You may have heard of bubonic plague, or black plague, as it is popularly known, disease, caused by bacteria Yersinia pestis which affected mainly Europe in the 14th century and caused more than 50 million deaths on the continent, according to the World Health Organization (WHO). The origin of the infection, according to historians, occurred in Asia and was transmitted through port cities — places of commercial activities in several regions.
Anyone who thinks that this is the problem of the past is wrong. According to WHO, from 2010 to 2015, there were 3,248 cases reported worldwide, including 584 deaths. Fortunately, inflammation is now easily treated with antibiotics and precautionary measures to prevent contagion.
History of bubonic plague
The Black Death was the most devastating pandemic in history. It affected not only the entire region of Europe, but also Africa and Asia, causing the death of about 75 million people.
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The disease, according to historians, may have started in Asia, having passed from one continent to another when traveling on rat fleas that lived on 14th century merchant ships. Fleas were the intermediate hosts of bacteria, transmitted to humans by the bites of these insects. .
Incidentally, rat feces were also highly contaminating, since their contact with the skin was enough for the Black Death to infect a person. At that time, ports were the main places of contagion, mainly because many of them were large urban centers, with a lot of people circulating.
two forms of the disease
Altogether, there are two main clinical forms of plague infection: bubonic, rarely spread from human to human, which affects the body’s lymphatic system (which produces defense cells); and pneumonic, being the most severe form of the disease, which affects the respiratory system.
Transmission and lethality
The disease, considered serious by the WHO, has a fatality rate of 30% to 60% of the cases for the bubonic type, and always fatal for the pneumonic type, when left untreated. In the beginning, the main transmitting agents were rats and fleas, which proliferated easily both in cities and in smaller villages due to poor hygiene conditions (there was no water treatment, toilets or sewage).
For transmission to take place, people had to be bitten by infected fleas. Later, in the most critical phase of the European pandemic, dissemination occurred through unprotected contact with infectious body fluids or contaminated materials, in addition to the inhalation of droplets from sneezing or coughing — just like covid-19.
WHO works to prevent epidemics of the plague with surveillance and support for countries at risk such as the Democratic Republic of Congo, Peru and Madagascar — the latter being the region that registers cases almost every year.
Symptoms and Diagnosis
Authorities and health advise that people infected with bubonic plague often develop an acute febrile illness with other nonspecific systemic symptoms after an incubation period of one to seven days. There may be sudden onset of fever, chills, body and head aches and weakness, vomiting, and nausea.
In bubonic plague, transmission is caused by the bite of an infected flea. Thus, the bacteria travels through the lymphatic system to the nearest lymph node, where it replicates in the body. The gland becomes inflamed, swollen and painful, which is why it is called a “bubo”. In more advanced cases of infection, the inflamed lymph nodes can develop into open, pus-filled sores. If not treated early enough, the disease can progress and spread to the lungs.
Pneumonic plague, or pulmonary plague, is the most virulent form of the disease. Incubation can last up to 24 hours. Any infected person can transmit the disease through saliva droplets, coughing or sneezing to other humans. It has up to 100% lethality if not treated early. Despite this, recovery rates are high if detected and controlled early (24 hours after symptom onset).
In both cases, confirmation of the pathology requires laboratory tests. Best practice is to identify the Y. pestis from a pus sample from a bubo, blood or sputum. A bacterium-specific antigen can be detected by different techniques, one of which is a laboratory-validated rapid test.
Treatments and Vaccines
Treatment for either type of plague should be done using antibiotics recommended by specialists. As with the coronavirus, it is necessary to isolate the person to avoid passing the disease on to other individuals.
It is recommended that treatment be started as soon as the first symptoms begin — as there is a risk of the plague leading to death in less than 24 hours, with the greatest risk in the first 15 hours after symptoms start. Drug administration involves common antibiotics for enterobacteria (gram-negative rods). The World Health Organization does not recommend a vaccine for the disease.
Source: World Health Organization