The Pennsylvania Department of Health is looking for a link between at least two dozen reported cases of salmonella in four southwestern Pennsylvania counties.

The Tribune-Review reports that the investigation is in its early stages, and health department investigators haven’t yet been able to find a common source for the 24 cases reported. The state health department is looking for "commonality" among the cases reported in the region in an effort to determine the source of the outbreak, said Richard McGarvey, spokesman for the department.

Health department nurses are contacting all patients reported suffering from the illness, asking where they ate, what they ate, where they went and what they did during the last three days. The questioning will get more detailed as a clearer picture of the outbreak’s scope develops.