Influenza, the flu, is a common, very infectious viral infection. Over the years, many people have used the term “the flu” to describe anything from a stomach bug to a bout of food poisoning, but influenza is a respiratory illness and doesn’t have anything to do with the gastrointestinal system – the system that runs from your mouth to your rectum.

People who are infected with an influenza virus may develop a serious condition called sepsis. Sometimes called blood poisoning, sepsis is the body’s often deadly response to infection or injury. Sepsis kills and disables millions and requires early suspicion and rapid treatment for survival.

Sepsis and septic shock can result from an infection anywhere in the body, such as pneumonia and urinary tract infections, and viral infections like the flu. Worldwide, one-third of people who develop sepsis die. Many who do survive are left with life-changing effects, such as post-traumatic stress disorder (PTSD), chronic pain and fatigue, and organ dysfunction (don’t work properly) and/or amputations.

Doctors have found that rates of sepsis and severe sepsis tend to go up during so-called flu season.

What Is Influenza?

There are different types of influenza. There is the annual seasonal influenza and others, such as the H1N1 influenza, avian flu, swine flu, and so on.
There are three separate types of viruses:

  • Type A: Type A influenzas affect both people and animals, such as birds. The animals help spread the virus, which can be very serious. The type A flus are the ones that cause most of the flu pandemics or epidemics. In 1918, the world was hit with the “Spanish flu,” which killed millions of people. It was feared in 2009, that the H1N1 virus would have similar outcomes.
  • Type B: Type B influenzas do not infect animals and do not cause epidemics or pandemics. They are generally not as serious as the type A flu, but they still can cause harm on occasion. 
  • Type C: Type C influenzas are milder than either types A or B. They do not cause epidemics or pandemics and they only affect humans.

The viruses that cause influenza are not static, which means they do not stay the same. They can change and mutate, turning into new viruses. This is why if you catch the flu one year, you can catch it again the next – because the virus has changed enough from the year before that your body doesn’t recognize it.

The types of influenza, such as H1N1, are named by their make up. There are 16 subtypes of hemagglutinin (the “H”) and nine subtypes of neuraminidase (the “N”). These are proteins that help make up the virus. Therefore, the name of the virus is given by which humagglutinin and which neuraminidase are present.

The most commonly known influenza is the seasonal one. This is a different virus that moves around the world each year.

How Do You Get Influenza?

Influenza is highly contagious. It is a respiratory infection, which means it is caught by coming in contact with the mucus membranes in your nose. This could be contamination of the air (someone next to you sneezing) or by touch. Someone who has the flu touches his nose or mouth and then touches an object, which you then pick up. If you don’t wash your hands, at some point, if you touch your mouth or nose, you have brought the virus close enough to infect yourself.