Columbus, Ohio (AP) -- Ohio has joined a multistate investigation to find the source of salmonella bacteria that has sickened at least 50 people in 18 counties since October.

The Ohio Department of Health is participating in a search being led by the U.S. Centers for Disease Control and Prevention, which says Ohio ranks second in the nation for number of cases.

Most people infected with salmonella develop diarrhea, fever and abdominal cramps 12 to 72 hours after infection. The illness usually lasts four to seven days, and most people recover without treatment.

Officials say steps to protect against the illness include careful handling and preparation of raw meat and frequent hand washing.

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