There are 10 secondary cases -- in which a person catches the liver disease from contact with someone who has it, not from the initial source, health officials said. Some of the secondary cases were included in the total number of hepatitis A cases, which reached 640 last week, department spokesman Richard McGarvey said.
"It's not unexpected, certainly when you have somewhere in the neighborhood of 640 cases, there's going to be a strong likelihood that family or other close contacts will develop hepatitis A," McGarvey said.
All 10 had direct links to people who ate at the Chi-Chi's restaurant in the Beaver Valley Mall, about 25 miles northwest of Pittsburgh.
That is good news for health officials, who were monitoring hospitals and health clinics throughout the region for cases of hepatitis A with no discernible source.
"Our fear was that if we couldn't make a link, we would have to start looking for a secondary source, which would be an exhaustive process," McGarvey said.
Though the investigation of the recent outbreak in Pennsylvania focused very quickly on the Chi-Chi's restaurant, health officials interviewed hundreds of people, sometimes two or three times, to pin down the likely source of the hepatitis A infection -- green onions.
Two of the victims who tested positive with secondary cases are Beaver County high school students, McGarvey said.
The Health Department notified the South Side Area School District last week that some students tested positive for hepatitis A. Health officials were advising anyone connected with those infected to go to their doctor or a health center for a shot of antibody that can ward off the liver-wasting disease if administered within two weeks of exposure.
Hepatitis A is contained in feces and an infected person can spread it for about two weeks before symptoms appear.
Victims identified as secondary cases ranged in age from 15 to 57, health officials said.