Symptoms are vomiting and diarrhea and it's very contagious.
The simple combination of soap and water can make all the difference when it comes to protecting yourself from the Norovirus.
"Many of the ways which people can stop the spread of the Norovirus are the same ways you can stop the spread of the influenza virus, which is hand washing, and if you're sick, stay home from work. If you're sick, stay home from school," said Dr. Edward Moreno, the Director of the Fresno County Department of Public Health.
Norovirus outbreaks are commonly associated with schools or cruise ships where it's easily transmitted person to person and on surfaces. It can also be transmitted through food and food handling.
A new strain typically emerges every two to three years. The latest version, the so-called 'Sydney' strain was responsible for more than half of all US Norovirus outbreaks in the last four months of 2012.
Moreno said Fresno County typically investigates one or two Norovirus outbreaks a month. So far, the new strain hasn't been detected.
"As the Sydney virus spreads across the United States, as the Sydney virus causes outbreaks in the San Joaquin Valley, we'll see if it's actually going to cause more outbreaks or more serious illness," said Dr. Moreno.