(Image source from: NBC Chicago)

Health officials in the United States of Illinois and Iowa are probing an outbreak of intestinal illness which caused over 30 people to have diarrhea and nausea after consuming McDonald's salads.

Over 20 people who consumed salads at Illinois McDonald's restaurant have suffered from an intestinal illness - Cyclosporiasis, while 15 suffered lowa, according to USA Today.

Cyclospora is a parasite more usually found in developing countries. Symptoms of cyclospora infection include looseness of the bowels, loss of appetite and weight, cramping, bloating or increased gas, sickness, weariness, and low-grade fever.

"Anyone who ate these salads since the middle of June and who developed diarrhea, especially watery diarrhea and fatigue, should see their health care provider and get tested for Cyclospora to ensure an accurate diagnosis and appropriate treatment," said Patricia Quinlisk, Iowa's public health medical Director, and epidemiologist.

Since mid-May, Public health officials in Illinois have counted 90 cases of cyclospora.

Nearly quarter of those who have fallen sick said they had consumed McDonald's salads withing days of suffering symptoms.

Both states health officials said McDonald's is cooperating with the states, Centers for Disease Control and Prevention, and the Food and Drug Administration investigation.

McDonald's said "out of an abundance of caution" it is in the process of removing salads from some restaurants and distribution centers and will resupply restaurants with salads from other suppliers, USA Today reported.

"Although a link has been made to salads sold in McDonald's restaurants in some Illinois cases, public health officials continue to investigate other sources," said Illinois public health director Nirav Shah.

"If you ate a salad from McDonald's since mid-May and developed diarrhea and fatigue, contact a health care provider about testing and treatment."

By Sowmya Sangam