Herpes Virus
According to the National Institute of Health, cold sores are caused by the herpes virus type 1. Once the body is infected, the virus resides in the body's nerve cells, often lying dormant for months or years. It is estimated that over half of the U.S. population over the age of 20 are infected with herpes type 1, making them susceptible to cold sores.
Transmission
The Mayo Clinic states that the cold sore virus can be transmitted either through direct contact (such as kissing) with an infected person or by sharing cups, lip balm, towels, razors and eating utensils with a person who has an active cold sore lesion.
Outbreaks
While the virus may lie dormant, an outbreak can occur at any time and can be triggered by different stressors, depending on the individual. Typical triggers are high levels of stress, overexposure to sunlight, fever and menstruation can commonly cause reactivation of the virus. The cold sore will usually appear in the same location each time, as the virus resides in the facial nerves beneath that location.
