Oral herpes is a very common infection of the mouth area. It is caused by the herpes simplex virus type-1 (HSV-1). When they are first infected, some people have symptoms while others do not. After the first infection, the virus becomes dormant (goes to sleep) in nerve tissues in the face for life. Periodically the virus is reactivated (wakes up) and causes cold sores in the mouth area. Cold sores (also called fever blisters) are small painful blisters of the lips, mouth or gums. The severity of the cold sores, and how often they recur, vary greatly between individuals. This suggests that the immunity of the infected person plays an important role.
The purpose of this study was to understand why some people have more severe cases of oral herpes than others. This was a pilot study to evaluate the possibility of doing future twin studies on HSV.
Twenty pairs of twins who reported a history of cold sores or fever blisters were invited to participate. The study involved a single hour-long visit to the University of Washington Twin Registry Research Center. At the visit, a clinician took a medical history, performed a physical exam, and drew about 7 tablespoons of blood from each participant. The clinician showed the participants how to collect their saliva at home, using a swab similar to a Q-tip. Participants were asked to collect one swab each day at home for 30 days, and mail the swabs back to the UW Twin Registry. They also completed a daily diary to record any symptoms they might be experiencing.
Data from this study suggested that there are genetic factors in the infected person that strongly influence the reactivation of the HSV-1 virus. The scientists applied for another grant to continue this important research.