Taco Bell has pulled several ingredients from its menu amid the spread of a parasitic infection that causes 'explosive' bathroom emergencies. 

The fast food giant has posted notices at several locations in the US saying it will not serve lettuce, pico de gallo, guacamole or cilantro onion due to the growing spread of the cyclospora parasite. 

The locations include several stores in Michigan, where nearly 1,000 residents have been sickened with cyclosporiasis, an infection caused by the cyclospora parasite that leads to sudden and severe gastrointestinal symptoms such as explosive diarrhea and vomiting. 

Local news outlets report the posted notice reads: 'We are currently unable to sell Lettuce, Cilantro Onion, Pico de Gallo, and Guacamole due to a nationwide recall. We apologize for the inconvenience. 

'Any items ordered that normally come with these items WILL NOT contain them.'

It is not clear what recall the company is referring to. No food recalls have been issued in connection with the spread of cyclosporiasis cases. 

Items that include at least one of these ingredients are tacos, the Crunchwrap Supreme and certain Cantina Chicken items. 

It's unclear if any Taco Bell consumers have been sickened by cyclosporiasis. Daily Mail has reached out to the chain for comment.  

The notices come as at least 1,900 cases of cyclosporiasis have been reported nationwide this year. No source of the parasite is known at this time and state and federal health officials are investigating. 

Health officials from 29 states have confirmed to the Daily Mail that they are experiencing cases. 

North Carolina and New York have reported the second- and third-most cases behind Michigan, with 145 and 125 confirmed illnesses, respectively. 

However, due to reporting delays, it is possible actual case counts are higher. Daily Mail is awaiting responses from other states. 

CDC data, which has not been updated since July 1, only shows 145 cases in 17 states.  

Cyclosporiasis is acquired through eating or drinking food or beverages contaminated with the parasite, often from feces. 

The cyclospora parasite particularly tends to cling to raw, fresh produce such as leafy greens, herbs and soft berries that have bumpy surfaces where contaminants can hide. 

Previous outbreaks have been linked to bagged salad kits, cilantro, basil and other leafy green produce - though no source or suspected source has been identified in this outbreak. 

Human-to-human transmission is rare. 

The Cleveland Clinic has warned: 'Cyclosporiasis is an illness you get from the parasite Cyclospora cayetanensis. It causes watery, and sometimes explosive, diarrhea and other stomach problems.'

Symptoms usually occur about a week after exposure. 

If not treated, cyclosporiasis could last for more than a month, with symptoms subsiding and reappearing multiple times. 

To prevent the disease, the CDC recommends avoiding consuming food or water at risk of contamination with feces and following general food safety preparation guidelines. 

Treatment consists of a course of the antibiotic trimethoprim-sulfamethoxazole, which is sold as Bactrim, Septra or Cotrim. 

Most people with a healthy immune system will recover without any treatment. 

Cases of cyclosporiasis tend to rise between May and August and it is more common in people returning to the US from foreign travel. 

As the Michigan Department of Health and Human Services (MDHHS) races to identify a source of the outbreak, it earlier this week issued warnings to restaurant workers to reduce the spread. 

For lettuce and greens, the department urged restaurants to buy whole heads of lettuce rather than prewashed, bagged lettuce or salad mixes, throwing away the outer two to three layers of leaves and washing inner leaves under running water. 

MDHHS also recommended in a press release washing cilantro and basil thoroughly under running water and separating the leaves. Green onions should be trimmed at the root end and have the outer layer removed before washing under running water.

And for raspberries, the department warns their bumpy surface makes them hard to clean, allowing the cyclospora parasite to hide in the crevices. Snow peas must also be washed under running water. 

The agency also noted heating foods to 158F (70C) can kill the cyclospora parasite, and all fresh produce should be washed under running water, even if you plan to peel it.  

MDHHS emphasized its food-related recommendations are especially vital for people at a higher risk of dehydration or with weakened immune systems, such as those on chemotherapy, organ transplant recipients, young children and older adults.