Acute respiratory viral infections are a large group of diseases that are morphologically and clinically similar. They cause inflammatory diseases of the respiratory system, as they are pneumotropic viruses. The frequency with which viral diseases of this kind attack humanity depends on the time of year, it increases significantly in the autumn-winter period. However, they circulate in the human population constantly, even in non-endemic times of the year.
These viruses are divided into two groups: RNA-containing (parainfluenza, influenza, respiratory syncytial virus) and DNA-containing (adenoviruses). Both those and others enter the human body through the airborne transmission route. Among all acute respiratory viral infections, adenovirus infection, as well as influenza and parainfluenza, are of the greatest importance for human health in terms of their effect on the body.
Influenza is an acute respiratory viral infection caused by influenza viruses. Only a sick person is contagious to others. The incubation period lasts two to four days. The first clinical sign of the onset of the disease is tracheitis, after which acute bronchitis may join. Influenza virus has the following effects on the body:
- immunosuppressive effect,
- inhibition of neutrophil activity (phagocytosis is suppressed), monocytic phagocytes (decrease in phagocytosis and chemotaxis), the immune system as a whole (allergy develops, toxic immune complexes appear);
- cytopathic effect on the epithelium of the trachea and bronchi (its dystrophy, necrosis and desquamation occur);
- vasopathic effect (plasma and hemorrhages, stasis).
The immunosuppressive and vasopathic effects of the virus are affected by the attachment of a secondary infection. These are local (pneumonia, rhinitis, tracheitis, pharyngitis, bronchitis) and general (discirculatory disorders, inflammation, dystrophy of the parenchymal elements) changes that cause viral diseases.
Not always with the introduction of the virus is the development of an acute infectious process. A latent (asymptomatic) and chronic form of the disease is also possible, which has serious consequences, especially in perinatal pathology.
If a mild form of influenza develops, then it proceeds favorably and ends after five to six days with a full recovery and restoration of the mucous membranes.
If the flu is moderate, then the pathological process involves not only the upper respiratory tract, but also small bronchioles, bronchi and pulmonary parenchyma. In the bronchi and trachea, inflammation of the serous-hemorrhagic nature develops, sometimes even with necrotic foci on the mucous membrane. The outcome of moderate flu is generally favorable: recovery occurs in about a month. But if it occurs in weakened people, children, the elderly, as well as in people with cardiovascular diseases, then pneumonia can begin. In this case, cardiopulmonary failure and even death may occur.
Severe influenza has two pathways:
- influenza toxicosis,
- flu with a pulmonary complication.
With a disease of severe influenza toxicosis, general intoxication quickly occurs. In case of fulminant flu, pulmonary edema is possible , as well as minor hemorrhages in the brain, in internal organs, mucous membranes, and skin. Often in such cases, death occurs. This usually happens on the fourth or fifth day of the disease from hemorrhage to vital centers or against the background of the development of increasing respiratory failure.
Parainfluenza is an acute influenza-like illness caused by the parainfluenza virus. It is characterized by lesions of the upper respiratory tract, as well as slight intoxication. Mostly children are sick, but there are times when an adult's body is also affected. With parainfluenza, laryngeal edema and acute laryngitis occur , which is complicated by asphyxia and false croup.
Adenovirus infections are acute respiratory viral diseases caused by adenoviruses. Routes of infection are identical to those characteristic of other acute respiratory viral infections. Sources of the disease are both the patient and the virus carrier. Infections are characterized by airborne transmission. In this case, the upper respiratory tract, lymphoid tissue, conjunctiva of the eyes are affected. There are two forms of the course of the disease: mild and severe. The mild form is characterized by the development of acute rhinolaryngotracheobronchitis in the catarrhal form, acute conjunctivitis, pharyngitis, as well as regional lymphadenitis. In a severe form of the disease, a secondary infection is characteristic, in which suppuration, necrosis and morphological changes in organs occur.
Viral Disease Prevention
You need to eat more foods that contain vitamins, and especially vitamin C. Do not forget about onions and garlic, because viruses are simply "afraid" of them. It is more often to be in the fresh air and ventilate the room, because enhanced air circulation will reduce the number of viruses in the room.
Be sure to carry out spring cleaning once a week. Viral diseases are “afraid” when we monitor personal hygiene, when we wash our hands with soap. Regular gargling and rinsing or dripping saline into the nose are also helpful. So we will reduce the concentration of viruses in the nasopharynx.