Webster's New World Medical Dictionary

infiltrate
To penetrate. For example, a cancer
may grow into, or infiltrate, surrounding tissues.
infiltrating ductal carcinoma of the breast
See 
breast, infiltrating ductal carcinoma of the.
infiltrating lobular carcinoma of the breast
See 
breast, infiltrating lobular carcinoma of the.
inflammation
A localized reaction that produces
redness, warmth, swelling, and pain as a result of
infection, irritation, or injury. Inflammation can be
external or internal.
inflammatory bowel disease
See 
bowel dis-
ease, inflammatory.
influenza
An illness caused by viruses that infect
the respiratory tract. These viruses are divided into
three types, designated A, B, and C. Symptoms of
influenza include fever, appetite loss, an achy feeling
throughout the body, and weakness. Most people who
get influenza recover completely in 1 to 2 weeks, but
some people develop serious and potentially life-
threatening medical complications, such as pneumo-
nia. Much of the illness and death caused by influenza
can be prevented by annual influenza vaccinations.
Commonly known as flu. See also 
influenza vaccine.
influenza vaccine
An immunization against cer-
tain types of the influenza virus. The “flu shot” is an
inactivated vaccine (containing killed virus) given
with a needle. The nasal-spray flu vaccine is a vac-
cine made with live, weakened flu viruses (some-
times called LAIV for “Live Attenuated Influenza
Vaccine”). The viruses in the vaccine change each
year based on international surveillance and scien-
tists’ estimations about which types and strains of
viruses will circulate in a given year. Antibodies to
the flu virus develop about 2 weeks after vaccina-
tion. See also 
influenza.