Outbreak Linked to Morel Mushroom Exposure - Montana, 2023

Area of Science:

• Foodborne illness epidemiology
• Mycology
• Public health investigations

Background:

• A significant gastrointestinal illness outbreak occurred in Bozeman, Montana, in March-April 2023.
• The outbreak led to severe outcomes, including hospitalizations and fatalities, linked to a local restaurant.

Purpose of the Study:

• To identify the source of the foodborne illness outbreak.
• To investigate the association between food consumption and illness among restaurant patrons.

Main Methods:

• A matched case-control study was conducted among restaurant patrons.
• Data collection involved interviews to determine food exposures and illness onset.

Main Results:

• Consumption of morel mushrooms was strongly associated with gastrointestinal illness.
• A dose-response relationship was observed, with raw morel consumption showing a higher risk than cooked.

Conclusions:

• Morel mushroom consumption, particularly when raw, poses a risk for gastrointestinal illness.
• Proper preparation, including thorough cooking, is crucial for mitigating health risks associated with morel mushrooms.
• Further research is needed to understand the toxins and optimal preparation methods for morel mushrooms.