Can Animal Sentinels Link Ecosystem and Human Health? Peter Rabinowitz MD MPH Yale University School of Medicine

Challenges in Human Environmental Health  Clinical Encounters Often hard to tease our environmental factors from other more “medical” risk factors. 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 Difficulty correlating human health outcomes (asthma, cancer, etc.) with environmental variables

The Problem: Linking Environmental Health and Human Health  Mobility of Human populations  Exposures low level  Long latency periods for some exposures

Can Animal Sentinels Be the Missing Link?

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

Traditional Human Health Perspective on (Non-lab) Animals  Do animals pose direct threat to human health? (“Us vs. Them”) Infectious agents Infectious agents RabiesRabies Plague, etc.Plague, etc. Toxic agents (food animals) Toxic agents (food animals) Mercury, PCBs in fish, etc.Mercury, PCBs in fish, etc.

Traditional Response: “Blame the Animal”  Avoidance Quarantine Quarantine Education Education Personal protection Personal protection  Vector/reservoir population control  Vaccines and drugs

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”

“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

“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?

Who Stays in the House All Day?

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  Family’s physician is is able to detect early asthma in teenager living in house

Why We Are Not There Yet  We don’t know much (anything?) about: How does cat asthma differ from human asthma? How does cat asthma differ from human asthma? Are cats more susceptible than humans to particular asthma triggers? Are cats more susceptible than humans to particular asthma triggers? Do cats have higher exposures to particular allergens? Do cats have higher exposures to particular allergens? Does asthma develop sooner in cats than humans Does asthma develop sooner in cats than humans Are there cases of cat asthma providing early warning for humans? Are there cases of cat asthma providing early warning for humans?

Example: Avian Influenza

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

Why We’re 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 don’t 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

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

The Canary Database: Animals as Sentinels of Human Environmental Health Hazards  (  An interdisciplinary project funded by the National Library of Medicine

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

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

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

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

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