News: Guest Posts
With their extremes of limb and coat, purebred dogs may seem more prone to health problems. And don’t breeders even compound defects, as they tinker with uniformity? Yet the dog of many varieties, a potluck of traits, outlasts them all.
Not quite, say U.C. Davis researchers in a recent study lead by Anita Oberbauer in Canine Genetics and Epidemiology. Their analysis of health records of 88,635 dogs, both purebred and mixed breeds, tilts assumptions. So does another recent study, in which they found both populations shared similar risk for 13 inherited disorders. One condition was even more prevalent in mixed-breeds.
Purebreds, and their health records, have made it easier to explore the genetics of diseases that get passed down, the researchers say. But as we hear about the studies, the belief that purebreds are less healthy grows. In fact, many breeds have proven more prone to some diseases, like Great Danes and hip dysplasia.
In this study, they sliced the data thinner. Could particular AKC breed groups, not just individual breeds, be the source? Do the diseases arise from dogs with genomic similarities like working and herding groups? The huge pack of canines, seen over 15 years at U.C. Davis veterinary teaching hospital, showed that ten inherited conditions are more common in purebred dogs. But surprise, not all purebred dogs.
A subset of pedigreed pups tied with mixed breeds for the disorders.
The conditions include aortic stenosis (narrowing above the aortic heart valve or of the valve); skin allergies; bloat; early onset cataracts (clouding of the lens inside the eye); dilated cardiomyopathy (enlargement of the heart chambers); elbow dysplasia (abnormal tissue growth that harms the joint); epilepsy (brain seizures); hypothyroidism (underproduction of thyroid hormones); intervertebral disk disease (affects the disks of the spine, causing neurological problems); and hepatic portosystemic shunt (abnormal blood circulation around the liver, rather than into it).
With a spotlight on the ten maladies, the researchers set out to learn which canines are more at risk. Purebreds were subdivided into categories, then compared to the mixed breeds.
For three conditions common across the purebreds—skin allergy, hypothyroidism, and intervertebral disk disease—many groups had higher prevalence than the mixes. But for seven others, most purebred groups were statistically neck and neck with mixed-breeds. (Aortic stenosis, gastric dilation volvulus, early onset cataracts, dilated cardiomyopathy, elbow dysplasia, epilepsy, and portosystemic shunt).
Terrier groups even bested the mixes for one problem, having less intervertebral disk disease.
Among the purebred groups, health differences were clear. Compared to mixed breeds, terriers and toys were more likely to have two disorders. Herding and hound groups were more burdened with four conditions. The non-sporting group, where pooches ranging from Poodles to Dalmatians fit in, were more likely to have five disorders. Working breeds, animals expected to have grit and vigor; six. Worst in health: the sporting group bred for outdoor stamina. They were more at risk for seven inherited disorders.
In fact, in three categories of dogs bred for endurance—herding, sporting, and working AKC groups—aortic stenosis, the heart condition present at birth, was higher. With narrower focus, other findings emerged. The researchers say the data “suggests that most breeds in the herding group are not at higher risk”—except the German Shepherd, which other studies have also found susceptible.
And while Retrievers were more affected by aortic stenosis, another sporting breed, the Spaniel, wasn’t. For a different malady, Spaniels were the unluckiest. Epilepsy was more prevalent in herding, hound, and sporting groups, particularly the Spaniel breeds.
Early onset cataracts beset both non-sporting and sporting breeds more often.
How did all of these health glitches arise? The study mentions other research that found some diseases, like elbow dysplasia, are more frequent in dogs of related ancestral origin. The so-called “liability genes” may hail from founding ancestors of related breeds, or be the result of human error in the quest for desired traits. This study, the authors say, “may shed light on the possible origin of certain inherited disorders in domestic dog evolution.”
For the ten diseases, the analysis found some purebreds genetically healthier than others. Flipped around, mixed breeds were no healthier than certain purebreds. But both populations may benefit from the work. According to the researchers, defining the lineage associations for such disorders may bring about new therapies.
Better, it could allow breeders to weed out the responsible genes to begin with. Especially at the local level. “Whether breeding reforms will mitigate inherited disorders in mixed-breeds will depend upon the locale,” the scientists say. That is, some regions have a greater potluck of breeds within their mixed-breeds.
Still, since most mixes have purebred ancestors, they say, improvement of the genetic health of purebreds “may trickle down to mixed-breed dogs.”
News: Guest Posts
Dog fed blue green algae supplement develops liver problem, report finds
A new report by researchers at U.C. Davis points to the need for oversight of nutrition supplements. The pills and powders fed to pets to boost their health come with no assurance of getting what you pay for—or more than you bargained for, like toxic contaminants.
In this case, a tainted organic algae powder was damaging the liver of an 11 year old Pug, who lost her appetite and was lethargic after several weeks use. The authors say it’s the first documented case of blue-green algae poisoning in a dog caused by a dietary supplement. (Most reports of illness involve dogs exposed to water containing certain blue-green algae toxins.)
Blue green algae supplements are sometimes fed to dogs to relieve arthritis or boost the immune system.
Many consumers believe these products can only be sold if they are safe for use, the authors say. “Unfortunately, the opposite has been demonstrated in several studies showing the contamination of blue-green algae supplements with microcystins.”
