Infectious laryngotracheitis: A serious threat to poultry health

Infectious laryngotracheitis (ILT) is a highly contagious disease of the upper respiratory tract in chickens. The Gallid alpha herpesvirus type 1, also commonly known as ILT virus (ILTV), causes ILT. Although ILT was first reported in the United States in 1925, it has also been reported in other countries/regions of the world, including Australia, Asia, and Europe. The outcome of infection can be influenced by several factors, including the host's age, exposure route, pathogenicity of the challenging virus, and initial viral load. In infected chickens, rough lesions are detected on the conjunctiva and throughout the respiratory system, but they are most commonly seen in the trachea and larynx. Other typical signs of the illness in poultry birds are expectoration of bloody mucus, severe dyspnea, coughing, gasping, and rales. Avian cell lines and embryodized chicken eggs are commonly used to isolate ILTV. Three types of ILT are associated with this infection: acute, chronic, and peracute. Chickens contract ILTV through the eyes and upper respiratory tracts. The main pathway by which ILTV is spread in poultry is through direct or indirect contact with sick/infected poultry birds, such as chickens and turkeys. No medication has been proven to be successful in curtailing clinical signs or lesion severity. Vaccination can prevent ILTV infection. Several biological and ecological characteristics of ILTV make its eradication from intensive poultry production locations quite likely. ILT is deemed a serious concern for poultry health, including its significant economic impact on the poultry industry. Therefore, this review highlights important comprehensive information regarding the impact of ILT in poultry, a major source of protein. In addition, a deeper understanding of the causes, signs, diagnosis, treatment, and prevention of ILT in poultry birds was comprehensively discussed.