Plague bacillus bacteria: description, features and treatment of infection

There are various diseases in the world. But not one among them caused such horror and fear as the plague. This disease from ancient times did not know mercy. She claimed millions of lives, regardless of gender, age, or human well-being. Today, the disease no longer brings a huge number of deaths and grief. Thanks to the wonders of modern medicine, the plague has been turned into a less dangerous disease. However, it was not possible to completely eradicate the disease. The plague bacillus (Yersinia pestis), which causes the disease, continues to exist in this world and affects people.

Pathogen ancestor

Several years ago, microbiologists began to conduct research in order to study the evolution of pathogens. The plague wand was also studied. Among the existing microorganisms, a genetically similar bacterium, Yersinia pseudotuberculosis, was found. It is the causative agent of pseudotuberculosis.

Studies have allowed scientists to draw one conclusion. When life began to emerge on the planet, there was no plague stick. About 15–20 thousand years ago, the causative agent of pseudotuberculosis existed. He was a consumer of dead organics, breeding in animal excrement around corpses buried in the ground. Some factors provoked its further evolution. Part of the causative agents of pseudotuberculosis transformed into a plague stick.

How did evolution happen?

In those places where the primary foci of plague arose, the causative agent of pseudotuberculosis lived in the burrows of marmots (tarbagans). Certain factors contributed to its evolution, that is, the appearance of the plague stick.

1. The presence of fleas on animals. When groundhogs hibernated, insects accumulated on their faces. This was the most favorable place for their habitation. In winter, in the hole there was always a negative temperature. Only the mouth and nose of the animals were a source of warm air.
2. The presence on the mucous membrane of the oral cavity of marmots of bleeding wounds. Flea-dwelling snouts have bitten animals throughout the winter. In places of prokusy bleeding occurred. They did not stop because the animals were sleeping and their body temperature was low. In active marmots, bleeding would stop quickly.
3. The presence of Yersinia pseudotuberculosis on the legs of animals. Tarbagany before hibernation buried entrances to burrows with their own droppings. Because of this, pseudotuberculosis pathogens accumulated on their paws.

When the animals hibernated, they covered their faces with their paws. Pathogens of pseudotuberculosis fell into the wounds formed due to flea bites. In the circulatory system of active animals, this bacterium could not survive. Macrophages would kill her instantly. But in the sleeping groundhogs for Yersinia pseudotuberculosis there were no threats. The blood was cooled to favorable temperatures, and the immune system was “disabled”. Of course, temperature rises arose, but rare and short. They created ideal conditions for the natural selection of pathogen forms. All these processes ultimately led to the emergence of the plague stick.

Past Disease Epidemics

Modern scientists cannot say whether the plague has always haunted people. According to the surviving information, only three major epidemics are known. The first of them - the so-called Justinian plague - began around the 540s in Egypt. For several decades, the plague wand devastated almost all the states of the Mediterranean.

The second epidemic, called "black death", was recorded in the middle of the XIV century. A plague wand has spread from a natural focus in the Gobi Desert due to dramatic climate change. The causative agent subsequently penetrated into Asia, Europe, and North Africa. The island of Greenland was also affected. The second epidemic has had a dramatic effect on population. A plague wand claimed about 60 million lives.

The third plague epidemic began at the end of the 19th century. An outbreak has been reported in China. For 6 months in this country 174 thousand people died. The next outbreak occurred in India. Between 1896 and 1918, 12.5 million people died from the causative agent of a dangerous disease.

Plague and modernity

Currently, scientists, analyzing the consequences of epidemics and studying important historical sources, call the plague "the queen of disease." At the same time, it no longer causes such fear and horror, because there were no longer large outbreaks in the world that claimed millions of lives.

According to the manifestations of the plague in the modern period, statistics are kept. The World Health Organization notes that between 2010 and 2015, 3,248 people developed the plague. Fatal outcome was in 584 cases. This means that 82% of people have recovered.

