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What to know
about anthrax
about anthrax
Medical
News Today
Anthrax is
caused by infection with Bacillus anthracis, a hardy, spore-forming
bacterium that can survive in extreme conditions for a long time.
The bacterium
is highly toxic.
Anthrax
infection is rare in the United States, but not uncommon elsewhere.
Anthrax is
common in livestock, and a potentially serious infectious disease in humans.
The spores occur naturally in soil, but anthrax only becomes active when it enters the body.
Bacillus
anthracis (B. anthracis) gained notoriety as a biological weapon in the 2001 in the
United States (U.S.), when anthrax powder was mailed in packages, leading to 22
cases of infection, including 5 fatalities.
However, the disease
is not unusual in the agricultural regions of the Caribbean, central and
southwestern Asia, Central and South America, southern and eastern Europe and
sub-Saharan Africa. How dangerous it is, depends on the type.
It is rare in
the U.S., but outbreaks occur very occasionally in grazing animals such as
deer. It is more likely in countries that do not routinely vaccinate animals
against the disease.
It cannot pass from one human to another.
Fast facts on anthrax:
Here are some
key points about anthrax. More detail is in the main article.
· Anthrax is a potentially fatal bacterial infection that is rare
in the U.S. but more common elsewhere.
· There are four types, depending on how it is transmitted.
· Anthrax can be spread through animals and animal products.
· Treatment is with antibiotics,
which must be started soon after infection.
· There is a possibility that anthrax could be used as a
biological weapon.
· A vaccine exists for people who are at risk, but not for the
general public.
What is anthrax?
B. anthracis bacteria
produce resilient spores that can cause a potentially deadly infection in
people and animals.
There are four
different forms of anthrax infection:
·
cutaneous
·
inhalation
·
gastrointestinal
·
injection
Each type is
caused by the B. anthracis bacteria entering the human body in
a different way. Each route of entry leads to a unique set of symptoms.
Causes
Anthrax
infection happens when the bacterium B. anthracis enters the
body through inhaling, swallowing, injecting, or through skin contact.
Anthrax spores
are resistant to many environmental stresses and normally lie dormant.
If they enter
the body of a person or an animal, they can develop into active growing cells,
due to the presence of water, sugars, and other nutrients.
Once active,
the bacteria multiply throughout the body, creating toxins that can cause
severe illness.
Anthrax consists of three proteins. None of these
proteins is toxic on its own, but combined, they can make a lethal mix,
disrupting cellular signaling pathways and stopping cells from working properly,
shutting down the host’s immune system, and leading to death.
The most common
form of anthrax, cutaneous anthrax, mostly spreads through contact with
contaminated animal products such as hides and hair.
People have
developed anthrax after using the hides of infected animals to make traditional
African drums.
Bioterrorism
If a person
deliberately releases a virus or bacteria that can lead to sickness or death,
this is known as a biological attack.
According to
the Centers for Disease Control and Prevention (CDC), if a biological attack
were to occur, the anthrax bacteria is “one of the most likely agents.”
There are
several reasons for this, for example:
· anthrax is easy to find in nature and easy to grow in labs
· an attack would be hard to detect
· it has previously been used as a weapon
Federal
agencies and health departments in the U.S. work together to ensure
preparedness for such an event.
However, they would
not know it had happened until a pattern of infection emerged.
This is because
it is rare, symptoms take a while to show, and they are also similar to
symptoms of other conditions, such as flu.
Symptoms
Each form of
anthrax has its own range of symptoms. For most forms, the symptoms appear
within a week of exposure to B. anthracis, but the symptoms of
inhalation anthrax can take over a month to develop.
Cutaneous anthrax
The most common
form of anthrax is cutaneous anthrax.
The symptoms
are as follows:
·
small itchy blisters or bumps
·
a painless swollen sore with a black center
·
swelling in nearby lymph glands and tissue
This is
considered the mildest form. With treatment, it is rarely deadly. Without
treatment, it may be fatal in 20 percent of cases.
