What is smallpox?
Smallpox is a contagious
infection caused by the variola virus. Smallpox can be deadly, so if an
outbreak happens, it is vital to stay away from infected people. Get vaccinated
if you have been around someone who has smallpox. And if you have symptoms,
seek medical care.
The telltale signs of smallpox are severe
illness with a high fever, then a body rash. Symptoms appear about 12 days
after the person is infected.
Before there was a vaccine, smallpox
used to cause death all around the world. Thanks to widespread use of the
vaccine, the last natural case of smallpox occurred in 1977. And in 1980 the
World Health Organization (WHO) declared that the spread of smallpox was
stopped and that the disease had been wiped out.
Because there is a slight risk of serious reactions and
even death from the smallpox vaccine, routine smallpox immunization ended in
the United States in 1972.
Smallpox virus is known to exist in
labs at the Centers for Disease Control and Prevention (CDC) in the U.S. and at
the Institute of Virus Preparations in Siberia, Russia. But it may also be in
other labs. Some people worry that terrorists could release the virus and
spread smallpox to many people.
What are the symptoms?
The first symptoms of
smallpox include a high fever, fatigue, a headache, and a backache. After 2 to 3 days of illness, a
flat, red rash appears. It usually starts on the face and upper arms, and then
it spreads all over your body. Over the next 2 to 3 weeks, the flat, red spots
become firm and dome-shaped and fill with pus. Then they scab over. Scabs fall
off 3 to 4 weeks after the rash first appears, and they leave pitted
incubation period for
smallpox is about 12 days. But symptoms can develop as
soon as 7 days or as long as 19 days after exposure.
You may mistake a severe
chickenpox rash for a smallpox rash at first. But
different viruses cause these illnesses and there are many
differences between chickenpox and smallpox rashes .
How is smallpox spread?
Smallpox is contagious. It
can be passed from one person to another through coughing, sneezing, or
breathing, or by contact with the scabs or the fluid from blisters. It can even
spread from an infected person's personal items and bedding. Smallpox is
easiest to spread during the first week of the rash. As scabs form, the person
is less contagious. But a person can spread the virus from the time the rash
first appears until all scabs have fallen off.
If a terrorist were
to release a small amount of the virus into the air, it is possible that it
could spread among a large number of people. The virus may be able to survive and infect
people for up to a day.