Isolation and characterisation of herpes virus from turkeys

Turkey herpesvirus (HVT) was isolated from the kidneys of 6 of 8 turkey poults from two flocks. The isolates were identified by syncytial-type of cytopathology, inhibition of plaque formation by 5-bromodeoxyuridine, formation of Cowdry type A intranuclear inclusions in cell cultures, and presence of herpes-type virions in negatively stained preparations and thin sections of infected cell cultures. One of these isolates inoculated into chickens proved apathogenic over an observation period of 10 weeks. Indirect immunofluorescence and serum neutralisation tests revealed serological relationship between these isolates and the strain NSW 1/70 of HVT. Staining of HVT-infected cell culture by Marek's disease herpesvirus (MDHV) antiserum showed intranuclear fluorescence but attempts to prepare HVT precipitating antigen or to demonstrate cross-precipiation between HVT and MDHV were unsuccessful.