Environmental Epidemiology at the LOD: HABsand IOOS

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Environmental Epidemiology at the LOD HABsand
IOOS

• Lorraine C. Backer PhD, MPH
• National Center for Environmental Health
• Centers for Disease Control and Prevention

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Overview

• Epidemiology
• Environmental epidemiology of HAB-related illness
• HAB-related illness surveillance system (HABISS)
• Potential contributions from IOOS

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Epidemiology

• The study of disease occurrence and its relation
  to the characteristics of individuals and their
  environment

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Epidemiologic Study Designs
Ill
Exposed
Not ill
Cohort study
Ill
Unexposed
Not ill
Exposed
Case
Unexposed
Case-control study
Exposed
Non-case
Unexposed
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A note of caution Epi means never having to say
youre certain

• One epidemiology study can
• Evaluate the relationships between exposure and
  the development of disease
• One epidemiology study cannot
• Determine that a given exposure actually causes
  the disease

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Algal Toxins and Environmental Epi Studies

• Issues we can address
• No taste or odor
• Very stable chemicals
• Represent many classes of chemicals
• Metabolite toxicities vary
• Issues we are having a hard time with
• Harmful in minute doses, often near the LOD
• Act at the molecular level
• Often present in the environment at
  concentrations near the LOD

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Epidemiologic Studies of Aerosolized Brevetoxins
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Brevetoxins
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Chemical and Physiologic Properties
Brevetoxin
Nerve Cell
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Effects on Animals
Flewelling et al. Nature 2005
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Effects on People--Neurotoxic Shellfish Poisoning
(NSP)

• Disease
• GI, neurologic symptoms
• History of eating shellfish

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Effects on People--Respiratory Irritation

• Early reports
• Woodstock et al. (1948)
• Music et al. (1972)
• More recently
• Marine Toxin Hotline, Miami
• Poison Information Center
• Monthly Report, December 2005
• Exposure/Report Date Age County
  ZipCode
• BLUEGREEN 2/6/2005 0 ARAPAHOE 80017
• JELLYFISH 12/8/2005 1 2 BROWARD 33063
• LIONFISH 12/16/2005 74 BROWARD 33069
• SHELLFISH 12/22/2005 44 INDIAN RIVER 32961
  
• CATFISH 2/26/2005 10 LEE
  33991
• RED TiDE 12/30/2005 45 MANATE
  E 34221

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Animal Models for Respiratory Effects

• Guinea pigs (Baden et al. 1982)
• Asthmatic sheep (Abraham et al. 2005)
• Effects mitigated by clinically available drugs

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Richard Pierce
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Brevetoxins in Sea Aerosols
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Brevetoxins Evidence of Potential Harm

• Chemical and physiologic properties
• Environmental impact
• Effects on animals
• Effects on people
• Induced effects in laboratory animal models
• Plus
• Exposure route
• Ability to measure the toxin in the environment

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Health Outcome Symptoms

• Throat irritation
• Nasal congestion
• Eye irritation
• Cough
• Wheezing
• Shortness of Breath
• Chest tightness
• Headache
• Itchy skin
• Diarrhea

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Epidemiologic Studies

• What are the health effects from environmental
  exposure to aerosolized toxins during Florida red
  tides?

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Collaborators

• Centers for Disease Control and Prevention
• Florida Department of Health
• Florida Department of Env Protection
• Florida Marine Research Institute
• Harbor Branch
• Lovelace Respiratory Research Institute
• Mote Marine Lab
• NIEHS
• South Florida Poison Information
• University of Miami School of Medicine
• University of North Carolina (Wilmington)

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Environmental Epidemiology Study Design
Prospective

• Recruit a study population
• On study days
• Conduct exposure assessments
• Assess health outcomes (symptoms, biological
  markers)
• Before and after spending time on the beach
• when there is no red tide (unexposed)
• when there is a red tide (exposed)
• Compare results for unexposed and exposed periods

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Recreational Exposure to Aerosolized Brevetoxins
During Florida Red Tides
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Study Design Recreational exposures

• Study participants
• Adults recruited as they visited the beach
• Health effects
• Symptom surveys
• Pulmonary function tests
• Inflammatory response
• Exposure assessment
• Counted Karenia brevis cells
• Analyzed brevetoxins in water and air

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Recreational Beach Visitors--Exposed or Unexposed?
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Recreational Beach VisitorsHealth Effects?
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Conclusions

• People respond to being on the beach during a
  Florida red tide
• Upper and lower respiratory irritation
• Inflammatory response
• Responses likely due to exposure to aerosols

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Occupational Exposure to Aerosolized Brevetoxins
during Florida Red Tides
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Study Design Occupational exposures to
aerosolized brevetoxins

• Study participants
• Recruited full-time lifeguards
• Health effects
• Refined symptom surveys
• Improved pulmonary function tests
• Exposure assessment
• Counted Karenia brevis cells
• Analyzed brevetoxins in water and air
• Added personal air sampling

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Defining exposure

• September 7 - 11, 2001 (red tide)
• N14
• Conducted study activities pre- and post-shift
• May 2 - 7, 2002 (no red tide)
• N17
• Conducted study activities pre- and post-shift

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Lifeguards--Exposed or Unexposed?
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Refining ExposureSeptember 2001 (Exposed) and
May 2002 (Unexposed)
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LifeguardsHealth Effects?
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What have we learned?

