Influenza-from a Public Health Perspective
Carina Blackmore, M.S. Vet. Med., Ph.D.
Bureau of Epidemiology
Florida Department of Health
Why Worry About Flu?
• > 6000 hospitalizations in Florida each year
• > 3000 pneumonia/ flu deaths in Florida each year
• nosocomial/ community outbreaks
• it’s preventable
• it’s unpredictable (epidemics/ pandemics)
• the public expect us to

Influenza virus
Influenza A (HxNy) 
Hemagglutinin & Neuraminidase Subtypes



Influenza virus-antigenic changes
• Drift
– -Minor Change, Same Subtype
– Associated with Epidemics
• Shift
– Major Change, New Subtype
      H1N1          H2N1
– Associated with Pandemic
     	
Pandemic Influenza vs. Bioterrorism Event
Comparison of Pandemic Flu and Bioterrorism Event

Why is flu not reportable in Florida?
• Sporadic cases-No
– Massive undertaking
– Diagnostics
• Outbreaks-Yes
• Mortality-Yes (vital statistics)
Goals of influenza surveillance in the U.S
• Determine when viruses are circulating
•  Identify strains and detect changes in strains
• Monitor influenza-related illness
• Measure impact of influenza on deaths
National surveillance
• Influenza Like Illness (ILI):

• Virus strains:

• Outbreaks:

• Mortality:	


Sentinel Physicians ILI Surveillance Network

70 Laboratories

State Health Dept. Epidemiologists

121 Cities Flu and Pneumonia Mortality System 
Florida surveillance
• 55 sentinel physicians in 2001-2002
• 2 WHO labs: DOH Jacksonville+Tampa
• Flu test data also from hospitals,  private influenza surveillance network
• 4 cities reporting mortality (Jacksonville, Miami, St Petersburg, and Tampa)
• Influenza outbreaks reportable to DOH


Influenza isolations and % ILI, Florida, 2001-2002
Influenza virus isolations and patients with ILI, 
Florida, 2000-2001
Influenza isolates by subtype, Florida, 2001-2002
The burden of flu illness highest in kids
But sick elderly more likely to die

Influenza Surveillance and Disease Prevention-Roles for Public Health
• Vaccination clinics
• Data dissemination to providers
• Prevention messages to the public
• Outbreak investigations/ management
– Cultures
– PCR
• Outbreak reporting


Pneumococcal Vaccination Coverage Levels, Persons Aged 65 Years and Older, U.S.,
 by Race / Ethnicity
Influenza Surveillance and Disease Prevention-Roles for Public Health
• Vaccination clinics
• Data dissemination to providers
• Prevention messages to the public
• Outbreak investigations/ management
– Cultures
– PCR
• Outbreak reporting


“The influenza clock is ticking.  We just don’t know what time it is.”