With the use of commercial health products on the rise, the risk is growing. While supplements are regulated by the FDA, there are no requirements for proving them safe or effective before marketing. That is, the industry “is largely self-regulated,” the report says.
Toxic blue-green algae blooms occur in Oregon’s Klamath Lake, where supplement manufacturers harvest much of their source material. In 1997, the state became the first to regulate the amount of mycrocystins allowed in supplements.
Adrienne Bautista, the lead researcher on the current report, says in an email that the tests may not catch every problem. The tests many companies use to certify their products are below the 1 ppb Oregon limit are often ELISAs, Bautista says, which mainly detect “the LR congener of microcystin.” But there are more than 100 other congeners likely to have similar modes of action that the tests are “quite poor” at finding. So even if the supplement tests below the 1ppb for this common toxin, others may still be present.
What could lower the risk from these particular supplements is to produce the algae in a lab-like setting, Bautista says. “By harvesting it naturally, you have no control over contamination from other algae.”
The researchers call for stronger oversight of dietary supplements for companion animals, and greater awareness among veterinarians.
With treatment and by stopping the supplement, the Pug made a full recovery.
Dog's Life: Work of Dogs
Expanding the frontiers of the canine capacity to help us carry on.
We can’t find our glasses, our car keys or the right word. We forget an appointment. We’re unable to bring to mind the name of a long-ago best friend. Many of us jokingly refer to these as “senior moments,” but the humor is only skin-deep. Underneath is the niggling worry that dementia—the term for a set of symptoms signaling a decline in mental abilities severe enough to interfere with our daily lives—lurks. This fear is fed by a sobering statistic: according to the Institute for Dementia Research and Prevention, in the U.S., at least 5 million individuals suffer from age-related dementias (Alzheimer’s disease accounts for roughly 70 percent of the total). These numbers will continue to rise as the population ages.
Severe memory loss is no laughing matter. The brain, a mysterious and complex organ, is, among other things, the repository of the very essence of who we are: our memories. Generally speaking, memory breaks down into three broad categories: sensory, short-term and long-term. Things as dissimilar as childhood recollections and how to walk, hold a spoon or comb our hair reside in our memory As damaged nerve cells (neurons) cease to function, they take much of this information with them. This is where dogs come in.
Dogs love routine. People with dementia have difficulty with routine, everyday activities. Roughly a dozen years ago, two people had the idea to put them together. When Israeli social worker Daphna Golan-Shemesh met professional dog trainer Yariv Ben-Yosef, they chatted about their respective occupations. As Ben-Yosef recalled, “It was clear to us that Daphna’s expertise in Alzheimer’s and my expertise with dogs could result in something new.” Together, Golan-Shemesh and Ben-Yosef pioneered the idea of training dogs to help those with dementia to not only feel better but also, to assist with daily activities.
Fast-forward to early 2012, when Alzheimer’s Scotland secured funding to study the possibility that specially trained service dogs could benefit people in the early stages of dementia. Four students at the Glasgow School of Art developed the initial concept as a service design project in response to the Design Council’s 2011 Living Well with Dementia Challenge. Focused on “finding practical solutions to social problems,” the competition required entrants to “design and develop products and services that rethink living with dementia, and launch them as real initiatives.” The Dementia Dog project grew from this call to action.
Dementia Dog is a collaborative effort, with Alzheimer’s Scotland, Dogs for the Disabled, Guide Dogs Scotland and the Glasgow School of Art pooling their respective areas of expertise. Last year, the research phase was completed, and the group is now in the early stages of a small-scale pilot program. As noted on the Dementia Dog website, the program “aims to prove that dogs can help people with dementia maintain their waking, sleeping and eating routine … improve confidence, keep them active and engaged … as well as provide a constant companion who will reassure them when they face new and unfamiliar situations.”
They are also developing programs for two more assistive functions: intervention dogs, trained to help the client with specifically identified tasks, and facility dogs, who enhance the emotional well being of those living in residential care.
The program’s dogs receive instruction at the Guide Dogs’ Forfar Training School. After 18 months’ work, the first two dementia service dogs—Kaspa, a Lab, and Oscar, a Golden Retriever—were certified last year, and two more dogs are currently being trained.
As noted in the program statement, the dogs help their people with core needs: support for daily living (exercise, balance, alerting to hazards, environmental safety), reminders (prompts to take medication), “soft” support (companionship, a bridge to social interaction, confidence building), and physical and emotional anchoring (staying with their person while the partner/caregiver shops, or helping their person feel safe and secure when alone).
The dogs are also trained to provide another critical service: getting their people home safely. The dogs’ collars are fitted with a GPS unit, and if the person doesn’t give the “home” command, the device helps families or law enforcement zero in on the pair’s location. Unlike guide dogs for the blind, dementia dogs operate at the end of a six-foot leash, which allows them to most effectively steer their people in the appropriate direction.
Dementia service dogs are being trained in the U.S. as well. DogWish.org, a California-based charity that trains and sponsors service dogs, lists “dementia dogs” as one of their training options, as does Wilderwood Service Dogs in Tennessee.
This service dog program taps into our almost primal love for dogs in a very personal way. The dogs of our present, the dogs of our past: their names and quirks and the bone-deep understanding of their nonjudgmental and unconditional love often stay with us when much else has been lost. A person living with dementia may not be able to recall what she had for breakfast or where she lives, but the dogs she loved? That’s another story.
