US examines produce items including lettuce amid cyclosporiasis outbreak

WASHINGTON – The US Food and Drug Administration (FDA) said on July 14 it was investigating multiple produce items, including lettuce, in an effort to identify the source of an unusually large cyclosporiasis outbreak, as the number of human cases continued to rise.

No deaths have been reported from the outbreak, but 141 people have been hospitalised and labs have confirmed 1,645 cases across 34 states since May, according to the US Centres for Disease Control and Prevention (CDC). The agency said it was aware of more than 5,100 additional reported cases that require more analysis and confirmation.

Cyclosporiasis is a parasitic intestinal infection that causes diarrhoea, nausea and other gastrointestinal symptoms. It can be contracted by consuming food – typically raw fruits and vegetables – or water contaminated with faeces, according to the CDC.

While the US has experienced outbreaks before, the scale and geographic spread of the outbreak in 2026 are significantly larger, prompting concern among health officials, who have so far not pinpointed the source.

US Senator Amy Klobuchar of Minnesota urged the CDC and the FDA to reinstate funding and staffing for federal and state food safety programmes to fight the outbreak.

“This is an active and evolving investigation,” said Gwen Biggerstaff, a CDC foodborne disease expert.

FDA examines produce items

The FDA said it was conducting traceback investigations to find a source of the outbreak, in which officials collect information from sick people on the foods they ate in the weeks before they became ill.

The Washington Post reported federal and state officials were investigating whether lettuce served at Yum Brands-owned restaurant chain Taco Bell may have been associated with an outbreak.

The company said it removed certain ingredients at select restaurants for precautionary reasons, adding that US health officials have not confirmed a link between the chain and the outbreak.

“We don’t have any food that folks should avoid at this point,” said Donald Prater, the FDA’s acting deputy commissioner for food.

Still, the CDC said it issued an alert to physicians to test for cases of cyclosporiasis. The agency said it was actively engaged in the US response, including helping states, but some experts said it was moving too slowly.

“I think the federal response has been far short of what we need,” said Michael Osterholm, an infectious disease expert at the University of Minnesota. Likewise, he said, messaging from the states has been “extremely poor”.

More cases expected

Biggerstaff told reporters that the CDC expects that case reports will continue to increase, potentially through the end of August. The agency said there was a roughly six-week lag between the onset of illness and the reporting of cases, which means more infections are likely to be identified as additional data is received.

The outbreak is centred in Michigan, where state officials have reported 3,309 cases. Ohio and New York have also reported high numbers of cases.

Evidence collected so far suggests that cases in Michigan, West Virginia, Kentucky and Ohio may be linked to one source, though that does not account for cases in several other states, Biggerstaff said.

“There are a number of other investigations that are going on, some single-state investigations as well as investigations for the cases that are not currently linked to a cluster or outbreak,” Biggerstaff said.

Osterholm said it was possible that the outbreak centred in Michigan was already over and no new infections were occurring given that many produce items only have a shelf life of about three weeks.

Prater acknowledged that produce moves through the food system quickly, but said the agency was looking at multiple clusters and sub-clusters, and it needs more information before it can determine whether the outbreak is over. REUTERS