Meet the experts: expert in infectious diseases Amesh A. Adalja, MD, senior research fellow at the Johns Hopkins Center for Health Security, William Schaffner, MD, infectious disease specialist and professor at Vanderbilt University School of Medicine

What is the 24 hour flu?

The 24-hour flu is usually a type of gastroenteritis, which is an inflammation of the intestines and stomach, says William Schaffner, MD, infectious disease specialist and professor at Vanderbilt University School of Medicine.

There are a whole host of things that can cause gastroenteritis, including viruses and bacteria. But “when people talk about a 24-hour stomach bug, they almost always mean norovirus infection,” says the infectious disease expert. Amesh A. Adalja, MD, senior researcher at the Johns Hopkins Center for Health Security.

Norovirus is a highly contagious virus that causes vomiting and diarrhea — and sometimes at the same time, according to Centers for Disease Control and Prevention (CDC). Norovirus is the leading cause of vomiting and diarrhea and foodborne illness in the US

It also takes less than 100 norovirus particles to make a person sick, and a patient with norovirus can shed billions of virus particles in vomit and feces. Basically, this is really, really contagious.

24 hour flu symptoms

Your exact 24-hour flu symptoms will depend on what exactly caused the illness. But if you do happen to have norovirus, you’ll likely have the following symptoms, according to the CDC:

• Nausea
• vomiting
• Diarrhea
• Stomach cramps
• Headache
• Fever
• Body aches

People with norovirus usually get better in one to three days, according to the CDC.

24 hour flu vs. food poisoning

There is some overlap between the 24-hour flu and food poisoning, given that you can get norovirus from food. (You can too get norovirus from touching surfaces or objects that are contaminated and then putting unwashed fingers in your mouth or by direct contact with someone who has the virus.)

You also have to consider this, according to Dr. Adalja: “Food poisoning is a very nebulous term that has no specific medical meaning.”

However, there are a few things that could indicate that you got sick from something you ate versus another way. “With food poisoning, you’re usually not the only person who gets sick,” says Dr. Schaffner. That is, if you happened to eat with your partner and you both got sick, chances are you both got food poisoning.

Also, with some forms of food poisoning, you might get sick right away and then feel better shortly afterward, Dr. Adalja says. “Norovirus can last 24 hours or more and can also be associated with fever and chills,” he says.

How long are you contagious with the 24-hour flu?

You will generally be contagious until you start to feel better. “Until the diarrhea or vomiting has stopped, you’re probably contagious,” says Dr. Schaffner. So while you’re still sick, do what you can to isolate yourself from the rest of your household as much as possible.

24-hour anti-influenza treatment

Unfortunately, there are no special medications you can take to treat norovirus. However, there are a few things you can do to make yourself more comfortable while riding it.

Dr. Schaffer recommends doing everything you can to keep your fluid intake up. If you struggle with nausea and vomiting, this means trying to drink small sips of water. “Eat only bland foods,” says Dr. Schaffner. “Avoid anything spicy or substantial. Whatever you put in your belly, make it easy to digest.”

When to see a doctor for the 24-hour flu

If you can’t keep anything down and you’re really struggling, Dr. Adalja says you can call your doctor for an anti-emetic (anti-nausea) drug like Zofran. This can help reduce vomiting so you can hydrate better, he explains.

But if you have signs of dehydration, such as not peeing often, feeling dizzy or dry mouth, you may need fluids in an emergency.

The good news about the 24-hour flu is that it usually doesn’t last long, and hopefully you’ll feel better in a day or so. But if you don’t or if you’re having trouble, call your doctor for next steps.