MADISON, Wis. (AP) -- State health officials are investigating a deadly E. coli outbreak in far southern Wisconsin.

Department of Health Services spokeswoman Stephanie Smiley says that nine people in Green County fell ill due to E. coli infections between mid-August and early September. She says one person has died, but declined to release any additional information, citing confidentiality concerns.

State and county health officials are still working to pinpoint the source of the E. Coli. Smiley says some of the infected are from the same household but declined to elaborate.

She says people can prevent infections by washing their hands, especially after the come into contact with cattle or manure, and avoid eating raw or undercooked meat.

Copyright 2011 The AP.