Influenza, also called grippe or flu, is an infection of the respiratory tract
in the nose, throat, and sometimes the lungs, caused by types of viruses
designated A, B, and C.
Types A and B cause epidemic disease, and type C causes sporadic disease. Type A
is the most common.
Influenza occurs as sporadic illness, epidemics, or pandemics. Typical symptoms
of influenza begin 2-3 days after exposure to the virus. The majority of
individuals has symptoms for about one to two weeks and then recovers with no
Sometimes stomatitis develop during the flu and dry swollen lips with ulcers may appear.
White coated tongue may also appear during flu.
The flu virus continually change over time, usually by changing the viral RNA
(mutation) and is often confused with the common cold, but flu symptoms are
usually more severe than the typical sneezing and stuffiness of a cold.