Influenza, commonly known as the flu, is a viral infection of the respiratory system that can cause mild to severe illness and at times can lead to death. Symptoms of the flu usually come on suddenly and can include):

• Fever or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Fatigue (tiredness)
• Loss of appetite
• Aching behind the eyes
• Shortness of breath
• Chest discomfort
• Hoarse, dry or sore throat
• Eye pain
• Vomiting and diarrhea (more common in children than in adults)

Its important to note that not everyone with the flu will have a fever. Symptoms of the flu can hit very quickly and may last several weeks. People with the virus are likely contagious from about a day before symptoms appear until about 5 to 7 days after they start. Children and people with weakened immune systems may be contagious for a slightly longer time. If you have emergency symptoms of the flu, such as difficulty breathing or shortness of breath, chest pain, ongoing dizziness, seizures, worsening of existing medical conditions, or severe weakness or muscle pain, get medical care right away.