Can Animal Sentinels Link Ecosystem and Human Health

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Can Animal Sentinels Link Ecosystem and Human
Health?

• Peter Rabinowitz MD MPH
• Yale University School of Medicine

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Challenges in Human Environmental Health

• Clinical Encounters
• Often hard to tease our environmental factors
  from other more medical risk factors.
• Environmental Health Tracking Initiatives
• Difficulty correlating human health outcomes
  (asthma, cancer, etc.) with environmental
  variables

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The Problem Linking Environmental Health and
Human Health

• Mobility of Human populations
• Exposures low level
• Long latency periods for some exposures

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Can Animal Sentinels Be the Missing Link?
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Potential Advantages of Animal Sentinels

• Animals may be more susceptible than humans to
  particular hazards
• Animals may be more exposed than humans to
  environmental hazards
• Shorter latency due to short lifespan,
  intergenerational period to see effects of
  chronic exposures

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Traditional Human Health Perspective on (Non-lab)
Animals

• Do animals pose direct threat to human health?
  (Us vs. Them)
• Infectious agents
• Rabies
• Plague, etc.
• Toxic agents (food animals)
• Mercury, PCBs in fish, etc.

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Traditional Response Blame the Animal

• Avoidance
• Quarantine
• Education
• Personal protection
• Vector/reservoir population control
• Vaccines and drugs

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Animals Sentinels and Shared Risk

• Is infection or toxin in an animal a sentinel
  event warning of a shared risk from
  environmental hazards?
• A conceptual leap from Us vs. Them

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Shared Risk Model

• Communication between animal and human health
  clinicians
• Early recognition of hazards
• Enhanced prevention and treatment
• Growing body of knowledge linking animal and
  human health

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Shared Risk Example Asthma

• Human prevalence increasing
• Attributed to multiple environmental factors,
  including respiratory irritants, mold and other
  allergens, inadequate , air quality
• Still difficult to correlate asthma rates with
  particular environmental variables, indoor vs.
  outdoor exposures play a role
• Could animals serve as asthma sentinels?

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Who Stays in the House All Day?
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Case of Shared Risk for Asthma

• Asthma is diagnosed in cat
• Testing of cat reveals reactions to several
  allergens and irritants in the environment
• Steps are taken to improve conditions that help
  both cat and humans
• Vet and MD talk
• Familys physician is is able to detect early
  asthma in teenager living in house

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Why We Are Not There Yet

• We dont know much (anything?) about
• How does cat asthma differ from human asthma?
• Are cats more susceptible than humans to
  particular asthma triggers?
• Do cats have higher exposures to particular
  allergens?
• Does asthma develop sooner in cats than humans
• Are there cases of cat asthma providing early
  warning for humans?

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Example Avian Influenza
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Shared Risk Ideal for AI

• Reports of AI infection in animals leads to quick
  interventions to reduce human exposure risk
• We reliably track animal cases of emerging AI
• And we use the animal data to better understand
  the environmental risk factors for both animal
  AND human infection

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Why Were Not There Yet

• Linkage between human cases and poultry exposure
  poorly understood- no evidence of wildlife-human
  transmission of HP H5N1
• We are still learning about environmental risk
  factors for spread and propagation
• We dont know about relative exposure risks of
  animals and humans or relative susceptibility
• Roles of companion animals poorly understood
• So the human health implications of AI being
  detected in an animal remains uncertain

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Animal Sentinel Evidence Linking Human and
Ecosystem Health
Sentinel Science (Evidence)
Human/animal Comparative Biology
Host Factors Medical
Latency
Genomics
Susceptibility
Exposure
Clinical Reports
Exposure Studies
Us vs. Them
Epidemiology
SharedRisk
Climate
Disease models
Environmental Factors Ecology
Urbanization
Vector ecology
Land use
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The Canary DatabaseAnimals as Sentinels of
Human Environmental Health Hazards

• (http//canarydatabase.org)
• An interdisciplinary project funded by the
  National Library of Medicine

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Canary Data

• Assembles studies of animals as sentinels
• Highlights evidence providing linkages to human
  health
• Data summaries
• Identifies evidence gaps

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• The project is searching the scientific
  literature for evidence that various animal
  species could fulfill any of the following
  sentinel criteria
• Increased Susceptibility
• Higher Exposure
• Shorter Latency
• Evidence of providing early warning for humans
• Role of environmental factors

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Use of Canary Data

• Veterinarian is seeing cat with asthma
• Checks Canary database, sees that cats are more
  likely than humans to react to ---
• Is able to use this info to screen for reaction
• Is able to use info to discuss with physician

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Use of Canary Data (cont.)

• Public health department is seeing mortality of
  birds
• Checks Canary database for ways to link to human
  health- including environmental variables (and
  human factors) associated with human risk from a
  zoonotic outbreak
• Able to prioritize and carry out interventions
  BEFORE human cases

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Thanks To

• USGS National Wildlife Health Center
• F. Joshua Dein
• Yale Center for Medical Informatics
• Prakash Nakdarni
• Dan Chudnov
• Yale School of Public Health
• Matthew Wilcox
• Yale Occupational and Environmental Medicine
  Program
• Lynda Odofin, Zimra Gordon, Ann Liu, Vivian Lee
• National Library of Medicine