Study On U_s Gene Structure Of ILTV And Attenuated Virus

Avian Infectious laryngotracheitis (ILT) is an important worldwide occurring acute respiratory disease of poultry characterized by gasping, expectoration of bloody mucus and increased tracheal mucosal thickness. The disease might lead to a severe economic loss due to a high mortality rate or reduced egg production. The causative agent designated as ILTV or gallid herpesvirus 1. ILTV field strains and conventionally attenuated live vaccine can establish latency in the central nervous system, and subsequent reactivations can lead to infection of naive chickens.The 13 kbp fragment from the unique short (Us) genome region of infectiouslaryngotracheitis virus (ILTV, gallid herpesvirus-1) has been sequenced, The analysed region contain seven major open reading frames (ORFs) designated PK, UL47, gG, gJ, gD, gI and gE, Alignment of the sequence revealed homology is 10-30% in alphaherpesvirus, differiation early from alphaherpesvirus.Attenuated virus by incubated in CEK, the pathological change appear in 9th, the 45th 1/50000 dilution can induce pathological change likewise, Infect SPF chiken with 0th,20th,40th virus, pathogenicity descend of 20th and 40th, did not induce infect chiken die but there are 2 dead in group of 0th, clinical symbtom did not obvious and shorted, it hurt some organs such as larynx, trachea, lung detect by pathology, induce infect chiken generate antibody for ILTV, has also been shown to induce protection against disease following challenge with virulent virus.