California health officials are investigating 31 cases of salmonella, including seven cases in San Diego County, linked to raw tuna commonly found in sushi.

The string of Salmonella Paratyphi B cases are among an outbreak of 53 cases in nine states, according to a news release from the California Department of Public Health.

Most the patients in the outbreak said they had eaten sushi containing raw tuna. Ten people have been hospitalized, though no deaths have been reported, health officials said.

People started getting sick on March 5, with the latest reported illness happening on May 13. Patients range from an infant to 83 years old, officials said.

The outbreak in California includes nine cases in Los Angeles County, six in Orange County, four in Riverside County, one in Santa Barbara County and four in Ventura County in addition to San Diego.

State health workers are investigating along with the FDA and the U.S. Center for Disease Control and Prevention to figure out the source of the outbreak.

Salmonella causes diarrhea, fever and abdominal cramps 12 to 72 hours after becoming infected. The disease can cause death if not treated promptly, health workers said.

More information about salmonella can be found here.