Vaccination against Louping Ill Virus Protects Goats from Experimental Challenge with Spanish Goat Encephalitis Virus

• Published in: Journal of comparative pathology Vol. 156; no. 4; pp. 409 - 418
• Main Authors: Salinas, L.M., Casais, R., García Marín, J.F., Dalton, K.P., Royo, L.J., del Cerro, A., Gayo, E., Dagleish, M.P., Alberdi, P., Juste, R.A., de la Fuente, J., Balseiro, A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2017
• Subjects: Animals; Encephalitis Viruses, Tick-Borne; Encephalitis, Viral - veterinary; experimental infection; Female; Flavivirus Infections - veterinary; goat; Goat Diseases - prevention & control; Goat Diseases - virology; Goats; Spanish goat encephalitis virus; Vaccination; Viral Vaccines - immunology; Spanish goat encephalitis virus; experimental infection; goat; vaccination
• ISSN: 0021-9975; 1532-3129
• DOI: 10.1016/j.jcpa.2017.03.004

Spanish goat encephalitis virus (SGEV) is a recently described member of the genus Flavivirus belonging to the tick-borne encephalitis group of viruses, and is closely related to louping ill virus (LIV). Naturally acquired disease in goats results in severe, acute encephalitis and 100% mortality. Eighteen goats were challenged subcutaneously with SGEV; nine were vaccinated previously against LIV and nine were not. None of the vaccinated goats showed any clinical signs of disease or histological lesions, but all of the non-vaccinated goats developed pyrexia and 5/9 developed neurological clinical signs, primarily tremors in the neck and ataxia. All non-vaccinated animals developed histological lesions restricted to the central nervous system and consistent with a lymphocytic meningomyeloencephalitis. Vaccinated goats had significantly (P <0.003) greater concentrations of serum IgG and lower levels of IgM (P <0.0001) compared with unvaccinated animals. SGEV RNA levels were below detectable limits in the vaccinated goats throughout the experiment, but increased rapidly and were significantly (P <0.0001) greater 2–10 days post challenge in the non-vaccinated group. In conclusion, vaccination of goats against LIV confers highly effective protection against SGEV; this is probably mediated by IgG and prevents an increase in viral RNA load in serum such that vaccinated animals would not be an effective reservoir of the virus.