What is Norovirus?🦠 With Infectious Disease Specialist Dr. Ambreen Allana Norovirus is currently the most contagious stomach illness spreading in the U.S. Often called the winter vomiting disease, it causes sudden vomiting, diarrhea, and stomach cramps. To protect yourself, wash your hands well, clean surfaces often, and stay home when you’re sick. If you experience severe or persistent symptoms, visit a trusted infectious disease specialist at a CLS Health clinic in the Greater Houston area. D