Pennsylvania State health officials first learned of a Hepatitis A outbreak when unusually high numbers of hepatitis A cases were reported in late October 2003. All but one of the initial cases had eaten at the Chi Chi’s restaurant at the Beaver Valley Mall, in Monaca, Pennsylvania.
Ultimately, at least 565 cases were confirmed. The victims included at least 13 employees of the Chi Chi’s restaurant, and residents of six other states (identity of the states was not given). Three persons died as a consequence of their hepatitis A illness. Over 125 were hospitalized. One man suffered liver failure, which required an emergency transplant. More than 9,000 persons who had eaten at the restaurant, or who had been exposed to ill persons, were given an injection of immune globulin as prevention against hepatitis A.
Preliminary analysis of a case-control study indicated fresh, green onions were the probable source of this outbreak. Previous hepatitis A outbreaks had been linked to green onions, and had involved patrons of a single restaurant, however this outbreak was unusually large. The FDA issued a statement dated December 9, 2003, reaffirming that this outbreak, as well as others recently, had been associated with eating raw, or undercooked, green onions. The investigation and trace-backs by the state health department, the CDC, and the FDA, confirmed that the green onions had been grown in Mexico.
The viral sequence of the outbreak strain was similar to the viral sequences obtained from persons involved in hepatitis A outbreaks that had occurred in September 2003, in the states of Tennessee, Georgia, and North Carolina. Green onions had also been implicated in these outbreaks.
Incubation period for Hepatitis A is 28 days (range: 15–50 days).