what causes tonsillitis
Causes of tonsillitis. Most cases of tonsillitis are caused by a viral infection. Viruses known to cause tonsillitis include: 1  rhinoviruses â which are viruses that cause the common cold. 2  the influenza virus. 3  parainfluenza virus â which causes laryngitis and croup.4  enteroviruses â which cause hand, foot and mouth disease.iruses known to cause tonsillitis include: 1  rhinoviruses â which are viruses that cause the common cold. 2  the influenza virus. 3  parainfluenza virus â which causes laryngitis and croup.
Tonsillitis is most often caused by common viruses, but bacterial infections can also be the cause.The most common bacterium causing tonsillitis is Streptococcus pyogenes (group A streptococcus), the bacterium that causes strep throat. Other strains of strep and other bacteria also may cause tonsillitis.onsillitis is most often caused by common viruses, but bacterial infections can also be the cause.