Pneumonic plague

The plague is a highly contagious infectious disease caused by the bacteria Yersinia pestis.

Pneumonic plague is the most serious form of plague. It can occur:

• as a disease in its own right (primary pneumonic plague)
• as a complication of bubonic plague (secondary pneumonic plague)

The illness can be cured by rapid treatment with antibiotics.

How high is the risk of infection?

Thanks to improved levels of hygiene, plague is now a disease that occurs rarely in isolated cases, primarily in tropical and subtropical regions of the world.

During outbreaks of plague, the risk of travelers becoming infected can increase. There is no risk of contracting plague in Germany.

Pneumonic plague has an incubation period of between one and three days. The incubation period is the time between getting infection and the appearance of the first symptoms.

The illness typically starts suddenly with flu-like symptoms such as:

• fatigue
• headache
• vomiting
• fever
• chills

Additional symptoms include impaired consciousness and an enlarged liver and spleen.

The condition of an infected person deteriorates rapidly.

Respiratory problems occur, such as shortness of breath and breathing difficulties, painful coughing with sputum and chest pain. Respiratory failure and shock may occur.

In addition, other severe symptoms may occur as a result of sepsis. These include:

• circulatory collapse
• organ failure
• hemorrhages (bleeding)
• blood clotting disorder with the skin turning purple
• death of tissue in the extremities

Pneumonic plague is caused by bacteria called Yersinia pestis.

In primary pneumonic plague, the infectious agents are spread from person to person via the inhalation of infectious respiratory droplets that are released when talking or sneezing.

The secondary form of the disease occurs when the bacteria spread to the lungs of a person already suffering from bubonic plague.

In rare cases, the bacteria can also be spread by droplet infection.

A total of 3,248 cases of plague in all its forms worldwide were reported to the World Health Organization (WHO) between 2010 and 2015, with 584 infections proving fatal.

For detailed information about the regions where plague still occurs, see the article about bubonic plague.

Pneumonic plague is the most serious form of plague. It can be cured if treated quickly with antibiotics.

If a patient cannot be treated quickly enough, the illness proves fatal within 24 hours in most cases.

At present, no vaccine to prevent plague has been approved anywhere in the world. If someone comes into contact with a person with plague, an antibiotic can be administered prophylactically, i.e., on a preventive basis.

The Foreign Office (Auswärtiges Amt) has published a leaflet about plague. It is aimed at people working in and traveling to areas with plague infections.
To the leaflet

Initial indications of pneumonic plague are detected when doctors take a detailed medical history of the patient. The doctor asks the patient, for example:

• whether they have stayed in an at-risk area in recent days
• where there are currently any known plague infections in the at-risk area
• whether the patient has had any contact with people who have plague

If the doctor determines, when taking the patient history, that the patient has been exposed to an increased risk of infection and is showing typical symptoms, this corroborates the suspicion of an infection with pneumonic plague.

To enable an accurate diagnosis, samples of blood or saliva are sent for laboratory analysis using special methods to detect the pathogen directly.

Anyone who gets pneumonic plague must be taken to hospital as quickly as possible and treated with appropriate antibiotics.

Initially, and during treatment, it is important to ensure that the drugs used are actually effective against the bacteria. This is because a number of infectious agents have now developed resistance to antibiotics.