Fish-Associated Foodborne Disease Outbreaks: United States, 1998-2015.

Each year in the United States, ∼260,000 people get sick from contaminated fish. Fish is also the most commonly implicated food category in outbreaks. We reviewed the Centers for Disease Control and Prevention Foodborne Disease Outbreak Surveillance System for outbreaks resulting from consumption of fish during the period 1998-2015. We found 857 outbreaks associated with fish, resulting in 4815 illnesses, 359 hospitalizations, and 4 deaths. The median number of illnesses per outbreak was three (range: 2-425). The annual number of fish-associated outbreaks declined from an average of 62 per year during the period 1998-2006 to 34 per year during the period 2007-2015. Hawaii (221 outbreaks [26%]) and Florida (203 [24%]) reported the most outbreaks. Among 637 outbreaks (74%) with a confirmed etiology, scombrotoxin (349 [55%]) and ciguatoxin (227 [36%]) were by far most common. Most outbreak-associated illnesses were caused by scombrotoxin (1299 [34%]), Salmonella (978 [26%]), and ciguatoxin (894 [23%]). Most hospitalizations were caused by Salmonella (97 [31%]) and ciguatoxin (96 [31%]). Norovirus (105 average illnesses; range: [6-380]) and Salmonella (54 [3-425]) caused the largest outbreaks. Fish types implicated most often were tuna (37%), mahi-mahi (10%), and grouper (9%). The etiology-fish pairs responsible for the most outbreaks were scombrotoxin and tuna (223 outbreaks), scombrotoxin and mahi-mahi (64), and ciguatoxin and grouper (54). The pairs responsible for the most illnesses were scombrotoxin and tuna (720 illnesses) and Salmonella and tuna (660). Of the 840 outbreaks (98%) with a single location of food preparation, 52% were associated with fish prepared in a restaurant and 33% with fish prepared in a private home. Upstream control measures targeted to the most common etiologies and controls during processing and preparation could further reduce outbreaks caused by fish.