Herpes simplex virus (HSV) is a double-stranded DNA virus. There are two viral types:
The majority of orolabial infections are caused by HSV-1. These infections are usually acquired during childhood through direct physical contact.
Genital herpes is a sexually transmitted infection and is most commonly caused by HSV-2. However, there is an increasing prevalence of genital HSV-1 infections in many countries, including the UK, USA and Scandinavia.
A 10-month-old infant presented with herpes simplex skin lesions.
C.D. Miller/Public Health Image Library.