Maine’s Center for Disease Control has warned health agencies and laboratories in the state to be on the lookout for E. coli poisoning in people who have traveled to Germany.

A large and deadly outbreak of shiga toxin-producing E. coli O104 is occurring in Germany, and some cases have been identified in travelers to Germany. This strain of E. coli is very rare and had not been seen in the United States prior to the outbreak.

As of June 2, the Robert Koch Institute of Germany reported 11 deaths and 520 patients with hemolytic uremic syndrome, or HUS, a severe condition associated with the E. coli infection that can lead to kidney failure.

In the United States, four suspected cases of infection by the E. coli strain have been identified in patients who recently traveled to Hamburg, Germany, where they were likely exposed, according to the Maine CDC alert.

Symptoms of the infection include severe stomach cramps, diarrhea (which is often bloody) and vomiting. Most people get better within 5 to 7 days, but some patients go on to develop HUS, usually about a week after the diarrhea starts.

Maine’s CDC is asking that any suspected cases in residents with a history of travel to Germany be reported immediately at 1-800-821-5821.

It also warned the medical community that antibiotics should not be given to patients with suspected infections until complete diagnostic testing can be performed and the infection is ruled out.

The source of the E. coli contamination in Germany is still under investigation, although officials have been testing bean sprouts that may have been served in salads.