LANSING — Michigan’s unprecedented cyclosporiasis outbreak has sickened 12,485 people since June, hospitalized at least 279 and contributed to the deaths of two residents, according to the latest figures from the Michigan Department of Health and Human Services.

The Aug. 6 figures fall slightly below earlier projections that the state would surpass 13,000 cases by the end of the first week of August.

Michigan has historically recorded only about 50 cases of cyclosporiasis annually. The current outbreak is the largest in the state’s history and one of the largest foodborne illness outbreaks recorded in the United States.

Thousands of additional infections have been reported in other states, including Indiana, Ohio, Kentucky, Kansas, Illinois, Oklahoma, West Virginia and Pennsylvania. The federal investigation has since expanded to include illnesses in 15 states.

Although the only reported deaths have occurred in Michigan, state and federal health officials continue investigating the outbreak and any additional sources of infection.

The number of newly reported cases and diarrhea-related emergency room visits has begun declining, however, leading the MDHHS to lift its earlier broad warning about consuming bagged lettuce and salad greens.

Officials said most products associated with the highest-risk exposure period in late June and early July have probably already been consumed or discarded. Consumers should continue avoiding any products specifically included in the federal recall.

Michigan health officials said both residents who died had significant underlying medical conditions. Cyclosporiasis and the dehydration associated with the illness may have contributed to the deterioration of their health, according to medical records.

The department declined to release additional details about the two people or their medical histories.

Earlier state data showed Wayne County had recorded the largest number of cases, with approximately 1,400 infections. Adults between the ages of 30 and 39 were the most heavily affected age group.

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. Although it is not generally considered life-threatening, it can cause serious complications among older adults, people with weakened immune systems and those with chronic medical conditions.

People become infected by consuming food or water contaminated with fecal matter. Fresh fruits, vegetables and leafy greens that are eaten raw have frequently been associated with previous outbreaks.

Symptoms include frequent watery diarrhea, nausea, stomach pain, cramping, bloating, loss of appetite, weight loss and fatigue. Some patients also experience vomiting, body aches, headaches or fever.

Without treatment, symptoms can persist for several weeks or longer. They may appear to subside before returning one or more times.

The Centers for Disease Control and Prevention had recorded 6,707 laboratory-confirmed cases nationwide by July 28, in addition to more than 11,500 suspected cases awaiting confirmation or further investigation.

Federal surveillance figures include laboratory-confirmed infections, while state health departments may also count probable cases. That difference helps explain the substantial gap between Michigan’s figures and the national confirmed total.

The CDC has said it is working with state agencies to update the national count as additional infections are confirmed.

The Food and Drug Administration reported on Aug. 5 that 6,358 illnesses in 15 states had been linked specifically to the multistate outbreak associated with recalled iceberg lettuce. Those illnesses are a subset of the wider number of Cyclospora infections detected nationally.

At least 278 people associated with the multistate lettuce outbreak were hospitalized, according to the FDA. Both reported deaths occurred in Michigan.

Lettuce under investigation

The record number of cyclosporiasis cases this summer has been attributed, at least in part, to recalled iceberg lettuce used in products sold through restaurants and retail stores.

An FDA traceback investigation found that numerous cases converged on shredded iceberg lettuce supplied by Taylor Farms de Mexico from central Mexico. The lettuce was served at certain Taco Bell restaurants owned or franchised under Yum Brands.

Taylor Farms initiated a voluntary recall July 17 and removed iceberg lettuce sourced from central Mexico from the U.S. market. Taco Bell said it stopped using lettuce from Taylor Farms de Mexico that same day.

The recall included certain Marketside-brand iceberg salad and shredded lettuce products sold at selected Walmart stores, in addition to products supplied to restaurants and other food-service customers.

The FDA initially reported a positive laboratory test from a lettuce sample but later reclassified that result as a false positive following additional review.

Federal officials emphasized that the revised laboratory finding did not invalidate the recall or the epidemiological and traceback evidence linking a portion of the outbreak to Taylor Farms lettuce.

Cases associated with exposure to the recalled lettuce have been reported in Arkansas, Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Missouri, Nebraska, New Hampshire, North Carolina, Ohio, Oklahoma, Pennsylvania and West Virginia.

The investigation remains active, and state and federal officials have not ruled out additional food sources. Several other Cyclospora outbreaks involving products that have not yet been identified are also under investigation.

The outbreak has affected consumer confidence and the food service industry. Lettuce sales declined as consumers struggled to determine which products were safe, while customer traffic at Taco Bell fell sharply during the height of the outbreak.

Some other restaurant chains also experienced declining customer traffic amid broader concerns about fresh produce, although health officials have not linked all those businesses to the recalled lettuce.

Multiple Michigan residents have filed lawsuits against Taco Bell, Taylor Farms and related suppliers, alleging that they became ill after consuming food containing contaminated lettuce.

One proposed federal class-action lawsuit was filed in the U.S. District Court for the Eastern District of Michigan on behalf of a woman who said she tested positive for Cyclospora after eating at a Taco Bell restaurant in Yale.

Former CDC officials and food safety specialists have warned that federal health agency staffing and budget cuts could impair the government’s ability to investigate and respond quickly to foodborne disease outbreaks.

Wade Syers, a statewide food safety specialist with Michigan State University Extension, said the deaths underscore the urgency of identifying outbreak sources and preventing additional illnesses.

“The reported deaths are a sobering reminder that cyclosporiasis is usually not life-threatening, but it can become very serious in vulnerable individuals,” Syers said.

He urged people experiencing persistent diarrhea, dehydration or worsening symptoms to seek medical care, particularly if they belong to a higher-risk group.

Updated health recommendations

Michigan health officials have lifted their earlier general recommendation that residents avoid prepackaged lettuce and salad greens because new case reports and diarrhea-related emergency visits have declined.

However, consumers, restaurants and retailers should discard any iceberg lettuce covered by the Taylor Fresh Foods recall.

The recalled Marketside products included certain 12- and 24-ounce iceberg salads and 8- and 16-ounce packages of shredded lettuce bearing specified use-by dates between July 18 and Aug. 3.

Because the recalled products have passed their use-by dates, officials believe most are no longer available for sale. Consumers should nevertheless check refrigerators and discard any recalled packages that remain.

Anyone who handled the recalled lettuce should thoroughly clean and sanitize surfaces and containers that came into contact with it to reduce the possibility of cross-contamination.

Washing produce under running water remains a recommended food safety practice, but washing alone may not completely remove Cyclospora. Chemical disinfectants commonly used at home are also not considered reliable methods for killing the parasite.

Cooking produce thoroughly to an internal temperature of at least 158 degrees Fahrenheit can kill Cyclospora.

Health specialists also recommend washing hands before, during and after food preparation, removing damaged portions and outer leaves from produce and keeping raw meat separate from fruits and vegetables.

Previous Cyclospora outbreaks have been associated with lettuce, raspberries, basil, cilantro and snow peas.

Health officials emphasized that consumers should not avoid all fresh produce. Instead, they should monitor official recall notices, discard recalled products and follow standard food-handling practices.

Anyone experiencing persistent diarrhea, signs of dehydration or worsening symptoms should contact a medical provider, especially after consuming shredded iceberg lettuce during the period covered by the recall.