Field Trials with the Herpes Virus of Turkeys (HVT) Strain FC126 as a Vaccine Against Marek’s Disease

Abstract

INTRODUCTION MAREK’S disease (MD) is a common lymphoproliferative disease of domestic chickens affecting the peripheral nerves and visceral organs. It is world-wide in distribution and is responsible for considerable economic loss, particularly in areas of high density poultry production. This highly contagious disease has recently been shown to be caused by a herpesvirus (Biggs et al., 1968; Witter et al., 1969). When a strain of “acute” MD virus (MDV) was passed continuously in cell culture it produced plaques which were larger (macroplaques) than those produced by the strain from which it originated and it also was non-pathogenic for chickens (Churchill et al., 1969). Chicks inoculated with this strain were protected from disease when subsequently challenged with a virulent strain of virus (Churchill et al., 1969) and the attenuated virus was effective against MD in field trials (Biggs et al., 1970). Witter et al. (1970a) isolated a herpesvirus from turkeys which…