:: anthrax
::
Anthrax (malignant
edema, woolsorters' disease)
What is anthrax?
Anthrax is an acute
infectious disease caused by the spore-forming bacterium Bacillus anthracis.
Anthrax most commonly occurs in warm-blooded animals, but can also infect
man. Anthrax spores can be produced in a dry form (for biological
warfare ) which may be stored and ground into particles. When inhaled
by humans, these particles cause respiratory failure and death within a
week.
Why has anthrax
become a current issue?
Because anthrax
is considered to be a potential agent for use in biological warfare, the
Department
of Defense (DOD) announced that it will begin systematic vaccination
of all U.S. military personnel.
Who gets anthrax?
Anthrax is most
common in agricultural regions where it occurs in animals. These include
South and Central America, Southern and Eastern Europe, Asia, Africa, the
Caribbean, and the Middle East. When anthrax affects humans, it is usually
due to an occupational exposure to infected animals or their products.
Workers who are exposed to dead animals and animal products (industrial
anthrax) from other countries where anthrax is more common may become infected
with B. anthracis. Anthrax in animals rarely occurs in the United
States. Most reports of animal infection are received from Texas, Louisiana,
Mississippi, Oklahoma and South Dakota.
How is anthrax
transmitted?
Anthrax infection
can occur in three forms: cutaneous (skin), inhalation, and gastrointestinal.
B. anthracis spores can live in the soil for many years and humans
can become infected with anthrax by handling animal products from infected
animals or by inhaling anthrax spores from contaminated animal products.
Anthrax can also be spread by eating undercooked meat from infected animals.
It is rare to find infected animals in the United States.
What are the symptoms
of anthrax?
Symptoms of disease
vary depending on how the disease was contracted, but symptoms usually
occur within seven days.
Cutaneous:
Most anthrax infections occur when the bacterium enters a cut or abrasion
on the skin, such as when handling contaminated wool, hides, leather or
hair products (especially goat hair) of infected animals. Skin infection
begins as a raised itchy bump that resembles an insect bite but within
1-2 days develops into a vesicle and then a painless ulcer, usually 1-3
cm in diameter, with a characteristic
black necrotic (dying) area in the center. Lymph glands in the adjacent
area may swell. About 20% of untreated cases of cutaneous anthrax will
result in death. Deaths are rare with appropriate antimicrobial therapy.
Inhalation:
Initial symptoms may resemble a common cold. After several days, the symptoms
may progress to severe breathing problems and shock. Inhalation anthrax
usually results in death in 1-2 days after onset of the acute symptoms.
Intestinal:
The intestinal disease form of anthrax may follow the consumption of contaminated
meat and is characterized by an acute inflammation of the intestinal tract.
Initial signs of nausea, loss of appetite, vomiting, fever are followed
by abdominal pain, vomiting of blood, and severe diarrhea. Intestinal anthrax
results in death in 25% to 60% of cases.
How soon after
infection do symptoms appear?
The incubation
period is usually within seven days.
When and for how
long is a person able to spread anthrax?
There are no reports
of the disease spreading from human to human. Direct person-to-person spread
of anthrax most likely does not occur.
Does past infection
with anthrax make a person immune?
A second attack
with this disease is unlikely.
What is the treatment
for anthrax?
Doctors can prescribe
effective antibiotics. Usually penicillin is preferred, but erythromycin,
tetracycline, or chloramphenicol can also be used. To be effective, treatment
should be initiated early.
What can be the
effect of not being treated for anthrax?
The disease could
be fatal in untreated cases.
Where is anthrax
usually found?
Although anthrax
can be found globally, it is more often a risk in countries with less standardized
and effective public health programs. Areas currently listed as high risk
are South and Central America, Southern and Eastern Europe, Asia, Africa,
the Caribbean, and the Middle East.
What can be done
to prevent the spread of anthrax?
Anthrax vaccine
is available for people in high-risk occupations. To prevent anthrax, carefully
handle dead animals suspected of having anthrax; provide good ventilation
when processing hides, fur, hair or wool; and vaccinate animals.
In countries
where anthrax is common and vaccination levels of animal herds is low,
humans should avoid contact with livestock and animal products, and avoid
eating meat that has not been properly slaughtered and cooked. For high
risk occupations, such as those exposed to potentially contaminated animal
hair, wool or hides, vaccination is recommended. An anthrax vaccine has
been licensed for use in humans. The vaccine is reported to be 93% effective
in protecting against cutaneous anthrax.
What is the anthrax
vaccine?
The anthrax vaccine
is a cell-free filtrate vaccine, which means it uses dead bacteria as opposed
to live bacteria. Anthrax vaccine is indicated for individuals who come
in contact in the workplace with imported animal hides, furs, bonemeat,
wool, animal hair (especially goat hair), and bristles; and for individuals
engaged in diagnostic or investigational activities which may bring them
into contact with anthrax spores.
