Persistence and latency of herpesviruses in experimentally infected turkeys

Herpesviruses have been isolated as the causal agents of disease in man and most species of animals (Nahmias, 1972). Because of their propensity to establish latent infections, herpesviruses have been extensively studied, since latent virus may provide the inoculum needed to establish a variety of acute recurring infections and perhaps initiate and maintain an oncogenic process. Significant accomplishments have included the demonstration that herpes simplex viruses induce latent infections in the spinal ganglia of mice and can be reactivated from the trigeminal ganglia of rabbits (Stevens and Cook, 1971; 1973; Stevens et al., 1972). In addition, Marek's disease virus of chickens has proven to be the only herpesvirus-induced neoplasm that can effectively be prevented by vaccination (Churchill et al., 1969; Okazaki et al., 1970a). One of the vaccine viruses is a cross-reacting herpesvirus of turkeys, which to date has not been associated with any pathology in chickens or turkeys (Witter et al., 19700). Recently, a cell-associated herpesvirus was isolated from male turkeys afflicted with yellow-colored semen containing high numbers of abnormal spermatids (Adldinger et al., 1974). This report represented the first evidence that a virus may be responsible for abnormal spermatogenesis and concomitant yellow pigmented semen in male turkeys. The proceeding literature review will discuss the following topics: 1) herpesviruses and latency; 2) properties and characteristics of turkey herpesviruses and their role in the etiology of yellow semen; and 3) normal and abnormal semen production in the domestic turkey.