C. M. Otto, A. B. Downend, J. A. Serpell, L. S. Ziemer, H. M. Saunders, W. Rumbeiha, and S. Fitzgerald

In response to the terrorist attacks on September 11, 2001, the largest search-and-rescue operation to occur in the United States began. Search-and-rescue (SAR) canines were deployed to the World Trade Center, Pentagon and Staten Island Landfill. Long-term medical and behavioral effects of disaster work on SAR dogs have never been evaluated. The data obtained from this prospective health and behavioral study of the dogs deployed to this large-scale disaster will provide critical information that can be used to better prepare future teams. Our monitoring will allow any health problems the dogs may encounter to be identified and treated early, and these dogs will serve as sentinels for health problems that may occur in the human workers at the disaster sites.

The study officially began in January 2002, with 97 SAR dogs deployed to the World Trade Center, Pentagon or Staten Island Landfill. After three years, 55 dogs are still participating. A control population of 55 (now 37) dogs, trained for SAR but not deployed as part of the 9/11 response, are also being monitored to control for any effects SAR training and other deployments might have on the dogs. The handlers complete health and behavior surveys annually. The dogs’ regular veterinarians draw blood and obtain chest radiographs, both of which are sent to the University of Pennsylvania for analysis.

After the study’s third year, health surveys have found that the deployed dogs have not had any increase in the frequency or severity of medical problems compared to the control dogs. No differences were noted between deployed and controls dogs in the 11 major traits on the behavior surveys. None of the radiographs found clinically relevant lung abnormalities in the first year. Analysis of the complete set of films is pending. Deployed dogs showed an initial stress response to deployment (lower peripheral blood lymphocyte and eosinophil counts and higher blood glucose concentrations) but these differences resolved in years 2 and 3. The deployed dogs also showed a transient response suggestive of exposure to antigens and mild toxins (higher blood values of globulin, bilirubin and alkaline phosphate). These changes also resolved in years 2 and 3. Despite differences between groups all average values were within normal limits. All dogs were screened for lead, mercury, PCBs and organic toxins in year 1, and all tests were negative.

As of September 11, 2005, the mortality rate in the deployed dogs (22.7%) is not statistically different than the rate in the controls (16.4%). The frequency of cancer as a cause of death in the deployed dogs (50.0%) is also not statistically different than the frequency in control dogs (44.4%). This rate is not unexpected in companion animals. Despite the fact that two deployed dogs’ lives were cut short after being hit by cars and that several of the control dogs were already geriatric when enrolled in the study, the difference in age of death between deployed (9.5 yrs) and control (11.8 yrs) dogs is not statistically significant. Continued vigilance is necessary to determine what, if any, long-term effects will manifest in these heroic dogs.

 Update: September 2006

Since the above abstract was presented, the mortality rate has increased as the dogs continue to age. As of September 1, 2006, the mortality rates in the deployed dogs (29.9%) and control dogs (21.8%) are still not significantly different (P=0.374). The frequency of cancer in deceased deployed dogs (41.4%) is also not different than in the control dogs (50.5%, P=0.873). The gap in the average age at time of death between deployed dogs (10.2 years) and control dogs (11.3 years) is shrinking and remains statistically insignificant (P=0.258).

Based on surveys completed by the handlers of 46 deployed dogs and 30 control dogs between September 2005 and June 2006, 18 deployed (39.1%) and 10 control (33.3%) dogs have retired. There is no significant difference in the likelihood of retirement between the two groups (P = 0.788). The majority (58.3%) of deployed dogs retired due to advancing age. The median age at which deployed dogs first retire (9 years) is not statistically different than the median retirement age for control dogs (7 years, P = 0.173). Exposure to the disaster sites does not appear to have affected the length of the careers of the deployed dogs.

Although a recent study of human rescue workers at the World Trade Center revealed an increased incidence of respiratory issues, similar problems have not been observed in the SAR dogs. There are several possible reasons for this finding. Human workers who were on the site during the collapse were more severely affected, but the dogs in this study were coming from all over the country and the majority didn’t reach the disaster site until at least the day after the collapse. There are also species differences that may have resulted in the dogs being less affected by exposure to Ground Zero. First, asthma is very uncommon in dogs, so they are less likely to experience the types of reactive airway disease affecting the human responders. Secondly, their nasal passages are much longer than a human’s, perhaps helping filter out more of the particulate matter.

 Other Information

Study website: www.9-11dogs.org

Otto C. M., Franz M. A., Kellogg B., Lewis R., Murphy L., and Lauber G., "Field treatment of search dogs: Lessons learned from the World Trade Center disaster," Journal of Veterinary Emergency and Critical Care 12(1):33-41. 2002.

Otto C. M., Downend, A. B., Serpell J. A., Ziemer L. S., and Saunders H. M., "Medical and behavioral surveillance of dogs deployed to the World Trade Center and the Pentagon: October 2001-June 2002," Journal of the American Veterinary Medical Association 225(6): 861-867, 2004.

Slensky K., Drobatz K. J., Downend A. B., and Otto C. M., "Deployment morbidity among search and rescue dogs," Journal of the American Veterinary Medical Association 225(6): 868-873, 2004.

Jones K. E., Dashfield K., Downend A. B., and Otto C. M., "Search and rescue dogs: An overview for veterinarians," Journal of the American Veterinary Medical Association 225(6): 854-860, 2004.

Media Inquiries

Please direct all media inquiries to Gail Luciani, director of communications, at (215) 898-1475 or luciani@vet.upenn.edu