See below. Norovirus is mainly spread by fecal-oral route. The virus is shed in stool and also by airborne droplets of vomitus. You contract the virus by eating contaminated food or drink, by touching a surface thats been contaminated or by exposure to the vomitus. If a person recently vomited, saliva would transmit the virus. You are mostly contagious during the acute illness and for several days after.