What is black plague?
The black plague (bubonic plague) is the disease responsible for having wiped out a third of the European population in the 14th century. Caused by the bacterium Yersinia pestis , its main characteristics are the appearance of black spots and blisters on the skin.
During the Middle Ages, when medicine was scarce, the disease was able to kill in a few days or weeks. Due to its high transmission capacity, it is estimated that the disease exterminated between 25 and 75 million people.
Contrary to what many believe, the black plague has not been extinguished. The Yersinia pestis is a host for fleas in rats and other rodents, and is present in these animals today. There are recent cases in the United States (2015), as well as endemics in Madagascar, the Democratic Republic of Congo, and Peru.
It is estimated that the black plague originated in Asia and arrived in Europe through Sicilian ports (Italy) in 1347. On board the merchant ships, in addition to seriously ill corpses and sailors, there were contaminated black rats (Rattus rattus). This species of rodent found it easy to live with people and found in medieval Europe the perfect habitat; the poor hygiene of the time left the streets full of garbage and sewage.
The rapid spread of infected rats in urban centers has caused the disease to continue to expand, even if the seaways were blocked. Since the church was opposed to scientific and pharmacological advances, it was common to accuse witchcraft of any attempt to find a cure. For this reason, many did not understand the origin and mechanisms of the disease, and it soon became popular knowledge that plague was, in fact, a divine punishment for sinners. However, the disease also attacked feudal clerics and lords, which caused many to begin to question the system of the time.
Some experts point out that the epidemic has come to an end thanks to the natural cycle of the disease. Due to the death toll, it became more difficult to spread the disease. In addition, many cities were closed to foreigners and quarantined their patients , so as to prevent transmission to others.
After this period, there were recurrent outbreaks until the 19th century and even today the black plague has not been eradicated. Because it is a disease linked to fleas in rodents, it is believed that the only way to end it would be to end rodents, which makes the process unfeasible.
Still, measures are taken by authorities to prevent and treat animal fleas in urban locations or close to large populations. In addition, basic sanitation in most inhabited areas helps to keep the disease under control in most parts of the world.
The black plague is caused by the bacterium Yersinia pestis and can show different symptoms depending on the place where it is lodged.
Despite being known as bubonic plague, this is only one of the classifications of the disease. The classification is done according to the affected location.
Bubonic plague takes its name from the appearance of buboes (blisters) on the skin, usually in the armpits and groins. The bacteria attacks the lymphatic system, which causes the lymph glands to swell. As a result of the degeneration of the area, buboes become greenish and then open highly contagious wounds. This type also causes tissue death ( gangrene ).
When the bacteria reaches the circulatory system, it causes hemorrhage and failure in several organs, which forms the black spots that gave rise to the name of the disease.
Pneumonic plague, which can be acquired through breathing or septicemic, attacks the lungs and airways. In this case, the infected person has a cough with blood and highly infectious pus. If left untreated, pneumonic plague is deadly.
It is also common for the bacteria to start affecting the lymphatic system, go to the blood and end in the lungs, making it possible for the same individual to develop the three types of plague.
Experts believe that the bacterium, which was host to rodent fleas, began to attack the human population when the infected mice died and the fleas started jumping and biting people, especially in the groin and armpits. There were even fleas that lodged in the clothes of human beings while looking for another animal to feed on, since the rats also died quickly from the disease.
The transmission from humans to humans is done through buboes with open wounds, in addition to secretions such as saliva, coughing and sneezing, in the case of pneumonic plague.
The black rat, the rodent responsible for the epidemic, is rare today. However, as the true vector of the disease is the flea, several other rodents may be related to the transmission of the black plague. In the United States, there are reports of transmission in areas where there are prairie dogs, natural rodents from North America, as well as black ferrets and Canadian lynx, animals that are also susceptible to fleas.
The incubation period for the bacteria is about 7 days, except when transmission is via the respiratory tract. In that case, the incubation time is reduced to 2 or 3 days.
Black plague symptoms vary according to their classification, but some symptoms are universal for all types. Are they:
- High fever (up to 40 ºC);
- Vomiting with blood;
- Body pain;
The other symptoms can appear progressively, as the bacteria gets lodged in other parts of the body:
- In the case of bubonic plague , blue-green, painful blisters appear, which can grow to the size of an apple and open;
- Moving on to septicemic plague , there is also the appearance of large and small black spots, or small and large amounts;
- In pneumonic plague , there is a painful, bloody cough.
In order to diagnose the black plague, it is necessary to investigate the patient’s secretions. For this, the doctor collects samples of the liquids from buboes, pus, blood or saliva, and deposits them in a culture medium for microscopic and biochemical analysis.
Once the diagnosis is confirmed, treatment must be started immediately: the individual must be quarantined and the authorities must be notified.
Black plague is an internationally mandatory reporting disease. This means that, regardless of where the person is, health authorities must be notified and the investigation of the case is mandatory.
In the Medieval Era, it was common for patients to die between 2 and 7 days after the onset of symptoms. Nowadays, with the advance of medicine, the disease can be treated and the death rate from black plague is low.
Treatment is done with antibiotics and there is a need for isolation for about 6 days. People living with the patient should also be examined.
It is worth remembering that treatment should be started as soon as possible, because in more advanced stages, mortality is 15%, even with treatment.
The antibiotics that have been shown to be effective against Yersinia pestis are:
- Streptomycin ;
- Tetracycline ;
- Chloramphenicol ;
- Gentamicin ;
- Doxycycline .
NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.
The biggest complications of the black plague are its high infectivity and high mortality in the case of pneumonic plague.
If the patient who feels ill does not seek medical attention, he can let the disease evolve and die, in addition to contaminating those close to him and installing a new outbreak of the disease.
Although it has not looked like this for many centuries, it is possible to prevent the black plague. The measures include removal of rodents and isolation of infected people.
Some measures to be taken to prevent black plague are:
- Eliminate vector breeding sites such as rodents and fleas;
- Eradicate rodents from housing areas;
- Promote basic sanitation in peripheral neighborhoods and small towns;
- Use insect repellents;
- Inform the authorities in case of suspected black plague;
- Keep patients diagnosed or suspected of having black plague in quarantine.
In the United States, scientists are developing an oral vaccine for rodents that transmit the disease. Vaccines will be given to animals in busy parks and squares in order to reduce the incidence of plague outbreaks.
Because it is a historical disease, the black plague is rarely talked about today, but it still exists and people need to be prevented. It is of utmost importance that patients with the symptoms go to the doctor and are treated.
If you have or know someone who has symptoms like the Black Death, see your doctor as soon as possible.