The diagnosis of ARVI can be found in any medical record of an adult. As for babies, unfortunately, it is found even more often in their cards. We are accustomed to associating these letters with high fever, snot and red throat, however, what this abbreviation actually means, not everyone knows.
“ARVI” stands for “acute respiratory viral infection”. As the name suggests: the infection has an acute course (as a rule, a high temperature suddenly rises, a stream pours from the nose, itching in the throat, etc. – it is impossible not to notice it), it is transmitted, as a rule, by airborne droplets or by contact ( you can read more about the ways of transmission of ARVI here ), affecting mainly various parts of the respiratory (related to respiration) tract, and certain viruses cause it.
Moreover, it is viruses – in the plural, since the term “ARVI” unites a fairly large group of them (more than 200). Such a combination happened due to the fact that these viruses cause similar symptoms, suggest the same treatment tactics (with a few exceptions), and the patient’s body suppresses them quickly enough, therefore, as a rule, an accurate diagnosis is not required.
Due to the inclusion of a large number of pathogens in one small term, ARVI is the most common infection and accounts for up to 60-70% (and in some sources the figure is 90%) of all infectious diseases.
In most cases, specific immunity is developed to the virus that caused ARVI (that is, a person gets sick only once, after which the corresponding antibodies remain in the body). However, since there are more than 200 viruses that can cause ARVI symptoms, then a given person may have more than 200 episodes of ARVI during his life (and in fact, for some, specific immunity is not produced, respectively, one such virus can be ill several times!). As for babies, their virgin immune systems have yet to get acquainted with all these viruses and develop antibodies to each of them. Accordingly, children under 6 years old have an average of 6-8 episodes of ARVI per year (some up to 12 episodes (especially if they attend kindergarten and other child care institutions)). About why children get sick more often than adults, in more detail here , but about who should be considered a frequently ill child – here .
In adults, the situation is more rosy: on average 2-4 cases of ARVI per year. Thus, those who often get sick with ARVI in childhood, in adulthood have antibodies to most viruses, respectively, get sick less often, and vice versa: those who did not get sick in childhood – get sick at a more mature age.
Moreover, you can catch ARVI at any time of the year, however, in the autumn and spring months, there are small fluctuations in the direction of increasing infection with ARVI of non-influenza etiology. In turn, influenza viruses are characterized by seasonality – they appear and actively spread during the winter-spring months. About why people get sick more often in the cold season – here .
Localization of inflammation
The symptoms of ARVI depend, first of all, on which part of the respiratory tract the virus caused the most severe inflammatory process. According to this criterion, ARVI can be divided into infections of the upper and lower respiratory tract. Moreover, the first are considered more common, these include:
- Rhinitis – inflammation of the nasal mucosa
- Sinusitis – inflammation of the sinuses (paranasal sinuses)
- Adenoiditis – inflammation of the adenoids (pathologically enlarged pharyngeal tonsil)
- Tonsillitis – inflammation of the tonsils (usually palatine)
- Pharyngitis – inflammation of the pharyngeal mucosa
- Laryngitis – inflammation of the larynx
Lower respiratory tract infections include:
- Pneumonia – inflammation of the pulmonary alveoli
- Bronchitis – inflammation of the bronchi
- Bronchiolitis (capillary bronchitis) – inflammation of the bronchioles (the smallest bronchi, less than two millimeters in diameter)
- Tracheitis – inflammation of the tracheal mucosa
Combinations are possible, for example, nasopharyngitis (the mucous membrane of the nose and pharynx is inflamed at the same time), tracheobronchitis (the inflammatory process occurs in the trachea and bronchi), etc. Sometimes there are signs of infection of the upper and lower respiratory tract at the same time, for example, laryngotracheitis (larynx and trachea), etc.
