The common cold (also known as nasopharyngitis, rhinopharyngitis, acute coryza, head cold, or simply a cold) is a viral infectious disease of the upper respiratory tract that primarily affects the nose. Signs and symptoms include coughing, sore throat, runny nose, sneezing, and fever which usually resolve in seven to ten days, with some symptoms lasting up to three weeks. Well over 200 virus strains are implicated in the cause of the common cold; the rhinoviruses are the most common.