Quoted: ?At any given moment, if we were to swab you ? we?d probably come up with five different rhinoviruses sitting in your nose but you?re not sick,? says Ann Palmenberg, a researcher at the Institute of Molecular Virology at the University of Wisconsin-Madison. Rhinovirus is the most common viral cause of the common cold, accounting for 30 per cent to 50 per cent of adult colds, and there are more than 150 strains of it.