Gastrointestinal anthrax
This can come
from eating raw or undercooked meat from an infected animal.
The symptoms of
gastrointestinal anthrax are:
·
abdominal pain and swelling
·
diarrhea
·
fainting
·
fever and
chills
·
flushing face and red eyes
·
headache
·
loss of appetite
·
nausea and vomiting
·
sore throat with
painful swallowing
·
swelling of neck and neck glands
Without
treatment, half of patients
die, but with treatment, 60 percent will survive.
Inhalation anthrax
The initial
symptoms of inhalation anthrax are:
·
chest discomfort
·
coughing up blood
·
nausea and vomiting
·
pain when swallowing
·
flu-like symptoms
As the disease
progresses, the individual is likely to experience:
·
breathing difficulties
·
low oxygen in blood
·
meningitis
·
shock
This is the
most deadly kind of anthrax. Without treatment, it is fatal in 85 to 90 percent of cases.
Injection anthrax
This has affected people who inject heroin in
Europe, but it has not been reported in the U.S.
The initial symptoms
of injection anthrax are:
·
abscesses in and around the injection site
·
blisters and bumps around the injection site
·
fever
·
a swollen sore near the injection site
As the disease
progresses, the following may develop:
·
meningitis
·
organ failure
·
shock
The effects
probably depend on how deep they are, but symptoms can also be confused with
those of other infections.
Tests and diagnosis
Anthrax shares
many symptoms with more common conditions, such as flu and pneumonia.
A health care
provider will rule these out first before considering anthrax, unless there is
a specific reason to suspect it.
If other
conditions are ruled out, then tests specific to anthrax may follow.
An anthrax
diagnosis can only be confirmed by measuring antibodies or toxins in the blood
or other tissue. The type of tissue sample and other types of test will depend
on the suspected form of anthrax.
Tests include:
· a skin biopsy to test for cutaneous anthrax
· stool testing for gastrointestinal anthrax
· chest x-rays or CT scans to
detect inhalation anthrax
· lumbar punctures to reveal anthrax meningitis
In 2014,
researchers researchers that a
“glow test” can detect the presence of deadly anthrax bacteria in hours instead
of days. This could significantly cut the time it takes to respond to a
potential bioterrorism attack.
Treatment
Anthrax must be
treated as quickly as possible, before the levels of toxins and harmful
bacteria within the body become too high for drugs to eliminate.
The standard
treatment for anthrax is with antibiotics and antitoxins. The type of
antibiotics will depend on how the infection occurred, the individual’s age and
medical history.
Antitoxin
therapies are currently being developed that target the toxins released
by B. anthracis, rather than the bacteria themselves.
Recently,
surgical removal of infected tissue has been used successfully to treat
injection anthrax.
In 2013, a team
of researchers discovered a new chemical compound from
the sea that could be used to treat anthrax and MRSA.
Prevention
Tips for
avoiding anthrax include:
· only eating meat that has been suitably slaughtered and cooked
· avoiding contact with raw animal hides, especially those of
cows, sheep, and goats
People who work
with fur, hides, and wool, especially if these are imported, should take extra
care.
Anthrax
molecules are made up of three proteins, none of which is toxic on its own. It
can be present in imported animal products.
If anyone is
exposed to the bacteria, antibiotics can prevent the symptoms of anthrax from
developing before the B. anthracis spores have time to
activate.
The U.S. Food
and Drug Administration (FDA) have approved a vaccine for anthrax, to be used
prior to exposure by adults who could be at risk.
These include
laboratory workers, handlers of animals and animal products, and some military
personnel. It is not available to the public.
The vaccine can
also be given after exposure, alongside antimicrobial therapy.
Anthrax remains
rare in the U.S. If a person has symptoms that resemble anthrax, it is most
likely a more common illness.
If a person
shows signs and symptoms after exposure to animals or animal products from
parts of the world where anthrax is common, however, it is best to contact a
health care provider.
To be
effective, treatment for anthrax must begin as soon as possible.
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