Only one of the APDIC calls was a potential match to a confirmed PCHD case.
During the 3-month study period, APDIC received 51 calls regarding foodborne illness, of which 50 were consistent with the diarrhea/gastroenteritis syndrome definition used.
Although APDIC has multiple coding categories that PCC specialists can use to code suspected cases of foodborne illnesses, the defined search strategy identified calls regarding potential foodborne illness reported to and classified by APDIC with high specificity and reasonable sensitivity.
For outbreak detection to be improved, a standard syndrome-based definition should be developed for APDIC to collect and code call data consistent with an established syndrome-based definition.
Comparing the incubation period noted for the majority of APDIC callers (<24 hours) with that for persons whose cases were identified by PCHD suggests that the two data sets are identifying persons from different populations.
Demographic and clinical data are missing from both the APDIC and PCHD databases.
On the basis of this analysis, prospective surveillance of APDIC's real-time foodborne illness complaint calls will be implemented.
Studies are needed to determine whether a temporal relationship exists between APDIC calls and PCHD cases; if such a relation is demonstrated, prospective monitoring of increases in APDIC calls might be predictive of increases in the number of foodborne illness cases.
APDIC might provide a useful addition to the PCHD's syndromic surveillance system and might assist in early detection of FBDOs.