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Through vaccination, it is possible to protect vulnerable calves with maternal antibodies against BRSV infection and reduce respiratory tract disease.

Summary Reasons for performing study: Currently, there is no recommended immunoprophylaxis against febrile respiratory diseases due to equine herpesvirus‐1 (EHV‐1) and ‐4 (EHV‐4) in horses below age 5–6 months. This is because of interference by maternally‐derived antibody (MDA) of vaccines. Objective: Unweaned equine foals are an important reservoir of EHV‐1 transmission; therefore, we experimentally assessed the efficacy of a live EHV‐1 vaccine in foals age 1.4‐3.5 months with MDA. Methods: Following vaccination and challenge, parameters assessed were virus shedding in nasal mucus, leucocyte‐associated viraemia, circulating virus neutralising antibody activity and clinical reactions. Results: Controlled challenge showed that a single intranasal dose of the vaccine afforded partial but significant protection against febrile respiratory disease, virus shedding and viraemia due to EHV‐1 infection, despite virus‐neutralising MDA. Conclusions and potential relevance: The prospective vaccine would be a significant step forward in reducing the incidence of the disease caused by EHV‐1 infection.

There are at least 16 recognised herpesviruses that naturally infect cattle, sheep, goats and various species of deer and antelopes. Six of the viruses are recognised as distinct alphaherpesviruses and 9 as gammaherpesviruses. Buffalo herpesvirus (BflHV) and ovine herpesvirus-1 (OvHV-1) remain officially unclassified. The prevalence of ruminant herpesviruses varies from worldwide to geographically restricted in distribution. Viruses in both subfamilies Alphaherpesvirinae and Gammaherpesvirinae cause mild to moderate and severe disease in respective natural or secondary ruminant hosts. Accordingly, the economic and ecological impact of the viruses is also variable. The molecular characteristics of some members have been investigated in detail. This has led to the identification of virulence-associated genes and construction of deletion mutants and recombinant viruses. Some of the latter have been developed as commercial vaccines. This paper aims to give an overview of the epidemiology and pathogenesis of infection by these viruses, immuno-prophylaxis and mechanisms of recovery from infection. Since there are 128 ruminant species in the family Bovidae, it is likely that some herpesviruses remain undiscovered. We conclude that currently known ruminant alphaherpesviruses occur only in their natural hosts and do not cross stably into other ruminant species. By contrast, gammaherpesviruses have a much broader host range as evidenced by the fact that antibodies reactive to alcelaphine herpesvirus type 1 have been detected in 4 subfamilies in the family Bovidae, namely Alcelaphinae, Hippotraginae, Ovibovinae and Caprinae. New gammaherpesviruses within these subfamilies are likely to be discovered in the future