Avian flu: symptoms
Last reviewed: 23.04.2024
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The incubation period of avian influenza (influenza A (H5N1)) is 2-3 days with fluctuations from 1 to 7 days.
Avian influenza has a sharp beginning. There are signs of avian influenza, which are expressed in severe intoxication. The body temperature from the first hours of the disease rises to 38 ° C, often reaching hyperpyretic values. The feverish period extends to 10-12 days, and in severe lethal cases - until the last hours of the patient's life. Characterized by chills, muscle and joint pain. In the midst of the disease (day 2-3), such symptoms of avian influenza as: catarrhal syndrome, manifested by the development of bronchitis, bronchiolitis, laryngitis; there may be signs of rhinitis. Characterized by pain in the throat and "flaming" orofaringitis. During this period, most patients develop primary viral pneumonia. In this case, shortness of breath, a damp cough with phlegm, possibly with an admixture of blood. Above the lungs are listened to hard breathing, wet raznochalernye wheezing, crepitus.
On the roentgenogram of the chest in the early period determine nonspecific changes in the form of diffuse, multifocal or individual infiltrates, which tend to rapidly spread and merge. In some cases segmental or fractional seals can be detected. Progressive course, an increase in dyspnea and the development of a respiratory distress syndrome are characteristic.
Along with intoxication and catarrhal syndrome, GI tract infection develops, manifested by repeated vomiting, secretory diarrhea and abdominal pain. Perhaps an increase in the liver, accompanied by an increase in the activity of serum transferases. A third of patients develop acute renal failure, creatininemia. In most patients, signs of damage to the nervous system are determined, there may be impairment of consciousness, development of encephalitis.
In the hemogram, leukopenia, lymphopenia, thrombocytopenia are recorded.
There may be variants of the course of the disease with fever, diarrhea and absence of signs of respiratory damage.
[Complications of avian influenza
Avian influenza is dangerous for the development of viral pneumonia, kidney damage, liver damage. Hemopoietic organs. It is these consequences that often lead to the death of patients. It has been established that the place of replication of the influenza virus of the H5N1 subtype in humans (at least among those who died as a result of the disease) is not only the respiratory tract, but also the intestine.
Risk factors for the development of severe forms of influenza A (H5N1) in humans:
- age of the patient (in children of five years and younger the symptoms of the disease are not pronounced);
- duration of manifestation of the disease before hospitalization (delay from hospitalization);
- anatomical level of the respiratory tract;
- degree of leukopenia of peripheral blood;
- presence of multiple organ dysfunction.
Mortality and causes of death
Avian influenza has a high mortality rate, which is 50-80%. Most often, patients die from complications in the second week of the disease.