Reactivation of latent bovine herpesvirus type 5 in cattle with polioencephalomalacia induced by ammonium sulphate

Pesquisa Veterinária Brasileira

Nadia David²  Sílvia O. Hübner²  Franklin Riet-correa¹  Danisa Halfen¹  Ricardo A. Lemos¹ 

[1] ,Universidade Federal de Pelotas Faculdade de Veterinária Pelotas RS ,Brazil

关键词: Polioencephalomalacia;    bovine herpesvirus type 5;    viral reactivation;    cattle;    Polioencefalomalacia;    herpesvírus bovino tipo 5;    reativação viral;    bovinos;   

DOI  :  10.1590/S0100-736X2007001000009

来源: SciELO

【 摘 要 】

In the state Mato Grosso do Sul, Brazil, outbreaks of meningoencephalitis by BoHV-5 and polioencephalomalacia (PEM) display similar epidemiological features, suggesting that meningoencephalitis may be associated with reactivation of a latent BoHV-5 infection, during the development of PEM. To test this hypothesis, four 7-8 months old steers negative for BoHV-5 antibodies were inoculated intranasally with BoHV-5 and received amprolium from day 35 to day 105 after inoculation. Because PEM was not produced during this period, ammonium sulphate was given from day 114 to day 180 after inoculation. Two uninfected control steers received amprolium and ammonium sulphate for the same periods. All inoculated cattle developed antibodies against BoHV-5 after inoculation and the virus was isolated from nasal swabs, indicating that they were infected. Two inoculated steers had clinical signs of PEM after 118 and 146 days after virus inoculation. One was euthanized after a clinical manifestation period of seven days and had severe lesions of PEM and meningoencephalitis. BoHV-5 was isolated from the central nervous system of this animal. The other animal recovered but continued to manifest chronic signs of PEM and was euthanatized. On histological examination, the cerebral cortex, caudate nucleus and thalamus had multifocal areas of malacia and mild meningoencephalitis of the cortex. BoHV-5 was not isolated from the brain. One uninfected control steer had signs of neurological disease on day 158 and had lesions of PEM without meningoencephalitis at necropsy. The simultaneous production of PEM and diffuse meningoencephalitis, with isolation of BoHV-5, in one steer treated with ammonium sulphate, 118 days after BoHV-5 inoculation, suggests that latent BoHV-5 was reactivated in this animal submitted to experimental induction of PEM.

【 授权许可】

CC BY-NC   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License