The cause and source of the illness are unknown, officials said. So is the total number of people affected. However, the Washington State Department of Health has received calls from 19 cheerleading 
squads all reporting at least one person sick. More than 1,000 cheerleaders competed in the event at Everett’s Comcast Arena and more than 3,000 spectators attended.
The investigation being conducted jointly by the Washington State Department of Health and the Snohomish Health District. So far, it has included collecting samples for testing at a laboratory, and sending a questionnaire to participants.
People who attended the event and have severe symptoms are advised to contact a health care provider.