• Exposure
• Local environmental sampling is critical
• About 80 of the inhaled brevetoxins deposited in
  upper airway
• New question
• Are we assessing maximum exposure?
• Added exercise component to increase ventilation

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Exposure to Aerosolized Brevetoxins During
Exercise

• Monark Ergomedic Weight Ergometer
• Study activities
• Symptom survey and spirometry
• Bike for 5 minutes, constant load
• Symptom survey and spirometry

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Exposure to Aerosolized Brevetoxins During
Exercise

• January 16-20, 2003 (no red tide)
• N 12
• Conducted study activities pre-shift
• March 27-31, 2003 (red tide)
• N 11
• Conducted study activities pre- and post-shift

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LifeguardsExposed Yet? or Unexposed?
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Results Defining ExposureJanuary 2003 and
March 2003
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Lifeguards exercisingHealth Effects?
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What have we learned?

• Healthy worker effect
• Next steps
• - Examine the allergic response

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Exposure to Aerosolized Brevetoxins in a
Sensitive Subpopulation (Asthmatics)
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Asthmatics--Exposed or Unexposed? (8 field
studies)
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Sensitive Subpopulation (Asthmatics)Health
Effects?
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What have we learned about Florida red tide?

• Aerosols from Florida red tides have a public
  health impact
• Acute symptoms and pulmonary effects
• Effects are different for healthy lifeguards and
  beachgoers compared to people with asthma
• Local conditions, particularly wind, critical in
  determining exposure
• Exposure and effects occurring at our current
  limits of detection

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Whats Next?

• Develop biological markers for very low dose
  exposures (acute and chronic)
• Laboratory studies to assess effects at the
  molecular level
• Refine exposure assessments

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Algal Toxins and Environmental Epi Studies

• Issues we can address
• No taste or odor
• Very stable chemicals
• Represent many classes of chemicals
• Metabolite toxicities vary
• Issues we are having a hard time with
• Harmful in minute doses, often near the LOD
• Act at the molecular level
• Often present in the environment at
  concentrations near the LOD

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Surveillance

• The ongoing, systematic collection, analysis, and
  interpretation of health data essential to the
  planning, implementation, and evaluation of
  public health practice, closely integrated with
  the timely dissemination of these data to those
  who need to knowapplication of these data to
  prevention and control

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Harmful Algal Bloom-related Illness Surveillance
System (HABISS)

• Purpose To reduce the public health impact of
  HAB-related human illnesses
• Characteristics
• Web-based
• Access data base
• Data accessible to partner states and CDC

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HABISS Components

• Human illnesses
• Animal illnesses
• HABs and the local environment

Photo Steven Holt
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HABISSData collection modules

• Contact information
• Case demographics
• Environmental data
• Exposure information
• Signs and symptoms
• Assessment and follow-up
• Parallel modules for animal events
• Other modules as needed

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HABISS Future Features

• Case definitions
• Mapping
• Modeling
• Prediction
• Real-time notification
• International participation
• EARS overlay
• PHIN compliance

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Environmental Epidemiology at the LOD

• Improved methods for analysis of toxins in
  environmental samples
• Improved methods to collect personal air samples
• Evaluated biological markers
• HABISS Surveillance system in place

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However

• What are the health effects from exposure
  aerosolized toxins during Florida red tides?

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How can OOS help?

• Improve exposure assessment!

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OOS Data for Public HealthPackaging Backbone
Data

• Physical
• Salinity, temperature, bathymetry, sea level,
  surface waves, vector currents, ice
  concentration, surface heat flux, bottom
  characteristics
• Chemical
• Water column contaminants, dissolved inorganic
  nutrients, dissolved oxygen
• Biological
• Fish species and abundance, zooplankton species
  and abundance, optical properties, color,
  phytoplankton species and abundance

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OOS Data for Public HealthLocal Forecasting

• Early warning of possible periodic increased
  health risks
• Similar to rainfall predictions or pollen counts
• Recreation and resource managers would need
  access to real-time data or rapid data
  interpretation resource
• Water conditions
• Toxin concentrations
• Microbe concentrations

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Local Nowcasting
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NOAA HAB Bulletins
Infrared Satellite Imagery
Forecast
Detailed Analysis
Wind Speed Graph
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OOS Data for Public HealthMonitoring and
Surveillance

• Improve monitoring and surveillance
• Improved timeliness of routine monitoring
• Trigger increased monitoring
• Improve risk prediction
• Allow for more targeted public health action
• Define antecedents of HABs

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OOS Data For Public Health Indicators

• Water quality
• Beach safety
• Seafood quality
• Assess when restrictions can be removed
• Human exposure
• Environmental data
• Sentinel animal health

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OOS Data for Public Health Disease Prevention

• Primary prevention
• Monitoring
• Educate target populations
• Industries and consumers
• Health care public health workers
• Sensitive subpopulations

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Summary

• Advanced the environmental epidemiology of HAB
  toxins
• To go further, improved exposure assessment is
  key
• OOS data can assist

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