Improvement in plaquing methods for the enumeration of anatid herpesvirus (duck plague virus)

The Holland strain of anatid herpesvirus (AHV) was 2-to 10-fold more efficiently plaqued under liquid medium or semisolid medium containing methylcellulose than in media containing agar, agarose, or Nobel agar. Virus adsorption was complete in 45 min, with the maximum virus titers obtained under liquid medium at 48 h postinfection. The AHV dose-response curve was linear. Pekin duck embryo cultures were more efficient than CCL-141 in plaque response and gave the maximum virus yield per cell. Virus titers were independent of avian cell passage number (to 6), fetal or newborn calf sera (to 10% v/v), and the presence of polyions during adsorption. The host range included cells from several species of Anseriformes and Galliformes.