Plague is a disease caused by Yersinia pestis (Y. pestis), a bacterium
found in rodents and their fleas in many areas around the world.
are we concerned about pneumonic plague as a bioweapon?
Yersinia pestis used in an aerosol attack could cause cases of the
pneumonic form of plague. One to six days after becoming infected
with the bacteria, people would develop pneumonic plague. Once people
have the disease, the bacteria can spread to others who have close
contact with them. Because of the delay between being exposed to
the bacteria and becoming sick, people could travel over a large
area before becoming contagious and possibly infecting others. Controlling
the disease would then be more difficult. A bioweapon carrying Y.
pestis is possible because the bacterium occurs in nature and could
be isolated and grown in quantity in a laboratory. Even so, manufacturing
an effective weapon using Y. pestis would require advanced knowledge
pneumonic plague different from bubonic plague?
Yes. Both are caused by Yersinia pestis, but they are transmitted
differently and their symptoms differ. Pneumonic plague can be transmitted
from person to person; bubonic plague cannot. Pneumonic plague affects
the lungs and is transmitted when a person breathes in Y. pestis
particles in the air. Bubonic plague is transmitted through the
bite of an infected flea or exposure to infected material through
a break in the skin. Symptoms include swollen, tender lymph glands
called buboes. Buboes are not present in pneumonic plague. If bubonic
plague is not treated, however, the bacteria can spread through
the bloodstream and infect the lungs, causing a secondary case of
are the signs and symptoms of pneumonic plague?
Patients usually have fever, weakness, and rapidly developing pneumonia
with shortness of breath, chest pain, cough, and sometimes bloody
or watery sputum. Nausea, vomiting, and abdominal pain may also
occur. Without early treatment, pneumonic plague usually leads to
respiratory failure, shock, and rapid death.
do people become infected with pneumonic plague?
Pneumonic plague occurs when Yersinia pestis infects the lungs.
Transmission can take place if someone breathes in Y. pestis particles,
which could happen in an aerosol release during a bioterrorism attack.
Pneumonic plague is also transmitted by breathing in Y. pestis suspended
in respiratory droplets from a person (or animal) with pneumonic
plague. Respiratory droplets are spread most readily by coughing
or sneezing. Becoming infected in this way usually requires direct
and close (within 6 feet) contact with the ill person or animal.
Pneumonic plague may also occur if a person with bubonic or septicemic
plague is untreated and the bacteria spread to the lungs.
plague occur naturally?
Yes. The World Health Organization reports 1,000 to 3,000 cases
of plague worldwide every year. An average of 5 to 15 cases occur
each year in the western United States. These cases are usually
scattered and occur in rural to semi-rural areas. Most cases are
of the bubonic form of the disease. Naturally occurring pneumonic
plague is uncommon, although small outbreaks do occur. Both types
of plague are readily controlled by standard public health response
a person exposed to pneumonic plague avoid becoming sick?
Yes. People who have had close contact with an infected person can
greatly reduce the chance of becoming sick if they begin treatment
within 7 days of their exposure. Treatment consists of taking antibiotics
for at least 7 days.
quickly would someone get sick if exposed to plague bacteria through
Someone exposed to Yersinia pestis through the aireither from
an intentional aerosol release or from close and direct exposure
to someone with plague pneumoniawould become ill within 1
to 6 days.
pneumonic plague be treated?
Yes. To prevent a high risk of death, antibiotics should be given
within 24 hours of the first symptoms. Several types of antibiotics
are effective for curing the disease and for preventing it. Available
oral medications are a tetracycline (such as doxycycline) or a fluoroquinolone
(such as ciprofloxacin). For injection or intravenous use, streptomycin
or gentamicin antibiotics are used. Early in the response to a bioterrorism
attack, these drugs would be tested to determine which is most effective
against the particular weapon that was used.
enough medication be available in the event of a bioterrorism attack
involving pneumonic plague?
National and state public health officials have large supplies of
drugs needed in the event of a bioterrorism attack. These supplies
can be sent anywhere in the United States within 12 hours.
should someone do if they suspect they or others have been exposed
Get immediate medical attention: To prevent illness, a person who
has been exposed to pneumonic plague must receive antibiotic treatment
without delay. If an exposed person becomes ill, antibiotics must
be administered within 24 hours of their first symptoms to reduce
the risk of death. Notify authorities: Immediately notify local
or state health departments so they can begin to investigate and
control the problem right away. If bioterrorism is suspected, the
health departments will notify the CDC, FBI, and other appropriate
can someone reduce the risk of getting pneumonic plague from another
person or giving it to someone else?
People having direct and close contact with someone with pneumonic
plague should wear tightly fitting disposable surgical masks. Patients
with the disease should be isolated and medically supervised for
at least the first 48 hours of antibiotic treatment. People who
have been exposed to a contagious person can be protected from developing
plague by receiving prompt antibiotic treatment.
is plague diagnosed?
The first step is evaluation by a health worker. If the health worker
suspects pneumonic plague, samples of the patients blood,
sputum, or lymph node aspirate are sent to a laboratory for testing.
Once the laboratory receives the sample, preliminary results can
be ready in less than two hours. Confirmation will take longer,
usually 24 to 48 hours.
long can plague bacteria exist in the environment?
Yersinia pestis is easily destroyed by sunlight and drying. Even
so, when released into air, the bacterium will survive for up to
one hour, depending on conditions.
a vaccine available to prevent pneumonic plague?
Currently, no plague vaccine is available in the United States.
Research is in progress, but we are not likely to have vaccines
for several years or more.
information obtained from the CDC
(Center for Disease Control and Prevention)