Herpangina is also known as mouth blisters. This summer, some local governments have put an alert on Herpangina.
The website of Kanagawa Prefectural Institute of Public Health
*Screenshot from the webpage above.
In the page, it is described that Herpangina brings about a high fever and blisters in the throat. There's the epidemic in summer just like Hand Foot Mouth Disease and many of the patients are young children. The virus is infected by cough and sneeze, or by broken blisters and excrements. So please wash hands well when you get home or after changing diapers.