Rapid detection of human herpes simplex virus type 1 in saliva

Herpes simplex virus type 1 (HSV1) can be rapidly identified in saliva from patients with acute herpetic gingivostomatitis, by in vitro amplification using the polymerase chain reaction and specific primers. Amplification of DNA results in a product of 110 bp length corresponding to the region 1381-1490 bp of the HSV1 thymidine kinase gene. The specificity of the reaction was demonstrated in three ways: (i) the presence of a Sma 1 restriction enzyme site in the amplified product sequence; (ii) Southern blot using a biotinylated HSV1-specific oligonucleotide probe and (iii) direct sequencing of amplified product. At high titres of virus (> 5 x 10(5) virions/ml saliva), saliva may be added directly to the amplification assay for detection purposes. However, at lower titres of HSV1 viral DNA must be purified from saliva before in vitro amplification. HSV was identified in the saliva from symptomatic patients with acute herpetic gingivostomatitis and was absent in saliva collected from controls.