Harmful Algal Blooms (HABs) and Public Health

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1 Harmful Algal Blooms (HABs) and Public Health Lorraine C. Backer, PhD, MPH National Center for Environmental Health Centers for Disease Control and Prevention

2 HABs and Public Health Harmful algal blooms (HABs) HABs and public health Public health response

3 Ancient Organisms New Problems? Blooms of cyanobacteria, dinoflagellates, diatoms occur naturally Harm Oxygen deprivation Light deprivation Toxin production

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6 Global Increase in Incidence of HABs: Impacts on Public Health Direct Seafood Recreational water Drinking water sources Indirect Ecosystem health

7 Characteristics of Algal Toxins No taste or odor Very stable chemicals Represent many classes of chemicals Metabolite toxicities vary Harmful in minute doses, often near the LOD Act at the molecular level Often present in the environment at concentrations near the LOD

8 Food Marine Toxin Diseases: Routes of Exposure Food chain bioconcentration Water Aerosol Skin contact

9 Marine Seafood Poisonings Paralytic Shellfish Poisoning (PSP) Neurotoxic Shellfish Poisoning (NSP) Diarrheic Shellfish Poisoning (DSP) Amnesiac Shellfish Poisoning (ASP) Ciguatera Fish Poisoning Fugu (Pufferfish tetrodotoxin) Possible Estuary Associated Syndrome (Pfiesteria toxins?)

10 Marine Toxin Foodborne Diseases: Clinical Onset Epidemiology Attack Rate = # ill/# exposed Symptoms Fatality Treatment Chronic disease sequellae

11 Neurotoxic Shellfish Poisoning (NSP) Acute onset (1/2-3 hr) High attack rate GI, neurologic Parasthesias Temperature reversal Not fatal Short duration (2 d) Supportive therapy

12 Paralytic Shellfish Poisoning (PSP) Acute onset (5-30 min) High attack rate Gastrointestinal, neurologic Fatality (1-60%) Short duration (days) Supportive Rx, Life support?chronic disease

13 Ciguatera Fish Poisoning Acute onset (1-24 hr) High attack rate Neurologic, gastrointestinal, cardiovascular, dermal, temperature sensation reversal Fatality (0.1-12%) Long duration (weeks to yrs) Rx: Supportive Mannitol may be effective Chronic disease: recurring symptoms Relationship with other diseases chronic fatigue Others?

14 Pfiesteria piscicida Poisoning?Pfiesteria poisoning?cryptoperidiniopsoid poisoning?possible Estuary Associated Syndrome (PEAS)?Onset?Attack rate?neurologic;?dermatologic;?other?fatality?rx?chronic Disease

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16 Reported Human Exposure to Cyanobacteria Toxins Brazil, 1996: Dialysis clinic 110 of 131 patients symptomatic 55 patients died Microcystin found in the water reservoir, dialysis center filter, patient samples Carmichael et al., 1996

17 Reported Human Exposure to Cyanobacteria Toxins Army recruits training during Microcystis bloom Swimming in full pack, eskimo rolls 2 soldiers had severe symptoms Elevated serum liver enzymes 8 others had lesser symptoms Turner et al., 1990

18 Reported Human Exposure to Cyanobacteria Toxins Liver cancer in rural China Association between drinking surface water and increased disease incidence 0.61 μg/l in areas of high disease incidence 0.36 μg/l in control areas Other risk factors for liver cancer prevalent The findings influenced public health policy Yu, 1994

19 Drinking Water Guidelines Australia Series of alert levels based on concentration of cyanobacterial cells Responses Increased monitoring Press release Bloom control and water treatment measures Provision of alternative drinking water source Burch et al., 1993

20 Drinking Water Guidelines WHO Provisional guideline for drinking water 1.0 μg/l for microcystin LR EPA draft TDI for microcytsin-lr µg/kg/day 80 kg person eating kg of fish/day Maximum concentration of 9.5 ng/gm

21 HABs: Public Health Response Epidemiologic studies Outbreak investigations Planned studies Surveillance Prevention

22 Exposures to Aerosolized Brevetoxins During Florida Red Tides

23 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)

