BHV1 infections - history and present state

Until the sixties BHVI was known in Europe to cause coital exanthema in bov ines as coital exanthema virus. In the USA, however; reports have already s hown the serological identity between the viruses causing infectious bovine rhinotracheitis (IBR), conjunctivitis and the genital tract viruses. The high losses in the USA lead to a fast development of parenterally appli cable attenuated vaccines. The occurrence of IBR and increasing numbers of genital infections mainly in artificial breeding centres in Gel-many lead t o the development of a locally administered attenuated vaccine originating from a genital strain. Next the phenomenon of latency was detected in the U SA and Australia. Vaccinations cannot prevent it. The development of marker vaccines makes it possible to differentiate betwe en vaccinated and previously field vir-us infected animals. But these vacci nes are also unable to prevent later infections followed by a latent state. If the marker vaccines ar-e live, it is possible that following an immunos uppression both viruses, field and vaccine are excreted.