ANTHRAX
from the General
Services Administration
WHAT IS IT?
Anthrax
is a bacterial, zoonotic disease caused by Bacillus anthracis. Anthrax occurs
in domesticated and wild animals, including goats, sheep, cattle, horses, and
deer, but other animals may be infected. Anthrax is an invisible bacteria that
can live in soil, water, and dead animals. Anthrax is an acute bacterial infection of the skin, lungs, or
gastrointestinal tract. Infection occurs most commonly via the skin route and
only very rarely via the others.
The cutaneous, or skin form, occurs most frequently on the hands and forearms
of persons working with infected livestock or contaminated animal products and
represents 95% of cases of human anthrax. It is initially characterized by a
papule which progresses to a fluid-filled blister with swelling at the site of
infection. The scab that typically forms over the lesion can be black as coal,
hence the name "anthrax," which is Greek for "coal." With
treatment, the case fatality rate should be less than 1% among cutaneous
cases. The fatality rate for untreated inhalational or
intestinal anthrax is over 90%.
The skin form of the human disease may be contracted by handling contaminated
hair, wool, hides, flesh, blood, or excreta of infected animals and from
manufactured products such as bone meal. Infection is introduced through
scratches or abrasions of the skin. The spores are very stable and may
remain viable for many years in soil and water. They will resist sunlight for
varying periods. The inhalation form is contracted by inhalation of the
spores and occurs mainly among workers handling infected animal hides, wool,
and furs. Under natural conditions, inhalation anthrax is exceedingly rare,
with only 18 cases having been reported in the United States in the 20th
century.
The gastrointestinal form of anthrax may be contracted by eating
insufficiently-cooked, infected meat. This form has not been seen in the U.S.
for decades.
Anthrax is not contagious, therefore quarantine and general decontamination of
an entire building or office are not necessary. Thorough cleaning is necessary
for any area where the spores may have been released.
WHAT IS THE TREATMENT?
Treatment with antibiotics beginning one day after exposure to a lethal
aerosol challenge with anthrax spores has been shown to provide significant
protection against death in test cases, especially when combined with active
immunization. Penicillin, doxycycline, and ciproflaxin are all effective
against most strains of B anthracis. Penicillin is the drug of choice
for naturally-occuring anthrax.
If untreated, inhalation anthrax is fatal. For post-exposure prophylaxis, the
administration of antibiotics should be continued for at least four weeks and,
if available, three doses of vaccine before the antibiotics are discontinued.
A vaccine is available and consists of a series of six doses over 18 months
with yearly boosters. This vaccine, while known to protect against anthrax
acquired through the skin, is also believed to be effective against inhaled
spores.
Effective decontamination can be accomplished by boiling contaminated articles
in water for 30 minutes or longer and using common disinfectants. Chlorine is
effective in destroying spores and vegetative cells. Remember, anthrax spores
are stable, able to resist sunlight for several hours and live in soil and
water for years.
HOW IS ANTHRAX MADE INTO A WEAPON?
Biological agents can be prepared and used either in liquid or dry form.
Procedures and equipment for preparing liquid biological agents are simple,
but the resulting product is difficult to disseminate into small-particle
effective aerosols. Conversely, procedures for producing dried biological
agents such as anthrax spores are complex and require more sophisticated
equipment, yet this product is readily disseminated by a number of devices.
If an organization has the capability to produce viruses by means of tissue
culture technology, then it could process a liquid agent into a dry powder.
The dried agent might have the consistency of bath powder. An ideal dry agent
should have free-flowing properties. If the powder were derived from a highly
sophisticated process, however, it would contain very small particles and be
highly charged with static electricity. A less sophisticated process yields a
coarse-appearing powder comprised of large particles (10-20 microns) and is
not particularly difficult to handle.
Unlike nuclear and chemical agents, biological agents are not detectable with
the five human senses. You would never realize you may have been exposed to a
biological agent until you started becoming sick with certain symptoms.
The Center for Disease Control and Prevention (CDC) is responsible for
coordinating all public health and should be contacted at the Emergency
Preparedness and Response Branch, National Center for Environmental Health for
assistance. Call 770-488-7100 or visit their website at http://cdc.gov/.
SYMPTOMS AND
EFFECTS OF ANTHRAX:
After an incubation period
of one to seven days, the onset of inhalation anthrax is gradual. Possible
symptoms include:
• Fever
• Malaise
• Fatigue
• Cough
• Mild chest discomfort followed by severe respiratory distress
A mild illness can
progress rapidly to respiratory distress and shock in two to four days. This
is followed by a range of more severe symptoms including difficulty breathing,
exhaustion, tachycardia, and cyanosis. Shock and death occur within 24-36
hours after onset of severe symptoms.