"That's where my suspicion lies right now," said department Medical Director Dr. Dean Sienko.
Three restaurant patrons have been hospitalized with dehydration, he said, and the outbreak appears to have spread to people in three states.
Specimens taken from multiple sick individuals are expected to yield lab results this afternoon, confirming whether norovirus is the culprit. The virus causes vomiting, diarrhea, nausea, a low-grade fever. It is transmitted by contact and can become airborne.
Norovirus afflicted more than 400 patrons at a Delta Township Carrabba's Italian Grill in January.
The Eastwood Towne Center restaurant voluntarily shut down Thursday for a thorough cleaning and is expected to reopen this week.
Health officials today are analyzing information collected from the 360 reported cases of illness and from restaurant patrons who did not fall ill.
"We've talked to more than 500 people," said Natasha Davidson, a health department spokeswoman.
The goal is to look for commonalities and to break down the results by day to see what item or items led to the illness and when.
"A virus gets into a restaurant," Sienko said, "and you get cross contamination."
He recalled working a case in Marquette in 1985 for the Centers for Disease Control and Prevention in Atlanta. Salmonella bacteria showed up in a restaurant in turkey then migrated to potato salad and finally to a green salad.
Bravo patrons reported becoming ill after visiting the restaurant between May 3 and May 11 when Bravo closed. The first report of illness came into the health department May 6.
Read more on this story in Wednesday's Lansing State Journal.
Contact Christine Rook at 377-1261 or firstname.lastname@example.org.