24 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

25 Study Design: Recreational 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 exposures

26 Recreational Beach Visitors Health Effects? Parameter Unexposed Exposure 1 Exposure 2 N = 36 N = 53 N = 40 Lung function (spirometry) No effects No effects No effects Inflammation (nasal swab) No change Mild to moderate increase 20 (38%) Mild to moderate increase 19 (47%) Symptoms No change Increase in URI Increase in LRI High Volume Air samplers (ng/m 3 ) <LOD (LOD = 10) Wind Mostly onshore Mostly onshore Mostly onshore

27 Study Design: Occupational exposures to aerosolized 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 brevetoxins

28 Lifeguards exercising Health Effects? Parameter Unexposed Exposed Lung function No changes No changes (spirometry) Symptoms None None Personal air samplers (ng/m 3 ) < LOD (LOD = 1.0) Wind Offshore Offshore to onshore

29 Exposure to Aerosolized Brevetoxins in a Sensitive Subpopulation (Asthmatics) Study participants > 12 years old Physician-diagnosed asthma Health effects Refined symptom surveys Pulmonary function tests Exposure assessment Counted Karenia brevis cells Analyzed brevetoxins in water and air Personal air sampling

30 Sensitive Subpopulation (Asthmatics) Health Effects? Parameter Unexposed Exposed Lung function (spirometry) Some decrements Some decrements (different) Symptoms Chest tightness Chest tightness, cough, eye irritation Personal air <LOD samplers (ng/m 3 ) LOD = 0.83 Wind Mostly offshore Partly onshore

31 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

32 Recreational Exposures to Microcystins

33 Collaborators National Center for Environmental Health, CDC California Department of Health Siskiyou County Mote Marine Laboratory Greenwater Laboratory National Center for Infectious Diseases, CDC Lovelace Respiratory Research Institute Karuk Tribe

34 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 a small lake when there is no cyanobacterial bloom (unexposed) when there is a cyanobacterial bloom (exposed): Compare results for unexposed and exposed periods

35 Current Status and Follow-up Parameter Microcystins in water (µg/l) Unexposed N = 7 < LOD LOD = 0.15 µg/l Exposed N = Microcystins in air (ng/m 3 ) NA < LOD 0.14 LOD = ng/m 3 Microcystins in blood <LOD LOD = µg/l < LOD Symptoms No change No change

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37 What have we learned about blue-green algae? Aerosols generated in lakes with bluegreen blooms producing microcystins contain measurable concentrations of this toxin Potential for exposure Potential for public health impact

38 Epidemiology of HAB-related illnesses what s next? Refine exposure assessments Develop biological markers for very low dose exposures (acute and chronic) Laboratory studies to assess effects at the molecular level

39 HABs: Public Health Response Epidemiologic studies Outbreak investigations Planned studies Surveillance Prevention Examples of recent advances

40 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 know application of these data to prevention and control Health data collection and interpretation Application Timely dissemination

41 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

42 HABISS Components Human illnesses Animal illnesses HABs and the local environment Photo: Steven Holt

43 Contact information Case demographics Environmental data Exposure information Signs and symptoms Assessment and followup Parallel modules for animal events Other modules as needed HABISS Data collection modules

44 HABISS Current Activities Data concordance workgroup Case definitions workshop Incorporating data from regional ocean observing systems (OOS) Developing international partnerships

45 HABISS Future Features Mapping, modeling, predicting Real-time notification EARS overlay PHIN compliance Expansion to other environmental diseases

46 HABs: Public Health Response Epidemiologic studies Outbreak investigations Planned studies Surveillance Prevention

47 Local Nowcasting

48 NOAA HAB Bulletins Forecast Infrared Satellite Imagery Detailed Analysis Wind Speed Graph

49 Outreach and Education Primary prevention Monitoring Educate target populations Industries and consumers Health care & public health workers Sensitive subpopulations

50 HABs and Public Health Harmful algal blooms (HABs) Marine seafood toxins Freshwater HABs Disease surveillance Prevention