MM Ebrahimi - Razi Vaccine and Serum Research Institute, Agricultural Research Education and Extension Organization, Karaj, Iran

Infectious laryngotracheitis (ILT) is a viral disease caused by gallid herpesvirus ۱, genus Iltovirus, subfamily Alphaherpesvirinae, family herpesviridae. It is mainly a disease of chickens, but it can also affect partridges, pheasants and peafowl. Clinical symptoms may vary from highly severe, withsome birds dying from asphyxiation, to so mild that it is indistinguishable from other mild respiratory diseases. In infected birds, the virus can be repelled later again without clinical symptoms.Laboratory diagnosis depends on virus isolation, detection of specific antibodies in the serum and histopathological examination of the trachea for characteristic syncytial cells; and intranuclear inclusion bodies’ formations is of diagnostic value.Isolation of the virus may be done by inoculation of suspected material on to the dropped chorioallantoic membrane of SPF embryonated eggs or its cell cultures. These methods are sensitive. Rapid methods include immunofluorescence on tracheal exudate and ELISA to demonstrate viral antigen in mucosal scrapings. PCR testing has been shown to be more sensitive to clinical material examination. Vaccine and wild-type viruses can be distinguished by PCR followed by restriction fragment length polymorphism or sequencing.ILT virus antibodies can be detected by virus neutralisation (VN) tests, AGID, indirect immunofluorescence or ELISA.ILT vaccines are usually prepared from attenuated live virus. Those available at present afford some degree of protection. A number of recombinant vaccines are also commercially available with various degrees of protective efficacy.

infectious laryngotracheitis, disease, prevention, control