Our tongue is home to over 600 species of known microorganisms at all times, but we are more likely to catch an infection on public transport. What is the source of the infectious disease? How does the infection mechanism work?
Pathogenicity of organisms
Infection with pathogens is called an infection. The term appeared in 1546 thanks to Girolamo Fracastoro. There are currently approximately 1,400 microorganisms known to science, they surround us everywhere, but infections do not develop in us every second.
Why? The fact is that all microorganisms are divided into pathogenic, conditionally pathogenic and non-pathogenic. The former are often parasites, and require a "host" for their development. They can affect even a he althy and resistant organism.
Opportunistic pathogens (E. coli, Candida fungus) do not cause any reactions in a he althy person. 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" implies that there is no danger when interacting with these organisms, although they can enter the human body and cause infection. The boundaries between opportunistic and non-pathogenic microflora in microbiology are extremely vague.
Source of infections
Infectious disease can be caused by the penetration of pathogenic fungi, viruses, protozoa, bacteria, prions into the body. The source of infectious agents is the environment that contributes to their development. Such an environment is often a person or an animal.
Getting into favorable conditions, microorganisms actively multiply, and then leave the source, ending up in the external environment. There, pathogenic microorganisms, as a rule, do not multiply. Their number gradually decreases until they disappear completely, and various adverse factors only accelerate this process.
Renewal of vital activity in microorganisms is obtained when they find a new "host" - a vulnerable person or animal whose immunity is weakened. The cycle can repeat itself continuously as the infected spread parasites to he althy organisms.
Environment as transmitter
It is important to understand that the environment is not the source of infection. It always acts only as an intermediary for the transmission of microorganisms. Insufficient humidity, lack of nutrients and inappropriate ambient temperature are unfavorable conditions for their development.
Air, household items, water, soil are first 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 hardy and can last for many years even under adverse conditions.
Anthrax is highly resistant. It remains in the soil for several decades, and when boiled, it dies only after an hour. He is also absolutely indifferent to disinfectants. The causative agent of cholera El Tor is able to survive in soil, sand, food and feces, and warming the reservoir to 17 degrees allows the bacillus to multiply.
Sources of infection: species
Infections are divided into several types, according to the organisms in which they multiply and to whom they can be transmitted. Based on these data, anthroponoses, zooanthroponoses and zoonoses are distinguished.
Zooanthronoses or anthropozoonoses cause diseases in which the source of infection is a person or animal. In humans, infection most often occurs through animals, especially rodents. Zoonotic infections include rabies, glanders, tuberculosis, leptospirosis, anthrax, brucellosis, trypanosomiasis.
Anthroponous disease is when the source of infection is a person, and it can only be transmitted to other people. This includes relapsing fever, typhoid fever, typhoid fever, chicken pox, gonorrhea, influenza, syphilis, whooping cough,cholera, measles and polio.
Zoonoses are infectious diseases for which the animal organism is a favorable environment. Under certain conditions, the disease can be transmitted to humans, but not from person to person. The exceptions are plague and yellow fever, which can circulate among humans.
Infection detection
An infected person or animal can cause a wide spread of the disease within one, several localities, and sometimes several countries. Dangerous diseases and their spread are being studied by epidemiologists.
When at least one case of infection is detected, doctors find out all the details of the infection. The source of infection is identified, its type and methods of spread are determined. For this, an epidemiological anamnesis is most often used, which consists in asking the patient about recent activities, contacts with people and animals, and the date the symptoms began.
Full information about the infected is extremely useful. With its help, it is possible to find out the route of transmission of the infection, the possible source, as well as the potential scale (whether the case will become a single case or a mass one).
The initial source of infection is not always easy to identify, there may be several at once. This is especially difficult to do with anthropozoonotic diseases. In this case, the main task of epidemiologists is to identify all potential sources and routes of transmission.
Transmission methods
There are several transmission mechanisms. Fecal-oral is characteristic of all intestinaldiseases. Harmful microbes are found in excess in feces or vomit, they enter a he althy body with water or by contact-household method. This happens when the source of the infection (a sick person) does not wash their hands well after going to the toilet.
Respiratory, or airborne, acts on viral infections that affect the respiratory tract. The transfer of microorganisms occurs when sneezing or coughing near uncontaminated objects.
Transmissible means the transmission of infection through the blood. This can happen when bitten by a carrier, such as a flea, tick, malarial mosquito, lice. Pathogens that are located on the skin or mucous membranes are transferred by contact. Penetrate into the body through wounds on the body or while touching the patient.
Sexually transmitted sexually transmitted diseases are mainly sexually transmitted diseases, usually directly through sexual contact. The vertical transmission mechanism represents infection of the fetus from the mother during pregnancy.
Specific transmission of infection
Each type of microorganism has its own mechanism by which viruses or bacteria enter the host's body. As a rule, there are several such mechanisms, and certain environmental factors can sometimes contribute to the transmission of parasites.
At the same time, the method that suits some microbes does not at all contribute to the transfer of others. For example, many pathogens of respiratory infections are absolutely powerless in front of gastric juice. Entering the gastrointestin altract, they die and do not cause the development of the disease.
Some mechanisms of entry of harmful microbes into the body can, on the contrary, accelerate the development of the disease. So, getting the causative agent of syphilis into the bloodstream with the help of an infected medical needle causes complications. The disease is getting worse.
Conclusion
Infection is a set of biological processes that arise and develop in the body when pathogenic microflora is introduced into it. The disease can affect both humans and animals. The main transmission mechanisms are contact, sexual, airborne, fecal-oral, vertical routes.
The source of infection is an environment favorable for the reproduction and spread of germs. Suitable conditions are often possessed by people and animals. The environment usually acts as an intermediary.
It usually does not have the conditions for the vital activity of pathogenic and opportunistic microorganisms. Prolonged stay in the external environment contributes to their extinction. In some cases, microorganisms are able to survive in soil, water, sand from several days to decades.
