Fresh basil, a staple of tomato sauces, salads and many other dishes, harbored a stomach-churning parasite that sickened at least 293 Floridians during the past few weeks, state health officials said Friday.
Now the Food and Drug Administration will try to trace the contaminated basil to the farm where it was grown and the wholesalers or individual stores that sold the produce.
In the meantime, the state’s top doctor said people do not have to shun fresh basil. Because no one has contracted the bug since early May, investigators think the contaminated herb is no longer on the market.
The parasite is called cyclospora, a single-cell organism that burrows into the intestines and causes recurring, often severe, diarrhea. Nearly 300 people in 32 counties have been confirmed with the illness, which is curable with antibiotics.
“We really haven’t had any recent cases, which would seem to indicate to me that there isn’t a current and present danger,” said Dr. John Agwunobi, secretary of the Florida Department of Health. “It strikes me at this point that it wouldn’t make a lot of public-health sense to urge people to stay away from basil.”
The state launched its investigation into the outbreak in late April, when a sudden spike in cyclospora infections caught attention from health officials.
As the weeks went on, the number of cases grew, and investigators found themselves helped and hindered by the magnitude of the problem. On one hand, the process was slow going because so many people had to be interviewed. On the other, the sheer number of people who reported similar eating experiences made it possible to identify the culprit more convincingly.
Agwunobi said medical investigators didn’t settle on basil before eliminating the more common sources of previous cyclospora outbreaks. He said fruits and vegetables with bumpy surfaces, such as raspberries, artichokes or Brussels sprouts, provide hiding places for the parasite to avoid being washed off.
“We started with three or four likely candidates,” Agwunobi said. “But as the cases continued to come in, it was easier to drop candidates because, often, people may not remember exactly what they have eaten in the past few weeks, but they remember absolutely what they haven’t eaten.”
Investigators could eliminate a suspect — raspberries, for example — after a large number of people reported no contact with the fruit in many months.
Because cyclospora infections aren’t fatal and rarely require hospitalization, Agwunobi said, the state had the luxury of carefully reviewing all the evidence before settling on a cause.
“Obviously, when you have a disease that is much more dangerous or debilitating than cyclospora, you’re more likely to pull the trigger even if you don’t have all your ducks in a row,” he said.
Cyclospora infections can cause loss of appetite, substantial weight loss, bloating, gas, stomach cramps, nausea, muscle aches and explosive diarrhea. People usually become sick within one week of consuming the parasite. The illness is cyclical — subsiding for a few days and giving its victims a false sense of recovery before coming back again with intensity.
People often are sick with cyclospora for weeks before a diagnosis is made because doctors don’t necessarily test for the parasite when a patient first complains of diarrhea. Victims may see their physicians two or three times before a laboratory test is done to confirm an infection. A combination of two antibiotics usually can clear up the illness.
The Centers for Disease Control and Prevention says there have been no reported deaths from cyclospora in the United States and that the illness cannot be passed among people. Victims can pick up the parasite only by eating the contaminated food product.
The state notified the FDA of its findings Friday, and the agency in a statement said it would start a “trace-back” investigation immediately.
“FDA is aggressively working with our federal and state partners to determine the source of the contaminated product and taking appropriate action to protect the public,” said Dr. Robert Brackett, director of the FDA’s Center for Food Safety and Applied Nutrition.
All told, 293 people have been confirmed with the illness. In Central Florida, the cases include four in Brevard, nine in Orange, one in Osceola, 11 in Polk, six in Seminole and one in Volusia. The highest numbers of cases have occurred on the west coast, including 45 in Pinellas, 35 in Hillsborough, 25 in Sarasota and 21 in Manatee.
