Health department officials in Marin County, CA, have confirmed three E. coli cases and a possible fourth. Three cases are reportedly children (two of whom have been hospitalized in stable condition), while the fourth person with a suspected case is an adult.

According to a Wednesday story in the Marin Independent Journal, no source for the infection has yet been found. Health officials said the individuals were exposed between Sept. 11 and Sept. 15 and that three of the victims live in Tiburon, and the fourth lives in Inverness.

Marin County public health officer Dr. Matthew Willis said E. coli most seriously affects children, elderly people and those with weak immune systems. He said the county is working with California Department of Public Health on potential links between the local cases and perhaps other, out-of-state ones.

“We contact the patients themselves to interview them about their food history. We try to determine where they’ve eaten and what they’ve eaten to see if there’s a common source,” Willis said.

E. coli infection typically affects people who eat raw dairy products or undercooked meat, according to the Centers for Disease Control and Prevention. Most people recover from the infection within a week, but some victims can die from E. coli if they develop a form of kidney failure known as “hemolytic uremic syndrome,” or HUS.

To limit the potential of getting an E. coli infection, practice good food hygiene practices such as washing hands with soap and water after changing diapers and using the bathroom and before preparing or eating food. Cook meats thoroughly and wash counters, cutting boards and utensils after they touch raw meat to avoid cross-contamination.

Symptoms of E. coli infection include severe stomach cramps, diarrhea, bloody diarrhea and vomiting. Anyone experiencing these symptoms is encouraged to visit their doctor.