As many as 40 restaurants may have served Hog Island Oyster Company in San Francisco, Sonoma, Petaluma, Bolinas, Sacramento, Sebastopol, Napa, and Santa Rosa. The oysters were contaminated with Norovirus and led to the January 3, 2019 closure and Tomales Bay (for at least one week) and a recall of the contaminated oysters. The victims, mostly identified in San Francisco at present, presented with the symptoms of Norovirus between December 29th of 2018 and January 5th of 2019.
California Department of Public Health officials have traced the likely source of the illnesses to oysters provided by Hog Island Oyster Company, though at present no epidemiological link has been confirmed.
According to a spokesperson, “it’s likely this represents contamination of the water itself” that led to the illnesses, and not anything that Hog Island Oyster Company has done itself in processing the oysters. One leading theory is that the bay received a great deal of rainwater that could have swept sewage into the bay.