
Influenza is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness and sometimes lead to death. The best way to prevent the flu is by getting a flu vaccine each year.
What is Influenza?
There are four types of seasonal influenza viruses: A, B, C, and D. Influenza A and B viruses circulate and cause seasonal epidemics.
- Influenza A viruses are further classified into subtypes according to the combinations of hemagglutinin (HA) and neuraminidase (NA), the proteins on the virus’s surface. Currently circulating in humans are subtype A(H1N1) and A(H3N2) influenza viruses. The A(H1N1) is also written as A(H1N1)pdm09 as it caused the pandemic in 2009 and subsequently replaced the seasonal influenza A(H1N1) virus, which had circulated before 2009. Only Influenza type A viruses are known to have caused pandemics.
- Influenza B viruses are not classified into subtypes but can be broken down into lineages. Currently, circulating influenza type B viruses belong to either B/Yamagata or B/Victoria lineage.
- Influenza C virus is detected less frequently and usually causes mild infections. Thus does not present public health importance.
- Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.
What are the Symptoms of Influenza?
The most common symptoms of the flu are:
- The sudden appearance of a high fever (38°C or more)
- A dry cough
- Body aches (especially in the head, lower back, and legs)
- Feeling extremely weak and tired (and not wanting to get out of bed).
Other symptoms can be:
- Chills
- Aching behind the eye
- Loss of appetite
- Sore throat
- Runny or stuffy nose
Having the flu is even more likely if you have been in contact with someone who already has it.
What is the Treatment for Influenza?

If you do come down with the flu, these measures may help ease your symptoms:
- Drink plenty of liquids. Choose water, juice, and warm soups to prevent dehydration.
- Rest. Get more sleep to help your immune system fight infection. You may need to change your activity level depending on your symptoms.
- Consider pain relievers. Use acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) to combat the achiness associated with Influenza. Children and teens recovering from flu-like symptoms should never take aspirin because of the risk of Reye’s syndrome, a rare but potentially fatal condition.
Recommended medication for flu:
- Amantadine Hcl – this medication belongs to an antiviral group of the drug. Amantadine Hcl works by blocking the growth of the Influenza A virus in the body. It also stops the spread of the infection.
What is a Serious Case of Influenza?
If you are young and healthy, the flu usually isn’t severe. Even though you may feel miserable while you have it, the flu usually goes away in a week or two with no lasting effects. But children and adults at high risk may develop complications that may include:
- Pneumonia
- Bronchitis
- Asthma flare-ups
- Heart problems
- Ear infections
- Acute respiratory distress syndrome
Pneumonia is one of the most severe complications. Pneumonia can be deadly for older adults and people with a chronic illness.
So it is also essential to take several measures to reduce the spread of infection, including:
- Wash your hands. Washing your hands often with soap and water for at least 20 seconds prevents many common infections.
- Avoid touching your face. Avoid touching your eyes, nose, and mouth.
- Cover your coughs and sneezes. Cough or sneeze into a tissue or your elbow. Then wash your hands.
- Clean surfaces. Regularly clean often-touched surfaces to prevent the spread of infection from touching the virus and your face.
- Avoid crowds. The flu spreads wherever people gather in childcare centers, schools, office buildings, auditoriums, and public transportation. Avoiding crowds during peak flu season reduces your chances of infection.
Also, avoid anyone who is sick. If you are sick, stay home for at least 24 hours after your fever is gone to lessen your chance of infecting others.