeks by means of a clinical scoring system. Both groups of vaccinated lambs had significantly lower (P<0·01) total clinical scores after challenge at three months and six months than the unvaccinated lambs.

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				S. B. Fleming, I. E. Anderson, J. Thomson, D. L. Deane, C. J. McInnes, C. A. McCaughan, A. A. Mercer, and D. M. Haig Infection with recombinant orf viruses demonstrates that the viral interleukin-10 is a virulence factor J. Gen. Virol., July 1, 2007; 88(7): 1922 - 1927. [Abstract] [Full Text] [PDF]