Trained dogs can sniff out a deadly deer disease

Date:
February 8, 2023
Source:
University of Pennsylvania
Summary:
A study has demonstrated that pet dogs could be trained to sniff out
chronic wasting disease, a deadly ailment that affects deer. The
proof- of-concept investigation suggests detection dogs could be
an asset in the effort to identify, contain, and manage the highly
contagious disease.


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FULL STORY ========================================================================== Charlie, Jari, and Kiwi are pet dogs with a superpower: Their sensitive
noses can distinguish between a healthy deer and one sick with chronic
wasting disease (CWD), all from a whiff of the deer's poop.


========================================================================== That's the finding of a study by scientists from Penn's School of
Veterinary Medicine, published in the journal Prion. Using feces
samples from CWD-positive deer and deer in which CWD was not detected,
the researchers trained the dogs to identify the odor of CWD, alerting
their handlers to its presence in the lab and in the field.

"We were already quite certain that the dogs could detect the volatile
organic compounds released by chronic wasting disease in feces," says
Amritha Mallikarjun, a postdoctoral researcher in Penn Vet's Working
Dog Center and lead author on the study. "Not only did we show this was possible, but we also answered a second, more interesting question,
which is, Can they detect the disease in a simulated field setting,
as they would if we were using the dogs to find the disease in the
landscape of a forest or on a deer farm?" The dogs indeed could, with
enough accuracy to suggest that detection dogs could be a useful strategy
in the fight to manage CWD.

"We learned a lot through the study and are now set up well to continue refining our training," says Cynthia Otto, the senior author on the
study and director of the Working Dog Center.

CWD is a disease that affects a variety of deer species, including
white-tailed deer, mule deer, and elk. Always fatal and highly contagious,
the disease can hide away in an affected animal for a year or two
before symptoms manifest: the deer losing weight -- "wasting" -- and
developing neurological signs, like stumbling and drooling. No cure or treatment exists.

The disease has been in Pennsylvania since 2012, and the state has
invested significantly in trying to contain it, with several tools in
place for keeping tabs on its spread. One hurdle is figuring out which
deer are affected. A healthy-looking but infected animal could shed
prions, malformed and infectious proteins, for many months or even years
before succumbing to the illness.

What's more, prions are known to bind to soil, potentially contaminating
the land on which other animals may roam.

The gold-standard diagnostic test can only be performed after death
by assessing an affected animal's brain. Some alternative tests have
been trialed that involve taking a biopsy from a potentially infected
animal while it's still alive, but deer are known to be highly stressed
by being captured, and collecting these samples can be physically and logistically difficult for the people involved as well.

The Working Dog Center, the Pennsylvania Department of Agriculture,
and the Wildlife Futures Program, a partnership between Penn Vet and the Pennsylvania Game Commission, were well positioned to try to contribute
an additional technique for managing the disease: dogs and their highly sensitive noses.

Ideally, dogs trained to discern CWD-positive from CWD-not-detected
feces in a forest or deer farm could help state agencies and private
landowners understand whether further testing or management would be
needed to keep their land and herds free from the disease.

First, scientists had to prove the dogs could make this distinction
reliably.

The Working Dog Center began by enlisting three dogs from their citizen
science program -- Labrador retrievers Charlie and Kiwi and Finnish spitz
Jari -- to train on the Center's "scent wheel," a contraption equipped
with eight ports, each containing a specific substance or scent.

The dogs proved adept at this task. Once they had been trained,
using samples provided by the U.S. Department of Agriculture and
processed by the Wildlife Futures Program, the dogs responded with
great specificity, passing by the not- detected samples 90-95% of the
time. Their sensitivity, however, was not as strong, alerting to just 40%
of the positive samples. Overall, the researchers found that the dogs
spent more time at the ports containing positive samples than those with not-detected samples, suggesting that they perceived a difference even
if they didn't always produce the trained response, such as a bark or
sitting down when they smelled the positive sample.

Moving toward a more naturalistic setting, the researchers then
experimented with having the dogs and their handlers try to discern CWD-positive samples placed throughout a large, privately owned field. To
avoid contaminating the soil or having the dogs come in contact with the samples, two-gram samples of feces were placed in jars with mesh lids
to allow the odor to waft out and then partially buried in the ground
in different areas.

The researchers observed that the dogs responded to the positive samples
more often than the not-detect samples in the field trial. In total,
they detected eight of 11 positive samples in the field, with a false
negative rate of 13%.

Both handlers and dogs seemed to improve as they went, their accuracy increasing after their first field search.

"Given the amount of time that we trained these dogs and the novel
environment, not to mention the fact that these are pet dogs and not
trained search dogs, our results are promising," says Mallikarjun. "As we
move forward and work with dogs that are specifically trained to search in
a field setting and devote their entire lives to detecting this odor, they
are going to do an even better job." That's a step the Wildlife Futures Program is already taking, with canine handlers training "professional" detection dogs how to canvas fields and forests, searching for CWD.

The researchers believe that, while dogs don't represent a silver bullet
in the fight against CWD, they may prove useful as an early warning
system, helping fill gaps in knowledge from other monitoring systems
and management approaches.

"These dogs could increase the odds of catching an outbreak early,"
says Lisa Murphy, a study co-author and co-director of the Wildlife
Futures Program.

The Penn Vet team is also collaborating with other groups not only to work
with detection dogs but also to identify the odor dogs may be responding
to in order to develop other systems for early detection. The lessons
learned could be broadly useful.

"If we're able to tap into what we've learned with chronic wasting
disease and apply it to other issues in agriculture and conservation,
these dogs could be a major asset," Otto says.

Amritha Mallikarjun is a postdoctoral fellow in the University of
Pennsylvania School of Veterinary Medicine.

Lisa Murphy is resident director of PADLS New Bolton Center, a professor
of toxicology, associate director of the Institute for Infectious and
Zoonotic Diseases, and co-director of the Wildlife Futures Program at
Penn's School of Veterinary Medicine.

Cynthia Otto is a professor of working dog sciences and sports medicine
and director of the Working Dog Center in Penn's School of Veterinary
Medicine.

Mallikarjun, Murphy, and Otto's coauthors were Penn Vet's Ben Swartz,
Sarah A.

Kane, Michelle Gibison, Isabella Wilson, Amanda Collins, Madison B. Moore,
Ila Charendoff, and Julie Ellis and the U.S. Department of Agriculture's
Tracy Nichols. Mallikarjun is corresponding author on the study.

The work was supported by the Pennsylvania Department of Agriculture and
the Wildlife Futures Program at the University of Pennsylvania School
of Veterinary Medicine.

* RELATED_TOPICS
o Plants_&_Animals
# Dogs # Veterinary_Medicine #
Animal_Learning_and_Intelligence # Prions
o Earth_&_Climate
# Ecology # Sustainability # Environmental_Policy #
Rainforests
* RELATED_TERMS
o Dog_skin_disorders o Dog_health o Guide_dog o Service_dog
o Prion o Pandemic o Hunting_dog o Therapy_dog

========================================================================== Story Source: Materials provided by University_of_Pennsylvania. Original written by Katherine Unger Baillie. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Amritha Mallikarjun, Ben Swartz, Sarah A. Kane, Michelle Gibison,
Isabella Wilson, Amanda Collins, Madison B. Moore, Ila Charendoff,
Julie Ellis, Lisa A. Murphy, Tracy Nichols, Cynthia M. Otto. Canine
detection of chronic wasting disease (CWD) in laboratory and field
settings. Prion, 2023; 17 (1): 16 DOI: 10.1080/19336896.2023.2169519 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/02/230208191721.htm

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