Influenza (Flu) is a contagious viral respiratory infection caused by Influenza viruses, mainly Influenza A and Influenza B viruses. It affects the nose, throat, and lungs and can range from a mild illness to a severe infection requiring medical care. Influenza spreads easily, especially during seasonal outbreaks, and can affect people of all ages.
The flu virus spreads from person to person through respiratory droplets released when an infected person coughs, sneezes, or talks. It can also spread by touching contaminated surfaces and then touching the mouth, nose, or eyes. Symptoms usually appear 1–4 days after exposure to the virus.
Influenza commonly causes sudden symptoms including fever, chills, cough, sore throat, body aches, and extreme tiredness. Unlike the common cold, flu symptoms often appear quickly and can be more intense. Most healthy people recover within a few days to two weeks, but influenza can cause serious complications in young children, older adults, pregnant women, and people with weakened immune systems.
Possible complications include pneumonia, worsening of asthma or COPD, sinus infections, ear infections, dehydration, and inflammation of the heart or brain in rare cases. Severe influenza can sometimes become life-threatening if not properly managed.
Doctors diagnose influenza through symptoms and medical history. In some cases, laboratory tests such as rapid influenza diagnostic tests (RIDTs) or PCR tests may be performed to confirm infection, especially in hospitalized or high-risk patients.
Treatment usually focuses on symptom relief, and antiviral medicines may be prescribed for certain patients, especially when started early.
Influenza is caused by infection with Influenza viruses, mainly:
Influenza A virus
Influenza B virus
The virus spreads through:
Coughing and sneezing droplets
Close contact with infected people
Touching contaminated surfaces
Contact with respiratory secretions
Risk factors include:
Lack of flu vaccination
Weak immune system
Older age
Young children
Pregnancy
Chronic diseases such as asthma, diabetes, or heart disease
Crowded environments
Influenza prevention methods include:
Getting an annual flu vaccine
Washing hands regularly
Avoiding close contact with infected people
Covering mouth and nose while coughing or sneezing
Avoiding touching face with unwashed hands
Staying home when sick
Keeping indoor areas well ventilated
Maintaining a healthy immune system
Flu vaccination is the most effective way to reduce the risk of infection and severe complications.