Talking about the plague inevitably brings to mind images of the Middle Ages with unsanitary conditions, countless rats and many deserted regions – after all, plague epidemics in the Middle Ages claimed over 20 million lives. Yet even today, plague bacteria are still fatal to 1000-3000 people each year, according to the WHO – the most recent being pneumonic plague, which broke out in northwest China.
Plague – what is it?
Plague is a bacterial disease that can take very different courses: In the worst case, it leads as pneumonic plague within a few days to death, the harmless variant leads to a mild flu-like reaction of the body with some fever and malaise (abortive form of plague). The plague bacteria can be transmitted to humans by bites from an infected flea or passed from person to person as a droplet infection, for example, when coughing.
How often do plague cases occur and where do they occur?
While Europe and Australia are considered plague-free, there are areas in Asia, Africa, and the Americas where regional plague outbreaks occur repeatedly. People who have a lot of direct contact with animals are particularly at risk: Hunters, veterinarians, but also shepherds or other people who live in cramped conditions with their animals. Particularly under poor hygienic conditions and in areas with a low standard of living, where many people – and also animals – live together in a confined space, infected fleas can infect people as well as rats and other rodents. Although conditions do not exist for the global spread of an infectious outbreak as in the Middle Ages, limited outbreaks of plague occur locally every year, sometimes resulting in several hundred or even thousands of deaths. The countries of Uganda, Congo, India, China were affected in recent years – but also in the southwestern United States there are now and then plague cases among cat owners whose animals prey on diseased prairie dogs.
Bubonic plague, pneumonic plague – what’s the difference?
The different forms of plague are actually caused by the same pathogen. In bubonic plague, on the one hand, painful lymph node swelling occurs locally at the site of the bite – the lymph nodes and tracts can form bulges up to 10 centimeters thick (hence the name). Second, the plague sufferer shows severe fever, flu symptoms, possibly unconsciousness. Bubonic plague often progresses to plague sepsis (sepsis=blood poisoning), in which the bacteria are dispersed with the blood to all organs, where they cause symptoms of illness. While bubonic plague is fatal in about half of all cases, plague sepsis is almost always fatal without targeted antibiotic treatment – after only 1 to 2 days. The clinical picture of pneumonic plague is similarly fatal. Here, too, up to 95% of all patients die within a few days – probably because direct contact of the pathogens with the lungs means that the body’s defense system cannot fight the infection until it is too late. Those affected cough, develop bloody sputum after a short time and lung failure with respiratory distress and blood backing up to the heart. Sometimes plague also begins with a sore throat, but similar to bubonic plague, it can degenerate into plague sepsis without treatment. Only abortive plague is a harmless variant, accompanied by mild cold symptoms. Once one has survived an attack of plague, there is lifelong immunity to this dangerous disease.
What can you do if you have a plague attack?
If plague is suspected, rapid administration of antibiotics such as streptomycin, tetracycline, or doxycycline is usually life-saving – reducing mortality to less than 20%. Detection of the pathogens in the blood confirms the diagnosis, but because of the dramatic course of the disease, treatment is usually started before a result is available. In addition, the destruction of infected fleas by means of insecticides and control of rodents in the affected area plays a special role. These measures prevent further individuals from becoming infected with the plague pathogens.
How can you prevent a plague outbreak?
Protective measures against flea bites in areas known for plague outbreaks, such as covering the legs and using modern insect repellents, are as natural for people staying in areas at risk as keeping rodents away.If you come into contact with the pathogens, it is advisable to take antibiotics for several days as a precaution. A vaccine against the plague pathogen exists, but it has limited efficacy and is poorly tolerated.
