Bubonic plague

Bubonic plague is a serious disease caused by the bacterium Yersinia pestis. It can start one to seven days after a person comes into contact with the bacteria. Common signs include fever, headaches, vomiting, and swollen and painful lymph nodes. Sometimes, the skin can become dark and damaged.

There are three main types of plague, and bubonic plague is the most common. It is usually spread by infected fleas that live on small animals like rabbits and hares. The bacteria enter through the skin and cause the lymph nodes to swell. Doctors can diagnose the disease by testing blood, sputum, or fluid from swollen areas.

Treatment with certain antibiotics can greatly reduce the chances of getting very sick. Without treatment, many people who get the disease may become very ill or pass away. However, with proper care, most people recover. The plague has been around for hundreds of years and may have caused big diseases in history, such as the Black Death, which affected many parts of the world.

Cause

See also: Disease vector

The bubonic plague is an infection of the lymphatic system. It usually starts when a flea, like the Oriental rat flea Xenopsylla cheopis, bites a person. These fleas live on rats and sometimes bite humans when rat numbers drop. The bacteria from the flea get into the body and quickly move to the lymph nodes, where they grow and cause illness.

Signs and symptoms

After being transmitted via the bite of an infected flea, the Y. pestis bacteria become localized in an inflamed lymph node, where they begin to multiply. Infected lymph nodes swell and become painful. Symptoms appear two to seven days after getting bitten and they include:

• Chills
• General ill feeling (malaise)
• High fever >39 °C (102.2 °F)
• Muscle cramps
• Seizures
• Smooth, painful lymph gland swelling called a bubo, commonly found in the groin, but may occur in the armpits or neck, most often near the site of the initial infection (bite or scratch)
• Pain may occur in the area before the swelling appears
• Gangrene of the extremities such as toes, fingers, lips, and tip of the nose.

The best-known symptom of bubonic plague is one or more infected, enlarged, and painful lymph nodes, known as buboes. These buboes will grow and become more painful over time. Additional symptoms include extreme fatigue, gastrointestinal problems, heavy breathing, coughing, and aching limbs.

Diagnosis

To find out if someone has plague, doctors need to test samples in a lab. The best way is to grow the bacteria from a small piece of the patient’s fluid. They can also look at special blood samples taken early and later in the sickness. Quick tests have been made to help doctors in the field spot the bacteria fast.

Doctors can take samples from swollen lymph nodes, blood, and lungs to check for the bacteria. Swollen lymph nodes are a key sign of bubonic plague, and a tiny amount of fluid can be taken from them. Blood tests look for bacteria in the blood, and lung tests and X-rays help find problems in the lungs.

Prevention

Bubonic plague outbreaks are stopped by controlling pests and using good cleaning methods. The disease spreads through fleas on rats, which can jump to humans. Keeping rat numbers low in crowded city areas is very important to stop outbreaks. For example, a machine called the Sulfurozador was used to spread sulphur dioxide to get rid of pests in Buenos Aires, Argentina, long ago. Things like chemoprophylaxis, sanitation, and vector control helped manage a later outbreak in Oran in 2003. In big European cities, one way to prevent the plague was to stop people and infected rats from mixing by keeping everyone apart for a while.

Treatment

Several types of antibiotic can help treat bubonic plague. These include aminoglycosides like streptomycin and gentamicin, tetracyclines such as doxycycline, and the fluoroquinolone ciprofloxacin. When treated, the chance of death from bubonic plague is much lower, around 1–15%, compared to 40–60% if not treated.

If someone thinks they might have the plague, they should get antibiotics right away, within 24 hours of feeling sick, to stay safe. Other ways to help include giving oxygen, fluids through a special tube, and support for breathing. People who have been close to someone with a lung form of plague are also given antibiotics to prevent getting sick. Using streptomycin quickly, within 12 hours of infection, has been very effective in fighting bubonic plague.

Epidemiology

Main article: Epidemiology of plague

Between 2010 and 2015, there were over 3,000 cases of a serious illness called plague around the world, with many people becoming very sick. Countries like the Democratic Republic of the Congo, Madagascar, and Peru had the most cases.

In the United States, from 1900 to 2015, there were about 1,000 cases. These cases mostly happened in places like California, Arizona, and New Mexico. In 2015, a few people in Yosemite National Park got sick with the illness.

In 2017, Madagascar had a big increase in cases, more than any recent time in that country. In 2018, a child in Idaho got the illness for the first time in almost 30 years.

In 2019, two people in Mongolia got sick while hunting animals, and in China, a few more people were treated for the illness. In 2020, there were more cases reported in China and Mongolia.

History

Yersinia pestis has been found in very old remains from around 3800 years ago. Scientists have used special methods to follow the movement of this germ across Asia and Europe between 2800 and 5000 years ago. Some people think this germ may have caused big changes in ancient societies.

First pandemic

Main articles: First plague pandemic and Plague of Justinian

The first known big outbreak happened in the years 541 to 549 AD and was called the Plague of Justinian. It started in the Sasanian Empire and quickly spread to the Eastern Roman Empire. Many people got very sick, and millions died over many years. The plague moved from city to city along trade routes.

Second pandemic

Main articles: Black Death and Second plague pandemic

In the Late Middle Ages, Europe faced its worst disease ever, known as the Black Death. From 1346 to 1352, about one-third of all people in Europe got sick and died. The disease started in Central Asia and spread to Europe through trade routes. Fleas on rats carried the germ from place to place.

Third pandemic

Main article: Third plague pandemic

The plague appeared again in the mid-1800s, starting in Yunnan, a part of China. It spread to many cities around the world through shipping. In 1894, a big outbreak happened in Hong Kong, and the germ was finally identified by a scientist named Alexandre Yersin. The disease continued to appear in small groups but became less common over time.

Society and culture

See also: Black Death in medieval culture

The huge loss of life and changes in society from plague outbreaks have made the topic important in many stories and histories. The Black Death is often talked about in old writings, with works by Chaucer, Boccaccio, and Petrarch being well-known examples. The Decameron, written by Boccaccio, tells a story about people who left Florence to escape the Black Death.

Later, books and movies like Albert Camus’s The Plague and Ingmar Bergman’s The Seventh Seal have used the idea of plague to talk about big questions about life and death.

Continued research

Scientists have done a lot of work to learn about where the plague came from and how it spread. They have found clues in old teeth and bones, helping them understand more about the disease and its effects on people long ago. Studies show that the plague might have hidden in rat populations for years, waiting to spread again.