Influenza

What is Influenza?

Influenza, commonly known as "the flu", is an infectious disease caused by an influenza virus.^[1] Symptoms can be mild to severe.^[4] The most common symptoms include: a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired.^[1] These symptoms typically begin two days after exposure to the virus and most last less than a week.^[1] The cough, however, may last for more than two weeks.^[1] In children, there may be nausea and vomiting, but these are not common in adults.^[5] Nausea and vomiting occur more commonly in the unrelated infection gastroenteritis, which is sometimes inaccurately referred to as "stomach flu" or the "24-hour flu".^[5] Complications of influenza may include viral pneumonia, secondary bacterial pneumonia, sinus infections, and worsening of previous health problems such as asthma or heart failure.^[2]

Sign and Symptoms;

Symptoms of influenza can start quite suddenly one to two days after infection. Usually the first symptoms are chills or a chilly sensation, but fever is also common early in the infection, with body temperatures ranging from 38 to 39 °C (approximately 100 to 103 °F).^[15] Many people are so ill that they are confined to bed for several days, with aches and pains throughout their bodies, which are worse in their backs and legs.^[16] Symptoms of influenza may include:

• Fever and chills
• Cough
• Nasal congestion
• Runny nose
• Sneezing
• Sore throat
• Hoarseness
• Ear pressure
• Earache
• Muscle aches
• Fatigue
• Headache
• Irritated, watering eyes
• Reddened eyes, skin (especially face), mouth, throat and nose
• Petechial rash^[17]