BioPort Corporation
is the sole manufacturer of the anthrax vaccine. BioPort, whose headquarters
is located in Lansing, Michigan, is owned by multiple shareholders. The
two main companies that make up BioPort are Intervac, headed by William
Crowe and Faud El-Hibri, and Michigan Biologic Products Inc.
The vaccine
is US Food and Drug Administration (FDA)-licensed and has been routinely
given in the US since 1970.
What is the protocol
for anthrax vaccination?
The immunization
consists of three subcutaneous injections given two weeks apart followed
by three additional subcutaneous injections given at 6, 12, and 18 months.
Annual booster injections of the vaccine are required to maintain immunity.
Are there adverse
reactions to the anthrax vaccine?
Like all vaccines,
anthrax vaccine may cause soreness, redness, itching,
swelling, and
lumps at the injection site. About 30% of men and 60% of
women report
these local reactions, but they usually last only a short while.
Lumps can persist
a few weeks, but eventually disappear. Injection-site
problems occur
about twice as often among women. For both genders,
between 1%
and 5% report reactions at the injection site of 1 to 5 inches in
diameter. Larger
reactions at the injection site occur in about one in a
hundred vaccine
recipients.
Beyond the injection
site, from 5% up to 35% will notice muscle aches, joint
aches, headaches,
rash, chills, fever, nausea, loss of appetite, malaise, or
related symptoms.
Again, these symptoms usually go away after a few days.
Serious events,
such as those requiring hospitalization, are rare. They happen
about once
per 50,000 doses. Severe allergic reactions can occur after any
vaccination,
less than once per 100,000 doses.
A moderate local
reaction can occur if the vaccine is given to anyone with a past history
of anthrax infection.
Acute symptoms
have varied. Depending on the vaccine lot used.
The most common
side effects reported are: mild discomfort (localized swelling and redness
at the site of injection), joint aches, and in a few cases, nausea, loss
of appetite, and headaches.
Are there any long
term side effects?
There have been
no long term side effects from the vaccine.
Should everyone
get vaccinated against anthrax?
Anthrax vaccine
is indicated for individuals who come in contact in the workplace with
imported animal hides, furs, bonemeat, wool, animal hair (especially goat
hair), and bristles; and for individuals engaged in diagnostic or investigational
activities which may bring them into contact with anthrax spores. The vaccine
should only be administered to healthy men and women from 18 to 65 years
of age since investigations to date have been conducted exclusively in
that population. Because it is not known whether the anthrax vaccine can
cause fetal harm, pregnant women should not be vaccinated.
Who should not
get vaccinated against anthrax?
People who should
not get the anthrax vaccine are those with a true hypersensitivity reaction
(serious allergic reaction) to a previous dose of the anthrax vaccine,
people infected with HIV, people who have other kinds of immune suppression,
pregnant women, and people under 18 and over 65 years of age. Other temporary
reasons for deferring anthrax vaccination include an acute respiratory
disease or active infection, and a temporary course of immune-suppressing
drugs such as steroids (e.g., prednisone).
People with
preexisting autoimmune illnesses such as rheumatoid arthritis, lupus, multiple
sclerosis are probably more likely to suffer a serious adverse reaction,
as are those with neurologic disease, such as those who had polio in childhood.
With the new DOD
vaccination program, is anthrax vaccine available to the civilian population?
Small quantities
are made available as needed to civilians who are exposed to anthrax hazards
in their work environment such as veterinarians, lab workers and others.
Anthrax vaccine is produced exclusively by the Michigan Biologic Products
Institute under contract to the Defense Department. Virtually all vaccine
produced is earmarked for military use in recognition of the documented
threat to military personnel.
How is anthrax
diagnosed?
Anthrax is diagnosed
by isolating B. anthracis from the blood, skin lesions, or respiratory
secretions or by measuring specific antibodies in the blood of suspected
cases.
Is there a treatment
for anthrax?
Doctors can prescribe
effective antibiotics. Usually, penicillin is preferred, but erythromycin,
tetracycline, or chloramphenicol can also be used. To be effective, treatment
should be initiated early. If left untreated, the disease can be fatal.
Where can I get
more information about the Department of Defense decision to require men
and women in the Armed Services to be vaccinated against anthrax?
The Department
of Defense recommends servicemen and women contact their chain of command
with questions about the vaccine and its distribution.
Members of the
Armed Services can find additional information at the DOD
Anthrax Vaccination Program site or by e-mail at avip@otsg.amedd.army.mil
Related Pages:
Related Sites:
2001
© Allright Reserved
by
Mohd
Hafiz Yahaya