DENVER An investigation into a listeria outbreak that has killed at least one person has expanded to include three states where possibly tainted cantaloupe was consumed, Colorado health officials said on Friday.
The Colorado Department of Public Health and Environment said in a release that of the nine confirmed cases of the gastrointestinal infection in Colorado, two suspected cases in Texas and one in Nebraska, all of the patients recently ate cantaloupe.
Chris Urbina, chief medical officer for the department, said officials haven't yet traced where the tainted melons were sold.
"While the investigation into the source of the listeria outbreak is continuing, it is prudent for people who are at high risk for listeria infection to avoid consumption of cantaloupe," Urbina said in a written statement.
Those mostly likely to be sickened by the bacteria include people over the age of 60, pregnant women and people whose immune systems have been weakened by disease or organ transplants, Urbina said.
Because the outbreak has gone multi-state, the U.S. Centers for Disease Control and Prevention is coordinating the investigation in conjunction with the U.S. Food and Drug Administration and the U.S. Department of Agriculture.
Although Colorado has reported 13 listeria cases since the beginning of August, just nine of the state's cases are linked to the current outbreak.
In the four other cases the cantaloupe link has been ruled out or laboratory results are still pending, the health department said.
Two patients have died in Colorado from listeria in the last month, but investigators can link just one death to the current outbreak.
People in the high-risk groups for contracting the infection should avoid unpasteurized soft cheeses, refrigerated smoked seafood, and deli meats unless they have been reheated to 165 degrees Fahrenheit.
Healthy people are usually unaffected by the bacteria. In severe cases, the infection can cause convulsions and stillbirths or miscarriages in pregnant women.
(Editing by Dan Whitcomb and Jerry Norton)