Bubonic plague is a form of the plague which manifests in the form of swollen lymph nodes, known as “buboes” historically. Many people think of the plague as a historical disease, but in fact there are up to 3,000 cases worldwide annually, according to the World Health Organization. Fortunately, this form of the plague is very easy to treat, especially if it is addressed early, and in areas where the plague is endemic, such as the American Southwest, doctors are usually adept at recognizing the early signs.
Like other forms of the plague, bubonic plague is caused by the Yersinia pestis bacteria. In the bubonic form of the plague, the bacteria are introduced into the body through the skin, via a bite from a flea which carries the disease from an infected rodent. Once the patient has been exposed, the bacteria start to spread through the body, causing the lymph nodes to swell and eventually rupturing the blood vessels, causing large bruises and black spots to appear under the skin.
The bubonic plague has played an important role in human history, ever since cases were first recorded around the sixth century. Before the advent of antibiotics, the plague was devastating, and it could stop armies in their tracks, empty cities, and decimate communities. During the medieval era in particular, bubonic plague was a major public health issue, and the “black death” swept across Europe in multiple waves which some historians estimate may have wiped out up to half of the population.
Most cases of this contagious disease are the result of exposure to infected rodents such as rats and prairie dogs. In the medieval era, people also passed the plague from person to person, because many homes were infested with fleas which could leap from patients to healthy people. Today, person to person transmission is much less common, thanks to better hygiene.
In addition to developing the distinctive buboes, patients also experience fevers, chills, nausea, headaches, and vomiting. Classically, the tongue also becomes white and thickened with advanced plague infection. The bacteria responsible for the disease are very susceptible to antibiotics, and most people infected in the modern day experience no long term ill effects as a result of their plague infections. When cases of bubonic plague are documented, public health officials usually track down the source of the exposure, and steps may be taken to protect the community, such as eradicating an infected rodent population.