Biological Agent - Anthrax
Anthrax is an acute infectious disease caused by a
spore-forming bacterium called Bacillus anthracis.
It is generally acquired following contact with anthrax-infected animals or
anthrax-contaminated animal products. Anthrax has received heightened attention
recently because of its use as a biological warfare agent.
- Bacillus anthracis, the etiologic agent of
anthrax, is a large, gram-positive, non-motile, spore-forming bacterial rod.
The three virulence factors of Bacillus anthracis
are edema toxin, lethal toxin, and a capsular antigen. Human anthrax has three
major clinical forms: cutaneous, inhalation, and gastrointestinal.
- Bacillus anthracis spores do not have a
characteristic appearance such as color, smell, or taste. Spores themselves
are too small to be seen by the naked eye, but have been mixed with powder to
- Anthrax infection can occur in three forms:
- Cutaneous (skin)
- Bacillus anthracis spores can live in soil for
many years. Humans can become infected with anthrax by handling products from
infected animals or by inhaling anthrax spores from contaminated animal
- Anthrax can also be spread by eating undercooked meat from infected
animals. It is rare to find infected animals in the United States.
- Direct person-to-person spread of anthrax is extremely unlikely to occur.
Communicability is not a concern in managing or visiting with patients with
Symptoms of disease vary depending on how the disease
was contracted, but symptoms usually occur within 7 days.
- Cutaneous: Most (about 95 percent) 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 centimeters in diameter, with a
characteristic black necrotic (dying) area in the center. Lymph glands in the
adjacent area may swell. About 20 percent of untreated cases of cutaneous
anthrax will result in death. Deaths are rare with appropriate antimicrobial
- Inhalation: Initial symptoms may resemble a
common cold. After several days, the symptoms may progress to severe breathing
problems and shock. Inhalation anthrax is often fatal.
- 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, and fever are followed by abdominal pain, vomiting
of blood, and severe diarrhea. Intestinal anthrax results in death in 25
percent to 60 percent of cases.
Anthrax Diagnosis & Treatment
Diagnosis: Anthrax is
diagnosed by isolating Bacillus anthracis from the
blood, skin lesions, or respiratory secretions or by measuring specific
antibodies in the blood of persons with suspected cases.
Treatment: Doctors can prescribe effective antibiotics.
Bacillus anthracis usually responds effectively to
several antibiotics including penicillin, doxycycline, and fluoroquinolones
(such as ciprofloxacin). To be effective, treatment should be initiated early.
If left untreated, the disease can be fatal.
In countries where anthrax is common and vaccination levels of animal herds
are low, humans should avoid contact with livestock and animal products and
avoid eating meat that has not been properly slaughtered and cooked. Also, an
anthrax vaccine has been licensed for use in humans. The vaccine is reported to
be 93 percent effective in protecting against anthrax.
The anthrax vaccine is a cell-free filtrate vaccine, which means it contains no
dead or live bacteria in the preparation. The final product contains no more
than 2.4 milligrams of aluminum hydroxide as an additive. Anthrax vaccines
intended for animals should not be used in humans.
The Advisory Committee on Immunization Practices has
recommend anthrax vaccination for the following groups:
- People who work directly with the organism in the laboratory,
- People who work with imported animal hides or furs in areas where
standards are insufficient to prevent exposure to anthrax spores,
- People who handle potentially infected animal products in high-incidence
areas (Incidence is low in the United States, but veterinarians who travel to
work in other countries where incidence is higher should consider being
- Military personnel deployed to areas with high risk for exposure to the
organism (as when it is used as a biological warfare weapon).
- First responders and workers involved in anthrax decontamination.
Pregnant women should be vaccinated only if absolutely
At Risk Workers
The following categories of employees could
potentially be exposed to anthrax:
- Workers Exposed Through Criminal/Terrorist Acts. Workers
whose jobs would not ordinarily involve anthrax exposure could be exposed
through acts of terrorism.Conventional thinking is that terrorists are likely
to target places where large populations can be found such as large buildings,
sporting events, or mass transit systems.
- Emergency Response Workers. Emergency responders, including
police, firefighters, emergency medical services workers, and others who are
responsible for responding to acts of terrorism may be exposed to anthrax.
Health and safety precautions, including personal protective equipment (PPE)
and respirators, used by emergency response workers will help protect them
against anthrax exposure.
- Health Care Workers. Health care workers in
occupational settings such as hospitals, clinics, and medical laboratories may
be exposed to anthrax as a result of contact with patients whose skin,
clothing, or personal effects are contaminated with anthrax spores, or through
contact with contaminated equipment.
- Anthrax is not a contagious disease.
