Dogs' noses sniff out bombs

On Christmas Day, 2009, a terrorist attempted to bring down Northwest Airlines flight 253 from Amsterdam to Detroit. Despite known intelligence, this alleged suspect slipped by airport security with a PETN explosive sewn into his underwear. He boarded the plane and tried to destroy it in flight.

If a detection dog was screening that airport security area, it's likely this suspect would have been discovered and this incident could have been avoided. Because of their high olfaction sensitivity, dogs play a special role in explosive detection at airports and provide invaluable assistance to law enforcement agencies that help deter terrorism worldwide.

Dogs outperform technology

The Animal Health and Performance Program (AHPP) at the Auburn University College of Veterinary Medicine was created with the mission to advance and disseminate knowledge in the area of animal health and performance. The AHPP is home to the Canine Detection Research Institute (CDRI) and the Veterinary Sports Medicine Program (VSMP).

The team at CDRI takes dogs' noses very seriously. A dog's nose can out-perform even the most sophisticated technology. "Dogs are sensitive, or more sensitive to at least some substances, than instrumental systems," says James M. Johnston, Ph.D., former Director of Behavioral Research at the Institute for Biological Detection Systems (IBDS) at Auburn University, now the CDRI.

"When we were developing the various detection dog applications, we realized that the dog could do even more than we were giving it credit for," says John Pearce, associate director at CDRI.

The dog's ability to detect odor is the focus of the CDRI's research and canine training program. Established in 1989, this one-of-a-kind facility is dedicated to studying canine olfaction. The Canine Detection Training Center (CDTC) is one of the largest canine detection training programs outside of the federal government. After 9/11, the CDRI established the CDTC, in order to train law enforcement agencies in dog detection principles.

After the closure of Fort McClellan in Anniston, Ala., Auburn University received 320 acres and 17 facilities of the former army base for its CDTC training center with a 99-year lease.

The CDRI conducts research and provides solutions for foreign and domestic military, government agencies and private industry applications. Its varied research program includes exercise physiology, olfaction, training, conditioning, nutrition, biomechanics, general performance and field and clinical veterinary medicine. The CDRI has developed advanced training, conditioning and search protocols that have drastically improved the performance of detection dogs.

Developing the elite

According to Pearce, one of the missions of the CDRI is to develop an ultimate breed that would develop into an excellent detector dog. The Australian Customs Service gave CDRI some Labrador Retriever breeding stock to lower the inbreeding coefficient. CDRI is also evaluating other breeds for future breeding stock, such as German Short-Haired Pointers.

"We're looking at different outside-the-box applications and how we can get a dog to do various tasks," Pearce says.

Recently, the CDRI developed an improvised explosives device (IED) detection dog and a vapor wake detection dog. These novel approaches have placed the dogs in vital roles such as protecting the President of the United States and the U.S. Capitol building during the inauguration, as well as helping protect soldiers and civilians in Iraq and Afghanistan. These dogs also work in airports around the U.S.

The IED detection dogs have successfully served with the U.S. Marine Corps Infantry in Iraq. "We didn't lose one Marine out of those units in which those dogs were deployed," Pearce says.

How dogs work

According to Johnston, dogs have the ability to use concentration gradient information to locate an odor source. The dog coming into contact with the periphery of a vapor plume will initially encounter only relatively low concentrations of target compounds.

Dogs are also extremely efficient in processing information. Minimal sampling effectively guides them to rapidly deploy to the odor source. Dogs are tasked to move from very low concentration gradients to higher vapor concentration gradients. Not only are dogs able to detect target odors, but they can discriminate them from non-target odors, even when the non-target odors are of higher concentration. Dogs are capable of learning a number of odor discriminations that can be demonstrated interchangeably. Alhough most target odors are actually comprised of many different odor compounds, the dog is thought to detect and respond to only a few and learn to recognize a substance in terms of its most abundant vapor constituents. In the case of explosives, the most abundant compounds are solvents.

Mobile detection

Besides the dog's sophisticated olfaction capabilities, the CDRI notes its other unique advantages over equipment technology. The vapor wake detection dog is intended for use in venues attended by large numbers of people such as airports. The dog can instantaneously sample plumes of air coming from persons and from what they are carrying through 'choke points' such as security screening areas, ticket and gate areas.

Unlike stationary equipment, dogs are mobile and can maneuver through crowds. They are also psychologically a deterrent against terrorist acts. Plus, dogs' vapor collection, signal processing and detection cycle times are instantaneous, and therefore less likely to be foiled by terrorists. Unlike equipment and machines that may be compromised, each animal is different.

"With the inclusion of the Animal Health and Performance Program, the CDRI team is able to address not only detection dogs, but bird dogs, retrievers, guide dogs and agility dogs," says Robert Gillette, DVM, MSE, Director of AAHP, CDRI and VSMP.

Through its research, the CDRI is also looking at the psychological component of a dog's performance, which can affect metabolic function and its ability to perform its designated tasks. It was once thought that when you work or exercise an animal, you were stressing the animal. But what the team is finding is that the work itself releases stress, and so the dog actually is in a better state of mind while working or exercising.

