CDC investigates Cyclospora parasite outbreak spanning 18 US states

The CDC is investigating a multi-state Cyclospora parasite outbreak linked to feces-contaminated produce and water.

A parasitic outbreak tied to feces-contaminated food and water has now reached 18 US states, prompting a formal CDC investigation. The culprit is Cyclospora cayetanensis, a microscopic parasite that causes cyclosporiasis, an intestinal illness whose symptoms include what the CDC describes as 'explosive' diarrhea, along with nausea, fatigue, and cramping. Michigan is among the states reporting surging case numbers. Cyclospora spreads when people consume food or water contaminated with infected feces — fresh produce is a common vehicle, as the parasite can survive on the surface of fruits and vegetables. It is not transmitted directly from person to person, and standard water treatment does not always eliminate it. While the CDC characterizes the illness as rarely life-threatening, it can produce severe and prolonged symptoms, particularly in people with weakened immune systems. Without treatment — typically the antibiotic combination trimethoprim-sulfamethoxazole — symptoms can last weeks or recur.

Why it matters

Outbreaks spanning 18 states signal a potentially widespread contaminated food supply source that has yet to be publicly identified. Vulnerable populations, including immunocompromised individuals, face the greatest risk of serious illness.

What's next

The CDC investigation is ongoing, and public health officials are working to identify the specific contaminated food source behind the multi-state outbreak.

Key facts

• Cases have been reported across 18 US states, with Michigan among those seeing surging numbers
• The parasite responsible is Cyclospora cayetanensis, which causes the intestinal illness cyclosporiasis
• Transmission occurs through produce or water contaminated with infected feces, not person-to-person contact
• Symptoms include 'explosive' diarrhea, nausea, fatigue, and cramping, and can last weeks without treatment
• The CDC says the illness is rarely life-threatening but can have severe effects, especially in immunocompromised people
• Standard treatment is the antibiotic combination trimethoprim-sulfamethoxazole

Bias & framing notes

Both sources are from The Guardian and draw on CDC information, so there is no meaningful divergence in perspective or framing. One article focuses on the investigative news angle (multi-state outbreak, CDC involvement), while the other takes an explainer approach to the illness itself — but the underlying facts are consistent across both.