NASHVILLE, Tenn. – in addition to a flu outbreak, some parts of Middle Tennessee are dealing with a stomach virus.

Dani Williamson, a nurse practitioner with Cool Springs Family Medicine, told Nashville's News 2 she's seen a number of cases in the past week.

“Gastroenteritis, [the] plain old stomach virus, it can last anywhere from 24 hours to several days,” Williamson said.

She said some of the symptoms include vomiting, diarrhea, lethargy, not being able to go to the bathroom, dry skin and dry mouth.

“There's not a whole lot you can do if it's just a virus,” she said.  “It has to run its course and it goes through the family.  when I was on all last week, I had phone calls that every single person in the family had it. it started with one and went all the way through.”

The weather may be partly to blame.

Cold temperatures, snowy conditions and school closings are all ingredients for an outbreak of illnesses.

“[The] winter is a good time for viruses to spread,” said Dr. William Schaffner, Chairman of Preventive Medicine at Vanderbilt University. ”The humidity is down and that permits virus spread, and people are spending a lot of time indoors, so they're close to each other.”

Schaffner said frequent hand-washing and avoiding people who are already sick are good ways to keep the germs away, but those who are already sick should stay home to avoid spreading them to other people.

The seasonal flu, according to the latest flu activity map from the CDC, is widespread in Tennessee and several other eastern states.Doctors have said getting a flu shot is the best way to protect against the seasonal flu virus. The Metro Health Department is offering the shots for $20 each at all three of its centers. Learn more about the flu and other viruses at CDC.gov.