Nearly 100 people have reported symptoms of viral gastroenteritis after a weekend swim meet at the U.S. Naval Academy in Annapolis, state health officials said.
Several athletes got sick on the pool deck during the finals session of the Maryland State Swimming Championships on Saturday, according to a letter on the Maryland Swimming website.
Of the 99 people who reported illnesses to Maryland Swimming after the weekend's events, 89 were swimmers, about seven or eight others were officials or coaches on the pool deck and others were parents or spectators, said Raymond Brown, the organization' s general chair.
"This is unprecedented," he said.
The state health department is still testing stool samples from people who were sick to determine exactly what pathogen caused the illness, said Dr. Lucy Wilson, chief of the health department's center for surveillance, infection prevention and outbreak response. However, the symptoms match those of viral gastroenteritis, which typically passes within 24 to 48 hours, she said.
Gastroenteritis is caused by noroviruses, which are normally transmitted through contact with an infected person, such as sharing food or a water bottle, or on dirty towels or bathroom doorknobs — "anything where the virus would be on the material," Wilson said.
The pool itself would be an unlikely source, she said. The naval academy follows federal guidelines for maintaining the pool and cleaning it after biologic material has entered the water. "It would be unusual in a chlorinated pool where they were doing proper protocol for that to be the source of transmission," Wilson said.
Teams from all over Maryland competed in the championships, which began Thursday night and concluded Sunday evening, Brown said. The majority of the more than 800 participants ranged in age from 9 to 18, he said.
One swimmer, at the conclusion of a Saturday event, vomited on the pool edge as he left the water, Brown said. Meet officials stopped the competition for at least 45 minutes to clean up the area, treat the water and check disinfectant levels, which were within the proper range, he said.
Competition officials told coaches Saturday night to prevent any competitors with symptoms from swimming, he said.
About 20 percent of scheduled participants did not return to the venue on Sunday, he said.
Meet officials contacted the Anne Arundel County health department Sunday, which inspected the facility, he said.
Health officials also instructed the organization that only swimmers who had been without symptoms for 24 hours should participate.
So far state officials are not aware of any deaths or hospital admissions as a result of this illness, Wilson said.
Recommendations to avoid the spread of noroviruses include cleaning vomit and feces from surfaces and staying home if you are sick, Wilson said. Competitors have been told to wait until they have been symptom-free for 24 hours before going back to swim practice, she said.