Moving from “Us vs. Them” to “Shared Risk”: Human and Animal Health are inextricably connected

As interest in the One Health initiative increases, one of the first things that crosses the mind of a human health professional learning of the concept is that with increasing contact between humans and animals, there is increasing risk of zoonotic disease: infections crossing from animals to humans. We know that among recently emerging infectious diseases, more than 2/3 are zoonotic in origin, meaning that they originated as animal diseases. And we know from history that many important infectious diseases, from TB to measles, can be traced to increasing contact between humans and domesticated animals in the past several thousand years.

It seems natural, therefore, that a typical attitude of human health care professionals towards animal infectious diseases is an “us vs. them”  perspective, in which the animal is seen as a reservoir for a lurking threat to unsuspecting humans who venture into too close proximity. An example is Hanta Virus Pulmonary syndrome, a rapidly progressive and often fatal disease causes by a virus that is carried asymptomatically by the deer mouse, a frequent inhabitant of sheds and other peri-domestic environments. While seeming not to harm its deer mouse host, the virus, when encountered through breathing airborne virus from mouse droppings, wreaks deadly havoc on infected humans. No wonder that the public health response is to “Seal up, Trap up and Clean up” to keep the animals as far away from humans as possible. 

The down side of the “us vs. them “ approach is that it ignores the role of the environment, and the fact that animal populations, just like human ones, are often dealing with the emergence and spread of infectious diseases related to underlying environmental change. To ignore this fact is to risk missing valuable information about environmental change from the occurrence of these emerging diseases.

As an alternative to the “us vs. them” approach to animal health, we have proposed the consideration of a “shared risk” approach, whereby disease events in animals are viewed  as possible indicators of environmental health hazards that could also be putting humans at risk.  Of course this sharing of risk applies to toxic hazards as well, following the example of the “canary in the coal mine”.  For example, a dog with lead poisoning could provide warning to humans living in the same household. In short, human health professionals should care about disease events in animals since they could be sentinel events for hazards to human health.  In the same way, animal health professionals should consider new disease outbreaks in humans as indicators of possible underlying environmental changes that could affect the health of animals as well.

Using the “shared risk” paradigm, tracking human and animal sentinel events globally could help detect and prevent new disease threats due to changing ecological and environmental conditions.

Readers can find evidence about animal and human sentinel events in the Canary Database.