It is a virus. Oral herpes can be transmitted by salivary transfer or possibly oral blood transfer. Once you have it, it stays almost forever. So, one has to be vigilant. Do not let your lips get dryed out and cracked. If they do crack then the virus gets active and a swelling usually occurs. This can be treated with Acyclovir and other anti viral drugs. Usually an outburst lasts 14 days.
Oral Herpes. Herpes simplex is a virus which is transmitted from human to human by direct intimate contact. It produces crops of little blisters which then break down into shallow painful and tender ulcers. Once you have the virus it remains in your body for a lifetime but may never produce symptoms. Oral infection can be transmitted to the genitals by oral sex.