Horizontal transmission dynamics of a glycoprotein G deficient candidate vaccine strain of infectious laryngotracheitis virus and the effect of vaccination on transmission of virulent virus

Abstract

Infectious laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes acute respiratory disease in chickens worldwide. The virus is horizontally transmitted and causes large outbreaks of disease. Recent studies have shown that a glycoprotein G deficient candidate vaccine strain of ILTV (ΔgG ILTV) is safe and protects birds from disease following challenge with virulent virus. This study examined the transmission dynamics of this candidate vaccine and of ILTV in field and experimental settings. The reproduction ratio (R 0, average number of secondary infectious cases from a typical infectious case) was calculated from the growth rate of disease epidemics in broiler flocks. Assuming a l..