The U.S. Centers for Disease Control and Prevention (CDC), on Thursday, said iceberg lettuce served at Taco Bell restaurants was the source of cyclosporiasis infections identified in five states.

The health agency, in a food safety alert, urged the public not to eat shredded iceberg lettuce from Taco Bell restaurants located in Indiana, Kentucky, Michigan, Ohio and West Virginia.

The agency said its officers alongside other public health officials had commenced an investigation into the multistate outbreak of cyclospora infections linked to lettuce served to consumers at the restaurants in the five affected states.

According to the CDC, Taylor Farms de Mexico, the Mexican subsidiary of Taylor Farms, which cultivates and packages fresh fruits and vegetables in Mexico for export, said it would voluntarily remove and recall its distributed shredded iceberg lettuce.

“Epidemiologic and traceback data show that shredded iceberg lettuce from Taylor Farms de Mexico served at some Taco Bell locations is contaminated with cyclospora and is making people sick,” CDC stated.

The disease control and prevention agency stated that about 1,644 people had been infected with cyclospora, 94 people hospitalised, but no deaths recorded.

“Based on epidemiologic information collected by CDC, a total of 1,644 people infected with Cyclospora and reporting exposure to Taco Bell have been reported by 5 states,” it said.

“There have been 94 hospitalisations, and no deaths have been reported. The true number of sick people in this multistate outbreak is likely higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because some people recover without medical care and are not tested for Cyclospora,” it added.

In a separate health advisory, the U.S. Food and Drug Administration (FDA) said cyclospora is a parasite that can only be seen under a microscope.

It said eating food or drinking water contaminated with cyclospora can cause an intestinal illness called cyclosporiasis, believed to infect only humans and spread through human faecal matter.

“Cyclospora is generally transmitted when infected feces (poop) contaminates food or water. It’s unlikely to be transmitted directly from person to person because the cyclospora parasite needs time (days to weeks) after being passed in feces to become infectious,” the FDA said.

It said most people infected with cyclospora develop diarrhoea and experience frequent bowel movements, adding that other common symptoms include loss of appetite, weight loss, stomach cramps, bloating, increased gas, nausea and fatigue.

“Vomiting, body aches, headache, and fever may be noted. Some people who are infected with Cyclospora do not have any symptoms. If not treated, the illness can lead to dehydration and severe complications that may require higher levels of care,” FDA stated.

It urged members of the public with the symptoms to contact healthcare providers to receive appropriate care.