In our language, there are more than 600 speciesknown microorganisms, but we have more chances to catch infection in public transport. What is the source of the infectious disease? How does the mechanism of infection work?
Infection with pathogensis called an infection. The term appeared in 1546 thanks to Girolamo Fracastoro. At present, about 1,400 microorganisms are known to science, they surround us everywhere, however, infections do not develop in us every second.
Why?The fact is that all microorganisms are divided into pathogenic, opportunistic and non-pathogenic. The former are often parasites, and require the presence of a "master" for their development. They can affect even a healthy and persistent organism.
Conditionally pathogenic microorganisms (intestinalrod, fungus candida) do not cause a healthy person no reactions. They can live in the environment, be part of the microflora of our body. But under certain conditions, for example, with weak immunity, they become pathogenic, that is harmful.
The term "non-pathogenic"Dangers of interaction with these organisms, although they can penetrate the human body and cause the development of infection. The boundaries between the conditionally pathogenic and non-pathogenic microflora in microbiology are very fuzzy.
Infectious disease can be caused bypenetration into the body of pathogenic fungi, viruses, protozoa, bacteria, prions. The source of infectious agents is the environment that promotes their development. This environment is often a man or an animal.
Getting into favorable conditions, microorganismsactively multiply, and then leave the source, finding themselves in the external environment. There pathogenic microorganisms, as a rule, do not reproduce. Their number gradually decreases until complete disappearance, and various unfavorable factors only accelerate this process.
Renew vital activity in microorganismsis obtained when they find a new "master" - a vulnerable person or animal, whose immunity is weakened. The cycle can be repeated continuously, while the infected will spread the parasites to healthy organisms.
It is important to understand that the environment is notsource of infection. It always acts as an intermediary for the transfer of microorganisms. Insufficient moisture, lack of nutrients and inadequate temperature of the environment are unfavorable conditions for their development.
Air, household items, water, soil first themselvesare exposed to infection, and only then transport the parasites into the host's body. If microorganisms are in these environments for too long, they die. Although some are particularly resistant and can persist even in adverse conditions for many years.
Strong resistance is possessed by the causative agentanthrax. In the soil, it persists for several decades, and when boiled, it dies only an hour later. He is also absolutely indifferent to disinfectants. The causative agent of cholera El Tor is able to persist in soil, sand, products and feces, and warming the reservoir to 17 degrees allows the sticks to reproduce.
Infections are divided into several types, according to what organisms they multiply and to whom they can be transmitted. Based on these data, anthroponoses, zooanthrotonoses and zoonoses are isolated.
Zooanthronoses or anthropozoonosis cause diseases,in which the source of infection is a person or an animal. In humans, infection most often occurs through animals, especially through rodents. Zoonotic infections include rabies, sap, tuberculosis, leptospirosis, anthrax, brucellosis, trypanosomiasis.
Anthroponotic disease is in the case,when the source of infection is a person, and it can only be transmitted to other people. This includes recurrent, typhus and typhoid fever, chicken pox, gonorrhea, influenza, syphilis, whooping cough, cholera, measles and poliomyelitis.
Zoonoses are infectious diseases, forwhose favorable environment is the animal's body. Under certain conditions, the disease can be transmitted to people, but from person to person - not. The exception is the plague and yellow fever that can circulate among people.
Зараженный человек или животное может стать cause widespread disease in one, several localities, and sometimes several countries. Dangerous diseases and their spread are studied by epidemiologists.
If there is at least one case of infectiondoctors find out all the details of the infection. There is a detection of the source of infection, determining its type and ways of spreading. To do this, most often used epidemiological anamnesis, which consists in questioning the patient about recent activities, contacts with people and animals, the date of manifestation of symptoms.
Full information about the infected is extremelyuseful. With its help it is possible to find out the path of transmission of infection, a possible source, and also the potential scale (whether the case will be single or massive).
The initial source of infection is notalways easy, there can be several of them at once. This is especially difficult to do with anthropo-zoonotic diseases. In this case, the main task of epidemiologists is the identification of all potential sources and transmission routes.
There are several transmission mechanisms.Fecal-oral characteristic of all intestinal diseases. Malicious microbes are in excess in the feces or vomit, they get into a healthy organism with water or by a contact-household method. This happens when the source of infection (a sick person) does not wash well after using the toilet.
Respiratory, or airborne acts in viral infections that affect the respiratory tract. The transfer of microorganisms occurs when sneezing or coughing near uninfected objects.
Transmissible implies transmissionthrough the blood. This can occur when a bite is a vector, such as a flea, tick, anopheus mosquito, lice. Pathogens that are located on the skin or mucous membranes are transferred by contact. They penetrate the body through wounds on the body or during contact with the patient.
Sexually transmitted mainly venerealdiseases, as a rule, directly during sexual contact. The vertical transmission mechanism represents fetal infection from the mother during pregnancy.
Each type of microorganism has its ownthe mechanism by which viruses or bacteria enter the host. As a rule, there are several such mechanisms, and certain environmental factors can sometimes contribute to the transmission of parasites.
At the same time, a method that fits onemicrobes, absolutely not conducive to the transfer of others. For example, many pathogens of respiratory infections are absolutely powerless against gastric juice. Getting into the gastrointestinal tract, they die and do not cause the development of the disease.
Some mechanisms for getting maliciousmicrobes in the body can, on the contrary, accelerate the progression of the disease. Thus, the entry of the causative agent of syphilis into the bloodstream with the help of an infected medical needle causes complications. The disease is more intense.
Инфекция представляет собой совокупность biological processes arising and developing in the body when pathogenic microflora are introduced into it. The illness can strike both the person, and an animal. The main mechanisms of transmission is the contact, sexual, airborne, fecal-oral, vertical paths.
The source of infection is an environment favorable toreproduction and propagation of microbes. Suitable conditions are often people and animals. The environment usually acts as an intermediary.
She usually does not have the conditions forvital activity of pathogenic and conditionally pathogenic microorganisms. Long stay in the environment contributes to their extinction. In some cases, microorganisms are able to persist in the soil, water, sand from several days to decades.
