Overview
The flu is a highly contagious respiratory infection caused by the influenza virus. Unlike the common cold, the flu has a sudden onset and is characterized by high fever and severe muscle aches.
Most healthy adults recover within 1-2 weeks. However, it can lead to serious complications such as pneumonia in children, the elderly, pregnant women, and people with chronic conditions.
Symptoms
Symptoms begin suddenly 1-4 days after exposure to the virus:
- High fever (38-40 °C)
- Severe muscle and joint aches
- Chills, shivering
- Extreme fatigue and weakness
- Headache
- Dry cough
- Sore throat
- Runny or stuffy nose
- Sometimes nausea, vomiting, diarrhea (especially in children)
Causes
The flu is caused by influenza A and B viruses. The virus spreads:
- Through droplets released during coughing and sneezing
- By touching contaminated surfaces
- Rapidly in closed, crowded environments
The flu virus mutates constantly, so new strains emerge each year.
Risk Factors
- Being over 65
- Children under 5 (especially under 2)
- Pregnancy
- Chronic conditions (asthma, COPD, heart, diabetes, kidney disease)
- Weakened immune system
- Severe obesity
- Healthcare workers
Complications
- Pneumonia (most common and serious complication)
- Bronchitis
- Sinusitis, middle ear infection
- Worsening of asthma or heart disease
- Myocarditis (inflammation of the heart muscle)
- Encephalitis (brain inflammation, rare)
When to See a Doctor
Seek immediate care for:
- Shortness of breath or rapid breathing
- Chest pain or pressure
- Persistent vomiting
- Sudden dizziness, confusion
- Fever above 39.5 °C lasting more than 3 days
- Bluish color or retractions in a child
Diagnosis and Treatment
Diagnosis is usually based on symptoms. Rapid flu tests may be done when needed.
Treatment:
- Plenty of fluids and rest
- Fever-reducing medicines (paracetamol, ibuprofen)
- Antivirals (such as oseltamivir) in high-risk groups; effective within the first 48 hours
- Antibiotics are only used when bacterial complications develop
Prevention
- Get the flu vaccine every year (especially if over 65, pregnant, or chronically ill)
- Wash your hands often
- Stay away from sick people
- Stay home when you are sick
- Cover your mouth with your elbow when coughing
- Maintain a strong immune system (sleep, nutrition, exercise)