The plague, or “Black Death,” wiped out millions of Europeans in the Middle Ages — but if you think it’s long gone, think again. It still exits, and it's on the rise this year in the United States. Would you recognize the symptoms?

woman with fever (Photo: Catalin Petolea/Shutterstock)

In April through August — a five-month period — 12 cases of human plague were reported to the Centers for Disease Control and Prevention (CDC), affecting residents of Arizona, California, Colorado, Georgia, New Mexico, Oregon and Utah. Two cases have been linked to visits to (or near) Yosemite National Park. Four patients have died. By contrast, from 2001 to 2012, the annual number of plague cases in the U.S. ranged from 1 to 17, the CDC says.

Related: Valley Fever: The West’s “Silent Epidemic”

Your chances of getting the plague are admittedly slim, but it’s worth taking some simple precautions and learning the symptoms. Modern antibiotics can treat the disease successfully, but prompt medical attention is critical to avoid complications and even death.

How people catch plague

Plague is caused by the bacterium Yersinia pestis, which lives in rats and sometimes other rodents, including squirrels, prairie dogs, chipmunks, mice and voles, as well as rabbits. It’s spread by infected fleas. You can contract plague when you are bitten by an infected flea, when you touch or skin infected animals or when you inhale droplets from the cough of an infected person or animal (especially cats, according to the CDC).

Plague is most common in the late spring to early fall, but it can infect people at any time of year. It's more common in the western U.S.

Minimize your risk

To minimize your risk of infection:

  • Do not pick up or touch any dead animals. If you must handle them, wear gloves.
  • Don’t feed squirrels or chipmunks.
  • Don't allow your household pets sleep in bed with you, since they could carry infected fleas or be infected themselves. Be sure to treat your animals for flea protection.
  • When you’re outside, prevent flea bites by using a DEET-based repellent on your clothes and skin. Wear long pants whenever you can.
  • Store your pet food where rodents can't get to the container.
  • If your pets are sick, get them to the vet as soon as possible.

Related:  Bug Spray Do’s and Don’ts

Symptoms of plague

You’ll probably feel suddenly feverish and exhausted if you develop plague. Other symptoms vary depending on which of the three main forms you contract.

Bubonic plague is the most common form. You may first notice a painful, swollen lymph node in your neck, armpit or groin. You may feel exhausted, run a fever and notice chills and a headache. These symptoms usually begin one to six days after infection. About 85 percent of all plague cases are bubonic plague.

Septicemic plague happens when the plague bacteria multiply in your blood. You may have a high fever, be exhausted and lightheaded and feel abdominal pain. The skin on your fingers, nose or toes may turn black and die. Shock and organ failure can occur.

Pneumonic plague is the least common. It can develop when you inhale droplets containing the bacteria or when you have bubonic or septicemic plague and the bacteria travel to your lungs. You may have fever, headache and weakness and develop pneumonia.

If you suspect plague, get checked out immediately by a doctor. Plague can be treated successfully with antibiotics if it’s caught early enough. If untreated, the death rate from plague can be 66 to 93 percent. When treated, it is still potentially fatal, but the death rate drops to about 16 percent.  

Related: What to Do If Your Pet Has Fleas

Kathleen Doheny is a Los Angeles journalist specializing in health, behavior and fitness topics.