What is Swine Influenza?

Swine Influenza (swine flu) is a respiratory disease of pigs
caused by type A influenza virus that regularly causes outbreaks
of influenza in pigs. Swine flu viruses cause high levels of illness
and low death rates in pigs. Swine influenza viruses may
circulate among swine throughout the year, but most outbreaks
occur during the late fall and winter months similar to outbreaks
in humans.

Swine Flu in Humans

Can humans catch swine flu?
Swine flu viruses do not normally infect humans. However,
sporadic human infections with swine flu have occurred.
How common is swine flu infection in humans?
In the past, CDC received reports of approximately one human
swine influenza virus infection every one to two years in the U.S.
What are the symptoms of swine flu in humans?
The symptoms of swine flu in people are expected to be similar
to the symptoms of regular human seasonal influenza and include
fever, lethargy, lack of appetite and coughing. Some people with
swine flu also have reported runny nose, sore throat, nausea,
vomiting and diarrhea.

Can people catch swine flu from eating pork?
No. Swine influenza viruses are not transmitted by food. You can
not get swine influenza from eating pork or pork products. Eating
properly handled and cooked pork and pork products is safe.
Cooking pork to an internal temperature of 160°F kills the swine
flu virus as it does other bacteria and viruses.

How does swine flu spread?
Influenza viruses can be directly transmitted from pigs to people
and from people to pigs. Human infection with flu viruses from
pigs are most likely to occur when people are in close proximity
to infected pigs, such as in pig barns and livestock exhibits
housing pigs at fairs. Human-to-human transmission of swine flu
can also occur. This is thought to occur in the same way as
seasonal flu occurs in people, which is mainly person-to-person
transmission through coughing or sneezing of people infected
with the influenza virus. People may become infected by
touching something with flu viruses on it and then touching their
eyes, mouth or nose.

How can human infections with swine influenza be
diagnosed?
To diagnose swine influenza A infection, a respiratory specimen
would generally need to be collected within the first 4 to 5 days
of illness (when an infected person is most likely to be shedding
virus). However, some persons, especially children, may shed
virus for 10 days or longer. Identification as a swine flu influenza
A virus requires sending the specimen to CDC through the
District of Columbia’s Public Health Laboratory.

What medications are available to treat swine flu infections in
humans?
There are four different antiviral drugs that are licensed for use in
the US for the treatment of influenza: amantadine, rimantadine,
oseltamivir and zanamivir. While most swine influenza viruses
have been susceptible to all four drugs, the most recent swine
influenza viruses isolated from humans are resistant to
amantadine and rimantadine. At this time, CDC recommends the
use of oseltamivir or zanamivir for the treatment and/or
prevention of infection with swine influenza viruses.

Is the H1N1 swine flu virus the same as human H1N1
viruses?
No. The H1N1 swine flu viruses are antigenically very different
from human H1N1 viruses and, therefore, vaccines for human
seasonal flu would not provide protection from H1N1 swine flu
viruses.

Want more information?
Additional information about swine flu and other related health
topics can be found at the website www.cdc.gov. The DC
Department of Health promotes the health and safety of the
District residents. For additional information, call (202) 442-9371.

Revised April 26, 2009