Animals Provide Early Warning of Bioterrorism Agents

Pets, wildlife or livestock could act as sentinels to provide early warning for humans and could help identify many ongoing exposure risks for certain bioterrorism agents, researchers at Yale School of Medicine have found in a study published in Emerging Infectious Diseases.

“Recent events including the emergence of West Nile Virus and Highly Pathogenic Avian Influenza are a reminder that physicians and public health professionals need to pay attention to disease events in animal populations,” said lead author Peter Rabinowitz, associate professor of internal medicine and occupational medicine at Yale School of Medicine. “In the event of a bioterrorist attack animals may be able to provide some warning, and it will be very important to coordinate human health and animal health responses.”

Rabinowitz and his colleagues conducted a systematic review of the scientific literature from 1966 to 2005 to determine whether animals could provide early warning of a bioterrorism attack, serve as markers for ongoing exposure risk and amplify or propagate a bioterrorism outbreak.

The study found that animals could provide an early warning to humans if clinical signs could be detected before human illness emerged or soon enough to allow preventive measures to be initiated. If a released biological agent persists in the environment (soil, water or air), active surveillance for sporadic illness in animals could help detect ongoing exposure risks. The geographic pattern of sick or dead animals could also be an indicator for the persistence of a biological threat.

Rabinowitz also said that animal populations such as wild birds, commercially shipped livestock and animals involved in the local or international pet trade could play a role in the maintenance and spread of an epidemic attributable to an intentional release of a biological agent. “Detecting the agent in such mobile populations could therefore signal the ongoing spread of the agent and provide an opportunity for interventions to prevent further spread,” said Rabinowitz.

Rabinowitz advises the public health infrastructure to look beyond passive surveillance of acute animal disease events, and to build capacity for active surveillance and intervention efforts to detect and control ongoing outbreaks of disease in domestic and wild animal populations.

The study was part of a National Library of Medicine funded project to create an online database of scientific evidence regarding animals as sentinels of human environmental health hazards, see project website at Canary Database.

Other authors on the study were Zimra Gordon, Daniel Chudnov, Matthew Wilcox, Lynda Odofin, Ann Liu and Joshua Dein.

Citation: Emerging Infectious Diseases, Vol. 12, 4: 647-652 (April 2006)