Cyclospora used to be a poorly understood disease of faraway places, with only three outbreaks ever reported in the United States. But in the last couple of months the Texas Department of Health connected two dozen cases to strawberries eaten at a private club and an upscale restaurant in Houston. The berries came from California, as does 80 percent of the nation’s crop. But then 37 people got sick after eating raspberries at a luncheon in South Carolina, and 95 people who ate strawberries at the same place did not. What’s more, investigators haven’t been able to find Cyclospora in California fields. ““Raspberries are the focus of the current investigation,’’ says Barbara Herwaldt, a medical epidemiologist at the CDC, ““but [it] is still ongoing, and we don’t have all the final answers.''
Muddling the investigation further, Cyclospora is new to the roster of dangerous germs. An ““emerging pathogen,’’ it wasn’t described scientifically until 1979, and researchers still can’t get it to grow in a laboratory. They do know it is a protozoan, a single-celled parasite about a hundredth of a millimeter in diameter that infects through fecal contamination. Symptoms don’t show up in most people until about a week after infection. Most labs don’t routinely perform the test to identify Cyclospora, so by the time people know they have it they probably don’t remember where they picked it up. Tracing its origin is easier when it infects groups of people at social events, but it also pops up in individuals. ““Many questions remain about the biology of the organism and how it spreads,’’ says Herwaldt. ““We’re basically starting from square one.''
Still, for California strawberry growers the news is the best thing since shortcake. They think the initial reports about ““the strawberry disease’’ cost them millions of dollars in sales – total sales in 1994 were $608 million. Raspberry farmers may be the next to suffer, though with American raspberries now coming into season, the suspect Guatemalan crop may soon be off the market anyway. As always, the CDC recommends washing produce, though it isn’t sure if that’s effective against Cyclospora. But scientists have found that the infection withers under treatment with antibiotics. For victims still curled up around their guts, that’s better than bringing some hapless berry to justice.
