When diners become ill and blame something they ate, state experts start sleuthing. They interview the victims, conduct food lineups and try to narrow down the suspects.
By Scott Joseph
Sentinel Restaurant Critic
July 20, 2005
Sometimes people think it's just a touch of the flu, a 24-hour bug. Upset stomach, cramps and diarrhea might be some of the discomforts they experience. But on occasion, these are actually indicators of a food-borne illness, and, for epidemiologists such as Dean Bodager, they aren't symptoms, they're clues.
Whenever there is an outbreak of food-borne illnesses, it falls to Bodager and other members of the Florida Department of Health to track down the source. Sometimes it's simple. Most outbreaks occur at the point of preparation -- a restaurant employee who didn't wash his or her hands properly, food that wasn't kept at the correct temperature to prevent bacteria growth, or some sort of cross-contamination.
But sometimes it's more difficult, such as when health officials learn of people who have fallen ill but did not eat at the same restaurant or buy food from the same market. That's when the epidemiologists have to become detectives, interviewing those who have been ill, dissecting their meals and eliminating suspects to find a common thread and, ultimately, the source.
Think of it as CSI: Food.
But unlike the forensic investigations on the CBS franchise "crime scene investigation" series, Bodager says, "It doesn't happen in one hour, and it doesn't happen in seven-minute segments."
Indeed, an investigation has been under way statewide since April involving an outbreak of cyclospora, an uncommon parasite that can be spread through food and water. There are 335 lab-confirmed cases in 35 counties throughout Florida. Cyclospora, which generally causes intense diarrhea and, as a result, weight loss, is completely treatable with antibiotics. There have been no new infections since May 29. The federal Food and Drug Administration is now involved in the tracking.
Although investigators have not yet zeroed in on the source of the contamination, they think they have the culprit, the vehicle that carried the pathogen: basil.
How the epidemiologists were able to narrow their search to a single ingredient, one that held a parasite that typically can take up to a week to make a person ill, is as intriguing as any network crime show.
Precise questions
It takes only two complaints of a suspected food-borne illness to launch Bodager and his colleagues into action. Two cases with a common association with a place or a product in time.
"In other words," says Bodager, "if we got a call, and someone said they were in XYZ restaurant, and, if someone else said the same thing, that would prompt us to do an investigation."
But, in a perverse sort of way, the more cases the better. A larger sample can help investigators pinpoint the source. But remember a lot of victims may not even know that their illness is the result of something they ate. So the health department might make phone calls, send faxes or e-mail alerts to health-care providers whose patients have complained of illness and hospital labs whose technicians may be seeing a pattern of infection.
Catherine Harwood of Merritt Island had to insist that her doctor test her for cyclospora. She and her husband, Bill, became sick several days after a rare dinner out at a Brevard County restaurant with their two small children, who were not affected.
Harwood, a former reporter for a Palm Beach television station and now a stay-at-home mom, suspected cyclospora because she had covered another widespread outbreak in the late '90s, one that involved raspberries. Still, it didn't dawn on her that it was the same parasite until a friend mentioned seeing a report about a new outbreak of infections. Coincidentally, she had an appointment with her family doctor that same day. She says her doctor was reluctant to test her for cyclospora but she persuaded him.
An epidemiologist from the Brevard County office of the state health department, who had been alerted with the test results from the lab, called her with the test results before her doctor's office could contact her. Just like any television detective, he had a few questions he wanted to ask.
Bodager says the questions investigators ask are carefully tailored to the specific type of infection. Bacteria have different profiles and each takes a specific length of time to cause illness. Hepatitis takes about 30 days, E. coli three to five days, salmonella poisoning one to three, sometimes five, days. Cyclospora can take up to a week and a half. By knowing the type of parasite or bacteria and when the person got ill, investigators know what period of time to look at to determine the point of infection.
But most people have a hard time remembering what they had for breakfast the same day. Getting someone to remember what they ate a couple of weeks ago takes patience and precision questioning.
"The best are those in a special occasion, like a wedding," says Bodager. But, barring something apparent, he tries to take them back by putting a calendar in front of them or going through credit-card receipts with them. A menu from a restaurant is a handy visual for prodding the memory, and sometimes investigators will use photos of foods, a sort of culinary lineup.
The bruschetta! That's it!
For Harwood, her visit to a restaurant was like a special occasion because her family rarely goes out to eat. And with two young children, she says her home meals feature a lot of frozen foods or prepared dinners. She was certain it was the restaurant meal. Her kids did not get sick, she says, because they did not eat the same things she and her husband had. Further, she was convinced she had digested the parasite from the salad because it was the only thing she could think of that would have included uncooked foods.
She had forgotten about the bruschetta until the investigator dug deeper.
Often served as an appetizer, bruschetta features slices of toasted bread topped with a mixture of chopped tomatoes and garlic . . . and basil.
For other victims who dine out more often, Bodager says, more rooting is needed. The protocol is to establish a three-day food history.
"We're going to ask them what we call exposure variables," he says. "We ask about their food: What kinds of foods did you eat, when did you eat them, who did you eat them with?" Even the time the food was consumed might be important.
Some questions may involve nonfood exposures, such as with other infected humans or with animals, as was the case with the recent outbreak of E. coli from a children's petting zoo.
But the search for the source of a food-borne illness might take a widespread dragnet. Produce, seafood and meats are shipped from throughout the world, and, as Bodager says, "It can be contaminated anywhere from the farm to the fork."
But just as important as talking with anyone who is ill or experienced symptoms is the questioning of those who were in the same place and ate the same foods but who didn't get sick.
Bodager says if you have an outbreak and you talk to 10 sick people who ate strawberries you might start to think strawberries are the cause. But then if you talk to 10 others who also ate strawberries but didn't get sick, you may be looking at the wrong suspect.
It's fairly easy to find those who are ill because they often present themselves to a healthcare provider or call the health department directly with a complaint. No one calls to report they are fine.
So the investigators have to do more detective work, which might include obtaining the credit-card receipts for a restaurant and calling the patrons. That can get you some well people, but it can also lead to more cases of people with the infection.
Often, says Bodager, they will call someone to say they're investigating an outbreak of food-borne illnesses and the person on the phone will ask, "How did you know I was sick?"
Just good detective work.
Scott Joseph can be reached
at sjoseph@orlandosentinel.com
or 407-420-5514.