In a 1.28-minute YouTube video clip that’s been viewed by more than 5.6 million people (go to see it for yourself), an elderly man with Alzheimer’s who’s lost almost all of his speech talks to and interacts with the family dog. It’s hard to imagine a better example of the very real value that dogs—purpose-trained or not—provide to the most vulnerable among us.
Read deeply touching comments from family members and caregivers about the ways dogs help their loved ones cope at dementiadog.org.
Wellness: Healthy Living
Investigating the microscopic worlds in our dogs may reveal pathways to better health.
The microbiome is the invisible world of the hundred trillion bacterial, viral and fungal microbes that live on us and in us—on our hair and skin, behind our ears and inside our eyelids. The bulk of these miniscule microbes are good guys, gut microbiota that congregate in the digestive tract, where they bolster the immune system, manufacture vitamins and digest food to generate nutrients and energy.
Microbial equilibrium is a delicate balancing act, and a broad spectrum of inflammatory and autoimmune diseases is linked to having too many microbes—or too few. For example, researchers know that significantly lower bacterial diversity is found in both people and dogs with chronic inflammatory bowel diseases.
Teasing out the biological interaction of trillions of miniscule microorganisms that colonize the body, and the role they play in well being, is a new frontier. Will it be a watershed moment in veterinary medicine? Scientists are hopeful. The human microbiome has become a hot topic in biologic investigations, and canine research is fast catching up, much of it inspired by the success of the Human Microbiome Project, launched in 2007 by the National Institutes of Health (NIH). Using stool and tissue samples to isolate microorganisms, researchers are mapping the diversity and normal profile of the human microbial community.
Another undertaking, the Human Food Project, invites the public to submit personal and family microbial samples along with samples from family dogs to better understand how a person’s microbiome compares to that of animals living in the same environment. (The project’s dog segment has been discontinued.) The analysis centers on the anthropological co-evolution of humans, animal and plant microbes to understand modern disease against the backdrop of our ancestral/microbial past.
It’s all about dogs at Companion PBx, a new startup that primarily targets the canine digestive tract. Its goal is to build a cumulative gut flora database and develop dietary products customized for dogs’ digestive health. In January 2015, the company launched a Kickstarter campaign to raise money for construction of the database.
According to Companion PBx Chief Science Officer Kelly Scott Swanson, PhD, who’s on the faculty at University of Illinois, Urbana-Champaign’s Department of Animal Sciences, “By sequencing the microbes in your pet’s sample, we obtain a fingerprint of the microbial community in your pet’s GI tract.”
Microbes in Common
Affected by age, environment, ancestry, evolution, genetics and diet, microbial communities vary widely between species and across individuals within a species. A recent study suggests that our housemates—including the family dog—may also affect the composition of our personal microbial signature.
If you and your significant other kiss, hug and/or share a bed with your dog, the three of you have more in common than you think. A study conducted by researchers at the University of Colorado, Boulder, revealed several similarities: Adults who share a dog have more similar mouth microbes than those who don’t. Dog-owning families have more diverse and different microbial colonies than dogless households. Parents tend to share more kinds of mouth bacteria with their dog than they do their children. And children raised with dogs have a wider variety of microbes than dogless kids (Song et al. 2013).
Whether these spit-swapped microbes serve a purpose or are just passing through is not clear. But research shows that children raised with dogs are less likely to be afflicted by eczema (Epstein et al. 2010) and asthma (American Society for Microbiology 2012).
The notion that microorganisms in the canine gastrointestinal tract might have unique properties is not new. Early Romans understood the medical value of a well-run therapy dog program. Health temples, the ancient equivalent of modern-day outpatient clinics, were staffed with live-in cynotherapists, gentle dogs who wandered about the grounds greeting patients and licking wounds. Were the dogs healing only psychosomatic injuries? Time and additional research funding will tell.
The idea that our microorganisms may to some extent be collectively beneficial is intriguing. People and dogs have been exchanging microbes for at least 30,000 years, since the first little cave girl kissed the first proto-dog puppy smack on the muzzle. That’s a long history of sharing. It’s possible that our microorganisms are at least symbiotic, and perhaps even played a role in the dramatic domestication of the dog.
Theoretically, many thousands of years ago, a population of carnivorous wolves or ancient proto-dogs (depending on where you stand in the dog-domestication debate) transitioned from a meat-heavy diet to one laden with grain, a consequence of the agrarian revolution.
Scientists know that the acquisition of a new diet is a fundamental driver for the evolution of a new species (Dale, Moran 2006). When species transition from carnivorous to omnivorous diets, the gut microbial community co-diversifies with the host and drives further evolution (Ley et al. 2008). As human diets changed, so too did those of Canis familiaris. Over time, as we incorporated these unique animals into our daily lives, we continued to reshape them.
In humans, autoimmune and inflammatory diseases are on the increase. Scientists can’t verify a similar pattern in dogs because epidemiological studies are rarely conducted in veterinary medicine. Additionally, many autoimmune conditions are diagnosed based on the patient’s subjective description of symptoms.
