Division of Disease Control and Health Protection

"The reason for collecting, analyzing and disseminating information on a disease is to control that disease. Collection and analysis should not be allowed to consume resources if action does not follow."

--Foege WH et al. Int. J of Epidemiology 1976; 5:29-37.

The Bureau of Epidemiology is available 24 hours a day, 7 days a week for consultation at our main number 850/245-4401. PLEASE NOTE: Consultation after 5 p.m. & on weekends is intended for emergencies.

Robin Oliveri, BS, Arboviral Surveillance Program Coordinator

With the onset of winter, the 2000 arbovirus surveillance season is coming to a close. The national West Nile virus surveillance program was successful in its objective to monitor the geographic and temporal spread of the virus over the eastern and southern United States. To date, the virus has been confirmed in the following areas: Connecticut, Washington, DC, Delaware, Massachusetts, Maryland, North Carolina, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Virginia, and Vermont. In all states with West Nile activity, dead bird surveillance proved to be the most sensitive indicator of local virus activity (see summary table for dates of confirmed first West Nile positives by category and state).

Due to Florida’s fluctuating winter weather patterns, the dead bird surveillance system will continue year-round. The Florida Departments of Health (DOH), Agriculture and Consumer Services, and the Fish and Wildlife Conservation Commission issued a joint press release on November 3, 2000, asking Floridians to help determine if WNV is in our state. Dead bird surveillance has proven to be an early indicator of WNV in other states and therefore the public is encouraged to report dead bird sightings, especially crows via the Internet.

The recent press release resulted in reports of 185 dead birds (a total of 427 have been reported since June), 16 of which were in adequate condition and are in the process of being tested. To date, all 18 birds with completed test results were negative for WNV.

Helen B. Mackley RN, BS, MPH Coordinator, Special BT Surveillance Activities

Carol A. Frank RN, BSN, CIC Infection Control Manager, Tallahassee Community Hospital

Detecting an unexpected change in a series of surveillance data points (aberrant change) is a new tool being tested to identify the onset and magnitude of local, state and national outbreaks of influenza-like illness and other syndromic outbreaks. Similar methods of aberrance detection may prove to be a useful early warning system for potential bioterrroism (BT) related outbreaks.

On December 4, 2000, the Bureau of Epidemiology commenced a pilot hospital-based outbreak and BT warning system by monitoring daily emergency department visits in a number of Florida hospitals. Infection control managers in the participating hospitals report each day by phone or internet the number of visits to their hospital emergency department the preceding day. Once data are received by the Bureau, they are graphed and monitored and any aberrant change (number of visits outside pre-set control limits) is investigated to determine the possibility of an outbreak (including a bioterrorist event). The statistical method being used to determine the pre-set control limits is called Statistical Process Control (SPC) and uses a computer based program which estimates upper and lower control limits for any series of measurement data.

For the 20^th of December, Tallahassee Community Hospital’s Carol Frank reported an increase in visits over the previous day’s 35 patients to 65. Although this change was not outside the pre-set control limits, it represented a significant increase in the expected number of daily visits for a mid-week day. On further examination it was found that on the Tuesday, December 19, a patient was admitted to the hospital who after investigation was thought to be suffering from meningococcal disease with findings of possible gram negative diplococci in spinal fluid. The ten night staff members exposed to the case were called to the emergency room the following morning to receive antibiotic prophylaxis, thus accounting for some of the unexpected increase in the number of patients. Subsequent investigations determined the diagnosis in the original patient as Group B Streptococcus bacterial meningitis infection.

It was the alert infection control manager who carried out this investigation prior to making her daily report, and provided the background on the event. The event and the way it was handled provides preliminary support to the assumption that the SPC aberration detection method has potential as an early warning system for aberrant changes which might be BT related. Such an ongoing communication evolving between the hospital sector and the local and state health departments can provide an important component in the Department of Health’s capacity to make a timely and informed response to any future bioterrorism event or other outbreak. It’s value for the state could be considerable.

Note from Carol Frank

"Reporting daily visit numbers has increased my awareness of events in the emergency department so I am convening a Bioterrorism Taskforce for the hospital. I also intend to do some follow up with the ED to identify the reason for each patient visit. I will use a retrospective data collection method based on the CDC’s enhanced surveillance form for special events to report the primary condition of the patient by one of 7 syndromes."