Washington, DC — Michigan health officials have confirmed the first two US deaths connected to the ongoing cyclosporiasis outbreak, which has sickened thousands of people nationwide and prompted a recall of iceberg lettuce distributed across dozens of states.

The Michigan Department of Health and Human Services (MDHHS) said 11,234 cases had been reported in the state as of July 30, including 193 hospitalisations.

The two people who died had significant underlying health conditions that may have been worsened by cyclosporiasis and dehydration.

The US Centers for Disease Control and Prevention (CDC) says the illness is generally not life-threatening, but severe dehydration caused by prolonged diarrhoea can lead to serious complications, particularly in vulnerable patients.

First US deaths

The deaths are the first reported in the United States in connection with this year's outbreak.

According to Michigan health officials, both patients had underlying health conditions that may have been affected by the intestinal illness and dehydration.

No further details about the individuals have been released.

Health officials say deaths from cyclosporiasis remain uncommon, despite the large number of infections reported this year.

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

People become infected after consuming food or water contaminated with the parasite.

According to the CDC, symptoms usually begin about one week after infection, although they can appear anywhere from two days to more than two weeks later.

Common symptoms include watery diarrhoea, fatigue, loss of appetite, weight loss, abdominal cramping, bloating, nausea and increased gas.

Without treatment, symptoms can last for several weeks or even longer.

Persistent diarrhoea can lead to dehydration, which poses the greatest health risk.

The CDC advises people experiencing symptoms to stay hydrated and seek medical care, noting that routine stool tests do not always screen for Cyclospora and that patients may need to specifically request testing.

Iceberg lettuce recalls

Federal health officials are investigating multiple outbreaks of cyclosporiasis this year.

The CDC, the US Food and Drug Administration (FDA) and state health departments are investigating a multistate outbreak linked to recalled iceberg lettuce distributed in nine states.

On July 17, Taylor Farms de Mexico recalled all iceberg lettuce sourced from central Mexico.

The recall also includes Marketside-brand products sold at Walmart.

The recalled lettuce was distributed to consumers, restaurants and retailers in at least 27 states.

The CDC advises consumers not to eat the recalled lettuce and to either throw it away or return it.

Officials also recommend washing any surfaces or containers that may have come into contact with the product using hot soapy water or a dishwasher.

Michigan investigators initially said lettuce or salad greens appeared to be a potential source of the outbreak but added that other food items have not been ruled out.

State officials said no specific grower or supplier has yet been identified in their investigation.

Separately, the CDC says it is also investigating other domestic outbreaks of cyclosporiasis that are unrelated to the iceberg lettuce recall.

Case numbers differ

The various case totals reflect different investigations rather than conflicting data.

Michigan alone has reported more than 11,000 cases during the outbreak.

Nationally, the CDC says it is aware of more than 18,000 confirmed or suspected domestic cases this season, although many are still undergoing laboratory testing.

The agency's multistate investigation into the recalled iceberg lettuce has so far identified 1,947 laboratory-confirmed cases across nine states, including 98 hospitalisations.

CDC officials note that federal figures often lag behind state reporting because only laboratory-confirmed cases meeting specific reporting criteria are included in national surveillance.

Health risks for vulnerable patients

Most people recover from cyclosporiasis, particularly when treated appropriately.

Doctors say the greatest risk is for people with underlying health conditions, older adults, immunocompromised individuals and anyone who develops severe dehydration after prolonged diarrhoea.

The two Michigan deaths involved patients with significant underlying medical conditions.

Infectious disease specialists say cyclosporiasis itself is rarely fatal, but dehydration can become life-threatening in medically vulnerable patients.

Health authorities continue working to identify additional sources of contamination while monitoring new infections.

The CDC says consumers should avoid recalled iceberg lettuce, wash fresh produce thoroughly, maintain good hand hygiene and seek medical care if symptoms develop.

Officials are also urging anyone contacted by local health departments to participate in interviews about foods consumed before becoming ill, saying the information is critical to tracing contaminated products and preventing additional infections.