Stomach Flu vs. Respiratory Flu: Here’s How to Tell Them Apart

Author: Sherry Farney

According to the Center for Disease Control and Prevention (CDC), influenza (flu) is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. 

There are two main types of influenza (flu) viruses: Types A and B. The influenza A and B viruses that routinely spread in people are responsible for seasonal flu epidemics each year. Most experts believe that flu viruses spread mainly by tiny droplets made when people with the flu cough, sneeze or talk. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose or possibly their eyes.

Symptoms may include fever, chills, fatigue, cough, sore throat, runny/stuffy nose, body aches, headaches, and occasionally vomiting and diarrhea.

"The most important step in preventing the respiratory flu is to get a flu shot every year,” said Sana Ahmed, MD, a member of McLaren Flint’s Family Medicine Residency Faculty. “Flu vaccine has been shown to reduce flu related illnesses and complications that can lead to hospitalizations and death."

Although norovirus, also known as the stomach flu, has virus in its name, it actually isn’t the flu at all as flu viruses are caused by the influenza virus. The stomach flu is caused by the norovirus. According to the CDC, it spreads very easily because people with the illness can shed billions of norovirus particles that you can’t see without a microscope, and it only takes a few norovirus particles to make other people sick.

Norovirus is spread through eating food or drinking liquids that are contaminated with it, or touching surfaces and objects that are contaminated and then putting your fingers in your mouth. You can also get it by having direct contact with someone who is infected with the virus, such as by caring for them or sharing food or eating utensils with them.

“Since stomach flu can spread through infected food, it is important to avoid raw meats and rinse fruits and vegetables before consuming,” said Dr. Ahmed. “If you have food that doesn’t look or smell right, don’t take a chance, throw it out.”

Symptoms can include nausea, vomiting, abdominal pain and diarrhea. Other symptoms may include fever, fatigue, and chills. 

"Both of these viruses can spread fast, lead to extreme illness, and be debilitating," added Dr. Ahmed. "It is important to take all preventative measures. Good hand washing is extremely important in preventing the spread of these illnesses. In addition, for the respiratory flu, it is important to get a yearly flu shot, cover your coughs and sneezes, and wear masks when appropriate. For the stomach flu, in addition to good hand hygiene, avoid eating raw meats and seafood and wash fruits and vegetables before consuming."