Why does flu cause symptoms

Young children may be able to spread the virus for a longer period of time. Influenza symptoms can include fever, headache, muscle pain, runny nose, sore throat, extreme tiredness and cough. Children may also experience nausea, vomiting or diarrhea. Although infections from other viruses may have similar symptoms, those due to the influenza virus tend to be worse. Symptoms can begin about 1 to 4 days, or an average of 2 days, after a person is first exposed to the influenza virus.

Fever and other symptoms can usually last up to 7 to 10 days, but the cough and weakness may last 1 to 2 weeks longer. If you get sick with influenza, home treatment can help ease symptoms. Follow the self-care advice below:.

Consult your health care provider early if you develop flu-like symptoms and you have a condition that puts you at higher risk of complications. You should also call your health care provider if your symptoms get worse, such as shortness of breath or difficulty breathing, chest pain or signs of dehydration such as dizziness when standing or low urine output. While this process causes some lung injury, most of the symptoms of the flu are actually caused by the immune response to the virus.

These cells express receptors that are able to sense the presence of the virus. They then sound the alarm by producing small hormone-like molecules called cytokines and chemokines.

These alert the body that an infection has been established. Cytokines orchestrate other components of the immune system to appropriately fight the invading virus, while chemokines direct these components to the location of infection. One of the types of cells called into action are T lymphocytes , a type of white blood cell that fights infection. When T cells specifically recognize influenza virus proteins, they then begin to proliferate in the lymph nodes around the lungs and throat.

This causes swelling and pain in these lymph nodes. After a few days, these T cells move to the lungs and begin to kill the virus-infected cells. This process creates a great deal of lung damage similar to bronchitis, which can worsen existing lung disease and make breathing difficult. In addition, the buildup of mucous in the lungs, as a result of this immune response to infection, induces coughing as a reflex to try to clear the airways.

Normally, this damage triggered by arrival of T cells in the lungs is reversible in a healthy person, but when it advances, it is bad news and can lead to death. Diagnosing flu Flu, and other kinds of viruses, can only be confirmed by a doctor after a nose or throat swab has returned positive results. What to expect with the flu Symptoms of the flu hit very quickly and may last several weeks.

A bout of the flu typically follows this pattern: Days 1—3: Sudden appearance of fever, headache, muscle pain and weakness, dry cough, sore throat and sometimes a stuffy nose. Day 4: Fever and muscle aches decrease. Hoarse, dry or sore throat, cough and possible mild chest discomfort become more noticeable. You may feel tired or flat. Day 8: Symptoms decrease. Cough and tiredness may last one to two weeks or more. What about flu complications? The flu can also make some existing medical conditions worse.

People at higher risk of severe complications associated with the flu include: pregnant women people aged over 65 Aboriginal and Torres Strait Islander people children under 5 years people with chronic medical conditions. When to seek medical attention See your doctor if you have any concerns.

Seek immediate medical attention if you experience any of the following symptoms: difficulty breathing chest pain sudden dizziness confusion severe vomiting fever with a rash. How can I avoid giving the flu to other people? It is important we all play our part in helping fight the flu and to protect our health system. Aside from getting your flu shot, follow these 3 simple steps to stop the spread of the flu: Step 1 - Cough or sneeze into your elbow If you feel a cough or sneeze is coming on, make sure to cough or sneeze into your elbow.

Step 2 - Wash your hands thoroughly and regularly Our hands are one of the top spreaders of viruses. The flu virus is carried in almost invisible droplets from saliva, sneezes, coughs, and runny noses. Flu viruses can live on surfaces such as lift buttons or handrails for up to 48 hours and are spread when people touch an infected surface. Wash your hands thoroughly and often with soap and water for at least 20 seconds — especially if you have been in a public place, or after blowing your nose, coughing, sneezing or using the toilet.

Keep your distance when you're sick or if you're around someone who is sick. For your yearly flu shot. Everyone 6 months and older should visit a healthcare provider every year to get a flu vaccine. The best time to go is soon after the vaccine becomes available in the fall.

If you develop flu symptoms. If you do get sick, it is important for you to call your doctor as soon as possible to receive prompt treatment with antivirals—especially if you are at high risk for complications. Antivirals can be effective in reducing the severity of flu and the duration of the disease. For flu complications. Pneumonia can be caused by the flu virus or by bacteria that get into the lungs when the body's defense system is weakened by the flu.

See a doctor if you:. Other infections that may be associated with the flu include sinusitis, bronchitis and ear infections. If your cough won't go away. You may have a cough that lasts for weeks to months after flu symptoms go away; and it may keep you up at night. This cough has been associated with asthma-like symptoms, and can be treated with asthma medications.

Consult a healthcare provider if you have this kind of cough.