ISOLATION OF INFECTIOUS LARYNGOTRACHEITIS VIRUS FROM PROXIMAL FEMORA OF LAME BROILER-CHICKENS

Two herpesviruses previously isolated from seven of 19 affected joint/ bone samples in an earlier survey of lameness in broilers were identif ied. They were characterised as infectious laryngotracheitis (ILT) vir us using serum neutralisation, immunofluroescence, restriction enzyme analysis and polymerase chain reaction techniques. In experimentally i nfected chicks, one of the isolates caused mild ILT and intranuclear i nclusion bodies were present in the tracheal epithelium after four day s. It is considered unlikely that these viruses were involved in the p athological changes in the affected legs. The possibility that ILT pat hogenesis and epidemiology are more complex than currently understood is discussed.