Plague occurs after a bite from an infected flea.   It can spread to humans when infected fleas from ground squirrels, prairie dogs, and other wild rodents bite a human. 

Cats and dogs also get plague or carry the infected fleas home to their owners.

What is the basic transmission cycle? Fleas become infected by feeding on rodents, such as the chipmunks, prairie dogs, ground squirrels, mice, and other mammals that are infected with the bacteria Yersinia pestis.

Fleas transmit the plague bacteria to humans and other mammals during the feeding process. The plague bacteria are maintained in the blood systems of rodents.  top

What are the signs and symptoms of plague?  The typical sign of the most common form of human plague is a swollen and very tender lymph gland, accompanied by pain. The swollen gland is called a "bubo" (hence the term "bubonic plague"). 

Bubonic plague should be suspected when a person develops a swollen gland, fever, chills, headache, and extreme exhaustion, and has a history of possible exposure to infected rodents, rabbits, or fleas. top

What is the incubation period for plague? A person usually becomes ill with bubonic plague 2 to 6 days after being infected.

When bubonic plague is left untreated, plague bacteria invade the bloodstream. When plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition.

Infection of the lungs with the plague bacterium causes the pneumonic form of plague, a severe respiratory illness.

The infected person may experience high fever, chills, cough, and breathing difficulty, and expel bloody sputum. If plague patients are not given specific antibiotic therapy, the disease can progress rapidly to death.top

Is plague treatable?  Yes. Treatment with antibiotics is effective during the early stages of disease.

If diagnosis and appropriate treatment are delayed, life-threatening complications may follow.

A doctor or hospital emergency room should be consulted as soon as symptoms appear and a history of exposure to potentially infected animals is very important in evaluating the risk from plague. top

You can prevent the spread of plague:

Follow these simple precautions to reduce the likelihood of being bitten by infected fleas:

• AVOID FLEAS! Protect pets with a flea treatment, and keep pets on a leash and out of wild rodent habitats.
• STAY OUT of areas that wild rodents inhabit. If you enter areas with wild rodents, wear insect repellent and tuck pants cuffs into socks to prevent flea bites.
• AVOID all contact with wild rodents, including squirrels; do not feed or handle them.
• DO NOT TOUCH sick or dead animals.
• PREVENT rodent infestations around your house: clear plants and materials away from outside walls, reduce access to food items, and set traps.
• TREAT known rodent sites around your home with flea powder or a suitable insecticide.
• SEE A PHYSICIAN if you become ill with a high fever and/or a swollen lymph node. Plague is a treatable illness.

SEE A VETERINARIAN if your pet becomes ill with a high fever and/or an abscess (open sore). Pets with plague can transmit the illness to humans. top