What is a Plague?


Plague is a bacterial infection that is extremely dangerous and serious. This condition is transmitted to human beings by fleas. It is a highly contagious infection. Historically, plague was known as “Black Death” and was responsible for killing millions of people throughout Europe in the 14th century.

Yersinia pestis is the specific bacterium that causes plague. It is most prevalently found in Africa, the United States, and Asia among small rodents. There are numerous ways that the plague infection can be transmitted. The most common, of course, is through fleas. However, direct contact with infected animals can also cause plague transmission. When the infection gets into the lungs, it can also be transmitted through inhalation which means that human-to-human transmission is also possible.

The plague occurs in three forms. These three forms are bubonic, pneumonic, and septicemic plague. Bubonic is the more common type and involves infection in the lymphatic system. The septicemic plague occurs when the infection moves into the blood, and finally, pneumonic plague is in the respiratory system.

What are the Symptoms of a Plague?

There are numerous symptoms of plague that a person can experience. Swollen lymph nodes are a common symptom of plague, particularly bubonic plague. The swelling can be about the size and shape of an egg and may occur in lymph nodes in the neck, groin, or armpits. Other signs and symptoms of bubonic plague include fever, muscle aches, and fatigue (essentially, flu-like symptoms).

Septicemic plague can cause many different symptoms as well including chills, fever, and weakness. It could also cause vomiting, nausea, diarrhea, gangrene in the extremities, and bleeding under the skin or in the mouth, rectum, or nose. Pneumonic plague can cause difficulty breathing as well as a severe cough, possibly coughing up blood. Nausea, vomiting, fever, and headache can also be symptoms.

Plague Causes

Plague is a bacterial infection caused by the Yersinia pestis bacterium. It is carried by fleas and can infect mammals, including humans, through a bite. Rodents are a common carrier of plague, and common mice and rats that live in and near human settlements can be carriers. When a plague outbreak begins in rodents, the rodents begin to die from the disease. This causes the fleas to leave the dead rodents and to seek other mammals for blood. This is often when humans become infected with the bacteria.

In addition to transmission from the bites of infected fleas, humans and other mammals can also get it from other infected mammals. Coming into contact with the tissue or fluid of a contaminated person will put you at risk of becoming infected.

How is Plague Treated?

Plague is a treatable condition, though it still has a high mortality rate of between 30 and 60 percent even today. Early treatment with powerful prescription antibiotics in a hospital setting is necessary to overcome the plague. Supportive therapy and other treatments may also be necessary to deal with symptoms or side effects like gangrene or high fevers. People who come into contact with infected animals or people who have the pneumonic form of the plague may also benefit from preventive antibiotic treatment to prevent the infection from occurring.

Plague Prevention

Because rodents and the fleas they carry are the main transmission source of plague, avoiding them is the best way to prevent infection. In areas that have had many rodents die recently, there is a risk of plague being present. Avoid going into areas that contain dead rodents or traveling to areas where there has been a large rodent population die off. Keeping areas around the home and workplace free of high grass and trash can discourage rodents from residing in those areas. Cats that eat rodents can become infected, so taking sick cats for treatment right away can prevent the spread of the infection. Veterinarians and cat owners should take precautions when caring for a sick cat until testing has been done to rule out the risk of plague.

Use precautions when in close proximity to wild mammals such as rabbits. Use gloves and a mask when skinning or handling a mammal after hunting. When a person has become infected, avoid contact with them when possible. If you care for an infected person, wear a mask to prevent a cough spreading the bacteria through infectious droplets.

Last Reviewed:
October 08, 2016
Last Updated:
January 05, 2018