Hepatitis probe following pattern
Less serious outbreaks in Knoxville and Atlanta show the way for Beaver County investigators
Sunday, November 16, 2003
By Christopher Snowbeck, Pittsburgh Post-Gazette
The extent and severity of the hepatitis A outbreak in Beaver County is worse than outbreaks that have hit other parts of the nation, but the process taking place to find out what caused it matches work done in other recent investigations.
The number of confirmed cases rose again yesterday to 510, while the number of deaths held at three.
Earlier this fall in Knoxville, Tenn. and Atlanta, investigators conducted countless interviews with sickened restaurant patrons, asking who ate what and when. They then analyzed restaurant menus and recipes to determine ingredients and went back to patrons three or four times, seeking more information through interviews. Finally, they interviewed people who ate at the restaurant and didn't get sick.
In the end, statistical analyses of all the data pointed to one suspect: Green onions.
It's not clear that green onions are the culprit in the Beaver County outbreak. Initially, investigators suspected a food worker with dirty hands might be the source, but they are now focusing on whether contaminated foods were brought into the restaurant.
That change was due, in part, to the ever-growing number of cases. But it means they might be joining their counterparts in Tennessee and Georgia in the difficult task of following the produce.
"The contamination of the onions could occur anywhere between the fields and putting them on the table," said Dr. Paul Blake, the Georgia state epidemiologist. "Where did it occur? I don't think anybody knows."
Interviewing the diners
In Pennsylvania, the state Department of Health's division of epidemiology -- with four physicians in Harrisburg and one in Pittsburgh -- is leading the efforts of roughly 35 public health nurses scattered around the state. Those nurses are interviewing hundreds of victims about what they ate at Chi-Chi's.
Beaver County restaurants are regulated by the Department of Agriculture and that department's local office in Richland has five people supporting the investigation. In the early stages of the investigation, John Stella, the regional food safety inspector, and his staff provided "trace-back" information about the sources of green onions at the restaurant.
Health investigators sought information on onions because of the other outbreaks and Stella provided the names and locations of the growers, distributors and shippers that brought the food to Beaver County. Because those sources are in Kentucky, Texas and California, the U.S. Food and Drug Administration has a role in the investigation.
Yesterday, the FDA issued an advisory saying that green onions and foods containing green onions should be cooked thoroughly to reduce or eliminate the risk of contracting hepatitis A. Foods such as salsa, green salads and tuna salad often contain raw or lightly cooked green onions.
Three investigators from the federal Centers for Disease Control and Prevention have also joined the hunt. There are now five CDC investigators and they are camped in a Health Department office in the region.
Along with the Pittsburgh-area physician who works for the state Health Department, the CDC investigators are analyzing data coming in from nurse interviews. That information is simultaneously available to the investigators in Harrisburg.
"They're trying to put together a statistical profile of who ate what, when they ate it, how much they ate," said Richard McGarvey, spokesman for the Health Department. "At one point you hope to be able to say, 'This is likely the food item that did it.' "
The doctors collected the menus and recipes from Chi-Chi's and, with that information, sometimes send follow-up interview questions back to nurses, McGarvey said.
Beyond helping collect this information, the CDC is comparing the strain of the virus sickening patients in Beaver County to that of other known hepatitis A viral strains.
Tracing the virus
Those tests have traced the strain of virus sickening people in Beaver County back to Mexico, according to Agriculture officials. But Health Department investigators have not commented on that assertion and Dean Cliver, a virologist for 41 years at the University of California-Davis, said it was difficult to interpret.
Cliver, who has studied hepatitis A and other varieties of outbreaks for 41 years, said some virus strains typically found in Mexico make their way to the United States through immigration or tourism. Mexican workers at farms in either the United States or Mexico likely don't carry hepatitis A virus, since most have immunity from childhood exposure, Cliver said.
But their children might be carrying the virus and parents in the field sometimes must simultaneously care for their children, Cliver said. Hepatitis A virus is transmitted through fecal matter of an infected person.
There is no evidence of a criminal investigation into the Beaver County outbreak. Beaver County District Attorney Dale Fouse said he did not know of any evidence suggesting criminal involvement in the outbreak and knows of no other agency looking into such a possibility.
