DETECTION OF FELINE HERPESVIRUS-1 DNA BY THE NESTED POLYMERASE CHAIN-REACTION

The thymidine kinase region of feline herpesvirus 1 (FHV 1) genome in ocular/nasal swabs from cats with clinical manifestations of upper res piratory disease was amplified by nested polymerase chain reaction (ne sted PCR). Two primer pairs were prepared for nested PCR. FHV 1 DNA in ocular/nasal swabs was extracted using instaGene-DNA purification mat rix. Nested PCR for the FHV 1 culture supernatants was ten times as se nsitive as single PCR. On comparing viral isolation with single PCR an d nested PCR for the detection of FHV 1 in ocular/nasal secretions, of 5 samples that yielded infectious virus in cell culture, 3 (60%) were positive in single PCR and 5 (100%) were positive in nested PCR. When 22 ocular/nasal swabs that did not yield FHV 1 were assayed, 3 were n egative in both single PCR and nested PCR, 2 were positive in both sin gle and nested PCR and 17 were positive in only nested PCR. Thus, FHV 1 was detected in 19/22 (86.4%) by the nested PCR and in 2/22 (9%) by single PCR. These results show that nested PCR is 4.8 (24 positive sam ples/5 positive samples) times as sensitive as single PCR.