What exactly is anthrax, and should you be concerned about it?
Anthrax is an infection caused by a bacterium (a type of germ) called
Bacillus anthracis (B. anthracis). Although it's most commonly
seen in grazing animals like sheep, pigs, cattle, horses, and goats, anthrax can
also occur in humans - although it's very rare.
In the environment, the anthrax-causing bacterium forms spores
(a version of the germ covered by a hard protective shell) that can
live in the soil for years. People can become infected by coming into contact
with these spores through a break in the skin (such as a cut or scrape), by
eating food (usually undercooked meat) contaminated by them, or by inhaling
spores (breathing them into the lungs). But anthrax is not contagious,
which means that it can't spread from person to person.
It's extremely unlikely that you or someone you know could get anthrax. In
fact, there are usually only one or two reported cases of anthrax per
year. Most of these have been in people who work with animals or animal
products.
Why Are People So Concerned About Anthrax? Anthrax that occurs naturally in the environment isn't a huge threat.
But B. anthracis can be grown in a laboratory and some people are worried
about anthrax germs being grown as a weapon.
The issue of laboratory-grown anthrax received lots of attention in 2001
after an anthrax outbreak in the United States. The outbreak scared a lot of
people, in part because five people died (which is very rare) and also
because the outbreak corresponded with the September 11 terrorist attacks.
However, bioterrorism experts believe that it is technologically difficult to
use anthrax effectively as a weapon on a large scale.
What Are the Signs of Anthrax?
There
are three main types of anthrax:
- Cutaneous
(pronounced: kyoo-tay-nee-us) or skin anthrax, can
occur if someone with a cut or scrape handles contaminated animals or animal
products. More than 95% of anthrax cases are of the cutaneous type, which is
the least dangerous form. A person with cutaneous anthrax will notice a small
sore that develops into a painless ulcer with a black area in its center. If
left untreated, the infection can spread to other areas of the body.
- Intestinal
anthrax can occur if someone eats undercooked
contaminated meat. Intestinal anthrax is far less common than cutaneous
anthrax, but it can make someone much sicker. Intestinal anthrax symptoms
include severe abdominal pain, nausea, vomiting, severe diarrhea, and bleeding
from the digestive tract.
- Pulmonary
(pronounced: pul-muh-ner-ee), or inhaled,
anthrax is the rarest form of anthrax - but it's also the most dangerous.
Pulmonary anthrax can only occur if someone breathes thousands of anthrax
spores into the lungs. Pulmonary anthrax usually seems like a common cold or the flu at first,
but it rapidly turns into severe pneumonia and
requires hospitalization.
It usually takes fewer than 7 days for a person to show signs of anthrax
infection. And symptoms of pulmonary anthrax can sometimes take months to
appear.
How Difficult Is It to Get Anthrax? It's very difficult to get anthrax. Just
being exposed to the spores or coming into contact with an infected animal
doesn't mean that a person will automatically develop the disease.
For example, to get pulmonary anthrax (the type of anthrax that killed
the five people in the 2001 outbreak), a person has to inhale thousands of
spores. This is extremely difficult to do when the anthrax spores are found in
soil or on infected animals. Even in the case of the man-made outbreak in 2001,
several of the people who were exposed were found to have B. anthracis
spores only in their nostrils when tested. These spores hadn't made it to their
lungs in sufficient amounts to cause a problem. In other words, the people had
been exposed to the bacteria but had not developed the disease.
How Is Anthrax Diagnosed and Treated? Medical professionals can diagnose anthrax by taking samples from the
skin sores or blood of people who are believed to have been exposed to B.
anthracis. These samples are then sent to a lab to check whether the person
has the bacteria in his or her system.
If anthrax is caught early, it is almost always
successfully treated with antibiotics. Although there is a vaccine for anthrax,
in the United States it is currently only recommended for people who are at risk
of coming into contact with B. anthracis. They include people who work
with B. anthracis in laboratories, people who handle potentially infected
animal products, and U.S. military personnel. The vaccine is not given routinely
to people in the United States and it hasn't been studied for use in people
younger than 18.
If you worry when you hear about anthrax, remember that it's very rare, and
it's unlikely that you will ever be exposed to the germs that cause anthrax. If
you're worried about it, talk to a science teacher or medical professional -
someone who can help you find the answers to any questions you may have about
anthrax. You can also learn more from the organizations listed in the Resources
tab at the right of this article.
Updated and reviewed by: Elana Pearl Ben-Joseph,
MD Date reviewed: August 2004 Originally reviewed by: Frederick
A. Meier, MD
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