The CDC now confirming 55 cases inf 12 states including Wisconsin.
13 people have had to go to the hospital.
Wisconsin was among the first states to get the alert about the bacteria called Campylobacater.
Initially the thought was the transmission occurred in the open petting areas of Petland Stores.
14 workers of Petland are among those who became ill.
The Milwaukee Emergency Center for Animals was the first local organization to sound the alarm.
But even then the staff thought the source could go beyond stores.
Dr. Lindsey Foster told the CBS 58 News that she thought contamination could easily be occurring in dog parks where dogs go to the bathroom.
The combination of not getting rid of the waste or washing hands enough making for a risky combination.
In expanding the outbreak alert, the CDC included states where there are no Petland locations.
In at statement sent to CBS 58 News, Petland's Public Affairs Director said she was pleased the CDC was expanding the investigation.
"Petland has been able to provide traceback for any puppy purchased as requested by the CDC," Petland's Elizabeth Kunzelman said. "However, more than 98% of people obtain their puppies from other sources, including shelters, rescues, friends, online and through local advertising."
Copyright 2023 by Cable News Network, Inc., a Time Warner Company. All rights reserved.