The plague is a severe, acute infectious disease transmitted from fleas to humans. Here you're informed of everything important!


The pest is a serious, acute infectious disease that can be fatal. Trigger of the typical plague is the bacterium Yersinia pestis. The plague is transmitted via fleas to humans. Especially in countries with low standards of hygiene, there are always small plague outbreaks. Here you can read everything important about the plague today and the Middle Ages.

ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in doctor's letters or on incapacity certificates. A20

Product Overview


  • description

  • symptoms

  • bubonic plague

  • Causes and risk factors

  • Examinations and diagnosis

  • treatment

  • Disease course and prognosis

Pest: Description

The plague is one of the major infectious diseases of the Middle Ages, triggered by the bacterium Yersinia pestis. The plague is actually not a human disease, but an animal disease, also called zoonosis. The bacteria live in rodents, especially in rats, and are transmitted from rat flea to humans. In rare cases, direct infection can also occur on diseased rodents. Especially with the lung plague is also possible to infect with other people.

One is particularly at risk in areas where people live closely together under poor hygienic conditions. Under these circumstances, the plague continues to occur again and again in small epidemics. In Europe, however, it has not played a role for some time. Great epidemics and pandemics that claimed millions of victims in the Middle Ages no longer exist today.

Quarantine disease plague

In addition to cholera, smallpox and yellow fever, the plague is one of the four quarantine diseases as defined by the World Health Organization (WHO). Ebola is also counted among the quarantine diseases in Germany and many other countries.

These are diseases that have a particularly threatening course of disease and can infect many people. For Pest and Co. there are special guidelines to avoid a worldwide outbreak:

  • Diseased persons must be screened in special infection departments.
  • A deprivation of liberty may be ordered, even without judicial hearing or disposition.
  • The right to physical integrity, as well as some other fundamental rights can be overridden.
  • If a country takes such action, it must immediately report it to the WHO.

Worldwide, WHO registers about 1,000 to 2,000 plague cases each year. However, this figure is very inaccurate, with more than 80 percent of the infections taking place in Africa and not all being reported to the WHO.

Plague in the Middle Ages

Particularly devastating was the plague in the Middle Ages. Everything important to read in the post: Pest in the Middle Ages.

Plague: symptoms

The incubation period between the infection and the first symptoms varies greatly with the plague and lasts between one and seven days. Basically, there are various forms of plague in humans with some different pest symptoms.

bubonic plague

Especially well known is the bubonic plague. It is characterized by a typical blistering on the skin. Read more about the signs of bubonic plague in the article bubonic plague.


In the lung plague, the bacterium Y. pestis affects the lungs. Pulmonary plague symptoms develop a few hours after the plague virus reaches the lungs. First, the patient suffers only from fever and general weakness, but it comes on the second day to bloody cough and chest pain. The pulse gets faster and the patient gets breathless. Vomiting and abdominal pain also occur due to a strong coughing sensation. Those affected are highly contagious throughout the duration of the disease.


Plague sepsis is a complication of bumpy or pulmonary plague: in approximately ten percent of all cases, the plague bacteria enter the bloodstream and cause blood poisoning (pest sepsis). Possible symptoms: falling blood pressure, high fever, confusion or lethargy and digestive problems.

The consequences of the plague sepsis are manifold. Particularly dreaded are the coagulation disorders, associated with bleeding inside the body. Din vascular occlusion can endanger the blood supply of organs, and thus harm the patient severely. Untreated, the plague septicemia leads to a circulatory failure. If blood flow in the body can not be maintained, the patient dies of pest sepsis.

Pest: causes and risk factors

That the plague is triggered by the bacterium Y. pestis, has only been known for over 100 years. That was also one of the reasons why the plague was able to cause so much damage before: they did not know how to protect themselves, nor what treatment was appropriate.

In addition, Y.Pestis have such a devastating effect in the history of mankind, because with a mechanism efficiently trick the human immune system: After it is attacked by the white blood cells and eaten, it simply divides further, and thus also proliferates within the defense cells. Normally, bacteria die in this process, and an infection can be efficiently eliminated by the body.

Infected fleas

Today it is known that the bacterium mainly occurs in rodents, and is transmitted from fleas to humans. Poor hygiene standards, domestic rats, and living in slums are therefore potential risk factors. The care of plague sufferers should only take place under strict safety precautions in order not to unnecessarily endanger the nursing staff.

