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Year 1998 - Volume 18, Number 3
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Acute and Iatent infection in sheep inoculated with bovine herpesvirus type-5 (BHV-5), 18(3/4):99-106
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ABSTRACT.- Silva A.M., Flores E.F., Weiblen R., Botton S.A., lrigoyen L.F., Roehe P.M., Brum M.C.S. & Canto M.C. 1998. [Acute and Iatent infection in sheep inoculated with bovine herpesvirus type-5 (BHV-5).] Infecção aguda e latente em ovinos inoculados com o herpesvírus bovino tipo 5 (BHV-5). Pesquisa Veterinária Brasileira 18(3/4):99-106. Depto Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, 97015-900 Santa Maria, RS, Brazil.
Experimental inoculation of lambs with bovine herpesvirus type 5 (BHV-5) reproduced several aspects of the BHV-5 infection in cattle. lntranasal inoculation was followed by eficiente viral replication and shedding, establishment and reactivation of latency, and even the development of meningoencephalitis in one animal. Lambs inoculated with the brazilian is o late EVl-88 showed transient hipertermia, nasal hiperemia and discharge ranging from serous to muco purulent. The animals shed virus in nasal secretions in titers up to 107,11 TCID50/ml during up to 16 days. One lamb showed clinical signs of encephalitis on day 10 post inoculation (pi), being euthanized in extremis on day 13. lnfectious vírus was recovered from severa) áreas of the brain of this lamb, including anterior and posterior cerebrum, dorso- and ventro-lateral hemisphere, cerebellum, pons, midbrain and olfactory bulb. Histological changes were observed in severa) regions of the brain, most consistently in the anterior cerebrum, ventrolateral cortex and midbrain, and consisted mainly of meningitis, perivascular mononuclear cuffing, focal gliosis, neuronal necrosis and intranuclear inclusions. Four lambs used as sentinels acquired the infection and shed virus starting at the 2nd day pi during up to 7 days. Lambs inoculated with the argentinian isolate A663 showed only mild respiratory signs, although they shed virus for up to 15 days. Administration of dexamethazone to the animals starting at day 50 pi was followed by reactivation of the latent infection and viral shedding during up to 11 days by 76.9% (10/13) of the inoculated lambs and 100% (3/3) of the sentinels. These results demonstrate that sheep are susceptible to BHV-5 acute and latent infection and suggest that natural infections by this virus in sheep may potentially occur. ln this sense, a possible role of this species in the epidemiology of BHV-5 infections awaits further investigation. |
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