Seattle Fire Infectious Disease
Monitoring Update

Last Updated: September 21, 2009

SUMMARY COMMENTS

The rate of patients found with influenza-like symptoms (ILS) started to increase in late August and the rate of ILS is significantly above the levels from the June-July period.  See charts and data links, below.

Influenza-like flu symptoms increased in mid-to-late August 2009.  Similar increases in ILS occurred the same period in 2007 and 2008. There also appears to be a "double-bump" this year and in prior years.  That is, the rate of ILS found increases in late August, drops in early September and starts a steady increasing again in mid-September.

SITUATION FOUND REPORT

On August 4, 2009, a report on the infectious disease (flu-like illness) monitoring program was presented to the Fire Department Medical Director and research team, and Fire Department upper management and paramedics.  Click here to review an edited version of the report (PowerPoint 2007)

SURVEILLANCE PROGRAM

The Seattle Fire Department is tracking symptoms of patients that firefighters come into contact with that may be related to flu: cough, fever, gastro, rash, respiratory.  Reports of these symptoms are entered into a computer system built by the Fire Department shortly after firefighters leave the scene of the incident.  The data is monitored by the First Watch surveillance application (www.firstwatch.net)

Alerts are sent via e-mail to individuals in Seattle Fire Department when symptoms found exceed thresholds established by the Department in consultation with First Watch.  These thresholds are common metrics used by other public health and EMS agencies for monitoring infectious disease outbreaks.

Flu Symptom Aggregate Charts

Chart 1: Flu-Like Symptoms.  This chart shows the percentage of patients with individual and combinations of flu symptoms.  This is a 14-day moving average since July, 2007.

Chart 2: Fever and all other combination of flu-like symptoms.  This chart shows the percentage of patients with only fever or patients with a combination of symptoms - i. e., Respiratory-Fever, Cough-Fever, Respiratory-Cough.  Patients with only one symptom of Cough, Respiratory, Rash, or Gastro are excluded.  This is a 14-day moving average since July, 2007.  The 7-day moving average chart (from January 1, 2009 to now) shows more dramatic fluctuations in ILS, particularly in the late-August-to-early September periods.

Chart 3: Cough, Fever, Respiratory with all other combination flu-like symptoms. This chart shows the percentage of patients with only fever or patients with a combination of symptoms - i. e., Respiratory-Fever, Cough-Fever, Respiratory-Cough.  Patients with only one symptom of Cough, Respiratory, Rash, or Gastro are excluded. This is a 14-day moving average since July 2007.  The 7-day moving average chart (from January 1, 2009 to now) shows more dramatic fluctuations in ILS, particularly in the late-August-to-early September periods.

Flu-Like Symptom Data.  This is a detailed list of incidents, incidents with flu symptoms, breakdown of patients by symptom and symptom combinations for each day since July 1, 2007. This table is used to generate the charts. 

STATISTICS SUMMARY