Two-year-old twin boys are in the hospital suffering from kidney failure after visiting a petting zoo linked to an E. coli outbreak, the Times Online reported Monday.

Aaron and Todd Mock visited the Godstone Farm in Surrey, England with their family on August 31 – two weeks before the farm was shut down because of a suspected E. coli outbreak. So far, 36 people have become ill after visiting the farm.

The twins’ mother, Tracy Mock – whose 5-year-old daughter is also ill – is demanding to know why authorities waited so long to shut down the farm after the first cases of E. coli were confirmed.

"If they had just shut the place down, my sons would not be in hospital on kidney dialysis machines," said Mock. "They are still in hospital. One has had a blood transfusion. My partner and I are taking turns to be there with them. The doctors say it could be weeks before they are fit to come home."

Around five to ten percent of those who are diagnosed with E. coli infection will develop a potentially life-threatening complication known as hemolytic uremic syndrome, where bacteria lodged in the digestive tract makes toxins that enter the bloodstream and destroy the red blood cells, according to the Centers for Disease Control and Prevention.

Symptoms of hemolytic uremic syndrome include:

—decreased frequency of urination;

—fatigue;

— loss of color in cheeks, eyelids.

Officials said the outbreak may have started in early August, but no cases were confirmed until August 27 because of the bacteria’s long incubation period.

Click here to read more from the Times online.