The number of people sickened by a hepatitis A (searchoutbreak at a Mexican restaurant continued to climb Tuesday, with state health officials confirming at least 300 cases.

Investigators hoped to pinpoint the source of the outbreak in the next week or so. Of the cases linked to a Chi-Chi's Restaurant (searchabout 25 miles northwest of Pittsburgh, 31 were in Ohio, eight in West Virginia, one in Florida, and one in South Carolina.

The outbreak is believed to have begun as early as September, state Health Department spokesman Richard McGarvey said. The restaurant voluntarily closed Nov. 2, and has not reopened.

Seattle lawyer William Marler said his firm has already filed a lawsuit against the restaurant.

Representatives for the Louisville, Ky.-based company said that a news conference planned for Wednesday had been canceled. The company did not say when it would be rescheduled.

"We realize that there has been a tremendous amount of speculation and confusion about this outbreak," chief operating officer Bill Zavertnik said in a statement late Tuesday. "We'd like to emphasize this remains an isolated incident."

Hepatitis A causes flu-like symptoms that may include fever, nausea, diarrhea, jaundice, fatigue, abdominal pain and loss of appetite. The infectious liver disease (searchusually clears up in about two months.