Sentinel Surveillance: an option for surveillance of infectious intestinal disease.

Sentinel surveillance systems offer advantages over passive surveillance which is known to have limitations due to incomplete reporting. Sentinel surveillance gathering data from selected sources was piloted as an option for surveillance of infectious intestinal disease (IID) in Malta. Between October 2004 and May 2005, 22 general practitioners (GPs) voluntarily participated in the study and reported on the number of IID cases (by age and sex) and all primary care encounters in their practice. The GPs' reporting activity lasted for 35 weeks, covering a total of 55,425 primary care encounters, of which 1.95% concerned IID. For every case reported via the routine passive notification system, seven cases would be picked up by this enhanced sentinel surveillance.