The hospitalization rate is the number that should stop you. Of 30 people identified in a multistate outbreak, 25 were hospitalized. That is 83 percent, far above what hepatitis A usually produces, and it reflects both the severity of these infections and the fact that milder cases never got counted.
Federal and state investigators traced the common exposure through food interviews. Of the people questioned, 76 percent reported eating ceviche, 75 percent reported eating raw or undercooked shellfish, and 52 percent reported eating raw or undercooked conchas negras, also called black clams or blood clams. Those rates were substantially higher than what a national food consumption survey would predict.
