Pierce County, Washington. Pierce County is a county in the U.S. state of Washington. As of the 2010 Census, the population was 795,225, making it the second-most populous county in Washington behind King County. The county seat and largest city is Tacoma.
You can be contagious from a few days up to two weeks or more, depending on which virus is causing your stomach flu (gastroenteritis). A number of viruses can cause gastroenteritis, including noroviruses and rotaviruses.
A: Symptoms of the flu usually last for  seven to 14 days, with the individual being contagious beginning a day before symptoms appear through the first week of the flu, according to Flu.gov. Young children and adults with weakened immune systems sometimes remain contagious longer.