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The Canary Database
Yale Occupational and Environmental Medicine Program
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What Are Animal Sentinels?

Domestic or wildlife animals may be "sentinels" if they give early warning of infection or chemical health threats in the environment.

Some well-known areas of study considering animals as sentinels include:

Canaries in Coal Mines

Well into the 20th century, coal miners in England and the US brought canaries into coal mines as an "early warning signal" for carbon monoxide and other poisonous gases. The birds, being more sensitive, would become sick before the miners, who would then have a chance to escape or put on protective respirators.

Emerging Infectious Diseases

The discovery of West Nile Virus in the western hemisphere was heralded by an outbreak of disease in wild birds. Other emerging diseases have demonstrated linkages between animal health events and human risk, including Monkeypox, SARS, and Avian Influenza.

Terrorism Agents

Some speculate that animals could provide early warning of a terrorist attack using biological or chemical agents. For example, when anthrax was inadvertently released from a Soviet weapons facility, livestock died at a greater distance from the plant compared to human cases.

Endocrine Disrupting Chemicals?

In recent years, reports of reproductive problems in animal populations, including developmental abnormalities and behavioral disturbances, have prompted concerns that chemical exposures could be affecting both animals and humans. Yet the evidence linking the animal disease events to human health is limited (see this Canary Database record for details about one of these studies).

Pets and household exposures

Dogs may provide early warning of lead poisoning hazards in a home, and certain cancers in dogs and cats have been linked to household pesticides. Pets may also provide early warning of risks from infectious diseases including Lyme Disease.

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