Changes

IBR may cause '''abortion''' if susceptible cows or heifers are infected during pregnancy.  Abortion is usually observed between '''4 and 8 months of gestation'''. Early embryonic death can also occur. Abortion is a consequence of '''respiratory infection of pregnant cows'''. Viraemia allows the virus to enter the uterine artery and cross the placenta. Abortion is due to a '''lytic infection''' of the fetus. All internal organs of the fetus, especially the '''liver and renal cortex''', show foci of necrosis. A generalized multifocal necrosis is diagnosed.<ref> Smith, K. C (1997) '''Herpesviral abortion in domestic animals'''. ''Vet Journal'', 153(3):253-268</ref> Infection of cows during the last trimester of gestation can lead to '''neonatal death''', and death of weak calves can occur during the first 2 weeks of life.<ref> Thiry, E., Detilleux, P., Vriese, A., Pirak, M., Pastoret, P-P (1984) '''Infectious bovine rhinotracheitis in the neonatal period: a review and a case report.''' ''Annales de Médecine Vétérinaire'', 128(1):33-40; 25</ref>

IBR may cause '''abortion''' if susceptible cows or heifers are infected during pregnancy.  Abortion is usually observed between '''4 and 8 months of gestation'''. Early embryonic death can also occur. Abortion is a consequence of '''respiratory infection of pregnant cows'''. Viraemia allows the virus to enter the uterine artery and cross the placenta. Abortion is due to a '''lytic infection''' of the fetus. All internal organs of the fetus, especially the '''liver and renal cortex''', show foci of necrosis. A generalized multifocal necrosis is diagnosed.<ref> Smith, K. C (1997) '''Herpesviral abortion in domestic animals'''. ''Vet Journal'', 153(3):253-268</ref> Infection of cows during the last trimester of gestation can lead to '''neonatal death''', and death of weak calves can occur during the first 2 weeks of life.<ref> Thiry, E., Detilleux, P., Vriese, A., Pirak, M., Pastoret, P-P (1984) '''Infectious bovine rhinotracheitis in the neonatal period: a review and a case report.''' ''Annales de Médecine Vétérinaire'', 128(1):33-40; 25</ref>

'''Latent infection can occur''', the viral cells residing in the '''trigeminal nerve''', and infected cattle can then shed the virus intermittently.  

'''Latent infection can occur''', the viral cells residing in the '''trigeminal nerve''', and infected cattle can then shed the virus intermittently particularly after stressful episodes.  

Other animals recover within 14 days, due to the rise of the specific immune response. Becoming latent is a common sequelae to infection and in terms of control, all animals on an endemic farm should be considered as potential latent carriers irrespective of their antibody status. Some highly virulent BHV-1 strains induce a high mortality rate.  

Other animals recover within 14 days, due to the rise of the specific immune response. Becoming latent is a common sequelae to infection and in terms of control, all animals on an endemic farm should be considered as potential latent carriers irrespective of their antibody status. Some highly virulent BHV-1 strains induce a high mortality rate.