(HealthDayNews) -- Plague may best be known as the disease that killed millions of people in Europe during the Middle Ages. But it's hardly a disease of the past.
Wild rodents in areas around the world are infected with plague, which is transmitted by bites from fleas infected with the bacteria yersinia pestis, according to the U.S. Centers for Disease Control and Prevention.
About 10 to 15 cases a year are reported in the United States (14 percent of them fatal) and the World Health Organization logs 1,000 to 3,000 cases globally.
A symptom of the most common form of human plague is a swollen and very tender lymph gland called a "bubo" (hence the term "bubonic plague").
Bubonic plague should be suspected when a person who may have been exposed to infected rodents, rabbits or fleas develops a swollen gland, fever, chills, headache and extreme exhaustion.
Antibiotics are effective against plague, but if an infected person is not treated quickly, the disease can progress rapidly to death.