The U.S. Department of Homeland Security is not actively involved in the hepatitis A investigation, but it is monitoring the involvement of the Department of Health and Human Services through the Centers of Disease Control, agency spokesman Brian Roehrkasse said.
Among all these agencies, the state Health Department remains in charge. And Dr. Andre Weltman, a public health physician, plays a key role -- in part because Weltman received the call Nov. 1 that got the investigation rolling.
It came from Dr. Marcus Eubanks, an emergency room doctor at The Medical Center Beaver. Late on Halloween night, Eubanks treated the hospital's sixth probable case of hepatitis A in four days.
That concentration was unusual enough, but Tammy Flaminio -- the wife of the sixth patient and a nurse at the hospital -- said three of the patients and her husband had eaten together at Chi-Chi's in early October. The four shared the seafood nachos, Flaminio said.
As the investigation unfolded during the first weekend of November, seafood nachos were ruled out as a possible source because some of the sick people had not eaten them. But investigators tied the outbreak to the restaurant and determined they needed to administer shots of immune globulin to patrons. The preventive shots work if given within 14 days of exposure, so time was of the essence.
The Health Department's immune globulin clinic opened Nov. 5, about eight days after the first patient turned up sick at the hospital. That was a much quicker response than was possible in Georgia, where the outbreak sickened about 250 people who ate at dozens of restaurants.
"No more than 5 percent of our cases went to any one restaurant," said Blake, the state epidemiologist. "By the time we knew about the problem, it was gone. ... It was too late to immunize anyone who ate at the restaurant."
The first Georgia case was reported during the week of Sept. 22 and, by Oct. 10, investigators "had incriminated the onions," Blake said.
The Knoxville outbreak -- and public health response -- was more similar to that in Beaver County. It centered around one O'Charley's restaurant, which is a chain restaurant, and sickened at least 80 people.
Many of those initially sick in the Knoxville outbreak were restaurant employees, which immediately focused attention on the eatery, said Jones, the Health Department director in Knoxville. Public health workers caught it quickly enough to administer immune globulin shots to more than 5,500 people.
Initially, Knoxville investigators thought the probable source was a worker with bad hygiene, since that's usually the cause of a restaurant problem.
But seven workers were sick -- an unusually high number, Jones said -- and lab tests showed none of them was infectious when people were apparently exposed to the virus in mid-August. Then word came of other outbreaks. First at a Chinese restaurant in Asheville, N.C., and then in restaurants in central and northern Georgia.
Knoxville investigators, assisted by the CDC, turned their attention to food sources and conducted extensive interviews with patrons about what they ate.
"It all came down to: If you didn't eat green onions, you didn't get sick," said Jones.
That was also the conclusion of the epidemiological work in Georgia, said Blake.
But coming up with a prime suspect is only the beginning of the detective work, said Blake. Investigators there have had several more weeks to determine where the contaminated produce came from, but there's still no answer.
Georgia officials hoped to find clues from a green onion-related outbreak in Knoxville -- perhaps one grower had supplied onions to all the restaurants. But scientists now think the relationship between the two outbreaks is questionable, since the RNA-fingerprint of the viruses in each state are different.
That was a tough break, said Blake, the Georgia state epidemiologist, because investigators need all the help they can get in solving a green onion problem that is becoming too widespread.
"There have been something like seven onion-associated outbreaks with hepatitis A that have been recognized and now we've had three more -- in Georgia, Knoxville and Asheville, N.C.," said Blake.
Similarly puzzling is the concentration of outbreaks -- including the one in Beaver County.
"Why would they occur at the same time? I just don't know," Blake said.
Two hepatitis A patients were discharged yesterday from UPMC Presbyterian, leaving one patient in critical condition and one in fair condition. Children's Hospital treated four children ages 3 and under yesterday. All were diagnosed with hepatitis A and were later released.
There were no hepatitis patients being treated yesterday at Allegheny General Hospital, which previously treated seven.
(Christopher Snowbeck can be reached at firstname.lastname@example.org or 412-263-2625.)
More on this outbreak: Chi-Chi's Hepatitis A Outbreak