Definition
The plague, formerly known as the “black death”, is a highly contagious infectious disease. There are two forms, bubonic plague and pneumonic plague. At around 90%, bubonic plague is the most common form of plague. The bacterium Yersinia pestis is responsible for the disease. The bubonic plague gets its name because of a characteristic symptom: there is a massive swelling of lymph nodes, the so-called peustbeulen (bubo) develop.
Bubonic plague
The pathogen causing bubonic plague is the bacterium Yersinia pestis. It is a gram-negative rod that belongs to the Yersinia family. Yersinia pestis is pleomorphic, which means that the bacterium can take different shapes, but in most cases it is oval.
The bacterium has no flagella and is immobile. Depending on the temperature, it forms a capsule, for example at 37°C, whereas no capsule is formed at cooler temperatures. Optimum temperatures for Yersinia are between 22 – 28°C.
In this temperature range the germs can multiply excellently. A special feature compared to other Yersiniae is that Yersiniae pestis are able to split urea. Yersiniae can survive for several months in saliva, faeces and pus.
They are often found in rodent dens or dried up in fleas or ticks. In the human body they also have various possibilities to multiply, both inside and outside the cell. Yersinia pestis are mainly transmitted by rodents like mice or rats.
Sometimes transmission occurs via parasites such as fleas or ticks, which ingest the pathogen when they feed on infected blood from a rat. The bubonic pest bacterium can be transmitted to humans by the parasites or rodents themselves. The most common way to transmit bubonic plague to humans is through flea bites.
These are the symptoms of bubonic plague
The first symptoms of bubonic plague usually appear two to six days after infection with the bacterium. These include: High fever Headache and aching limbs Chills Dizziness Disease and weakness Plague bumps In the area of the flea bite or infection site, an inflammation of the lymph vessels and lymph nodes occurs. The inflamed lymph nodes swell and form very painful bumps (plague bumps, bubbles).
The plague bumps can grow up to ten centimetres in size. If left untreated, the purulent plague bumps can lead to an ulcer. The plague bumps can even affect the blood vessels, which means that the bacteria enter the bloodstream.
If this happens, dangerous blood poisoning (sepsis) can develop. The pathogens can spread via the bloodstream from other organs and cause, for example, meningitis (pestmeningitis) or pneumonic plague in the lungs. The pathogens can cause skin bleeding all over the body and eventually kill the skin.
The fingers, toes and nose are usually affected. These symptoms explain the former name of the plague, “black death”. – High fever
- Headaches and aching limbs
- Chills
- Swindle
- Sickness and weakness
- Plague bumps
In the case of bubonic plague, the lungs are not primarily affected, unlike in the case of pneumonic plague.
However, if left untreated, bubonic plague can lead to a distribution of the bacteria in the blood. Then the Yersinia bacteria have the possibility to enter the lungs and cause pneumonic plague. Those affected cough up mucus and often suffer from shortness of breath. Coughing, blue-dyed lips, chills and fatigue are classic symptoms. Pronounced irritation of the throat can also cause vomiting.
