Cyclosporiasis cases spread across U.S., Delaware confirms first infection

A parasitic infection that causes severe gastrointestinal illness is spreading across the United States, and Delaware has just confirmed its first case. The disease, cyclosporiasis, is caused by a microscopic parasite that infects the small intestine and typically spreads through contaminated food or water. As of mid-July, health officials in multiple states are tracking a widening outbreak that has already sickened dozens of people across several regions.

Shelby County, Tennessee has emerged as one of the hardest-hit areas, with confirmed cases climbing to eleven. In nearby Hamilton County, health officials are also monitoring an active cluster of infections. The situation is not contained to the South: Erie County in Pennsylvania has reported a fresh surge in cases, suggesting the outbreak is moving geographically and may not yet have peaked. Delaware's confirmation of its first case marks the infection's arrival in yet another state, expanding the footprint of what public health authorities are treating as a coordinated outbreak rather than isolated incidents.

Cyclosporiasis typically causes watery diarrhea, loss of appetite, weight loss, and abdominal cramping that can persist for weeks if untreated. The infection is treatable with antibiotics, but diagnosis can be tricky because the parasite's eggs are not always visible in standard stool tests. People infected often do not realize what they have until symptoms have already taken hold. The disease spreads when someone consumes food or water contaminated with the parasite's oocysts—a dormant stage that can survive in the environment for weeks or months.

What makes this outbreak particularly concerning is that health officials have not yet pinpointed a common source. In past cyclosporiasis outbreaks, investigators have traced infections to specific produce items—berries, lettuce, or herbs imported from endemic regions. Without knowing what is causing this current wave, public health agencies cannot issue targeted warnings to consumers or retailers. The lack of a clear source means people cannot easily protect themselves beyond general food safety practices.

The geographic spread across Tennessee, Ohio, Pennsylvania, and Delaware suggests either multiple separate contamination events or a widely distributed product that has reached multiple states. Health departments in affected counties are working to interview patients about their recent food and water consumption, looking for patterns that might reveal the culprit. This detective work is slow and often incomplete—people's memories of what they ate two or three weeks ago are hazy at best.

For now, health officials are urging the public to remain vigilant about food safety: wash produce thoroughly, avoid eating raw vegetables from unknown sources, and drink only treated water. Anyone experiencing persistent diarrhea and abdominal pain should see a doctor and mention the possibility of cyclosporiasis, since many physicians may not immediately think of a parasitic infection. As the case count continues to climb across multiple states, the outbreak serves as a reminder of how quickly foodborne illnesses can spread in a connected food system, and how difficult it can be to stop them once they have begun.