By Christopher Snowbeck, Pittsburgh Post-Gazette
Investigators are closer to pinning the hepatitis A outbreak in Beaver County on contaminated green onions, and now say it's unlikely that restaurant workers with poor hygiene caused the problem.
Green onions still haven't been nailed down as the contamination source at the Beaver Valley Mall Chi-Chi's where more than 500 people picked up the disease, but the viral strain here is very close to the strains that sickened more than 300 this fall in Tennessee, Georgia and North Carolina.
Those strains are common in Mexico, and green onions, which are widely grown in Mexico, have been implicated in the outbreaks.
The 12 food handlers at Chi-Chi's with confirmed cases of hepatitis A all got sick about the same time as patrons, meaning that they could not have transmitted the virus, said Joel Hersh, director of epidemiology for the state Department of Health.
"The food handlers are not implicated at this point," he said.
The Beaver County outbreak stands as the largest hepatitis A outbreak ever at a U.S. restaurant, with 520 confirmed cases as of yesterday. But it all could have been caused by just one or two boxes of contaminated onions.
"I could imagine some scenarios where you wouldn't have to have many boxes of onions contaminated to have this big of an outbreak," said Dr. Beth Bell, an investigator with the Centers for Disease Control and Prevention.
As investigators closed in on a theory of the source, an additional patient was hospitalized at UPMC Presbyterian Monday night. Yesterday afternoon, two hepatitis A patients were reported in fair condition at the hospital and one remained in critical condition, UPMC said.
Yesterday's total -- up just 10 from Monday -- marked the fourth consecutive day of negligible increases in the overall incidence of the disease. Last week, the totals jumped dramatically each day, rising by 80 cases on Friday alone.
"I'm reluctant to say it's over, but I'm hopeful that we won't see another spike and that we won't see secondary cases," said Hersh.
Health officials still have not found any "secondary" cases of people who have been infected by patients sickened in the initial outbreak. Knowing that such cases could lead to a second wave of infections, health officials have been providing shots to close contacts of those currently sick as well as to some co-workers.
The U.S. Food and Drug Administration has not yet concluded whether the green onions at Chi-Chi's came from Mexico, but they are actively investigating the possibility, said Dr. LeAnne Jackson, FDA's health science policy adviser. The state Department of Agriculture traced the onions to sources in Arlington, Texas, Salinas, Calif., and Newport, Ky.
The onions shipped from Texas and California were grown in those areas, but it wasn't clear to agriculture investigators where the Kentucky onions were grown. FDA has not visited any of the U.S. farms to look for problems, Jackson said.
She did not say what sort of penalties a U.S. farm could face, but a Mexican farm with unsanitary practices could be excluded from trading with the United States.
"We're working with the Mexican government to determine which farms were involved and what practice may have occurred to contribute to contamination so we can prevent this in the future," Jackson said of the Tennessee outbreak. "We acted as soon as we had information to indicate that the product itself came from Mexico."
Jackson wasn't sure what the FDA did in 1998, when CDC investigators pinned a restaurant outbreak in Ohio on green onions that came from either a farm in California or two farms in Mexico.
In that outbreak, 42 people were sickened with hepatitis A -- some with symptoms that lasted for months -- but there were no deaths, said Joe Evans, director of environmental health services for the Mansfield-Richland County Health Department. Evans was one of the investigators on the outbreak until he became one of those who got sick.
"This is one of those areas, like the military and highways, where we have to look to a federal agency -- or an international agency -- if we're going to open up borders," Evans said. Still, he said, "In a global economy, you cannot fully protect yourself."
Bell, the CDC investigator on the Beaver County case, also tracked the possible sources of the Ohio green onions. That case suggested several possible points during the harvesting of green onions that could allow for contamination, she said. One is contaminated water. Another is field workers who must simultaneously care for small children who are infected. Many adults in Mexico are immune to hepatitis A because they were exposed to it as children.
"Green onions are handled extensively at the time of harvest," she said. "They're also iced down, so I suppose it's theoretically possible that the ice could be contaminated with the virus."
(Christopher Snowbeck can be reached at email@example.com or 412-263-2625.)