But this is not the case with itchy skin. Dogs who scratch themselves incessantly are highly likely to have allergies. When researchers compared microbial colonies on the skin of healthy dogs to those of dogs with allergies, they found that non-allergic dogs have much richer and diverse skin microbial communities (Hoffmann et al. 2014).
But when it comes to proving causality, scientists wisely err on the side of caution. It’s not understood if a change in the microbiome causes certain conditions, or if it occurs as a consequence of the conditions. Nor is it absolutely clear that more diversity is better than less. At this point, scientists cannot say with confidence exactly what a healthy microbiome should look like in the dog.
Moreover, what seems logical may not be so. For instance, anyone who has lived with a poop-eating pooch has wondered why some dogs do and other don’t. Are coprophagic dogs seeking microbes lacking in their gut? Surprisingly, research involving mice suggests that this might not be the case; coprophagia in germfree mice is the same as in conventional lab mice (Ebino et al. 1987).
Other questions arise: Are the microbiomes of individual dog breeds more similar to each other than they are to those of other breeds? And could these isolated microbial communities drive breed-specific ailments?
Jan Suchodolski, DVM, a Texas A&M veterinary medical and biomedical sciences researcher who studies dog and cat gastrointestinal diseases, says that this doesn’t seem to be the case. As he noted, “So far, we do not have any clear evidence that gut microbiomes are more similar within breeds. Environmental influences such as age, diets and antibiotics, and especially the effects of GI disease, are larger than any breed effect.
“It may be possible that we missed an effect, as we have not evaluated thousands of animals. But if there were a breed effect, it would probably be very minor. Even within puppies of the same litter, the microbiome shows huge inter-animal variation, so the animal effect is much stronger than any other effect.”
Idiopathic canine inflammatory bowel disease (IBD) is a gastrointestinal condition in which the digestive tract is chronically inflamed. Symptoms include vomiting, diarrhea and weight loss. Dogs with IBD have significantly lower bacterial diversity as well as microbial communities that are distinct from those of healthy dogs. In 2014, Dr. Suchodolski and his colleagues conducted a study of 22 companion dogs, half of whom suffered from idiopathic IBD (Minamoto et al. 2015). They wanted to know if traditional treatments—steroids and special diets—directly or indirectly created a more robust microbial community.
After treatment, the sick dogs felt a lot better. However, there was no change in their gut microbiota. The researchers concluded, “This study demonstrates intestinal dysbiosis [microbial imbalance] and altered serum metabolite profiles in dogs with IBD. But medical therapy doesn't seem to affect the intestinal dysbiosis.”
It could be that, rather than triggering the condition, microorganisms are compromised by it. Researchers also suspect that biological environmental stresses are involved in ways not yet understood. Dr. Suchodolski added, “It may be that we need longer follow-up periods of treatments to see potential improvements. Another reasonable theory is that with the current standard therapies—for instance, immunosuppression—we just control clinical signs, but the underlying etiology of the disease is ongoing.”
When it comes to treating dogs for myriad problems, vets often prescribe antibiotics, and for good reason: antibiotics save lives. But the war on infection sometimes puts good bacteria in the line of fire, too. When assaulted by repeated antibiotic use, some classes of gut bacteria struggle to recover. If the affected bacteria play a pivotal role in autoimmune health, overuse of antibiotics may coincide with a decrease in healthy autoimmune responses.
Antibiotics are not the only culprits. Scientists suspect that in human births, Cesarean deliveries may contribute to an increase in autoimmune weaknesses as well. In a vaginal birth, the fetus departs the womb without a single microbe but acquires them by passing through the mother’s birth canal. By the time the newborn takes his first breath, he is covered with colonies of bacteria that kick-start his immune system, establish a healthy digestive tract, help shape his growing brain and even protect him from psychiatric disorders. C-section babies start life without the microbes they would have picked up from vaginal delivery, suggesting that the colonization of the newborn might be delayed (Jakobsson et al. 2014).
Medical disorders connected to non-vaginal delivery and the slow introduction of protective bacteria have not been studied in the dog. Considering that a number of breeds with exceptionally flat, wide skulls—such as the Boston Terrier, French Bulldog and Bulldog—must have their pups delivered via C-section, it’s an area that deserves further study.
Or is diet the problem? Commercially manufactured dog chow was introduced in the U.S. in the mid-1920s. By the 1950s, processed dog food like Friskies, Sergeant’s and Purina were widely available through local grocery stores. Today in the U.S., we spend more than $10 billion a year on commercial pet food. The question arises: has the increase in autoimmune diseases paralleled the rise in popularity of processed dog food?
Because veterinary practices typically don’t collect this type of empirical data, the answer is, at best, a guess. But many dog owners think so, and have eliminated or cut back on processed foods in favor of raw meat and vegetables. However, as of now, there is no definitive evidence to show that fresh foods modulate the gut microbiota.
Sophisticated DNA sequencing technology has opened up the invisible world to scientific scrutiny. But determining its impact on the host species is difficult and time-consuming. Researchers need to locate and identify a microbe’s fingerprint, then remove a sample and grow it in a culture, a process especially difficult with shyer microbes that are destroyed by oxygen or stomach acid.
To figure out why we get sick and the role microbes play in illness, researchers must first determine how these trillions of organisms interact with each other. And the fact that scientists can prove a problem exists doesn’t mean they know how to fix it.
Developing therapeutic dog foods that target specific vulnerabilities may help, but will take time to develop. Although the probiotic movement may oversell their benefits, probiotics (friendly bacteria like those that live in the gut) are effective in some cases. And prebiotics, foods that encourage growth of good bacteria already present, may help as well.
The University of Pennsylvania School of Veterinary Medicine (Penn Vet) is recruiting dogs with acute symptoms of diarrhea and/or vomiting for a new clinical trail that will evaluate the role of the intestinal microbiome—the community of “good” bacteria that live in the gut—on chronic gastrointestinal diseases. Therapy will include simple diet change, treatment with antibiotics or combination therapy with steroids for more complicated cases.
Penn Vet researchers anticipate that their study may reveal how gut microbiota influence and respond to treatment, which in turn could lay the groundwork for future projects using treatments such as prebiotics, probiotics or fecal transplants (transferring “good” microorganisms from a donor’s healthy stool to the patient’s gastrointestinal tract). According to Research Assistant Professor Dr. Daniel Beiting, “Whereas past studies have used a single method to sequence bacterial DNA, the Penn Vet study will use a more sophisticated approach called metagenomics, generating a much more comprehensive catalog of bacteria in the stool and providing insight into what they might be doing.”
Penn Vet is currently looking for dogs with chronic gastrointestinal problems. People interested in enrolling their dog in the study—Evaluating the Role of the Microbiome in the Resolution of Canine Chronic Enteropathy—should email Penn Vet’s Veterinary Clinical Investigations Center at firstname.lastname@example.org, or call (215) 573-0302.
Future possibilities are exciting. In the meantime, kiss your dog. It’s good for you in more ways than one.
Good Dog: Studies & Research
Dogs’ remarkable ability to sniff out disease is opening doors to earlier cancer detection.
Cancer. The very word strikes fear in us. A voraciously living thing, cancer is an uncontrolled division of abnormal cells that destroy nearby healthy tissue. Because the natural, life-building process of cell division isn’t perfect, cancer has always been part of the human experience, one that eventually has an impact on everyone—if not directly, then when a relative, friend or companion animal is diagnosed with it.
The fact that human illness often comes with a signature odor is also old news. Infectious diseases such as cholera, diphtheria, smallpox, pneumonia, tuberculosis, typhoid fever and yellow fever have long been known to produce signature odors. Parents and doctors have used their noses to detect things like strep throat (metallic-smelling breath), phenylketonuria or PKU (in which the baby’s sweat smells like locker-room towels), even schizophrenia (a musty smell).
Mammals evolved using odors to find food, avoid illness-inducing spoiled or poisonous food, detect toxins in the environment, distinguish friend from predator, and assess well being. Following our noses is likely one of the key reasons humans, canines and other mammals developed large brains: to process all those smells.
Dogs are quite up front about this smelling stuff, greeting each other with a thorough sniff from tip to tail (or vice versa), quickly gathering a wealth of information through their noses. Humans do the same thing, just not quite so boldly. Historically, we’ve taken advantage of dogs’ superior sense of smell to track people and animals and to detect drugs, bombs and chemicals.
What is new is the increasing role dogs are playing in helping us detect minute, microscopic things we can’t see and certainly can’t smell, like cancer in its earliest stages, when it’s most treatable.
What exactly are dogs picking up with their remarkable olfactory sense? Turns out, it’s volatile organic compounds, or VOCs. Simply put, VOCs are chemicals coming from a living or once-living organism that can pass into the surrounding air (“volatile” in this case means easily evaporated at normal temperatures). VOCs, which can be natural or human-made, are both numerous and ubiquitous. Our bodies constantly emit an incredible array of VOCs, some of which are odorous and some of which are not.
VOCs are first secreted at the cell level, finding their way into our blood, breath, skin, sweat, urine and feces and from there into the air, rather like the dead skin cells (dander) we slough off on a daily basis. VOCs vary depending the individual’s age, gender, diet and health, and possibly even genetic background. Just as our fingerprints and irises are uniquely individual, so is our fragrance.
Illness resulting from infectious diseases and metabolic disorders, including cancer, influence and change our VOCs—our odor profile. While we may or may not smell the change, dogs certainly can. The average dog has a sense of smell that is between 10,000 to 100,000 times keener than the average human’s, and the part of the dog’s brain that analyzes smell is proportionally 40 times greater than ours. This allows them to detect specific odors, including specific VOCs, in parts per trillion. One scientist described this as being able to detect one rotten apple in a barrel of two million.
Dogs often display intense interest in a new cut on their person’s leg or arm, putting their nose close to the wound and sniffing with purpose several times. When they do this, they’re inhaling the VOCs put out by the body’s blood and changing skin cells as they waft into the air. It’s not a stretch to understand how, using dogs’ built-in and potentially life-saving ability, individual dogs can be trained to detect and alert to specific VOCs associated with a wide variety of conditions in a more general way.
Cancer has been the most recent focus of this sort of research. The earlier cancer is detected, the better the patient’s chances are for survival. Dogs can detect certain cancers with high levels of accuracy long before some of the more traditional diagnostic methods. The trick is identifying the signature VOC that relates to a specific type of cancer so that the dog can be trained to alert to it.
Researchers are making great progress. Dogs have been trained to detect ovarian cancer in blood samples, distinguishing it from other gynecological cancers and healthy control samples. They have also been trained to detect melanoma, bladder, colorectal and lung cancer in patients’ urine, tumor or breath samples. Because this research is in its early stages, it’s not yet clear whether the dogs are detecting VOCs from the cancer cells or from other metabolic processes often seen in patients with cancer.
Italian researchers were able to train two German Shepherds, Liu and Zoey, to sniff out VOCs associated with prostate cancer in urine samples with 98 percent accuracy. The study’s remarkable results—far better than those achieved with standard PSA tests—were based on samples from 362 men with prostate cancer and 540 men with either non-neoplastic prostate disease or non-prostatic tumors. Liu and Zoey could tell the difference.*
Using chemical-analysis techniques such as gas chromatography and mass spectrometry, researchers are regularly adding VOCs to the list of components known to be associated with specific cancers, infectious diseases and metabolic disorders. This work is opening doors not just to improvements in the art of diagnosis but also, to the understanding of disease processes, which leads to better treatment, novel therapies or perhaps prevention.
Scientists are also reverse-engineering the dog nose to come up with electronic or artificial sniffers to detect those same VOCs, enhancing doctors’ ability to quickly and definitively diagnose various diseases and conditions in a simple, non-invasive way without using a dog. In 2013, over a thousand journal articles discussed the electronic nose in some way.
Before long, physicians may be waving an electronic nose over our bodies to diagnose illness, as Dr. McCoy did with Captain Kirk and Spock on Star Trek. If so, we’ll have our dogs’ wet, cold and very keen noses to thank.
*Lead researcher Gianluigi Taverna, MD, chief of the prostatic disease unit at Humanitas Research Hospital in Milan, presented these results in May 2014 at the annual scientific meeting of the American Urological Association, and referred to the highly trained dogs as “Ferraris.”
Good Dog: Studies & Research
Harvard study makes it official: dogs are good for us.
If you live with a dog, chances are you’re familiar with canine de-stressing techniques. Perhaps you’ve felt a wave of relief from burying your face in fur after a difficult day at work, or experienced a release of calming chemicals after being met with a particularly enthusiastic greeting. And maybe those daily dog walks have helped you shed a few pounds or led to some welcome social interactions with other people and their dogs. And doesn’t life seem to have more meaning because there’s a living creature depending on you?
To dog people, the emotional, physical and even spiritual benefits of canine relationships tend to be obvious. These benefits feel as real to us as the saliva-soaked tennis ball we’re holding in our hands. That’s why it can be so hard to understand why the non-dog world hasn’t caught on to all these life-altering advantages. Even worse is the fact that many people who have never lived with a dog seem to think we may be making all this up—that the only place these benefits exist is in our heads.
Science in Action
Thanks to a special report from Harvard Medical School (HMS), we now have something important to share with these nonbelievers—proof! Get Healthy, Get a Dog is the first publication to compile hundreds of research studies from around the world that document the physical and psychological benefits of dog ownership. Taken together, these studies provide the most complete picture yet of the many ways in which dogs enrich human life: from lower cholesterol and improved cardiovascular health to weight loss, companionship, defense against depression and longer lifespans.
“The most common reaction we’ve been getting from people about this report is that they are so grateful that someone has finally put into print what they’ve known intuitively all along,” said medical editor Elizabeth Pegg Frates, MD, who supervises the Lifestyle Medicine Interest Group at HMS, teaches a college course on lifestyle medicine at the Harvard Extension School, and directs the Wellness Programs at the Spaulding Stroke Research and Recovery Institute, an HMS affiliate.
The 50-page report is the result of a collaboration between HMS and Angell Animal Medical Center, a leading veterinary hospital based in Boston. Get Healthy, Get a Dog approaches the dog/human relationship as a two-way street, so half of it is devoted to the human—what the dog does for the person—and half is devoted to the dog—what the person should do for the dog. Frates tackled the former, and Lisa Moses, VMD, who heads the Pain Management Service at Angell Animal Medical Center, covered the latter, which includes sections on nutrition, exercise, training and responsible pet ownership. Moses also makes a compelling case for adopting a dog rather than going to a breeder or pet store.
“We didn’t want to create the impression that a dog is some kind of tool for achieving better health,” says Moses in explaining the dual focus. “We wanted to emphasize that it’s the relationship that provides these benefits—it’s not the pet. And for that relationship to develop and be sustained, you have to do your part.”
Doing your part often means going for walks in the rain, sleet or snow, at all hours of the day and night. In fact, one of the primary health benefits of owning a dog is that it boosts your activity level. There have been about a dozen studies conducted on the link between dogs and human exercise, including one that compared 536 dog owners with 380 non-owners. Those with dogs were found to be fitter, thinner and less likely to have chronic health conditions, such as high blood pressure and diabetes. A study in Missouri that paired public housing residents with certified therapy dogs for five 20-minute walks a week found that participants lost an average of 14.4 pounds without changing their diets. (The report points out that most weight-loss programs and anti-obesity drug trails can’t boast such good results.)
