What virus causes throat infection?

Many causes. Many sore throats are caused by a viral illness, such as: the common cold, the most common type of viral infection. Infection of the voice box (laryngitis). Mononucleosis (mono, "the kissing disease"), a viral infection that tends to cause a persistent sore throat. Other viral infections, such as mumps, herpangina, or influenza. Can also cause sore throat.