The reasons for the weakening of the "grip" of the pathogen

The plague wand has become less dangerous for several reasons. Firstly, people began to observe the rules of hygiene, cleanliness. For example, you can compare the modern period with the Middle Ages. Centuries ago, in Western Europe, people threw all food waste and feces directly onto the streets. Due to environmental pollution, the townspeople suffered from various diseases, dying from the plague.

Secondly, modern people live far from the natural foci of the disease. Infected rodents and fleas are most often encountered only by hunters and tourists.

Thirdly, today medicine knows effective methods of treating and preventing a dangerous disease. Specialists have created vaccines, identified drugs that can kill the plague stick.

And now about the pathogen

If we talk about the structure of plague bacillus, then Yersinia pestis is a gram-negative small bacterium. It is distinguished by pronounced polymorphism. This is confirmed by the occurring forms - granular, filiform, bulbous, oblong, etc.

Yersinia pestis is a zoonotic bacterium belonging to the Enterobacteriaceae family. The genus name Yersinia was given to this microorganism in honor of the French bacteriologist Alexander Yersen. It was this specialist who, in 1894, during a study of the biological materials of people who died from a dangerous disease, was able to identify the pathogen.

A microorganism that can cause epidemics with a high mortality rate, after discovery, has always been of interest to microbiologists. Since the discovery of Yersinia pestis, specialists have studied the structure of the bacterium (plague bacillus) and its features. The result of some studies conducted by domestic scientists, was the compilation in 1985 of the classification of the pathogen isolated on the territory of the USSR and Mongolia.

Stick penetration methods

The causative agent of plague lives in the body of small mammals. In the circulatory system, the bacillus multiplies. A flea during the bites of infected animals becomes a carrier of infection. In the body of the insect, the bacterium settles in the goiter, begins to multiply intensively. Due to the increase in the number of sticks, the goiter is clogged. The flea begins to experience severe hunger. To quench it, she jumps from one owner to another, spreading the infection between animals.

The stick enters the human body in several ways:

• with a bite of an infected flea;
• during unprotected contact with contaminated materials and infected body fluids;
• by inhalation of infected small particles or fine droplets (airborne droplets).

Forms of the disease and symptoms

Depending on the methods of penetration of the plague bacillus into the body, 3 forms of the disease are distinguished. The first of them is bubonic. With such a plague, the pathogen enters the human lymphatic system after a flea bite. Due to the disease, the lymph nodes become inflamed, become the so-called buboes. In the later stages of the plague, they turn into purulent wounds.

The second form of the disease is septic. With it, the pathogen enters directly into the circulatory system. Buboes do not form. The septic form occurs when there are two ways that the plague stick can penetrate the human body - after a bite of an infected flea, and also after contact with infected materials (pathogen penetration through skin lesions).

The third form is pulmonary. It is transmitted from infected patients by airborne droplets. Pulmonary plague is considered the most dangerous. Without treatment, the outcome of disease progression in most cases is fatal.

Plague treatment

For a long time, mankind did not know about the methods of penetration of the plague stick, did not know how to stop a deadly disease. Doctors came up with various bizarre methods that did not lead to a cure. For example, in the Middle Ages, healers prepared incomprehensible potions from plants, crushed snakes, advised people to quickly and permanently flee from an infected area.

Today, plague is treated with antibiotics from the aminoglycoside group (streptomycin, amikacin, gentamicin), tetracyclines, rifampicin, chloramphenicol. Lethal outcomes occur in cases where the disease proceeds in fulminant form, and specialists are unable to timely identify the pathogenic bacterium.

Plague stick, despite the achievements of modern medicine, still refers to insidious pathogens. The foci of the disease in nature occupy about 7% of land. They are located on the desert and steppe plains, in the highlands. People who have visited the natural foci of the plague should pay attention to their health. When the pathogen enters the body, the incubation period lasts from several hours to 9 days. Then the first symptoms occur - suddenly the body temperature rises to 39 degrees and above, cramps, chills, severe head and muscle pain, difficulty breathing. With such symptoms, immediate medical attention is required.