Salmon-Challis National Forest, Idaho. It is the second largest National Forest in the continental United States. In 1876, the US Congress created an office to evaluate the conditions of forests in the US. In 1891, President Theodore Roosevelt assigned the control of the newly named, national forests to the US Forest Service.
Cold sores are caused by certain strains of the herpes simplex virus (HSV). HSV-1 usually causes cold sores.
A person doesn't need to have a cold to get a cold sore. Cold sores can be brought on by other infections, fever, stress, sunlight, cold weather, hormone changes in menstruation or pregnancy, tooth extractions, and certain foods and drugs. In a lot of people, the cause is unpredictable. Here's how a cold sore develops: