A few people on here have recently suffered through norovirus I believe along with their UC. Might want to avoid these in the future.
Oysters harbor, transmit human norovirus: Avoid raw ones
"Oysters not only transmit human norovirus; they also serve as a major reservoir for these pathogens, according to research published August 28 in Applied and Environmental Microbiology, a journal of the American Society for Microbiology. "More than 80 percent of human norovirus genotypes were detected in oyster samples or oyster-related outbreaks," said corresponding author Yongjie Wang, PhD.
www.sciencedaily.com/releases/2015/08/150828135213.htm