What is Influenza?
Flu or influenza can spread from person to person. Caused by influenza viruses, this viral infection of the respiratory tract spreads by breathing in droplets from coughs and sneezes containing the virus, touching infected surfaces and can cause complications like pneumonia. Influenza or flu is a seasonal infection and is most common in the winter months.
Influenza Flu Symptoms
Influenza is not simply a common cold. In a majority of cases, flu symptoms appear within two to three days following contact with the virus. Since influenza spreads easily, it can affect a large group of people in a short span of time. Flu symptoms usually appear 2–3 days after exposure to the virus.
Common Flu Symptoms in Adults and Children
Most people with influenza may experience:
- Sudden high fever
- Dry cough
- Body aches (especially in the back, head, and legs)
- Extreme tiredness or weakness
- Chills and sweating
- Extreme tiredness or weakness
- Chills and sweating
- Loss of appetite
- Pain behind the eyes
- Runny nose or sore throat
- Sneezing
Tip: If you were in close contact with someone who has the flu, your chances of getting it are higher. Children may also experience ear pain, vomiting, or diarrhoea along with flu symptoms.
Influenza A Symptoms
Influenza A is the most common type and can infect humans and animals. It often causes sudden fever, severe body aches, fatigue, and cough. This type can lead to outbreaks and sometimes severe complications, especially in children, elderly, or people with weak immunity.
Influenza B Symptoms
Influenza B mainly affects humans and usually causes milder flu symptoms than type A. Common signs include fever, sore throat, runny nose, and tiredness. While it’s less likely to cause pandemics, it can still make you feel very unwell.
Influenza C Symptoms
Influenza C typically leads to mild respiratory symptoms, like a slight fever, cough, and runny nose. Most people recover without needing medical treatment, and it rarely causes severe illness.
Influenza D Symptoms
Influenza D primarily affects cattle and is rarely seen in humans. There are very few reported cases in people, and symptoms are usually mild if it occurs.
Influenza Flu Causes
The flu or influenza is caused by the influenza virus. The virus spreads through air in the form of droplets when someone with the flu infection talks, coughs or sneezes. The most common types that infect people are Influenza A, B and C. Both Influenza B and A are seasonal and a majority of people contract the viruses in winter months. While influenza A and B cause severe symptoms, Influenza C is not seasonal and does not cause severe symptoms.
Influenza virus is constantly evolving with new strains appearing often. When an individual first contracts the viral infection, it gives long-term protection against similar strains of influenza.
Note: Bird flu and swine flu are both subtypes of Influenza A.
When to See a Doctor For Influenza?
Seek medical attention if you experience:
- High fever that won’t go down
- Difficulty breathing
- Severe body aches or weakness
- Signs of dehydration (especially in children and elderly)
Influenza Flu Diagnosis
For the diagnosis of influenza, a doctor conducts a physical examination, determines the symptoms of flu, and orders tests that detect influenza viruses. Influenza and other kinds of viruses can be confirmed by a doctor after a throat and nose swab has returned positive results for an individual.
Other types of tests for influenza may include:
Antigen tests help identify viral proteins referred to as antigens. An example of an antigen test for influenza is a rapid influenza diagnostic test.
A molecular test determines the genetic material from the influenza virus. PCR (Polymerase Chain Reaction) tests and NAAT (Nucleic Acid Amplification) tests are common molecular tests.
Influenza Risk Factors
A range of risk factors may lead to an elevated risk of catching a flu virus or having complications associated with an influenza infection.
Age
Seasonal influenza virus tends to have more serious outcomes in young children of the age two and younger. Also, adults older than the age of 65 are at a greater risk of catching the flu with worse outcomes.
A Compromised Immune System
A weakened immune system that doesn’t clear out the flu virus quickly, may be at a greater risk of experiencing complications associated with influenza. An individual may have a weakened immune response due to illnesses or a certain type of treatment for an ailment.
Chronic illnesses
People with chronic conditions are at an increased risk of flu complications. Examples of such conditions are; asthma, heart disease, diabetes, problems with the airway, nervous system disorders, a history of stroke or kidney and liver disease.
Influenza Treatments
Medications
- It’s important to remember that since the flu is a viral infection, antibiotics will not support treatment and must not be taken. Contrastingly, antiviral medications prescribed by the internal medicine doctor or flu specialist, and started in the first two days after the onset of flu symptoms, may shorten the length of the illness.
- Simple pain relievers and decongestants can help improve how you feel while the body’s immune system fights off the viral infection.
Home Care
It is common to feel extremely tired or weak until the body temperature returns to normal (approximately 3 days). Rest helps the body make the most of its energy to fight the viral infection.
The time span during which the adults with the flu can spread the viral infection is usually around three to five days in adults, and up to seven days in younger children after the first symptoms appear.
Extra fluids help rehydrate and compensate for the fluids lost during fever (through sweating).
Point to remember: If your urine is dark, it’s an indication that you may need to drink more water. Try to drink a glass of water every hour while you are awake.
Prevention
As per Centers for Disease Control and Prevention, individuals of the age six months and older must receive the influenza vaccine. It works by exposing an individual to a small dose of flu virus that helps the body develop immunity to fight the disease. Remember, vaccination will not treat an existing influenza infection. Other preventive steps that can help reduce the spread of the viral infection include:
Wash your hands for at least 20 seconds with soap and water. If soap and water isn’t available, use an alcohol-based sanitizer with a minimum 60% alcohol content.
Keep your hands away from the mouth, nose and eyes and avoid touching your face frequently.
Cover your sneezes and coughs
Sneeze or cough into a tissue or elbow and then wash your hands.
Clean often-touched surfaces on a regular basis to prevent the spread of infection from touching surfaces exposed to the virus.
Influenza spreads easily in crowds, for example, in schools, office buildings, auditoriums and on public transportation services. Avoid crowds during peak flu season to lower the chances of infection.
Article By Dr. P Venkata Krishnan
Sr. Consultant - Internal Medicine
Artemis Hospitals
Frequently Asked Questions
What is flu or influenza?
Influenza or flu is a highly contagious infection caused by a virus and affects the respiratory tract. In most cases, the flu usually spreads by breathing in droplets from sneezes and coughs containing the virus.
How long can influenza flu last?
A majority of influenza flu symptoms go away in four to seven days. However, the cough and feeling of tiredness may last for weeks. In some cases, the fever may recur and also cause a loss of appetite.
Is influenza serious?
For individuals who are young and healthy, the flu usually isn’t serious. Children of the age two and younger or older adults above the age of 65 may develop serious health problems after the flu, called complications.
Is influenza curable?
Yes, influenza is curable. If you contract the flu virus, antiviral drugs may be a treatment option. These drugs make the illness milder and shortens the time span for which you are sick. Antiviral drugs work best if started early, ideally within two days after the onset of influenza flu symptoms.
