The flu - acute virus illness, is transferred airborne by. It is characterized by the acute beginning, a fever, an intoxication and a lesion of a respiratory tract.

Etiology, pathogenesis. Originators of a flu concern to family of viruses which include a sort of viruses of a flu-A, a sort of viruses of a flu-B and a flu-C. Viruses of a flu-A are sectioned into many serotypes. Constantly there are new antigenic variants. The virus of a flu quickly perishes at warming, drying and under influence of various disinfectant agents. Infection atriums are the top departments of a respiratory tract. The virus of a flu selectively amazes a cylindrical epithelium of respiratory ways, especially tracheas. Rising of permeability of a vascular wall leads to disturbance of microcirculation and occurrence of a hemorrhagic syndrome (a pneumorrhagia, nasal bleedings, a hemorrhagic pneumonia, an encephalopathy). The flu causes depression of an immunologic reactivity. It leads to an exacerbation of various chronic diseases - rheumatic disease, a chronic pneumonia, a pyelitis, a cholecystitis, a dysentery, a toxoplasmosis and so forth, And also to occurrence of secondary bacteriemic complications. The virus is kept in an organism of the patient usually within 35 days from the beginning of illness, and at complication by a pneumonia - till 10-14 days.

Signs, current. The incubation interval proceeds from several o'clock till 3 days (more often 1 2 days). The typical flu begins was acutely, is frequent from a cold fit or a chilling, the body temperature quickly raises and already in the first day the fever reaches a maximum level (38-40 degrees). Attributes of an intoxication (delicacy, an adynamia, a sweating, a pain in muscles, a strong headache, a pain in opinion of) and signs of a lesion of respiratory ways are marked.

Complications: pneumonias (up to 10 % of all patients and up to 65 % hospitalized sick of a flu), frontal sinusitises, genyantrites, otites, toxic damage of a myocardium. During a flu epidemic the diagnosis of difficulties does not represent. During interepidemic time on a flu this disease meets seldom (35 % of all cases of acute respiratory diseases) and proceeds often in the form of the easy and erased forms. In these cases the flu is difficult for distinguishing from acute respiratory diseases of other etiology. For acknowledgement of the diagnosis of a flu the express a method (detection of a virus in a material from a nose by means of fluorescing antibodies) is used. Retrospective diagnostics - revealing of increase of a credit of specific antibodies at research of didymous Serums: first Serum undertakes till fifth day of the disease, the second - in 12-14 days; increase of antiserum capacities in 4 times and more is diagnostic.