A severe stomach illness linked to prepackaged salad has struck two new patients in Iowa, state health officials said on Wednesday, as the bug spread through 16 states.
The salad mix has been blamed for most of the 145 total cases in Iowa and the 78 in Nebraska of the rare parasite cyclospora, which causes gastrointestinal illness. The two states account for nearly two-thirds of at least 378 cases in the United States since mid-June.
The cause of outbreaks in other states is still under investigation, but officials with the federal Centers for Disease Control and Prevention said they are working to determine whether the prepackaged salad mix, the brand name of which has not been released, is responsible for outbreaks in states from New York and New Jersey to Florida and Texas.
At least 21 people have been hospitalized in three states with the bug, CDC officials said.
Symptoms caused by the one-cell parasite include watery diarrhea, vomiting and body aches. The virus is commonly associated with contaminated fresh produce and can be difficult to wash off.
Officials in Iowa and Nebraska said the salad mix was distributed nationally and there is no indication that local produce was involved in the outbreak.
The mix, sold as prewashed and ready to eat, was described by health officials as a combination of iceberg lettuce, carrots and red cabbage.
The product has been pulled from the shelves in Iowa and appears to have been consumed by the stricken residents in mid-June, health officials said. It was unclear whether the product had been removed from distribution in Nebraska.
Nebraska health officials said earlier this week that the same salad mix appeared to be responsible for the outbreak there as well.
New cases are being reported in Nebraska daily, officials there said, but it is unlikely that the same batch is still on shelves or in refrigerators, as the product's shelf life is short.
Cyclosporiasis symptoms usually manifest within several days of eating the contaminated food, and include diarrhea, cramps, nausea and fatigue. If not treated, the illness may last from a few days to a month or longer and patients have been known to relapse, the CDC said.
The first cases were reported in Iowa in late June, with the majority of the illnesses logged in early July. The CDC has not released the age range of those infected, but said it was working closely with the U.S. Food and Drug Administration and state officials to gather more information.