Download How do people become infected with plague? What is the basic

How do people become infected with plague?
People most commonly acquire plague when they are bitten by a flea that is infected with the plague
bacteria. People can also become infected from direct contact with infected tissues or fluids while
handling an animal that is sick with or that has died from plague. Finally, people can become
infected from inhaling respiratory droplets after close contact with cats and humans with pneumonic
plague.
What is the basic transmission cycle of plague?
Fleas become infected by feeding on rodents, such as chipmunks, prairie dogs, ground squirrels,
mice, and other mammals that are infected with the bacterium Yersinia pestis. Fleas transmit the
plague bacteria to humans and other mammals during a subsequent feeding. The plague bacteria
survive briefly (a few days) in the blood of rodents and for longer periods in the fleas. An illustration
of plague ecology in the United States is available.
Could one person get plague from another person?
Yes, when a person has plague pneumonia they may cough droplets containing the plague bacteria
into air. If these bacteria-containing droplets are breathed in by another person they can cause
pneumonic plague. Human-to-human transmission is rare and typically requires direct and close
contact with the person with pneumonic plague.
What is the incubation period for plague?
A person usually becomes ill with bubonic plague 2 to 6 days after being infected. Someone
exposed to Yersinia pestis through the air would become ill within 1 to 3 days.
When bubonic plague is left untreated, plague bacteria can invade the bloodstream. When plague
bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe
and often fatal condition called septicemic plague. Untreated bubonic plague can also progress into
an infection of the lungs, causing pneumonic plague. If plague patients are not given specific
antibiotic therapy, all forms of plague can progress rapidly to death.
How do people become infected with plague?
People most commonly acquire plague when they are bitten by a flea that is infected with the plague
bacteria. People can also become infected from direct contact with infected tissues or fluids while
handling an animal that is sick with or that has died from plague. Finally, people can become infected
from inhaling respiratory droplets after close contact with cats and humans with pneumonic plague.
What is the basic transmission cycle of plague?
Fleas become infected by feeding on rodents, such as chipmunks, prairie dogs, ground squirrels, mice,
and other mammals that are infected with the bacterium Yersinia pestis. Fleas transmit the plague
bacteria to humans and other mammals during a subsequent feeding. The plague bacteria survive briefly
(a few days) in the blood of rodents and for longer periods in the fleas. An illustration of plague ecology
in the United States is available.
Could one person get plague from another person?
Yes, when a person has plague pneumonia they may cough droplets containing the plague bacteria into
air. If these bacteria-containing droplets are breathed in by another person they can cause pneumonic
plague. Human-to-human transmission is rare and typically requires direct and close contact with the
person with pneumonic plague.
What is the incubation period for plague?
A person usually becomes ill with bubonic plague 2 to 6 days after being infected. Someone exposed
to Yersinia pestis through the air would become ill within 1 to 3 days.
When bubonic plague is left untreated, plague bacteria can invade the bloodstream. When plague
bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and
often fatal condition called septicemic plague. Untreated bubonic plague can also progress into an
infection of the lungs, causing pneumonic plague. If plague patients are not given specific antibiotic
therapy, all forms of plague can progress rapidly to death.
How is plague diagnosed?
The first step in plague diagnosis is evaluation by a health worker. If the health worker suspects plague,
samples of the patient’s 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.
Laboratory confirmation will take longer, usually 24 to 48 hours. Often, presumptive treatment with
antibiotics will start as soon as samples are taken, if plague is suspected.