Of course, the fact that regular exercise helps people lose weight and get healthy isn’t exactly breaking news. The insights come from the critical role the dog plays as a fitness partner—offering everything from enthusiastic encouragement to obnoxious pestering. Unlike a human partner, a dog is not going to suggest ducking out to a movie. “The dog support was always positive, while the human support could be positive (friends, family), negative (saboteurs) or inconsistent,” wrote Frates. Another reason that people tend to adhere to an exercise program if a dog is involved is the perception that the dog needs them. In one study, 72 percent of participants cited this as the reason they stuck to the activity schedule for the full 50 weeks of the trial.
“Sometimes people find that the dog becomes the excuse for taking care of themselves,” says Moses. “It may not be acceptable to them to be so self-oriented, but if it’s about the dog, then it’s okay.”
The American Heart Association (AHA) uncovered another piece of canine magic: a dog appears to help someone who is obese overcome his or her embarrassment about being seen in public doing physical activity.
It’s likely that increased exercise plus the calming effects of dogs (which we’ll get to later) contribute to lowering blood pressure. One study actually tested dog ownership as a treatment for high blood pressure. Thirty people with borderline hypertension were randomly assigned to either adopt a dog right away or defer adoption to a later date. After five months, the segment of new dog owners experienced significant declines in systolic pressure (the top number, which measures the highest arterial blood pressure). The group that had been asked to defer adoption experienced these same declines once they had taken their new dogs home and spent time with them. In 2013, the AHA went as far as to say that pet ownership “is a reasonable strategy for reducing heart disease risk.”
And there’s more good news on the cardiac front. A study of nearly 6,000 men and women in Australia found that dog owners of both sexes had lower triglyceride levels than non-owners, and male dog owners also had lower total cholesterol levels.
Beyond these formidable physical benefits are the psychological ones, which according to Frates “are hard to overstate.” Dogs make us feel less isolated. They pull us into a social world inhabited by other people walking other dogs. (Seventy percent of dog walks lead to at least one spoken interaction with a stranger.) And they help us meet the basic human need for companionship. Two large, long-term studies that followed people from childhood to old age found that those who were more engaged with others—whether those others were people or animals—lived longer. Those longer lives may also be more purposeful. A dog’s total dependency can make that person feel wanted and give life a sense of meaning.
Moses knows this phenomenon first hand. Her grandfather spent more than a decade as primary caretaker for his wife, who suffered from rheumatoid arthritis and cardiovascular disease. During all those years, he had a succession of dogs to care for—or was it the other way around? After his wife died, his beloved Terrier mix Lady succumbed to kidney failure. “At age 92, unbeknownst to us, he went out and adopted another dog,” Moses says. “Having a dog was the reason he got up in the morning. It was his entire life. He was a living testament to the power of the human/canine bond.”
There are other indicators that dogs are particularly helpful to older people. The HMS report cites a year-long study from Canada that found elderly dog owners to be more capable of performing daily activities, such as dressing and feeding themselves. This is likely because in attending to their animal companions, seniors are reminded to take care of themselves. They also have a structure in place, thanks to the need for regular pet meal times and walks, which reinforces their own self-care habits.
At the other end of the age spectrum, children learn important life skills from early bonding with the family dog. That bonding can lead to stronger human connections later in life, according to a Tufts University study, which also found that kids who’ve forged emotional connections to dogs have more empathy, feel more self assured and do better in social settings.
“How else would you get your kids to touch and love something?” asks Frates, the mother of two teenage sons. “For boys especially in this culture, there are very few acceptable ways of encouraging this type of bonding and intimacy.”
There is even evidence that exposure to a dog from infancy onward reduces the likelihood that even the most allergy-prone kids will develop problems. Only 19 percent of babies living with dogs developed pet allergies, compared to 33 percent of babies who grew up in dog-free homes, according to one study.
As those babies grow up and become college students, the dog benefits continue. Several psychological studies have found that college-age adults tend to find more stress relief in turning to their dogs than in seeking comfort from parents or siblings. Still other adults were found to shake off the blues just by thinking about their dogs … which brings us to the magic of oxytocin.
Having a dog can be like having your own a prescription for oxytocin with unlimited refills—except that rather than dispensing this drug, your dog incites you to release it. Also known as the “love,” “bliss,” and “bonding” hormone, oxytocin inspires positive feelings. It helps stave off depression and limit the release of the stress hormone cortisol. You can get an oxytocin infusion by petting your dog, by laughing at the silly things she does, and even by looking into her loving eyes, a conclusion confirmed by recent study
Dogs also offer an alternative to meditation sessions and yoga classes when it comes to learning the Buddhist practice of mindfulness. Every dog walk is typically an exercise in experiencing the present moment: savoring an especially aromatic fire hydrant, having a satisfying roll in the grass or interacting with a new neighbor. Dogs put us more in touch with nature and help us put aside our worries about the future and regrets about the past to focus on the here and now.
While all the information contained in Get Healthy, Get a Dog has been meticulously reviewed and objectively compiled, Moses and Frates are hardly dispassionate observers. Both say their lives have been greatly enriched by their relationships with their dogs. They do, however, come from very different ends of the dog spectrum. Moses, who shares her home with a rescue named Rudy, describes her love of canines as developing “in utero.” This was due largely to the influence of her grandfather and the fact that he treated his Beagle mix, Friday, like one of the grandchildren.
