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The CDC lists six biological diseases as
"high-priority" biological agents that pose a risk to national
security, and also describes more than two dozen chemical agents that
could be used as terrorist weapons.
I. BIOLOGICAL
WARFARE:
A. ANTHRAX
Anthrax is an acute infectious disease caused by the spore-forming
bacterium Bacillus anthracis. The spore produces a toxin that can be
fatal.
HOW DOES IT SPREAD?
The spores can spread by inhalation or ingestion.
SYMPTOMS:
Usually symptoms appear within seven days. Inhalation anthrax infection
can start out like a common cold before acute symptoms such as severe
breathing problems and shock [Pneumonic Anthrax. Infection by consuming
contaminated food is characterized by inflammation of the intestinal
tract, leading to vomiting of blood and severe diarrhea
[Gastro-intestinal Anthrax]. Death can occur within 24 hours of the
onset of acute symptoms.
TREATMENT:
A delay in the use of antibiotics -- even in terms of hours -- may
lessen chances for survival.
1. POST EXPOSURE PROPHYLAXIS - Exposure
to aerosolized spores x hrs-1d merits prophylaxis:
*Preferred antibiotic: Ciprofloxacin 500mg PO bid x 60d
*If susceptible: Amoxicillin 500mg PO tid x 60d
*If susceptible: Doxycycline 100mg PO bid x 60d
*Not studied in animals but active in vitro: Clindamycin, macrolides
& chloro
Direct physical contact: with alleged B. anthraxis (anthrax threat):
Wash exposed skin & exposed clothes with soap & water, refer
meterial to lab & contact Health Dept.
2. THERAPY
*Empiric: Ciprofloxacin 400mg IV q12h, then 500mg PO bid x 60d
*If susceptible: Penicillin G 4mil units IV q4h, then oral agent x 60d
*Alternatives to Ciprofloxacin: Ofloxacin 400mg q12h, levofloxacin 500mg
IV qd, gatifloxacin 400mg IV qd, followed by oral fluoroquinolone each x
60d
*Other antibiotics active in vitro: Clindamycin, chloramphenicol,
macrolides, vancomycin, aminoglycosides, first generation
cephalosporins, expanded spectrum penicillins.
PREVENTION:
Vaccine [low availability - mostly for military use].
B. BOTULISM
Botulism toxin -- the most potent lethal substance known to man -- is
made by the Clostridium botulinum.
HOW DOES IT SPREAD?
Botulism toxin can be inhaled or ingested via contaminated food or
water.
SYMPTOMS:
Double vision, slurred speech, dry mouth and muscle weakness, which also
starts at the top of the body and works its way down. Symptoms begin
from six hours up to two weeks after exposure. Death can be caused by
paralysis of the breathing muscles within 24 hours.
TREATMENT:
*Preferred (CDC): Trivalent antitoxin (A 7500IU, B 5500IU & E
8500IU) 1 vial diluted 1:10, slow IV infusion over 30 min.
*Miscellaneous support: IV hydration, tube feedings, abx for ID
complications
*Mechanical ventilation: 20-40% adults [for Respiratory failure]
*Concern: Report to Health Dept.
PREVENTION:
Vaccine
C. PNEUMONIC PLAGUE
The causative agent of plague, Yersinia pestis, is found in rodents and
their fleas.
HOW DOES IT SPREAD?
The plague bacterium could be disseminated by aerosol, resulting in the
pneumonic form with the potential for secondary spread of cases through
respiratory droplets of those infected.
SYMPTOMS:
Within one to six days after exposure, the first signs of illness are
fever, headache and weakness, which can lead to shock and death within
two to four days.
TREATMENT:
*Preferred antibiotics: Doxycycline 100mg PO bid x7d or ciproflox 500mg
bid x7d
*Alternative antibiotics: Chloro 1gm PO qid x7d; Streptomycin 1gm IM
bid; gentamicin 5mg/kg/d x 10d
*In Pregnancy: Doxycycline 100mg PO bid x7d or cipro 500mg PO bid x7d
*Infection control: 1)surgical mask, gowns, gloves & eye protection
until case treated >48hrs
*Other: Isolate or cohort pts; warn lab - Biosafety level 2
D. SMALLPOX
The variola virus, commonly known as smallpox, was eradicated from the
world in 1977, except for stocks of it kept in two World Health
Organization reference labs. It is unknown whether it is being held in
other labs in violation of WHO policy.
Smallpox comes in two forms: variola minor or the more deadly variola
major.
HOW DOES IT SPREAD?
The smallpox virus is relatively stable and the dose required for
infection is small, making it a candidate for aerosol release. It could
then be further spread by the saliva droplets of infected people.
SYMPTOMS:
The incubation period is about 12 days following exposure. Symptoms
include fever, fatigue and aches, followed by a rash with lesions and
can lead to death within the first two weeks of the illness.
TREATMENT:
*Vaccine <3-4d contact; PREVENTION: isolation + vaccine.
*Antibacterial agents to treat secondary bacterial infections of skin.
PREVENTION:
Vaccine
E. TULAREMIA
The causative agent of tularemia is Francisella tularensis, considered
one of the most infectious pathogenic bacteria known.
