Table of contents:
- Infection transmission mechanism
- The main routes of transmission and impact on them
- Prevention of infectious diseases
- Importance of immunization
Video: Infectious Diseases - Causes, Symptoms And Prevention
2023 Author: Riley Dean | [email protected]. Last modified: 2023-05-24 12:07
Infectious diseases are very common in the modern world. The pathways of infection can be very different: harmful microbes can enter the human body both by airborne droplets and through food or blood.
The content of the article:
- 1 Mechanism of transmission
2 Main modes of transmission and impact on them
- 2.1 Infectious Diseases - Airborne and Dust Route
- 2.2 Infectious diseases: Fecal-oral or alimentary transmission
- 2.3 Infectious diseases - contact and household transmission
- 2.4 Infectious diseases - a vector-borne route of transmission
- 2.5 Infectious diseases - transplacental transmission
- 3 Prevention of infectious diseases
- 4 Importance of immunization
Infection transmission mechanism
The mechanism of transmission of infection is a complex process that consists of three phases, following one after the other: 1) elimination of the pathogen from the infected organism; 2) the presence of the pathogen in the external environment (or in the organism of the animal carrier); 3) the introduction of the pathogen into a susceptible organism.
The method of removing the pathogen from an infected organism depends on its location in the body. When the pathogen is localized in the intestine, it is excreted in the feces and sometimes with vomit. If the pathogen is in the respiratory system, it is excreted with air and droplets of saliva. In cases where the pathogen is in the blood of a person, it is transmitted to a healthy person mainly by blood-sucking insects.
There are the following main variants of the transmission mechanism: contact, airborne, fecal-oral, transmissible. These mechanisms of transmission of pathogens are carried out using specific pathways and factors of transmission.
The main routes of transmission and impact on them
- airborne transmission (flu, colds, chickenpox, whooping cough, tuberculosis, diphtheria, measles, rubella, etc.) - masks are used for prevention, ventilation, preventing the accumulation of a large number of people in the room;
- alimentary (food) transmission route (all intestinal infections, salmonellosis, dysentery, viral hepatitis A) - personal hygiene, washing hands, food, the absence of flies in the premises plays an important role;
- sexual (contact) transmission (viral hepatitis B, C, HIV AIDS, genital herpes, syphilis, gonorrhea, papillomatosis) - an important point in the prevention of such infections is the absence of promiscuous sex with frequent changes of partners and the use of condoms;
- the blood route of transmission (most often - viral hepatitis B, HIV AIDS) - in this case, sterile surgical instruments, refusal of tattoos (especially at home) will help prevent infectious diseases, that is, all efforts are aimed at preventing damage to the integrity of the skin and mucous membranes.
Infectious Diseases - Airborne and Dust Route
It is the most common and fastest way to transmit infectious diseases. Many viral and bacterial infections are transmitted in this way. When talking, screaming, crying, sneezing and coughing with droplets of mucus, a huge amount of the pathogen is released. In this case, the pathogen is capable of dispersing over distances of more than 2-3 meters around the patient, being in suspension for a very long time and, thanks to Brownian motion and the presence of an electric charge, moving over great distances.
Human infection occurs by inhalation of air with mucus droplets containing the pathogen. Of course, the highest concentration of the pathogen will be in the immediate vicinity of the source of infection. But if the pathogen has a pronounced pathogenicity, and the body is highly susceptible, then often even a small concentration of the pathogen in the air is enough to pick up the infection.
For example, medicine knows cases of transmission of measles, chickenpox, influenza viruses over very long distances, through stairwells, ventilation ducts and corridors.
Many organisms die very quickly in the environment (measles, chickenpox and influenza viruses), others are resistant and can retain pathogenic properties in the dust for several days. The dusty mechanism of transmission of the pathogen is possible with diphtheria, scarlet fever, salmonellosis, tuberculosis, etc.
Infectious diseases: Fecal-oral or alimentary transmission
With this method, the factors of transmission of the pathogen are food, water, contaminated hands, flies, and household items.
This route of transmission is characteristic for the transmission of viral and bacterial intestinal infections, for example, for staphylococcal enterocolitis, shigellosis, salmonellosis, infections caused by gram-negative opportunistic pathogenic microbes (Klebsiella, Proteus, Pseudomonas aeruginosa, citrobacter), somewhat less often for poliomyelitis, jarculosis tulularemia …
Transmission of the pathogen with food is possible with scarlet fever, diphtheria, hepatitis A, yersiniosis, rotavirus gastroenteritis, etc.
A person can become infected by eating meat and milk from sick animals that have not been sufficiently heat treated.
