Almost always it causes fever and cough. It also is common to cause sore throat, fatigue, muscle aches, decreased appetite, headaches and runny nose. Very rarely can cause diarrhea and vomiting. The symptoms you should worry about are those that lead to a rapid progression to severe respiratory distress and medical assistance is then necessary.
Treatment of influenza is supportive care, making the person more comfortable – increasing fluid intake and getting plenty of rest. Antibiotics do not kill viruses and have no role in treating influenza in otherwise healthy people.
Antiviral drugs for influenza are an important adjunct to influenza vaccine for the treatment and prevention of influenza. However, they are not a substitute for vaccination. When taken before infection or during early stage of the disease (within two days of illness onset), antivirals may help prevent infection, and if infection has already taken hold, their early administration may reduce the duration of symptoms by one to two days. Be aware that the Pandemic (H1N1) 2009 virus has been found to be resistant to the antivirals amantadine and rimantidine.
In severe influenza, admission to hospital, intensive care, antibiotic therapy to prevent secondary infection (such as Pneumonia) and breathing support may be required.