Cases of the parasite that causes 'explosive' symptoms have surged in the US, with thousands of new additional cases pushing the outbreak to a new record high.

Some 10,468 lab-confirmed cases of cyclosporiasis across 47 states have been reported to date, up 6,707 from last week, the CDC confirmed in an update Tuesday.

However, officials believe the true toll could stretch past 22,000, as 12,255 additional reports are still awaiting laboratory confirmation and investigation.

Two deaths from the parasite were recorded yesterday in Michigan, while 517 people nationwide have also been hospitalized. 

Many of the newly reported cases were in Michigan and Ohio, which are at the center of the outbreak.

Local health departments in these states have reported more than 15,000 cases alone and over 300 hospitalizations. There is a lag between local and federal data. 

Cyclospora, the parasite behind the illness cyclosporiasis, is spread through consuming food or water that is contaminated with human feces. 

Symptoms include 'explosive' diarrhea, abdominal cramps and vomiting in patients. The disease normally resolves in two weeks and is rarely fatal, although it can trigger potentially life-threatening dehydration.

The updated figures come amid a major outbreak of the disease linked to shredded iceberg lettuce from Taylor Farms, that was sold at Taco Bell and other stores.

In North Carolina, authorities are probing lettuce, cilantro and parsley as a potential source of the infections. In Michigan, health officials have not pinpointed a specific source but have urged people to thoroughly wash and trim certain produce before consuming them. These items include lettuce and leafy greens, cilantro, basil, green onions, raspberries and snow peas.

A total of 15 states have recorded cases in the major outbreak so far. 

Health officials are currently tracking six outbreaks of cyclosporiasis in the US.  The separate outbreaks do not mean that each is not related, experts say, but suggest that health officials have identified a common food source for each cluster of infections.

Nationwide, CDC officials said patients sickened with cyclosporiasis were ages one to 98 years old, with an average age of 44 years, and 56 percent were female. 

Most patients became sick on July 4.

The largest previously recorded outbreak was in 2019, and led to 4,703 domestic and internationally acquired cases. This was primarily linked to fresh basil imported from Mexico alongside other causes. 

Typically, the US only records a few hundred cases every year, which are linked to travelers returning from countries where the parasite is common, including Mexico, Central America, South America and the Caribbean. 

Fresh produce can become contaminated if it is washed or irrigated with water contaminated by human sewage. 

Experts say that it is also theoretically possible for people to become infected by touching surfaces that have been touched by a sick individual who did not wash their hands after using the toilet.  

Previous outbreaks have been linked to bagged salad kits, cilantro, basil and other leafy greens.

Unlike norovirus or routine food poisoning, however, symptoms often come and go rather than resolving after a few days.

Without treatment, experts say the illness can persist for weeks or repeatedly return.

Anyone with diarrhea lasting more than a few days should seek medical care and specifically ask for a cyclospora test, as it is not routinely ordered, Dr Swapnil Patel, vice chair of medicine at Hackensack Meridian Jersey Shore University Medical Center, told the Daily Mail.

The test detects cyclospora DNA in stool samples and typically requires one to three samples.

Treatment for the infection consists of the antibiotic trimethoprim-sulfamethoxazole, sold under the brand names Bactrim, Septra and Cotrim.