DIFFERENTIATION OF INFECTIOUS LARYNGOTRACHEITIS VIRUS-STRAINS BY POLYMERASE CHAIN-REACTION

Oligonucleotide primers derived from infectious laryngotracheitis viru s (ILTV) DNA clones of vaccine and virulent strains were used to devel op a polymerase chain reaction (PCR) for the identification and differ entiation of ILTV strains. The PCR followed by restriction endonucleas e analysis was used to group four strains of ILTV. A 458-bp sequence t hat for the LT-IVAX ILTV strain contains a unique BamHI site was ampli fied by PCR and digested with BnmHI restriction endonuclease. From the sizes of the resultant DNA fragments the virulent strain was distingu ished from the three low virulence strains.