The plague is caused by a bacterium called Yersinia pestis that can affect both animals and humans.
There have been many outbreaks of plague in human history, which have killed more than 200 million people around the world. Perhaps the most widely known plague is the Black Death of 14th century Europe. This was bubonic plague.
Outbreaks of plague are a rare occurrence today.
There is only one cause of plague, but there are three different types of illness that the infection can cause. They are bubonic, pneumonic and septicemic plague.
The incubation period for the plague is 1 to 10 days.
In all forms of plague, symptoms begin with flu-like complaints like fever, chills, muscle pain, weakness and headache, and can include nausea, vomiting, diarrhea and abdominal pain.
Today, several antibiotics can effectively treat plague.
There is a vaccine to protect people who are at high risk of exposure to the disease, such as military personnel under certain operational circumstances, or animal handlers in plague endemic areas. The vaccine requires multiple doses, frequent booster shots are needed and it can have significant side effects. The vaccine is not available for general public use.
A few cases of bubonic plague still occur occasionally. For instance, 10 to 15 cases occur every year in the southwestern United States. In 1996, two deaths were attributed to plague in the United States. These cases resulted from contact with infected wild animals.