Nine Cyclosporiasis Cases Linked to Contaminated Lettuce at NH Hospital

Nine people fell ill at Cheshire Medical Center in Keene, New Hampshire, after eating lettuce served in the hospital's cafeteria. All nine cases have been confirmed as cyclosporiasis, a parasitic infection that causes severe gastrointestinal distress. The outbreak, discovered in late July, has triggered an investigation into the facility's food supply chain and raised questions about how contaminated produce made its way into a medical institution where patients are already vulnerable.

Cyclosporiasis is caused by the parasite Cyclospora cayetanensis, which contaminates fresh produce—particularly leafy greens—grown in regions where sanitation infrastructure is inadequate or where water sources are compromised. The infection typically produces cramping, diarrhea, nausea, and fatigue that can persist for weeks if left untreated. For hospitalized patients, many of whom may already be immunocompromised or recovering from surgery or illness, the added burden of a foodborne parasitic infection represents a serious complication.

The outbreak at Cheshire Medical Center is not an isolated incident. Cyclosporiasis outbreaks linked to contaminated lettuce and other produce have occurred periodically across the United States, often traced back to imported vegetables or those grown in areas with known water quality issues. What distinguishes this case is that it occurred within a hospital—an institution theoretically subject to stricter food safety protocols than most restaurants or retail establishments.

Health officials have begun tracing the lettuce supplier to determine the source of contamination. The investigation will likely examine where the produce was grown, how it was handled during transport, and what storage and preparation procedures were followed at the hospital before it reached patients' plates. If the contamination originated with a specific supplier or farm, authorities may need to issue broader alerts to other hospitals, schools, restaurants, and retailers that received produce from the same source during the relevant time period.

The discovery of nine confirmed cases suggests the outbreak may have been caught relatively early, though it's possible additional cases could emerge in the coming days or weeks as the incubation period for cyclosporiasis can extend up to two weeks. Hospital officials have likely already removed the contaminated lettuce from service and are reviewing their produce sourcing and food safety procedures. For the nine patients who contracted the infection, treatment typically involves antiparasitic medication, though some cases resolve on their own with supportive care.

This incident underscores a vulnerability in the food supply chain that affects even institutions with dedicated food safety staff. Hospitals depend on suppliers to deliver safe produce, and while most suppliers maintain rigorous standards, contamination can occur at any point—in the field, during harvest, in transit, or in storage. The outbreak also raises questions about testing protocols: whether hospitals routinely test produce for parasites, and whether such testing would have caught this contamination before the lettuce was served.

As the investigation continues, health officials will be watching for any connection between this outbreak and cyclosporiasis cases reported elsewhere in New Hampshire or neighboring states during the same period. If the contaminated lettuce was distributed more widely, the true scope of the outbreak could be considerably larger than the nine confirmed cases at Cheshire Medical Center.