- Because the most likely exposure route for health care workers is dermal
contact, normal health and safety precautions (such as wearing latex/nitrile
examination gloves) will protect these workers against cutaneous anthrax
- Livestock Workers. Anthrax is most common in occupations
involving animals, animal hides, or fibers. Grazing animals such as cattle,
sheep, goats, and horses are chief animal hosts of anthrax. Occupations
susceptible to exposure include shepherds, farmers, butchers, handlers of
imported hides or fibers, weavers, veterinarians, and veterinary pathologists.
Anthrax can be found globally. However, it is more common in developing
countries or countries without veterinary public health programs.
An emergency action plan (EAP) describes the actions
employees should take to ensure their safety if a fire or other emergency
situation occurs. Well-developed emergency plans and proper employee training
(such that employees understand their roles and responsibilities within the
plan) will result in fewer and less severe employee injuries and less structural
damage to the facility during emergencies. A poorly prepared plan is likely to
lead to a disorganized evacuation or emergency response, resulting in confusion,
injury, and property damage. If your facility has a credible risk of anthrax
exposure, you should add anthrax-specific information to your Emergency Action
Plan. This may include:
- Emergency identification: Provide guidance on
how to recognize a potential emergency situation (such as an anthrax threat or
release, suspicious mail, etc.).
- Initial actions: Upon identification of a
potential anthrax threat or release:
- Do not panic.
- Isolate contaminated areas.
- Minimize exposure to others.
- Turn off local fans or ventilation units and shut down the air handling
system in the building, if possible.
- Keep track of people who may have come into contact with the anthrax.
Give this list to both the local public health authorities and law
- Notify the proper authorities once the area has
- Call 9-1-1 for local fire and law enforcement
assistance. Call the Federal Protective Service if your building is managed
- Notify the National Response Center at (800)424-8802.
The NRC will notify the appropriate parties responsible for aiding in
mitigation of these events.
- Contact the owner or operator of the facility.
- Notification: A description of the alarm system
to be used to notify employees (including disabled employees) to evacuate
and/or take other actions.
- Evacuation policy: An evacuation policy,
procedures, and escape route assignments so employees understand who is
authorized to order an evacuation, under what conditions an evacuation would
be necessary, how to evacuate, and what routes to take.
- Account for employees: Procedures to account
for employees after the evacuation to ensure that everyone got out.
- Organizational structure: Define an
organizational structure that defines the roles and responsibilities of
employees in the event of an emergency.
- Employee training: A description of how
employees will be informed of the contents of the plan and trained in their
roles and responsibilities.
- Contact information: The names, titles,
departments, and phone numbers of employees who can be contacted for
additional information or clarification of some aspect of the plan.
- Off-hour contacts: A list of key personnel who
should be contacted during off-hours emergencies.
- Emergency drills: Conduct emergency drills to
help ensure that the actions outlined in the EAP are carried out properly and
Anthrax Threat at Your Facility
The actions that will constitute an appropriate response
for an anthrax threat will depend on how the threat was discovered and the
credibility of a threat at your facility. Discovery of anthrax may occur
in several ways:
- Physical evidence (such as a suspicious package containing powder),
- Epidemiological or medical observations (such as individual cases of
- Unsubstantiated threat (such as a phone call or letter stating that
anthrax has been used).
Emergency Plan Response Training
The five levels of training for employees who
initially respond to an emergency are listed from the lowest to highest level of
First Responder awareness level: First
responders at the awareness level are individuals who are likely to witness or
discover a hazardous substance release and who have been trained to initiate
an emergency response sequence by notifying the proper authorities of the
release. They would take no further action beyond notifying the authorities of
First Responder operations level: First
responders at the operations level are individuals who respond to releases or
potential releases of hazardous substances as part of the initial response to
the site for the purpose of protecting nearby persons, property, or the
environment from the effects of the release. They are trained to respond in a
defensive fashion without actually trying to stop the release. Their function
is to contain the release from a safe distance, keep it from spreading, and
Hazardous Materials Technician: Hazardous
materials technicians are individuals who respond to releases or potential
releases for the purpose of stopping the release. They assume a more
aggressive role than a first responder at the operations level in that they
will approach the point of release in order to plug, patch, or otherwise stop
the release of a hazardous substance.
Hazardous Materials Specialist: Hazardous
materials specialists are individuals who respond with and provide support to
hazardous materials technicians. Their duties parallel those of hazardous
materials technicians. However, those duties require a more directed or
specific knowledge of the various substances they may be called upon to
contain. The hazardous materials specialist would also act as the site liaison
with federal, state, local, and other government authorities in regards to
On-scene Incident Commander: Incident
commanders will assume control of the incident scene beyond the first
responder awareness level.
Each of the above levels of training requires
employers/employees to have sufficient training or to have sufficient experience
to objectively demonstrate competencies listed in 29 CFR
1910.120(q)(6). Certification of training is required by OSHA
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