Contagion via breathing air

If the pathogens migrate from an infected person from the blood and lymph into the lungs, so-called secondary pulmonary plague develops. Concerned, in turn, can directly infect other people, via the breath. When coughing or sneezing a person suffering from pulmonary plague, the bacteria in small droplets in the air and can be inhaled by a healthy person. The resulting disease is called primary lung plague.

Risk factor travel

Today, the plague is no longer found in many countries around the world. A big risk factor is therefore the place of residence, or the country in which one travels. The plague still occurs in the following regions:

  • Africa (especially Central South and East Africa)
  • Asia (especially Russia, Middle East, China, Southeast Asia, Myanmar)
  • Central and South America (tropical and subtropical regions)
  • North America (southwestern US)

On the other hand, the risk is higher when traveling to less civilized areas where western hygiene standards can not be met. This is especially true in crisis areas or regions of natural disasters. If you stay in such areas, you should take some protective measures to protect yourself from the plague:

Do not offer rodents such as rats habitat in the immediate vicinity of the house.

  1. Treat pets as regularly as possible against fleas to prevent transmission to humans.
  2. DEET-containing mosquito sprays reduce the transmission of fleas to humans.
  3. Clothes that have had contact with rodents or sick people should not be worn.
  4. Avoid contact with sick or dead rodents.

Pest: examinations and diagnosis

In order to successfully detect the infection, the doctor must receive important information about the history of the disease in order to express the suspicion "plague". For example, he asks the following questions:

  • Have you recently traveled to a high risk country?
  • Did you have contact with rodents?
  • Did you notice insect bites?
  • Are you a laboratory worker at security level S3?

Physical examination

Subsequently, the doctor will physically examine the patient and look for example for swollen, painful lymph nodes, or even the typical bumps of bubonic plague.

In bubonic plague, only the local lymph nodes are affected first. Only after a few days, the disease continues to spread, and it can swell other lymph nodes. At an early stage it is therefore important to palpate the lymph nodes in different parts of the body and compare them with the opposite side.

Suspected lung plague is often characterized by less obvious symptoms such as cough, bloody sputum, and fever. In a lung plague, the plague bacterium is detectable in the sputum and saliva. The patient must already be severely isolated in case of suspected plague, so as not to unnecessarily endanger other people.

Laboratory evidence of the plague pathogen

To finally prove the plague, the plague bacterium is detected in the body. For this purpose, the doctor stings into a swollen lymph node and sends the sample to the laboratory.

If there is a suspected plague, very strict safety regulations apply. Only special laboratories with a high safety level (S3) may cultivate such bacteria. Since there is rarely a suspicion of plague, there are very few centers that are familiar with the evidence. One of the most important reference addresses is the Max von Pettenkofer Institute for Medical Microbiology of the LMU in Munich.

In addition to the direct pathogen detection, a blood test is important. On the basis of this test, it can be determined whether the bacterium is already in the blood (see also: Pestsepsis), and whether the immune system has already recognized the pathogen.

Pest: treatment

If the diagnosis plague is made, the patient is isolated. The room may only be entered under strict safety and protection regulations. Every unnecessary contact is avoided.

The plague is being treated with antibiotics nowadays. The drugs of choice are antibiotics such as streptomycin, gentamycin, tetracyclines such as doxycycline or chloramphenicol. It is important to have a quick diagnosis and early start of therapy to prevent complications such as plague sepsis.

In Madagascar, it has been observed that some antibiotics are no longer effective against the plague pathogen. This means that the bacteria have become resistant to these drugs. In this case, other antibiotics must be avoided.

To ensure that no one is infected with the infected patient, a patient with bubonic plague stays in an isolation room at least two days after starting antibiotic therapy. With a lung plague, it is at least four days after the start of antibiotic therapy.

Pest: Disease course and prognosis

If the bubonic plague is recognized in good time and treated consistently, the prognosis is good and almost all patients survive. If left untreated, 50 to 60 percent of those affected die. In the case of pneumonic plague and plague sepsis, almost all patients die of the plague if not treated quickly.

If the doctor makes the diagnosis in good time and starts antibiotic therapy, the mortality rate of the pneumonic plague and plague sepsis drops to about 15 percent. After surviving pest infection is largely immune to re-infection. However, it can sometimes come to a renewed illness.

There is a vaccine against the plague, which protects against the pathogen for only six months. Their efficiency has never been properly investigated. In Germany, there is no vaccination recommendation for the pest vaccine, since there is virtually no risk of infection. In the US, the pest vaccine is no longer used. New pest vaccines are in development, but have little relevance to Germany, as well as the pest even.

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