Federal officials are investigating a new outbreak of infections caused by E. coli.

The outbreak has sickened 37 people so far, according to the Food and Drug Administration. The agency has not released any patient information, including wher they live.

FDA investigators have begun traceback efforts, but the agency is not yet releasing information about what food or foods are being traced. The FDA has not started any sample testing related to investigating this outbreak.

The Centers for Disease Control and Prevention have not released any information about the outbreak.

about E. coli infections
Food contaminated with E. coli usually does not look, smell or taste bad. 

Anyone who has developed symptoms of E. coli infection should seek medical attention and tell their doctor about their possible exposure to the bacteria. Specific tests are required to diagnose the infections, which can mimic other illnesses.

The initial symptoms of E. coli infections vary for each person but often include severe stomach cramps and diarrhea, which is often bloody. Some patients may also have a fever. Most patients recover within five to seven days. Others can develop severe or life-threatening symptoms and complications, according to the Centers for Disease Control and Prevention (CDC).

about 5 percent to 10 percent of those diagnosed with E. coli infections develop a potentially life-threatening kidney failure complication known as a hemolytic uremic syndrome (HUS). Symptoms of HUS include fever, abdominal pain, tiredness, decreased frequency of urination, small unexplained bruises or bleeding, and pallor. 

Many people with HUS recover within a few weeks, but some suffer permanent injuries or death. This condition can occur among people of any age but is most common in children younger than five years old because of their immature immune systems, older adults because of deteriorating immune systems, and people with compromised immune systems such as cancer patients. 

People who experience HUS symptoms should immediately seek emergency medical care. People with HUS will likely be hospitalized because the condition can cause other serious and ongoing problems such as hypertension, chronic kidney disease, brain damage, and neurologic problems.