Fifth disease is a medical condition characterized by a rash that resembles a slapped cheek. Most commonly found in children, the disease is caused by parvovirus B19, which is often transmitted through direct contact with respiratory secretions (like saliva or nasal mucus) of infected people. Symptoms of fifth disease that can appear before the rash include low-grade fever, chills, and body aches. There is no treatment to kill the virus; however, this is usually a mild illness among children and adults who are otherwise healthy.