Washington, Sep 14 (IANS): The multistate outbreak of intestinal illness, likely linked to salads from McDonald's restaurants, that affected over 500 people in the US with diarrhoea and nausea appears to be over, the Food and Drug Administration (FDA) said.

"A total of 511 laboratory-confirmed cases of Cyclospora infection causing diarrhoea and nausea were reported in people from 15 states and New York City who consumed salads from McDonald's restaurants," FDA said in a statement.

However, "as of September 11, the outbreak appears to be over," it added.

Cyclospora cayetanensis is a microscopic parasite of humans. When food or water contaminated by this parasite is consumed, it can cause an intestinal illness called cyclosporiasis.

The FDA, along with Centres for Disease Control and Prevention (CDC), investigated distribution and supplier information for romaine and carrots but did not identify a single source or potential point of contamination for this outbreak.

According to the CDC, 24 people were hospitalised but no deaths were reported.

Epidemiologic and traceback evidence indicated that salads purchased from McDonald's restaurants were a likely source of this outbreak, the report said.

In a statement on July 13, McDonald's voluntarily stopped selling salads at over 3,000 locations in 14 states. The company has since reported that it has replaced the supplier of salad mix in those states.

The Cyclospora symptoms included diarrhoea, with frequent, sometimes explosive, bowel movements, loss of appetite, weight loss, stomach cramps/pain, bloating, increased gas, nausea, and fatigue.

But, for some people who are infected with Cyclospora, there were no symptoms.

The health officials advised people with symptoms of cyclosporiasis to contact their health care provider.