What Is the Plague?
The plague is a serious bacterial infection
that can be deadly. Sometimes referred to as the "black plague," the
disease is caused by bacterial strain called Yersinia pestis. This bacteria is found on animals
throughout the world and is usually transmitted to humans through fleas.
The risk of plague is highest in areas that
have poor sanitation, overcrowding, and a large population of rodents.
In medieval times, the plague, or "black
death," was responsible for the deaths of millions of people in Europe.
Today, there are only 1,000 to 2,000 cases reported worldwide each year, with
the highest incidence in Africa.
Plague is a rapidly progressing disease that
can lead to death if untreated. You should call a doctor right away or go to an
emergency room for immediate medical attention.
Types of Plague
There are three basic forms of plague:
The most common form of plague is bubonic
plague. It’s usually contracted when an infected rodent or flea bites you. In
very rare cases, you can get the bacteria from material that has come into
contact with an infected person.
Bubonic plague infects your lymphatic system (the immune
system), causing inflammation. Untreated, it can move into the blood and cause
septicemic plague, or to the lungs, causing pneumonic plague.
When the bacteria enter the bloodstream
directly and multiply there, it’s known as septicemic plague. When they’re
left untreated, both bubonic and pneumonic plague can lead to septicemic
When the bacteria spread to the lungs, you
have pneumonic plague — the most lethal form of the disease. When someone with
pneumonic plague coughs, the bacteria from their lungs are expelled into the
air. Other people who breathe that air can also develop this highly contagious
form of plague, which can lead to an epidemic. Pneumonic plague is the only form of the plague that can
be transmitted from person to person.
How Plague Spreads
People usually get plague through the bite of
fleas that have previously fed on infected animals like mice, rats, rabbits,
squirrels, chipmunks, and prairie dogs. It can also be spread through direct
contact with an infected person or animal, or by eating an infected animal. Plague
can also spread through scratches or bites of infected domestic cats.
It’s rare for bubonic plague or septicemic
plague to spread from one human to another.
Signs and Symptoms of the
with the plague will usually develop flu-like symptoms two to six days after
infection. There are other symptoms that can distinguish between the three
forms of the plague:
Bubonic Plague Symptoms
Symptoms of bubonic plague generally appear
within two to six days. They include:
You may also experience painful, swollen
lymph glands, called buboes.
These typically appear in the groin, armpits, neck, or site of the insect bite
or scratch. The buboes are what give bubonic plague its name.
Pneumonic Plague Symptoms
Pneumonic plague symptoms may appear as
quickly as one day after exposure to the bacteria. These symptoms include:
sputum (saliva and mucus or pus from the lungs)
Septicemic Plague Symptoms
Septicemic plague symptoms usually start
within two to seven days after exposure, but septicemic plague can lead to death before symptoms even appear.
Symptoms can include:
(blood may not be able to clot)
turning black (gangrene)
What to Do if You Think You
Might Have the Plague
Plague is a
life-threatening disease. If you have been exposed to rodents or fleas, or if you have
visited a region where plague is known to occur, and you develop symptoms
of plague, contact your doctor
Be prepared to tell your doctor about any recent
travel locations and dates. Make a list of all over-the-counter medications,
supplements, and prescription drugs you take. Make a list of people who have
had close contact with you. You should tell your doctor about all your symptoms
and when they first appeared.
When you visit the doctor, emergency room, or
anywhere else where others are present, wear a surgical mask to prevent
spreading the disease.
How the Plague Is Diagnosed
If your doctor suspects you may have plague, they
will check for the presence of the bacteria in your body.
A blood test can reveal if you have
septicemic plague. To check for bubonic plague, your doctor will use a needle
to take a sample of the fluid in your swollen lymph nodes. To check for pneumonic
plague, fluid will be extracted from your airways by a tube that is inserted
down your nose or mouth and down your throat. This is called an endoscopy.
The samples will be sent to a laboratory for
analysis. Preliminary results may be ready in just two hours, but confirmatory
testing takes 24 to 48 hours. Often, if the plague is suspected, your doctor
will begin treatment with antibiotics before the diagnosis is confirmed. This
is because the plague progresses rapidly and being treated early can make a big
difference in your recovery.
Treatment for the Plague
The plague is a life-threatening condition
that requires urgent care. If caught and treated early, it is a treatable
disease using antibiotics that are commonly available.
With no treatment, bubonic plague can
multiply in the bloodstream, causing septicemic plague, or in the lungs,
causing pneumonic plague. Death can occur within 24 hours after the appearance
of the first symptom.
Treatment usually involves strong and effective
antibiotics, intravenous fluids, oxygen, and sometimes breathing support.
People with pneumonic plague must be isolated from other patients. Medical
personnel and caregivers must take strict precautions to avoid getting or
Anyone who has come into contact with people
with pneumonic plague should also be monitored and they are usually given
antibiotics as a preventive measure.
Outlook for Plague Patients
Plague can lead to gangrene if blood vessels
in your fingers and toes disrupt blood flow and cause death to tissue. In rare
cases, plague can cause meningitis,
an inflammation of membranes that surround your spinal cord and brain. Getting
treatment as quickly as possible is crucial to stop the plague from becoming
How to Prevent Plague
Keeping the rodent population under control in
your home, workplace, and recreation areas can greatly reduce your risk of
getting the bacteria that causes plague. Keep your home free from stacks of cluttered
firewood or piles of rock, brush, or other debris that could attract rodents.
Protect your pets from fleas using flea
control products. Pets that roam freely outdoors may be more likely to come
into contact with plague-infected fleas or animals. If you live in an area
where the plague is known to occur, the CDC recommends not allowing pets that
roam freely outside to sleep in your bed. If your pet becomes sick, seek care
from a veterinarian right away.
Use insect repellent products or natural
insect repellants like citronella when spending time outdoors.
If you have been exposed to fleas during a
plague outbreak, visit your doctor immediately so your concerns can be
There is currently no commercially available
vaccine against plague in the United States.
Plague Around the World
Epidemics of plague killed millions of people
(about one-quarter of the population) in Europe during the Middle Ages. It came
to be known as the "black death."
Today the risk of developing plague is quite
low, with only 1,000 to 2,000 cases reported to the World Health
Organization (WHO) each year. In 2013, there were only 783 cases reported worldwide, with 126
deaths. Outbreaks are generally associated with infested rats and fleas in the
home. Crowded living conditions and bad sanitation also increase the risk of
Today, most human cases of the plague occur
in Africa. The countries in which the plague is most common are Madagascar, the
Democratic Republic of Congo, and Peru.
The plague is rare in the United States, but the
disease is still sometimes found in the rural southwest, and in particular
Arizona, Colorado, and New Mexico. The last epidemic of plague in the United
States occurred in 1924 to 1925, in Los Angeles. There are an average of seven cases reported each year in the United States,
most of which have been in the form of the bubonic plague. There has not been a
case of person-to-person transmission of the plague in the United States since