he course of influenza takes the form of a group of suddenly occurring symptoms such as:
- fever above 38°C,
- muscular pain and/or headache.
In the course of influenza infection, apart from the symptoms listed above, the following clinical symptoms often appear suddenly in the patient:
- generalized symptoms: shivering, general feeling of malaise, weakness, lack of appetite,
- joint and bone pain,
- upper respiratory tract symptoms: congestion of the throat mucosa, rhinitis, dry unproductive cough,
- drowsiness – this symptom is rarely present in adults. However, it occurs in about 50% of cases in children aged under 4 years of age. Infants and small children may show apathy, unwillingness to eat, respiratory difficulties connected with nasal obstruction, and gastrointestinal symptoms: nausea, diarrhoea and vomiting.
Where the influenza virus infection is uncomplicated, the patient’s condition normalises after about seven days. The symptoms that persist the longest could be:
- cough – even up to two weeks,
- continued feeling of illness and weakness – especially in the elderly or people with chronic diseases.