Over the past month, the Listeria outbreak linked to Colorado cantaloupes has grabbed headlines as the numbers of sicknesses and deaths push higher. But a series of E. coli O157:H7 outbreaks have been piling up under the radar, and health officials have been unable to identify what’s causing them.

At least 4 separate E. coli outbreaks have arisen in 4 different states within a month’s time. And as of Thursday, none of them had been traced back to a source, making it impossible for authorities to warn customers about what foods or locations to avoid in order to protect themselves. 

Many cases involved in these epidemics have been severe. In total, they have caused at least 50 illnesses and 1 death in the affected states, which include:

Michigan

Health officials have reported E. coli illnesses among two children and one adult from the Maple Rapids area of the state. The children have both been hospitalized with hemolytic uremic system (HUS), a life-threatening complication of an E. coli infection that can cause kidney failure. 

The same strain of the bacteria appeared this summer among victims who had attended the Clinton County Fair. Officials remain unsure whether there is a connection between the two clusters of illnesses. 

“This strain of E. coli is very potent and troublesome,” said Dr. Robert Graham, Medical Director at the Mid-Michigan District Health Department. “We urge everyone to take precautions to prevent becoming infected by this germ,” he said, according to The Morning Sun.

Missouri

The St. Louis County Health Department is reporting 22 cases of E. coli in the metro area. Of these victims, at least 6 have been hospitalized. The source of the bacteria is currently unknown; however investigations are pointing towards produce sold at local grocery stores. However, no food is currently under recall, reported stltoday.com. 

The Missouri Department of Health and Senior Citizens continues to look into the origin of the outbreak, and in the meantime is encouraging anyone who experiences stomach cramps, nausea or diarrhea to seek medical attention.

North Carolina

A total of 21 E. coli cases, nine confirmed and 11 suspected, are being investigated. So far, 8 of the 9 confirmed victims are known to have visited the North Carolina State Fair, which began October 13 in Raleigh and ended Sunday. 

However, officials have been unable to determine a common food vendor or attraction visited by victims, reported newsobserveer.com Thursday.  

Seven of the confirmed victims are children, two of whom remain hospitalized in intensive care.  

In 2004, an E. coli outbreak sickened 108 people who attended the State Fair’s Crossroads Farm Petting Zoo. It was later determined that animal feces at the exhibit were the source of the bacteria. 

Wisconsin

An outbreak of E. coli began in this state in mid-August, and the number of cases has now risen from 10 in mid-September to 15. One 20-month-old girl is reported to have died from infection. Two patients developed HUS. 

So far, health officials have identified a common cluster of illnesses among students of Abe Lincoln Elementary School in Green County. However, the campus is not thought to be where the bacteria originated.

The Illness

The incubation period for E. coli O157:H7 can range anywhere from 1 to 10 days after exposure. Symptoms of infection include watery diarrhea, which can sometimes become bloody, vomiting, stomach cramps and fever, although fever is uncommon. 

Approximately 6 to 10 percent of cases result in HUS. Most individuals who do not develop this complication recover in around two weeks.