How is the rise of norovirus in the northeast affecting the Philadelphia region?
PHILADELPHIA (CBS) -- The CDC said highly contagious stomach bugs are spreading across the country with the northeast having the highest number of cases right now.
South Jersey and parts of Pennsylvania are seeing outbreaks of norovirus, the gastrointestinal bug causes uncomfortable symptoms and can be dangerous for some.
The stomach bug is estimated to infect some 20 million Americans every year, causing nearly half a million emergency room visits annually, many of them young children.
According to the CDC, the northeast region of the U.S. currently has the highest positivity rate for norovirus.
"It's a very contagious virus, very contagious," said Dr. Dodi Iannaco, who is with Virtua Health in South Jersey. "Within the past two to three weeks we've seen more cases."
Norovirus is a known problem on cruise ships but it can spread anywhere, easily, through contact with an infected person, ingesting contaminated food or water, or touching surfaces with the virus and then touching your mouth.
It's also airborne.
"You can inhale it and you can get sick that way as well," Iannaco said.
Symptoms can include diarrhea, vomiting, nausea and stomach pain.
"If someone is really fatigued, really lethargic, really getting tired, unable to keep fluids down, that's the time it's a good idea for them to come to the emergency room for evaluation," Iannaco said. "Dehydration being the biggest risk, and that really is going to be evident by a change in your level of energy."
The elderly and the very young are most at risk for the worst cases.
The best prevention is hand washing. Doctors said viruses tend to resist hand sanitizers, so soap and water is best.
Because the virus can spread through food, the CDC also said you should wash fruits and vegetables well and make sure to cook foods like shellfish thoroughly.