Detection of differences in genomic profiles between herpes simplex virus type 1 isolates sequentially separated from the saliva of the same individual

BackgroundHerpes simplex virus (HSV) is assumed to cause recrudescent lesions, usually through endogenous recurrence and rarely through exogenous re-infection. The occurrence of exogenous re-infection in genital and corneal HSV infections has been previously demonstrated using genomic analysis, while exogenous re-infection in oral-facial HSV infections has not been shown.ObjectivesTo confirm the occurrence of exogenous HSV re-infection in oral-facial HSV infections.Study designSeven isolates (isolates 1–7) of herpes simplex virus type 1 (HSV-1) were sequentially separated from the same individual. Genomic profiles of HSV-1 isolates were studied: (i) by analysis of 20 RFLPs (restriction fragment length polymorphisms) and (ii) by the determination of nucleotide sequences of a PCR-amplified DNA fragment encompassing reiteration VII (hypervariable region) that belongs to sequences containing short tandem repeats.ResultsIsolates 1–5 were the same (F83 genotype) and isolates 6 and 7 were the same (F84 genotype), although isolates 1–5 were markedly different from isolates 6 and 7 in genomic profiles.ConclusionsThe infection associated with isolates 6 and 7 was due to exogenous re-infection with F84 genotype virus, thus indicating the occurrence of exogenous HSV re-infection in oral-facial HSV infections.