An outbreak of infectious laryngotracheitis in California broilers.

Infectious laryngotracheitis (ILT) was diagnosed as the cause of an outbreak of respiratory disease in broiler chickens in California. The classical form of ILT is characterized by dyspnea, gasping, coughing, and expectoration of bloody exudate. Most of the broilers submitted to the diagnostic laboratory showed a non-classical presentation of ILT, in which mucoid tracheitis and conjunctivitis were the most consistent lesions. Historically, most of the ILT cases diagnosed in our laboratory have consisted of layers with classical signs and lesions. It is not known whether this non classical presentation of ILT in broilers is due to differences in the way broilers respond to ILT infection or to the nature of the ILT virus isolate.