By Audrey Pavia

As the world struggles to find a way to get back to normal life amid the pandemic, specially trained dogs may be able to help. The U.S. Army's Combat Capabilities Development Command Chemical Biological Center has been working to train nine dogs to detect the presence of the COVID virus in humans.

Indeed, recent research being conducted by the army at Aberdeen Proving Ground, Md., in conjunction with the University of Pennsylvania School of Veterinary Medicine Working Dog Center, has shown dogs can be trained to detect the presence of the novel coronavirus in the human body. The dogs are taught to recognize proteins created by the human immune system when it responds to a COVID infection.

The dogs involved

Eight Labrador retrievers and one Belgian Malinois are currently enrolled in the study, which trains dogs to detect the presence of the virus before a person starts showing symptoms of infection.

"The science behind a dog's ability to conduct tasks such as tracking and trailing missing persons and detecting ovarian cancer in human urine samples is based upon the dog's olfactory acuity and proficiency in analyzing a volatilome," says Patricia Buckley, PhD, research scientist at the center. "The volatilome is comprised of the entire set of volatile organic compounds (VOC) produced by an organism. The VOC profile emanating from the body is loaded with information, reflecting the unique metabolic state of an organism, and can even be diagnostic of a disease."

Dr. Buckley explains exploiting the VOC signatures of a single organism or a population can provide information on health status, biosecurity, biosurveillance, and disease transmission.

"The use of detection dogs is well established as a rapid and mobile technology for the detection of VOCs from drugs, explosives, and humans," she says. "However, the next frontier is harnessing their olfactory abilities for disease detection in order to address a global public health pandemic."

In the case of detecting COVID, the dogs never actually have any exposure to the live virus, but are instead trained to detect the biomarkers associated with the disease in humans.

TADD

This highly specialized training is being taught by a Hagerstown, Md.-based working dog trainer, who specializes in training dogs for tactical work. The training began in May 2020 using a training aid delivery device (TADD), a specialized containment vessel that has a gas-permeable membrane. The TADD allows dogs to train on potentially hazardous material, like human saliva and urine from infected patients, by letting the odor of the training aid out, but not the actual training aid.

The TADD itself was first developed by the army center in 2013 as a laboratory device. It was designed to contain hazardous substances needed for testing and evaluation of new detection equipment. Five years later, it was redesigned so it could be used in field settings without fear of breaking it if it was dropped or roughly handled.

The TADD is essentially a container, ranging in size from one to eight ounces. A membrane covers its mouth and allows VOCs emitted by a hazardous substance to flow out of the container while the hazardous substance remains inside. This makes the TADD safe for dogs being trained on live substances because explosive powders and narcotics stay under the membrane and do not go up into a dog's nose.

Another feature of the TADD is its actual components emit very little odor.

"Plastic and rubber materials can be very stinky to dogs and interfere with their detection of the substances we're looking for," says Michele Maughan, PhD, a researcher at the center. "We knew the TADD would be perfect for containing COVID-19 patient samples of saliva or urine because we knew this odor profile would be quite nuanced and require the dogs to key in on some really low VOC molecules. It's important the containment system, the TADD, doesn't compete with the target odor."

For the COVID detection training, the TADD was attached to a specialized wheel, and the dogs were taught over six to nine weeks not only to detect the scent of COVID human biomarkers, but to keep searching for hours at a time. Dogs have to be able to detect in the parts per trillion range, so they must have a strong drive to stay interested.

Army researchers are getting close to becoming able to test the dog's abilities on actual humans with the virus.

"The human screening portion of the study will occur at the University of Pennsylvania," Buckley says. "We are still recruiting volunteers to be a part of this important work, specifically people who have been tested in the past 48 hours or are going to be tested."

The study involves eligible participants wearing a cotton T-shirt for one night that has been shipped to them.

The ultimate goal for specially trained COVID detection dogs is to provide screening at the entrances to crowded public places such as at airports, sports stadiums, or at border control checkpoints. If the study is successful, these detection dogs may become a part of our regular lives as we fight to defeat this virus.