Nine people in southeast Nebraska have tested positive for E. coli infection in unrelated incidents.

Vicki Duey of the Four Corners Health Department said five people have tested positive for E. coli infection since her office was alerted last week.

She's looking at whether food served at a public event may have sickened at least 25 people.

Duey said the health department is currently looking at meat served at the event as a possible cause. She said all of the 25 people who displayed symptoms of e-coli poisoning are recovering.

She won't say where the event took place, but her department covers Butler, Polk, Seward and York counties.

Meanwhile, state epidemiologist Tom Safranek said there are four confirmed cases of E. coli infection in the Auburn area of Nemaha County. He said three of the four sick people live in the same house, and the fourth came in contact with them.

The cause of those illnesses is under investigation.

For more information about e-coli poisoning, how it's caused and how to prevent it, click here.