Illnesses and Conditions
: Anthrax-Common Questions
What is anthrax infection?
Anthrax is an infection caused by a bacteria called Bacillus Anthracis.
The name anthrax comes from the Greek word "anthrakas" which means
"coal" reflecting the black rash caused by infection of the skin
by this bacterium. The bacteria is naturally found in soil and
can infect livestock. Most of the animal infections occur in South
and Central America. There have been outbreaks of human anthrax
as well. In the USA there were about 130 cases/year of human anthrax
in the early 1900's. Between 1993-2000 there were no reported
human anthrax cases in the USA. It is not surprising that most
physicians in North America have never seen a case of anthrax
during the course of their practice.
How is anthrax spread to humans?
Anthrax is usually found in sheep, cattle and other animals. The
infection however is not considered contagious; in other words
it cannot be transmitted from one infected person to another.
The anthrax bacterium is a type that can make spores. By enclosing
itself in a microscopic wall, almost like a cocoon, the spore
form of the bacteria can last a long time(years) outside of a
living body. Once the spores get inside a body they start to multiply
and cause an infection. Most of the human infections, which are
very rare, to begin with, result from contact with infected animals
or animal parts such as sheepskin.
What is the difference between contact with the spore
and actually getting anthrax?
This is a very important point. Just because a person comes into
contact with anthrax spores does not mean that he or she will
develop the infection. The spores have to be a certain size and
enter the body in large numbers(up to 50,000) in order to cause
an infection. Just because a person touches or comes into contact
with a spores does not automatically mean that infection will
What type of infection does anthrax cause?
The anthrax bacteria can cause 3 types if infection in humans
depending on the way the spores enter the body.
Skin: a skin infection can result if
the bacterium gets in through a cut or tear on the skin. Once
it causes an infection, a rash is formed and the bacterium can
possibly enter the blood stream This type of infection has a mortality
rate of about 20% if untreated.
Gastro-intestinal: the spores enter
the body through the stomach and intestines of after eating meet
infected with anthrax. The mortality rate in untreated cases is
thought to be between 25-60%. This is very rare in North America
where meat is stringently controlled for infection.
Inhalation: the spores(in sufficient
numbers and size) get into the lungs causing symptoms of a chest
infection including, cough, difficulty breathing and fever. The
anthrax bacterium can then get into the blood and dangerously
infect the covering of the brain, causing meningitis. This form
of anthrax is considered very deadly with a mortality rate of
over 90% if untreated.
How is anthrax infection confirmed?
Specimens taken by swab either from the nose or the skin are sent
to a Microbiology laboratory where they look for the anthrax bacteria.
This process takes at least several days. Today there exist more
sophisticated portable equipment that can actually screen for
and detect the bacteria within minutes.
Why and when are antibiotics prescribed?
In the recent cases of contact with anthrax most people did not
develop any serious infection. These people came into contact
with the anthrax spores(in other words the bacterium was found
on their skin or nasal passages). Only these people were given
antibiotics. It is important to note that most of these people
were otherwise well and antibiotics were given as a precautionary
step. Obviously if there is an active infection antibiotics are
also necessary. Additionally if public health authorities suspect
that certain groups of people(such as postal workers etc) where
possibly exposed to anthrax spores they may recommend antibiotics
as a precaution, even without testing.
Is there a vaccine against anthrax?
Animal vaccines exist that protect animals form anthrax. There
is also a vaccine for humans that has been used mostly to protect
high risk individuals such as livestock farmers(working in areas
where there is a high rate of anthrax spores present), laboratory
workers and more recently, because of the fear of bio-terrorism
or biological warfare, army troops. In order to be effective,
multiple doses need to be given to an individual over a prolonged
period of time. After the initial shots, a booster vaccine is
given annually. The human anthrax vaccine, considered to be 93%
effective be has not been used in people less than 18 years or
older than 65 years.
What can people do to prevent exposure to anthrax?
According to security authorities it is essential not touch or
open any suspicious or unexpected pieces of mail. Taking antibiotics
just in case is not recommended. Over-use of antibiotics can cause
more problems than it solves. Only persons who have had proven
contact(by laboratory tests)need to take antibiotics. Also, certain
groups of people who work where anthrax bacteria spores were found
may need to take antibiotics. This decision is made, based on
the individual situation, by public health officials.
It is important to keep in mind that:
Contact with the anthrax spores does not necessarily mean an infection
A very large number of anthrax spores must enter the body to cause
It is very difficult to make spores small enough and in enough
quantity to deliberately cause infection
Antibiotics are prescribed to prevent an anthrax infection in
proven contacts with the bacteria, whether they have an active
infection or not
Antibiotics may also be prescribed to certain groups of people(i.e.
postal workers) working in a area where anthrax spores were found
Anthrax is not contagious: in other words cannot spread form an
infected person to another
Antibiotics taken just in case without proven or suspected contact
are not necessary
The information provided in this site is
designed to be an educational aid only. It is not intended to
replace the advice and care of your child's physician, nor is
it intended to be used for medical diagnosis or treatment. If
you suspect that your child has a medical condition, always
consult a physician.
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