Influenza (or as it is commonly known, the Flu or the grippe) is a contagious disease, caused by an RNA virus of the orthomyxoviridae family. It rapidly spreads around the world in seasonal epidemics. The name comes from the old medical belief that unfavorable astrological influences cause the disease. The common cold is a mild viral infectious disease of the nose and throat; the upper respiratory system. Symptoms include sneezing, sniffling, running/blocked nose (often these occur simultaneously, or one in each nostril); scratchy, sore, or phlegmy throat; coughing; headache; and tiredness. Colds typically last between three to five days, with residual coughing lasting up to three weeks.