Based on the foregoing, the question arises: what is the reason for such a variety of localization sites of inflammation, if we are talking about the same diagnosis – ARVI? The fact is that, despite the similarity of the symptoms caused, the viruses that cause ARVI can be divided into smaller groups (taking into account their preferred localization). Today there are:
- 113 serotypes of rhinovirus (they prefer to cause inflammation of the nasal mucosa, after meeting the virus, the body, as a rule, develops strong immunity, which does not exclude the possibility of infection with other serotypes);
- 41 serotype of adenovirus (characterized by damage to the mucous membranes of the upper respiratory tract, conjunctiva, lymphoid tissue; a combination of fever, pharyngitis and conjunctivitis makes it possible with almost 100% probability to assume an adenovirus infection; after meeting, the body also develops strong immunity, which does not exclude the possibility of infection with other serotypes);
- 30 enteroviruses (Coxsackie, poliovirus and ECHO (echo); can affect: mucous membrane of the oropharynx, eyes, intestines, central and peripheral nervous systems, skin, muscles, heart, liver, in boys, testicular damage is possible; often accompanied by diarrhea (even in the absence of high temperature), rashes; after a meeting, the body develops strong immunity, which does not exclude the possibility of infection with other serotypes);
- 5 parainfluenza (moderately pronounced general intoxication with damage to the upper respiratory tract, mainly the larynx; persistent immunity, as a rule, does not cause, respectively, you can get sick with the same virus several times);
- 3 reoviruses (affect the upper respiratory tract, sometimes the small intestine; nausea, vomiting, abdominal pain, conjunctivitis, swollen lymph nodes, liver and spleen are often added to the standard fever, runny nose and cough; viruses are highly resistant to an increase / decrease in temperature, ultraviolet radiation and standard disinfectants, which are used to disinfect premises; there is a possibility of infection from animals by the fecal-oral route; specific immunity is developed after a disease);
- 3 influenza (mild forms are difficult to distinguish from other viruses; in severe forms, cerebral edema, vascular collapse, hemorrhagic syndrome can develop; dangerous complications, bacterial infections (especially in children); there are features in terms of prevention (vaccination) and treatment (anti-influenza drugs ); since serotypes A and B (especially A) are often mutated, it is not possible to develop specific immunity);
- 2 respiratory syncytial viruses (they prefer the lower respiratory tract, they are considered the most common cause of bronchiolitis and pneumonia in children under 1 year old; they do not leave persistent immunity, so you can get sick with one virus several times);
- 2 metapneumovirus (causes lower respiratory tract infections, but, as a rule, in a less severe form than respiratory syncytial viruses);
- coronaviruses, bocavirus and others. From time to time, scientists discover new strains.
The disease caused by each of the listed viruses has its own characteristics in terms of the choice of the section of the respiratory tract in which it causes inflammation. So, rhinoviruses usually stop on the nasal mucosa (accordingly, the manifestations of ARVI are limited to a week-long runny nose, which in babies is sometimes mistaken for a “runny nose on the teeth”), and the respiratory syncytial virus will not stop until it reaches the lower respiratory tract.
However, this selectivity is influenced by a significant number of factors: the degree of ability of a given virus to infect a given organism (here we usually talk about high and low immunity, about hardening), age, environmental conditions, tactics of therapy, etc. For example, the same rhinovirus with “lowered immunity”, dry air, irrational drinking regimen may well go down and cause acute pharyngitis. In addition, in about a third of cases, several pathogens may be involved.
In connection with the above, it is not always possible to establish a specific pathogen during the examination. Of course, virological studies make it possible to clarify the specific type of pathogen, but this, as a rule, is not required, since understanding the site of inflammation localization, as well as the viral nature of the infection, is sufficient to select the treatment tactics. Thus, the diagnosis of ARVI, bronchitis or ARVI, nasopharyngitis will be quite enough.
However, there are exceptions to this rule. It definitely makes sense to conduct an express test for influenza with a sharp rise in temperature to 39-40 degrees during the period of activity of influenza viruses, as well as conducting a strept test with the development of angina. Thus, ARVI (acute respiratory viral infection) is the most widespread infectious disease in the world with an acute course that affects various parts of the respiratory tract and is caused by various viruses (more than 200), after meeting with which, as a rule, specific immunity is developed, not preventing infection with other serotypes.