Types of Flus: The 4 Flu Strains, Explained

For many people, flu season comes with the threat of a standard virus that comes around every year. The flu, also called influenza, is a contagious respiratory infection caused by a variety of flu viruses. Four different varieties, in fact: A, B, C, and D. 

While flu viruses are detected year-round, activity is most common in the fall and winter months — often beginning in October and lasting as late as May.

Influenza A

Type A influenza is the most common strain and the one usually responsible for the majority of seasonal flu cases, especially the most severe instances. Symptoms include fever, chills, body aches, coughing, sneezing, sore throat, and exhaustion. An influenza A infection may last for about one to two weeks.

This strain of the flu is found in humans and in animals. Influenza A is spread from person to person by people who are already infected. Experts believe the virus can be spread through tiny droplets when people with the flu talk, cough, or sneeze. It is also believed that the virus can be transmitted through touching objects or surfaces that have the flu virus on them.

These viruses are the ones that tend to change rapidly, which is why scientists need to continually update the vaccines yearly to protect people from the next mutated form.

Influenza B

Type B flu is also known to contribute to seasonal flu and has very similar symptoms to influenza A. One of the main differences is influenza B is only spread from human to human and cannot infect animals. 

Like the A virus, illness caused by influenza B may persist for a week or two. During a typical flu season, it is either influenza A or B that dominates.

Influenza C

Type C flu only affects humans, and is considered much milder than types A and B. Most people who contract influenza C will experience symptoms similar to those of a cold. In healthy people, influenza C usually goes away on its own in three to seven days.

Influenza D

Influenza D is different from the rest. It is not known to affect humans. Instead, it causes illness in cattle. 

To date, the influenza D virus has not demonstrated the ability to be passed from animals to humans, although scientists suggest that such a jump may be possible.

Who is most at risk?

Children under the age of 5 are at high risk of developing flu complications like pneumonia, dehydration, and brain dysfunction.

Influenza is also especially serious for adults 65 and older because of their weaker immune systems.

Other people at high risk of flu complications are pregnant women and those with asthma, diabetes, HIV/AIDS, or cancer.

Flu Prevention 

There are some steps you can take to avoid spreading germs that lead to respiratory illnesses like the flu:

  • Avoid close contact with people who are sick
  • Stay home when you’re sick
  • Cover your mouth and nose when coughing or sneezing
  • Wash your hands often
  • Avoid touching your eyes, nose, and mouth
  • Clean and disinfect surfaces

Get Vaccinated

The number one way to prevent catching the flu is to get a flu shot. The CDC suggests everyone 6 months of age and older should get a flu vaccine every year.

American Family Care specializes in the treatment of flu symptoms and prevention. We can diagnose seasonal illnesses at any one of our convenient walk-in clinics through our on-site lab testing services. We also provide flu shots to help protect your immune system.  

Click here to find an American Family Care near you.

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