Michigan has reported the first two deaths in the United States linked to a cyclospora outbreak, marking a turn in a season of illness that has spread across much of the country. The deaths were confirmed by the Michigan Department of Health and Human Services, which had been tracking cases through the spring and summer.

Cyclospora is a microscopic parasite that infects the small intestine and causes cyclosporiasis, an illness whose hallmark is watery diarrhea that can last for weeks if untreated. People usually become sick after eating fresh produce or drinking water contaminated with the parasite. The most common symptoms are frequent, sometimes explosive bouts of diarrhea, along with loss of appetite, cramping, nausea and fatigue.

Nationally, the outbreak has grown to more than 11,000 recorded cases, according to figures tracked by the Centers for Disease Control and Prevention, making it one of the larger seasonal clusters of the disease in recent years.

Cyclosporiasis tends to appear in the warmer months in the United States, and outbreaks in past years have been traced to imported fresh produce, including leafy greens and herbs. The parasite is not spread directly from person to person, because it needs time in the environment to become infectious after leaving the body. That biological detail shapes how outbreaks unfold: they are driven by contaminated food or water rather than by casual contact among people.

For most otherwise healthy people, the illness is treatable. A course of antibiotics can clear the infection, and doctors also advise rest and fluids to counter the dehydration that the diarrhea can bring on. Left untreated, symptoms can persist and recur over a period of weeks. The risk of severe outcomes is higher for older adults and for people with weakened immune systems.

Public health guidance during cyclospora seasons centers on food safety. Officials generally recommend washing fresh produce thoroughly, though washing alone does not guarantee removal of the parasite, and they encourage people with prolonged diarrhea to seek medical care and testing so that cases can be identified and treated.

The scale of this year's outbreak, now above 11,000 cases, and the first confirmed deaths have drawn renewed attention to how the parasite moves through the food supply and how quickly it can be diagnosed. Investigations into the sources of seasonal cyclospora cases can be difficult, in part because people often eat many different fresh foods before falling ill, and because the delay between exposure and symptoms complicates efforts to pinpoint a single item.

Health authorities continue to monitor the outbreak as the case count is updated.

References

1. 1.Michigan Department of Health and Human Services — the two reported deaths and state case tracking
2. 2.Centers for Disease Control and Prevention — national case count above 11,000 and cyclosporiasis clinical and epidemiological information
3. 3.CDC food safety guidance — recommendations on washing produce and seeking care for prolonged diarrhea