DENVER — It’s officially cold, flu and stomach flu, also known as viral gastroenteritis, season. But do you know how to tell the difference between these three common winter illnesses?

Take this quiz to find out. 

1. Symptoms come on gradually over the course of 1 to 3 days.

This can be a cold or the stomach flu. Symptoms usually start 1 to 3 days after the exposure to the virus, and can last for a 1 to 2 weeks usually.

2. The stomach flu is caused by the flu virus. (T/F) 

False. The most common causes of the viral gastroenteritis are norovirus and rotavirus. People usually get it from eating or drinking contaminated food or water, on surfaces, or by sharing items like silverware and food. The flu is caused by the influenza viruses A, B, and C. 

3. You have gastrointestinal symptoms like nausea, vomiting and diarrhea commonly with this. 

Most commonly this is the stomach flu. But, you can also get some GI-type symptoms with the flu as well.

4. You feel like you got hit by a semi-truck. Sudden onset of high fevers, chills, body aches, cough. What do you have?

The flu. The sudden onset, high fevers, and muscle aches are what distinguish it from everything else. The flu is not something which lingers. The flu shot helps prevent you from getting the flu. And, even if you get the flu, you still have a milder form if you have had the flu shot.

5. Hand sanitizer kills the viruses that cause these illnesses.

Hand sanitizer does not kill norovirus, which is a common cause of the stomach flu. It is helpful if that is all you have, but soap and water is always best. At least 20 seconds of scrubbing those hands (which is about how long it will take you to sing happy birthday twice).

6. This type of stomach flu virus is commonly associated with outbreaks on cruise ships. 

Norovirus. Just a few weeks ago, an entire Royal Caribbean cruise ship had to be turned around because so many passengers and crew got sick.

7. Is highly contagious and gets passed by coughing and sneezing or in the air.

Both the flu and colds are spread through the air. It's important to cover your mouth when you cough. And, maybe avoid the handshake during the winter season.

8. Antibiotics can be used to help treat colds. (True or False)

False. Colds are most commonly caused by adenovirus, rhinovirus and coronavirus. Antibiotics are used to treat bacterial, not viral illnesses.

9. Common symptoms can include sneezing, low-grade temperatures, coughing, sore throat, runny nose and can last for up to 3-4 weeks. What is it?

The common cold. Many people can have symptoms that linger, especially the cough, for weeks after. Time and treating the symptoms is key.

Follow 9NEWS Medical Expert Dr. Comilla Sasson on Facebook and Twitter. Have a medical question or health topic idea? Email Dr. Comilla at c.sasson@9news.com