Infection of children most often occurs through milk and dairy products (sour cream, cream, ice cream, cream). Milk outbreaks are characterized by a rapid increase in morbidity, massiveness and damage to children's groups.
Water as a transmission factor plays an important role in infection with typhoid fever, shigellosis, tularemia, leptospirosis, hepatitis A, cholera. The causative agents of these diseases enter the water with the excretions of people and animals, when draining wastewater, washing off sewage from the surface of the earth. The most dangerous are closed water bodies (shallow lakes, ponds, wells).
Infectious diseases - contact and household transmission
This route of transmission is carried out through direct communication or through contaminated environmental objects.
Through direct contact, you can become infected with diphtheria, scarlet fever, tuberculosis, syphilis, herpes infection, scabies, helminths, erysipelas.
The transmission of the pathogen through household items (linen, dishes, toys) is carried out with shigellosis, helminthiasis, typhoid, scarlet fever, tuberculosis, diphtheria.
Infection of children often occurs through the hands. At the same time, a patient, contaminating his hands with feces, can infect environmental objects, for example, dishes, toys, pens, walls of the room. A healthy child, contacting these objects, infects the hands and infects the mouth.
Infectious agents often enter the soil and form spores there. In this form, they remain viable for many years. If the spores get on the wound surface of the skin or in the mouth, a disease occurs (tetanus, gas gangrene, botulism).
Infectious diseases - a vector-borne route of transmission
This pathway is carried out by living vectors, which are often biological hosts of pathogens and less often mechanical carriers.
Live vectors are divided into 2 groups:
Specific - blood-sucking arthropods (fleas, lice, mosquitoes, mosquitoes, ticks). They ensure the transmission of a strictly defined infection, for example, fleas - plague, lice - typhus, mosquitoes - malaria, ticks - arbovirus encephalitis. In their body, pathogens multiply or go through a development cycle
Infection is transmitted by biting or rubbing the contents of a crushed carrier into the skin.
Nonspecific - transmit the pathogen in the form in which it was received
For example, flies on the legs and body carry pathogens of acute intestinal infections, the hepatitis A virus, typhoid, paratyphoid.
Infectious diseases - transplacental transmission
This is the route of transmission of the pathogen through the placenta from the mother to the fetus.
Transplacental transmission is especially important for viral infections. Thus, the possibility of intrauterine transmission of rubella, cytomegaly, measles, chickenpox, mumps, hepatitis B virus, enteroviruses has been proved.
Among bacterial infections, this route of transmission is possible with leptospirosis, staphylococcal, streptococcal infections.
The outcome of intrauterine infection of the fetus depends on the timing of the infection of the pregnant woman. If infected in the first three months of pregnancy, the embryo may die (miscarriage) or a child with developmental defects may be born. After 3 months of pregnancy, intrauterine fetal death is also possible or a child will be born with signs of a congenital infection.
Prevention of infectious diseases
Like any other disease, infectious diseases are easier to prevent than to cure later. For this, the prevention of infectious diseases is used, which prevents the development of an infectious process.
Allocate social and individual prevention. Individual prophylaxis includes: vaccinations, hardening, walking in the fresh air, playing sports, proper nutrition, adherence to the rules of personal hygiene, rejection of bad habits, life and rest, environmental protection. The public includes a system of measures to protect the health of collectives: the creation of healthy and safe working and living conditions in production, at the workplace.
In order to prevent, limit the spread and eliminate infectious diseases, immunization is carried out through preventive vaccinations. This type of prevention of infectious diseases is directly related to the creation in the human body of immunity (immunity) to a certain infection through immunization and is called specific immunization of infectious diseases. There are two main types of immunization:
- active immunization (vaccination) - after the introduction of a vaccine into the human body (antigen of the pathogen or live weakened microorganisms), specific antibodies are formed, which, even when infected, prevent the development of an infectious disease. Currently, active immunization is being carried out against such infectious diseases: tetanus, whooping cough, diphtheria, viral hepatitis B, poliomyelitis, measles, rubella, epidparotitis ("mumps"), tuberculosis.
- passive immunization - ready-made antibodies to a certain infection are injected into the body, which is used for emergency prevention of infectious diseases (emergency prevention of tetanus).
Importance of immunization
It must be remembered: the more people are vaccinated, the higher herd immunity and the barrier to infectious diseases. It is possible to defeat the infection if the entire population is covered by vaccination.
Whatever the method of prevention, its use will help prevent the disease, which is especially important for incurable infections such as HIV / AIDS, rabies and viral hepatitis.
Find out more:
- Intestinal Infection: Salmonellosis - Symptoms and Treatment
- Trichomoniasis - symptoms, causes, diagnosis and treatment
- Invasion in humans: varieties, signs, symptoms