HOW DOES IT SPREAD?
Humans can become infected with tularemia through bites by infected
anthropods, contact with contaminated water or food, and inhalation of
infective aerosols.
SYMPTOMS:
Earlier symptoms of infection by aerosol could be similar to those of
influenza or atypical pneumonia. The symptoms can occur within a few
days or as long as two weeks after exposure. If untreated, the patient
experiences progressive weakness and weight loss and can die within two
weeks.
TREATMENT:
*Vaccine [of difficult availability]
*Antibiotics
PREVENTION:
A vaccine is currently under review by the U.S. Food and Drug
Administration
F. VIRAL
HEMORRHAGIC FEVERS
Viral hemorrhagic fevers (VHF) refers to a group of illnesses caused by
several distinct families of viruses. While some of these viruses cause
relatively mild illnesses, others cause severe, life- threatening ones,
such as Ebola.
HOW ARE THEY SPREAD?
Many VHF viruses are known to naturally reside in an animal or insect
host, however the hosts of some VHF viruses remain unknown, including
that of Ebola and Marburg viruses. Some VHF viruses can be transmitted
by the body fluids of infected people.
SYMPTOMS:
Reactions vary depending on the type of VHF, but symptoms often include
fever, fatigue, dizziness, muscle aches and exhaustion. Severe cases
cause bleeding under the skin and in internal organs. Some types of VHF
cause kidney failure.
TREATMENT:
Generally there are no treatments other than supportive therapy for VHFs.
PREVENTION:
Vaccines are available for only two VHFs: yellow fever and Argentine
hemorrhagic fever.
II. CHEMICAL
WEAPONS:
A. HYDROGEN CYANIDE
Hydrogen cyanide is an extremely flammable, colorless gas or liquid. It
gives off toxic fumes in a fire and is highly explosive.
HEALTH EFFECTS:
Exposure irritates the eyes, the skin and the respiratory tract.
Symptoms are burning and redness for the skin and eyes. Inhalation
causes confusion, drowsiness and shortness of breath, leading to
collapse. The substance can affect the central nervous system, resulting
in impaired respiratory and circulatory functions. Exposure can be
fatal.
ANTIDOTE:
Fresh air in the case of inhalation and rinsing with plenty of water in
the case of skin or eye exposure.
B. CHLORINE
Chlorine is a greenish-yellow gas with a pungent odor that is heavier
than air. It reacts violently with many organic compounds, creating a
fire and explosion hazard.
HEALTH EFFECTS:
Chlorine is corrosive to the eyes and the skin and can cause tearing,
blurred vision and burns. Inhalation may cause labored breathing and
lung edema. The symptoms of lung edema often do not manifest until a few
hours after exposure. High exposure levels may result in death.
ANTIDOTE:
Fresh air in the case of inhalation and rinsing with plenty of water in
case of exposure to skin and eyes.
C. SARIN
Sarin is a highly toxic compound in both its liquid and vapor state that
attacks the central nervous system.
HEALTH EFFECTS:
Sarin can cause death minutes after exposure. It enters the body by
inhalation, ingestion, through the eyes and the skin. Symptoms vary but
commonly include a runny nose, watery eyes, drooling and excessive
sweating, difficulty in breathing, dimness of vision, nausea, vomiting,
twitching and headache. It kills by attacking the body's voluntary
muscle and gland "on switch," causing the muscles to tire so
they can no longer sustain breathing.
ANTIDOTE:
Immediate treatment is decontamination by removing clothing and flushing
eyes and skin with water. Hospitals in many communities are stocking the
antidotes.
D. VX
VX is a highly toxic compound in both its liquid and vapor form that
attacks the central nervous system. It is considered at least 100 times
more toxic by entry through the skin than the nerve-agent sarin, and
twice as toxic by inhalation. VX can persist for long periods under
average weather conditions and for months in very cold conditions.
HEALTH EFFECTS:
VX can cause death minutes after exposure. It can enter the body by
inhalation, ingestion, through the eyes and through the skin. Symptoms
can vary but commonly include runny nose, water eyes, drooling,
excessive sweating, difficulty in breathing, dimness of vision, nausea
and twitching. It kills by attacking the body's voluntary muscle and
gland "on switch," causing the muscles to tire so they can no
longer sustain breathing.
ANTIDOTE:
Immediate treatment is decontamination by removing clothing and flushing
the eyes and skin with water. Hospitals in many communities are stocking
the antidotes.
E. SULFUR MUSTARDS
Sulfur mustards are vesicants and alkylating agents, more commonly known
as blister agents. They are colorless when pure but are generally a
yellow to brown color and have a slight garlic or mustard odor. Sulfur
mustard in vapor and liquid forms can be absorbed through the eyes, skin
and mucous membranes.
HEALTH EFFECTS:
Sulfur mustards cause skin, eye and respiratory tract injury. They may
also cause bone marrow suppression and neurologic and gastrointestinal
toxicity. Although cellular changes occur within minutes of contact,
pain and other clinical effects are delayed for one to 24 hours.
ANTIDOTE:
There is no antidote for sulfur mustard toxicity. Decontamination of all
potentially exposed areas within minutes after exposure is the only
effective means of decreasing tissue damage.
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