The effect of (S)-1-(3-hydroxy-2-phosphonyl-methoxypropyl)cytosine (HPMPC) on bovine herpesvirus-1 (BHV-1) infection and reactivation in cattle.

A reproducible pattern of respiratory disease was produced in calves inoculated intranasally with a pathogenic strain of bovine herpesvirus-1 (BHV-1). A latent infection was established which could be reactivated by means of corticosteroid administration. Groups of calves were given a single dose of 20 mg/kg of (S)-1-(3-hydroxy-2-phosphonyl-methoxypropyl)cytosine (HPMPC) either the day before or the day following virus inoculation. The drug markedly reduced clinical signs and virus replication; the therapeutic dose appeared to be more effective than the dose given one day before virus inoculation. The establishment of latency was not prevented and a single dose of HPMPC, the day before a course of dexamethasone (6 weeks after the acute infection), did not prevent virus shedding.