Acute and latent infection by bovine herpesvirus type 2 in a guinea pig model

Bovine herpetic mammillits is a self-limiting cutaneous disease of the udder and teats of cows associated with bovine herpesvirus 2 (BoHV-2) whose pathogenesis is poorly understood. This article describes the use of guinea pigs (Cavia porcellus) to study the pathogenesis of BoHV-2 infection. Twelve weanling female guinea pigs inoculated subcutaneously with BoHV-2 in the genitalia and teats developed local hyperemia, edema, vesicles, ulcers and scabs. Infectious virus was recovered between days 3 and 7 post-infection (pi) from the genital area (9/12) and teats (1/12); and all inoculated animals seroconverted (virus-neutralizing titers of 16-128). Histological examination of lesions revealed lymphoplasmacytic perivascular infiltrates and intranuclear inclusion bodies in keratinocytes. PCR examination of tissues collected at day 35 pi detected latent viral DNA predominantly in lumbosacral spinal segments. In another experiment, eight females inoculated with BoHV-2 in the genitalia and treated with dexamethasone (Dx) at day 35 pi developed mild to moderate local signs, yet no virus could be recovered from lesions. PCR examination of spinal segments from these animals confirmed the presence of latent viral DNA. These results demonstrate that guinea pigs are susceptible to BoHV-2 infection and therefore may be used to study selected aspects of BoHV-2 biology.