infectious laryngotracheitis n a severe highly contagious and often fatal disease of chickens and pheasants that affects chiefly adult birds, is caused by a herpesvirus (species Gallid herpesvirus 1 of the subfamily Alphaherpesvirinae) related to the two viruses causing Marek's disease, and is characterized by inflammation of the trachea and larynx often marked by local necrosis and hemorrhage and by the formation of purulent or cheesy exudate interfering with breathing
Medical dictionary. 2011.