Initially, when it was recognized that dogs had the ability to detect various substances, the effort was made to understand the dog's capability and to try to design machinery and technology to mimic the ability. That was a portion of the mission of the original IBDS. "What we found during the 1990s was that we can develop instrumentation that can perform some of the tasks that a dog can do, but we've never been able to develop instrumentation that would beat the whole package of the dog's capabilities," Gillette says. It is difficult to maneuver an instrument to determine where the source is — you have to take a machine to the source. "Machines can be developed that detect certain levels of certain chemicals or odors, but we still don't have the whole package," Gillette says.

Although according to regulations a dog can't invade the private space of an individual, that doesn't mean that a dog can't smell air or vapors within a given area. "It's not our intention for the dogs to directly smell people," says Gillette. "In large areas such as airports, train stations and event gatherings, what we can do is have the dog smell vapors within its reach." The distance is somewhat dependent on many factors, especially how the scent is deployed from the source. For example, in a subway location, the air moves within an enclosed space and in and out. This creates a different air flow than in an open airport terminal.

In the case of the incident on Northwest Airlines flight 253, how close would a trained detection dog have to have been to have picked up that explosive? Probably not that close. Certainly if vapor wake detection dogs were utilized in the airport, they might be able to detect explosives within that environment, on persons or within a carry-on.

In the general case of the airport scenario, does the dog have to be within inches of its target? Not necessarily. "A dog can be within 10 to 50 feet and can pick it up the scent," Gillette says. "Within any venue, such as an airport, if we can find an area where there is a bottle neck, then that compresses the potential sources within the space where a dog can work, scent or detect. Even if a person walking with an explosive backpack moved within an area, a dog-handler team could go into that area at a later time, up to 15 minutes afterward, detect the device and follow that scent trail through the terminal to where that person was standing."

Smell and detect

The dog smells the area around it for the odor it has been trained to detect and indicate. Once the dog does, it will go to the area of the source where the scent is. Handlers can either bring the source of the scent to the dog, or locate the dog within a security gate location or access or entry point to detect odors of potential explosives on people walking by. You can also have a dog work within a group or congregation of people, or within an audience at an event.

At any location, typically the detection dog smells baggage or equipment. It also investigates areas like trash bins or places where explosives may have been left. If there is a random bag left in an area and no one knows what it is, the dog can check it. "Those are more of your typical detection dog scenarios," Gillette says.

"What we've found is that we haven't really tapped the full potential of the dog yet," Gillette says. "We found that by optimizing the metabolism of the dog, with correct nutrition and good exercise programs, dogs are performing activities that help strengthen them to handle the rigors of work and that they're able to work, longer periods of time before they fatigue."

The CDRI team is not forcing the dogs to do things that they don't want to do, but they select dogs that have the drive and desire to perform various tasks. "At some point, you want the dog to be performing at an optimum level, not maximized," says Gillette. At a maximal level, recovery time is too long. So they want the dogs to be functioning optimally so they're not stressing their systems. That allows the dog to think, to detect and to be able to utilize all its olfaction abilities to its greatest potential.

"We've found with exercise programs, conditioning programs and good diets and supplements, we can actually increase the detection ability of the dogs," Gillette says. "We treat the detection dog like an athlete and manage them with conditioning and proper nutrition that enhances the dog's abilities."

The CDRI Vapor Wake Detection dogs detect and trace explosive odors to their source. The dogs' training could have given them the ability to have detected the PETN explosive sewn into the underwear of the alleged bomber on Dec. 25th. "It is quite often that the TSA does that here in the U.S., where a dog would go and smell the plane," says Gillette. "And it is done at random, so in a sense it is as much of a deterrence, as it is to detect any substances." Could the TSA adopt a program where dogs are used on random flights once the passengers were seated, and a detection dog walks through the cabin to check for potential explosives or devices? "I think that the detection dog should be included in any security plan," states Gillette.

The worldwide terrorism deterrent program may not be based solely upon the dog, but detection dogs may be a key component to a successful defense strategy against explosive attacks in this country or anywhere in the world. When it comes to dogs, their noses knows.

Ancestry and noses

Going back to dogs' canine ancestor, the wolf, odor detection has been critical to the survival of the pack — it detects prey and allows the pack to communicate. A wolf may detect a moose up to 1.5 miles downwind, and under most circumstances, it can detect an animal three hundred yards downwind. It has been estimated that the olfactory area or smelling apparatus of the dog, the wolf's relation, is 14 times as large and 100 times more sensitive than a human's. Depending on the environmental conditions and how the scent cone or plume is dispersed, bird dogs may smell birds at 50 to 100 yards.

The dog's brain is dominated by an olfactory cortex, and its olfactory bulb is about 40 times larger than the human olfactory bulb relative to brain size, with up to 200 million smell-sensitive receptors. Researchers have determined that dogs are capable of sensitivity to tens of parts per billion (ppb) to 500 parts per trillion (ppt).

Ed Kane, PhD, is a researcher and consultant in animal nutrition. He is also an author and editor on nutrition, physiology and veterinary medicine with a background in horses, pets and livestock. Kane is based in Seattle.