• An infectious disease caused by an Influenza virus. Symptoms usually start two days after exposure to the virus and most last less than a week. Cough may last for more than two weeks.
    • Nausea and vomiting may be present in children, but are not common in adults.
  • Complications of the disease may include viral pneumonia, secondary bacterial pneumonia, sinus infections, and worsening of previous health problems such as asthma or heart failure.
  • Other name: Flu
  • Around 33% of people with influenza are asymptomatic
  • Symptoms of influenza may include:
    • Fever and extreme coldness (chills shivering, shaking)
    • Cough
    • Nasal congestion
    • Runny nose
    • Sneezing
    • Body aches, especially joints and throat
    • Fatigue
    • Headache
    • Irritated, watering eyes
    • Reddened eyes, skin (especially face), mouth, throat and nose
    • Petechial rash
  • There may be difficulty in distinguishing between the common cold and influenza in the early stages.
    • Flu – high fever with a sudden onset and extreme fatigue
    • Influenza – mixture of symptoms of common cold and pneumonia, body ache, headache, and fatigue.
  • Of the symptoms enumerated, the combinations of fever with cough, sore throat and/or nasal congestion can improve accuracy of diagnosis.
  • Occasionally, can cause severe illness
    • Primary viral pneumonia or secondary bacterial pneumonia.
    • Obvious symptom is trouble breathing.
    • Additionally, if a child (or presumably an adult) seems to be getting better and then relapses with a high fever, bacterial pneumonia can be suspected.


  • Physician may do/request:
    • History & Physical Exam
    • Laboratory tests



  • Rest, drink a lot of fluids, avoid alcohol and tobacco use.
  • Medications like acetaminophen (paracetamol) for fever and pain relief.
    • Children and teenagers with flu symptoms (particularly fever) should not take aspirin during an influenza infection (especially influenza type B)
      • Might develop Reye’s syndrome – rare but potentially fatal liver disease
    • Antiviral medications
      • Neuraminidase inhibitors: oseltamivir, zanamivir
      • M2 protein inhibitors: amantadine, rimantadine

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