BIOSENSE: Use of Biosurveillance Software to Detect Clusters of Visits for Diarrhea Fort Worth, Texas, August 31, 2010

Background:  Several tools have been developed to for real time disease detection.  Electronic Surveillance System for the Early Notification of Community Based Epidemics (ESSENCE) and BIOSENSE provide tools to detect unusual increases in cases that may signify a public health event and issue alerts. On September 1, 2010, JPS Health Network Infection Control and Prevention Department was contacted by the Tarrant County Public Health to investigate a cluster of nine visits for diarrhea that occurred at a hospital in Fort Worth, Texas, on August 31.

Objective:  Investigate a BIOSENSE report for a cluster of diarrhea cases and determine if an outbreak response and public health intervention is warranted.

Methods:  We examined the chief complaint sub syndrome diarrhea during the time period August 18 through September 16 using BIOSENSE and ESSENCE to gather baseline data for the diarrhea cluster. We decided to use ESSENCE to investigate the cases as our staff was more familiar with this program. Demographic data gathered utilized our medical records databases to determine if any cases had been hospitalized and/or had laboratory work completed. 

Results: Our queried results for BIOSENSE had nine cases and ESSENCE generated thirteen cases. No cases had a stool sample collected. The age range was 2-60 years old and males represented 54% of the cases. One patient was admitted to the hospital for an unrelated event.  Five of the cases (38%) returned to our facility 24 hours later for follow-up. Four of the five cases were members of the same household that had no signs of diarrhea or dehydration when they initially visited the emergency room.

Conclusions:   Although the BIOSENSE Alert did not result in a public health intervention, it provided an opportunity for our facility and the public health department to identify gaps in preparedness, investigation and response towards an event. Weaknesses identified were access to the biosurveillance programs, training on using biosurveillance, and a protocol for investigating cases. No one at our facility had access to BIOSENSE. The process to gain access was quick and simple, but our facility did not receive the initial notification for the diarrhea cluster alert and we were eventually notified by our local health department. Another issue with the BIOSENSE program was that new record numbers are generated to investigate cases, rather than using existing patient or medical record numbers. The record numbers could not be used to look up patients at our facility. We had to use ESSENCE to query for diarrhea cases to start our investigation. As a result of these gaps identified, we were able to get our staff and other infection control analyst in our county access and training with the biosurveillance programs.