Tonsillitis's an infection of the tonsils and will often, but not necessarily, cause a sore throat and fever. Types There're 3 main types of tonsillitis: acute, subacute and chronic. Acute tonsillitis can either be bacterial or viral in origin. Subacute tonsillitis's caused by the bacterium Actinomyces. Chronic tonsillitis, which can last for long periods if not treated,'s mostly caused by bacterial infection. Symptoms Symptoms of tonsillitis include a severe sore throat (which may be experienc… (More on Tonsillitis)