Pathogenesis of pigeon herpesvirus infection

Experiments were designed to investigate the pathogenesis of pigeon herpesvirus (Pigeon herpesvirus 1, PHV) infection. Experimental pharyngeal infection of susceptible pigeons may be followed by viral localization and development of lesions outside the upper digestive and respiratory tracts. Viraemia was detected during the primary infection in some pigeons previously treated with cyclophosphamide (Cy). After primary infection, viral re-excretion was twice provoked by Cy-treatment in all pigeons except one, and was as heavy as that following the initial infection. During the first episode of re-excretion one pigeon presented viraemia, died a few days later with signs of encephalitis, and PHV was isolated from the brain. No viraemia could be detected during the second episode of re-excretion and virus was only isolated from the pharynx and trachea, probably by contamination via the larynx. Virus was never isolated from genital organs taken from either dead or killed animals, but sublethal infection of pigeon embryos could be produced experimentally. It was also shown that, after cell infection, PHV can be transmitted in vitro from cell to cell in the presence of high titres of specific antibodies. PHV can thus be spread either by tissue contiguity, even in the presence of specific antibodies, or by viraemia especially when the pigeons are immuno-suppressed. © 1981.