[Preliminary trial of syndromic surveillance to early detection of nosocomial infection outbreak].

OBJECTIVE

To detect nosocomial outbreaks early we construct syndromic surveillance for inpatients with fever, respiratory symptoms, diarrhea, vomiting, or rash and evaluate it statistically.

METHODS AND MATERIALS

In hospital using electronic medical records since August 1999, we studied the number of inpatients with a certain symptoms from 1999 to 2005. To prospectively detect outbreaks after January 1, 2005, we first estimated the baseline using data from August 1, 1999 to the day before any given day. We then predicted the number of patients on the day and judge whether an outbreak has occurred, evaluating this by checking it sensitivity and specificity to detect outbreaks other than those with previous patterns.

RESULTS

From August 1999 to December 2005, 115,532 patients had fever, 126,443 respiratory symptoms, 87,923 diarrhea, 32,858 vomiting, and 11,212 In 2005, in prospective detection, 23,617 had fever, 23,698 respiratory symptoms, 14,671 diarrhea, 5,893 vomiting, and 2,486 rash.

DISCUSSION

This hospital had a nosocomial Noro virus outbreak on January 27, 2005. Syndromic surveillance identified an outbreak of vomiting at a 0.1% criterion. Our system thus detects nosocomial outbreaks and is of practical use. The next step will be ward-by-ward examination, after which we will experiment with rapid information collection, analysis, reports of results, and investigation by infection control teams.