The herpes simplex viruses can be found in the sores seen on infected people and they get released when these sores break. The virus may also be released directly from the skin and not necessarily from a visible sore.

The infection spreads through genital and oral secretions and is usually acquired during sexual contact or oral sex with an infected person. A person can get even infected if the skin comes into contact with an infected individual.

An infected person may spread the virus even if there are no visible sores or symptoms; therefore, a person who has been infected in the past can still pass on the infection to a sexual partner.