JULY 1–ST. LOUIS– At least 99 people have contracted salmonella at St. Louis Children’s Hospital, and the source of the intestinal illness remains a mystery.

The number of cases could rise because several people are still being tested, a hospital spokeswoman said Monday. The most recent case of the bacterial infection was confirmed Friday.

According The Associated Press, the cafeteria at the hospital was closed June 6 after city health officials learned that three hospital employees were sick.

The hospital has taken samples from more than 400 people who visited the hospital or ate in the cafeteria since May 1. The cafeteria reopened June 15 after two days of cleaning.

Salmonella can be found on several kinds of food, but especially on raw meat, eggs, dairy products and seafood. It is blamed for 1,000 deaths every year in about 40,000 cases nationally. The illness causes diarrhea, fever and abdominal cramps