On April 21, 2015, Hospital A in Lancaster, Ohio, reported a suspect botulism case. Within two hours, four more patients with similar clinical features arrived at the emergency department. All had eaten at a widely attended church potluck meal on April 19. Botulism is a rare but severe neuroparalytic illness, with a mortality rate of ~60% if untreated. In anticipation of more patients, CDC sent an unprecedented 50 doses of botulinum antitoxin to Ohio. We investigated to confirm the diagnosis, identify additional patients, and determine the source of exposure.
METHODS:
A case was defined as illness in a person who ate potluck food and developed ≥1 symptom of botulism during April 19–29. We identified all persons who consumed potluck food, administered a food exposure questionnaire, interviewed a food preparer, and collected leftover food. Laboratory testing of clinical and food specimens was performed for botulinum neurotoxin and Clostridium botulinum.
RESULTS:
Among 77 persons who consumed potluck food, 29 (38%) met the case definition. Median patient age was 64 (range: 9–87) years. Twenty-five (86%) patients received botulinum antitoxin. Eleven (38%) patients were intubated. One patient died. Twenty-one (91%) of 23 persons who reported consuming homemade potato salad and five (10%) of 50 who reported not consuming it became ill (risk ratio: 9.1; 95% confidence interval: 3.9–21.2). Interviews with the preparer revealed improper home canning of potatoes. Patient and potato salad specimens yielded botulinum neurotoxin and C. botulinum type A.
CONCLUSIONS:
This was the largest United States botulism outbreak in 37 years. The epidemiologic and laboratory investigations implicated potato salad prepared with improperly home-canned potatoes. Early recognition and rapid response likely reduced mortality.