Plague is a disease of infectious nature. This anthroponogenic disease affects the lymphatic system, lungs, skin and other organs. It is known since ancient times and in different centuries during epidemics thousands and even millions of lives were carried away.
Plague is a particularly dangerous disease. Its causative agent is a bacterium from the genus Iersinia (Pasteurella) pestis. A plague microbe belongs to the family of enterobacteria. There are different foci of this disease (natural, urban). In natural conditions, the natural reservoir of pathogenic Yersinia is wild rodents. These are gerbils, gophers, hamsters. In urban conditions, the disease spreads gray, red and black rats. But this is the reservoir of infection. The plague carrier is an ordinary rat flea. Pathogenic microorganisms penetrate the blood with feces of parasites through scratching. From the person to the person the pulmonary form is transferred. In general, infection occurs when direct contact with a living or dead animal or products and objects of use, seeded Yersinia. There are fewer cases with an air-drop transfer mechanism.
Immediately at the site of the introduction of plague germs, no pathological changes are observed. Plague is a disease primarily affecting the lymph nodes. Therefore, the entire infectious process will develop there. At the site closest to the entrance gates, small areas of necrosis form. This is the result of the action on the body tissues of a strong plague "mouse" toxin. Then the patient develops periadenitis. The affected lymph node - bubo - increases in size, possibly its suppuration followed by opening.
The development of such a form of infection as a pulmonary plague is somewhat different. The disease occurs when pathogenic bacteria are introduced from foci (buboes or skin) with blood flow into the human lungs. As a rule, this is a secondary form that develops against a background of cutaneous or bubonic plague. In this case, the patient has a complication in the form of a hemorrhagic-necrotic infection process. Secondary-pulmonary plague proceeds according to the type of pneumonia.
Perhaps, in medicine, not so many diseases are more dangerous than the plague. The symptoms of the disease are very specific and depend on the localization of the pathogen. The incubation period, as a rule, does not exceed 6 days. The disease almost never proceeds in a chronic form, it develops lightning fast. The first sign is acute intoxication. Patients are disturbed by a strong headache, multiple petechiae are observed. Also affected is the spleen and cardiovascular system. The cutaneous form of the disease is very rare. Bubonic plague is much more common . With this clinical form of the disease, a persistent and extensive inflammation in the lymph node is formed. So-called buboes are formed. They are very painful on palpation. With the septic form, formation of several foci of infection is noted. Illness of plague in humans (clinical picture can be seen in medical reference books) is characterized by high lethality and the ability to cause outbreaks of epidemics. But it should be noted that in the last 50 years it was recorded only in some countries of Africa.