Search and rescue dogs show no medical, behavioral effects tied to 9/11

Research on canine responders continues

September 11, 2011 (published)
By Phyllis DeGioia

A decade after the deadliest terror attacks in U.S. history, research continues on the health of search and rescue (S&R) dogs that were deployed to 9/11 disaster sites.

While many human responders suffer from respiratory illnesses, studies show that medical setbacks for their canine counterparts are almost nonexistent.

Studies from the University of Pennsylvania School of Veterinary Medicine were published in 2010, and twice in 2004. Each revealed that the dogs did not have any adverse health or behavioral consequences tied to the experience.

This conclusion holds true for S&R dogs that were at the World Trade Center (WTC), the Pentagon and the Fresh Kills Landfill on Staten Island that took debris from the collapsed World Trade Center.

Conducted by Penn researchers, the studies compared 95 S&R dogs that worked at 9/11 disaster sites to a control group of 55 S&R dogs that did not work in those areas. The death and cancer rates in the 9/11 dogs is the same as those in the control group, although the 9/11 dogs had a slightly longer lifespan of 12.5 years compared with 11.8 years, the study showed. Soon after the deployment ended, elevated liver values (bilirubin concentration and alkaline phosphatase activity) indicated that the 9/11 dogs were filtering toxicants, but those levels soon became normal. Exposure to air pollutants at the site was not associated with lung or sinus damage in the dogs. One of the 2004 studies found no significant differences in behavior between the 9/11 and control groups.

Human responders, however, have been found to suffer from lasting health problems tied to their deployment at 9/11 disaster sites. The authors’ interpretation of a study published in the Sept. 3, 2011, issue of “The Lancet” states that “nine years after the 9/11 WTC attacks, rescue and recovery workers continue to have a substantial burden of physical and mental health problems.”

Dr. Cynthia Otto researches the health of search and rescue dogs that worked 9/11 disaster sites. Photo courtesy of University of Pennsylvania School of Veterinary Medicine.
Cynthia M. Otto, DVM, PhD, DACVECC, spearheaded these studies. She is a board-certified emergency and critical care veterinarian and a tenured associate professor of critical care at Penn. Otto cared for dogs at Ground Zero. 

Otto addressed her research findings with the VIN News Service. Here is an excerpt of that interview:

Q. How has the veterinary community responded to these studies?
A. We haven’t had a whole lot of response because the news is good. 

Q. Was the conclusion a surprise for you? 
A. It was absolutely a surprise, we were expecting problems. We wanted to know if post-traumatic stress syndrome (PTSD), all of these health problems, were real. At Ground Zero there were lots of rumors that circulated about S&R dogs after Oklahoma City — rumor had it that six months later they all died of Salmonella. We knew it was ridiculous, and we knew we needed data. 

Q. Did something you expect to see not happen? 
A. We expected respiratory problems, a higher rate of cancer. 

Q. Do you plan to continue research on this topic, and if so, on what area will you concentrate? 
A. Absolutely. It is the legacy of 9/11 working dogs. It’s research on health, genetics and conditioning, on every piece of what makes working dogs successful. We want to try to put it together and move things forward. We have something funded by the AKC Companion Animal Fund. One goal is detecting DNA to get a DNA bank of successful detection dogs. Another goal is a breeding and training site: How do we apply genetic findings, physical conditioning, how do we optimize these dogs?

Q. How does this information contribute to veterinary medicine? What do you think it contributes to human medicine?
A. We found statistically significant changes at year 5 on heart size, and there are some cardiac issues in the human responders. We saw a spike in immunoglobulins in the first year. We’re paying attention to cancer with particular attention to the immune system, but it’s still early. We still have a fair number of control dogs left because they were a year younger. The impact for humans is that we may have some sentinels of disease here. Perhaps they’re subtle, but it might make them aware of subtle differences. The psychological study involved humans and dogs. S&R dogs do not get PTSD, but some military dogs get it. 

At Ground Zero, Dr. Cynthia Otto kneels behind personnel from four search and rescue teams with whom she worked. Photo courtesy of University of Pennsylvania School of Veterinary Medicine
Q. Even though your studies say there were no long-term health effects, you saw enlarged hearts. Isn’t that a long-term effect?
A. There are not obvious long-term effects on their health. We did see changes in their heart size but that was not associated with any increase in overt heart disease, so there are some differences that are relatively subtle which may have a health impact but we couldn't measure an actual effect on the dog's performance.

Q. How does it feel delving into the medical experiences of these particular S&R dogs? 
A. I’m so proud of them. We have a psychologist we were working with. The handlers are very dedicated people; the bond they have with their dogs is incredible. The bond gives them resilience to handle the stress. The impact the dogs have on handlers is significant. 

VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email

Information and opinions expressed in letters to the editor are those of the author and are independent of the VIN News Service. Letters may be edited for style. We do not verify their content for accuracy.