About 4 billion people worldwide have the herpes simplex virus in either its oral form (HSV-1) or genital form (HSV-2), with the oral form being by far the most common type. In the United States alone, more than 1 in 6 people between the ages of 14 and 49 live with genital herpes.

Both strains present with a sore or a blister that tingles or itches and can rupture and ooze fluid. Generally, symptoms first emerge within 20 days of exposure and typically last seven to 10 days. 

The physical signs that you've contracted the herpes simplex virus include tingling, itching or burning where the sore appears. Your symptoms may resemble the flu, and you may experience urinary problems and eye infections.

We've compiled six basic facts everyone should know about herpes. A few might surprise you.

1. Interchangeability

The two main types of herpes are sometimes interchangeable. “Herpes” usually refers to one of two strains. There's oral herpes,