11.   If untreated, infection results in death.

12.   In the most serious cases, infection can result in encephalitis, or swelling of the brain, and can be deadly.

13.   In the most serious cases, infection can result in encephalitis, or swelling of the brain, which can lead to death.

14.   In the most serious but rare cases, infection can result in swelling of the brain.

15.   In the most serious cases, infection can result in encephalitis, or swelling of the brain.

16.   The bacteria are common and infection usually results in sore throats or tonsillitis.