Veterinarija ir Zootechnika

Infectious laryngotracheitis (ILT) is a respiratory viral infection, particularly common in adult chickens. The disease widely distributed in several countries causes severe economic losses. ILT virus (ILTV) is a double-stranded DNA which belongs to Alphaherpesvirinae subfamily of Herpesviridae family. Infected and latently carrier chickens are sources of ILTV infection, while the aerosol is the main route of the virus transmission. The acute epizootic form of ILT is characterized by a sudden onset, a rapid spread, and a high mortality rate with severe conjunctivitis, dyspnoea, gasping, coughing, expectoration of blood mixed with mucus, and drop in egg production. However, chickens in the mild enzootic form show less signs with a morbidity rate up to 5% and a mortality rate between 0.1% and 2%. The most characteristic post-mortem lesions are haemorrhagic tracheitis with the presence of a yellow cheesy plug in the respiratory tract. Despite diagnostics of signs and lesions, the confirmation of ILTV infection occurs via conventional isolation, detection of the virus in the affected tissues, as well as using recent molecular techniques. Prevention of ILTV infection depends on some key lines, including biosecurity measures and vaccination. Both live attenuated and recombinant vaccines are used for the prevention and control of ILTV infection. Therefore, the present review focuses on susceptibility, transmission, clinical picture, diagnosis, differential diagnosis, immune response, and prevention and control.