Infectious diseases: list, symptoms, treatment, prevention

In the middle of last century, mankind has achieved certain successes in the fight against some infections. But, as it turned out, it's too early to celebrate the final victory over such an affliction as infectious diseases. The list includes more than 1200 items, and is constantly replenished with newly discovered diseases.

How infectious diseases were studied

Mass illness is known to man since ancient times. There is evidence that as far back as the 5th century BC. Philosophers and doctors guessed about the existence of some tiny, invisible to the eye of living organisms, capable of causing diseases that are characterized by rapid spread and high mortality. In the Middle Ages, however, these materialistic views were forgotten, and outbreaks of mass illnesses were explained solely by the punishment of God. But they already knew about the fact that the patients had to be isolated and also to destroy the contaminated things, buildings and corpses.

Knowledge accumulated gradually, and the middle of the 19th century was marked by the birth of a science such as microbiology. Then the causative agents of many diseases were discovered: anthrax, cholera, plague, tuberculosis and others. Infectious diseases have since been isolated as a separate group.

Terminology

The word "infection" in Latin means "contamination", "contamination". As a biological concept, this term refers to the penetration of a microscopic pathogen into a more highly organized organism. It can be either a person or an animal, or a plant. Then the interaction between the micro- and macroorganism systems begins, which, of course, proceeds not in isolation, but under specific environmental conditions. This is a very complex biological process, and it is called infectious. As a result of this interaction, the macroorganism either is completely released from the causative agent of the disease, or dies. The form in which the infectious process manifests itself is precisely the specific infectious disease.

Common characteristics of infectious diseases

About the onset of an infectious disease can be said, if after a meeting of the pathogen and the macroorganism, in particular a person, a disruption of the vital functions of the latter occurs, the symptoms of the disease appear, and the antibody titre increases in the blood. There are other forms of infectious processes: a healthy carrier of the virus in the presence of immunity or natural immunity to the disease, chronic infections, slow infections.

In addition to the fact that all infectious diseases begin with pathogenic microorganisms-pathogens, there are other common characteristics for them. Such diseases are contagious, that is, they are capable of being transmitted from a sick person or animal to a healthy one. Under certain conditions, epidemics and pandemics may arise, that is, the massive spread of the disease, and this is a very serious threat to society.

In addition, infectious diseases, the list of which can be viewed in any medical reference book, always occur cyclically. This means that during the course of the disease, certain time intervals alternate between each other: the incubation period, the stage of the disease precursors, the period of the height of the illness, the period of recession, and, finally, the period of recovery.

The incubation period has no clinical manifestations yet. It is shorter the higher the pathogenicity of the pathogen and the greater its dose, and can be as several hours, and several months and even years. The precursors of the disease are the most common and rather vague symptoms on the basis of which it is difficult to suspect a specific infectious disease. Typical for her clinical manifestations are maximum at the height of the disease. Then the disease begins to fade, but for some infectious diseases relapses are characteristic.

Another specific characteristic of infectious diseases is the formation of immunity in the process of the disease.

Infectious Disease Pathogens

Infectious diseases are caused by viruses, bacteria and fungi. For the introduction to be successful for a pathogenic microorganism successfully, one meeting of the macro- and microorganism is not enough. Certain conditions must be met. The actual state of the macroorganism and its protective systems is of great importance.

Much depends on the pathogenicity of the pathogen itself. It is determined by the degree of virulence (virulence) of the microorganism, its toxigenicity (otherwise - the ability to produce toxins) and aggressiveness. Environmental conditions also play a big role.

Classification of infectious diseases

First of all, infectious diseases can be systematized depending on the pathogen. In general, viral, bacterial and fungal infections are isolated. Separately, chlamydial, mycoplasmal, rickettsial, spirochaetic infections are isolated, although chlamydia, mycoplasmas, rickettsia, and spirochaetes belong to the bacterium kingdom. Viruses are, perhaps, the most common pathogens. However, bacteria can cause many ailments. Among the most famous - such as angina, meningitis, cholera, plague, bacterial pneumonia, tuberculosis, tetanus. To fungal infectious diseases, or mycoses, include candidiasis, dermatophytosis, onychomycosis, lichen.

Most often, infectious diseases are classified according to the localization of pathogens, taking into account the mechanism of their transmission, but this applies to those diseases that spread from person to person. Accordingly, intestinal infectious diseases transmitted by fecal-oral route (astroviral infection, poliomyelitis, cholera, typhoid fever) are isolated. There are infectious diseases of the upper respiratory tract. The method of infection is called airborne (ARVI, diphtheria, scarlet fever, influenza). Infectious diseases can still be localized in the blood and transmitted through insect bites and medical manipulations. It's about injections and blood transfusions. These include hepatitis B, plague, typhus. There are also external infections that affect the skin and mucous membrane and are transmitted by contact.

During the evolution of each type of causative agent of infectious disease, their entrance gates of infection were fixed. Thus, a number of microorganisms penetrate the mucous membranes of the respiratory tract, others - through the digestive tract, the genital tract. It happens, however, that the same pathogen can enter the human body simultaneously in different ways. For example, hepatitis B is transmitted through blood, from mother to child and by contact.

As for the sources of infection, anthroponoses are distinguished if the disease comes from a person, and zoonoses, if the carriers of the infection are animals. It must be said that zoonotic pathogens are not released into the environment when they enter the human body, so the intensity of zoonoses is an order of magnitude lower than anthroponosis. Zoonoses include brucellosis, botulism, plague, tularemia, rabies, anthrax, foot and mouth disease, tetanus. As a rule, several mechanisms of transmission of infection are characteristic for zoonoses .

There are three main habitats of infectious agents. This is the human body, the body of animals and the inanimate environment - the soil and water.

Symptoms of infectious diseases

Common symptoms of infectious diseases include malaise, headache, pallor, chills, aching muscles, fever, sometimes - nausea and vomiting, diarrhea. In addition to general, there are symptoms that are characteristic of only one disease. For example, a rash with meningococcal infection is very specific.

Diagnostics

As for diagnosis, it should be based on a comprehensive and comprehensive study of the patient. The study includes a detailed and thorough survey, a survey of organs and systems, and necessarily an analysis of the results of laboratory studies. Early diagnosis of infectious diseases presents certain difficulties, but it is of great importance both for timely adequate treatment of the patient and for organizing preventive measures.

Treatment

In the treatment of such ailments as infectious diseases, the list of which is so frighteningly extensive, there are several directions. First of all, these are measures aimed at reducing the activity of the pathogenic microorganism and neutralizing its toxins. For this, antibacterial drugs, bacteriophages, interferons and other agents are used.

Secondly, it is necessary to activate the body's defenses, using immunomodulating drugs and vitamins. Treatment must be comprehensive. It is important to normalize the functions of organs and systems disturbed by the disease. In any case, the approach to treatment should take into account all the individual characteristics of the patient and the course of his illness.

Prevention

To protect yourself and your loved ones from the threat such as infectious diseases, the list of which includes diseases of viral, bacterial and fungal nature, it is necessary to remember about quarantine measures, vaccination, strengthening of immunity. And sometimes, in order to be saved from infection, it is enough to observe elementary rules of personal hygiene.