Frates, on the other hand, was terrified of dogs after being bitten on the shoulder by a Doberman. The experience, which happened when she was eight years old, was so traumatizing that she spent the next three decades crossing the street to avoid close contact with a dog, even a little one. Finally, though, it wasn’t any particular dog who changed her mind, it was her commitment to health. As a physician specializing in lifestyle medicine, Frates thought she had all the bases covered—diet, exercise, meditation. But when she took a health and longevity quiz to determine her “real” age (as opposed to her chronological one), she was surprised that one of the questions concerned dog ownership.
Intrigued by the implications, she began to review the existing literature, much of which has been summarized in this special report. She also purchased a Goldendoodle she named Reesee, from a breeder in West Virginia. “Everything has been different for me since then,” Frates says, adding that she and Reesee are regular running buddies. “When we go running, she is so happy and I’m happy because she’s happy. You just appreciate the world in a much different way.”
Frates believes that if something like the Harvard Health Report had been available years ago, she would have explored the joys of dog ownership much sooner. Now, she hopes that the report will encourage other non-dog people to reconsider their position. “We’re hoping to encourage people to take the leap of getting to know a dog,” she says. “And perhaps we’ll also be able to encourage more dog adoptions—that’s a focus that Lisa brought to the project.”
That’s because the nonprofit Angell Animal Medical Center, where Moses works, is part MSPCA, the nation’s second oldest humane society, and has a very active adoption component. (Now that she realizes the situation for homeless dogs, Frates says she would adopt in the future.) Get Healthy, Get a Dog includes a section on “Adopting a Dog,” which provides information on determining the right breed for your home and suggestions on finding breed rescue groups and shelters. It also urges people to stay away from pet stores, where the dogs typically come from puppy mills.
Moses hopes readers will follow the report’s suggestions and reap the amazing benefits of dog ownership.
“Dogs are more important now than ever before,” she says. “Because people are living longer and so many live alone and don’t have kids. This is the moment for the human-animal bond.”
The report is available as a printed document, a PDF or both and can be purchased online at health.harvard.edu/staying-healthy/get-healthy-get-a-dog.
Male dogs, like their human counterparts, can get prostate cancer. Fourteen percent of men will develop this type of cancer, but 99% will survive because of advances in available treatment options. Now clinical trials, performed by Dr. Bill Culp, VMD, DACVS, at the UC Davis Veterinary Medical Teaching Hospital, are investigating similar treatments for dogs. One recent recipient of the innovative procedure is Kopper, a 14-year-old Belgian Malinois from Tennessee. Kopper, who worked to protect his community for the majority of his life, is a retired K-9 officer who was diagnosed with prostate issues by the University of Tennessee’s (UT) veterinary hospital. Veterinarians there were familiar with Dr. Culp’s clinical trial and referred Kopper’s family, Matt and Heather Thompson of Maryville, Tennessee, to UC Davis.
Matt, a corporal with the Blount County (TN) Sheriff's Department K-9 unit, along with Heather, traveled the 2,500 miles to California to see Dr. Culp. The treatment that was administered to Kopper is similar to a procedure in human medicine that has taken hold in the past few years for treatment of non-cancerous prostate enlargement. Known as prostatic transarterial embolization, the treatment is emerging as a minimally invasive alternative to other prostate cancer therapies.
Dr. Culp, along with a colleague who performs similar procedures on humans, Dr. Craig Glaiberman, MD, successfully performed Kopper’s procedure. Luckily, Kopper and his family returned home within a few days. To date, Kopper’s prostate has decreased in size, and he has been doing well. The hope for Kopper and all dogs undergoing this minimally invasive treatment, is that a decrease in tumor size will improve the quality and length of life for dogs with prostate cancer.
Dr. Culp continues this clinical trial. Recruitment of more dogs with naturally occurring prostate cancer is needed to help evaluate the effectiveness of prostatic transarterial embolization as an accepted standard-of-care procedure. To learn more about the trial, please see www.vetmed.ucdavis.edu/clinicaltrials.
News: Guest Posts
Can be toxic to dogs
Often, dogs are the first alert. Their willingness to swim in and drink slimy water makes them sentinels for some of the most powerful natural poisons on earth.
A Labrador Retriever enjoying a family outing in June collapsed after swimming in a Minnesota lake. He died that day at the vet’s office. Tests are pending but the vet suspects the dog was poisoned by cyanobacteria, also known as blue-green algae (BGA).
While most algae are harmless, some species of BGA produce toxins that can kill a dog within minutes. Those that survive, or dogs who are often exposed to low levels of toxins may develop health problems such as chronic liver disease, and possibly tumors; damage that may go unnoticed until it’s severe. Humans can be sickened, too, though deaths are rare.
Dog deaths are another matter.
As health agencies weigh the human risks that lie in recreational and drinking water from harmful algal blooms, they’ve been looking closely at animal deaths.
In New Mexico, 100 elk died last August after drinking water tainted with BGA. When it comes to pets, researchers suspect many deaths are missed because people don’t even realize their dogs were exposed. Vets may not recognize the symptoms, and tests to detect the toxins can be costly and complex.
A study published in 2013 found 368 cases of dogs that died or were sickened by BGA in the U.S. between the late 1920s and 2012. The authors say these “likely represent a small fraction of cases” in the U.S. each year. “The vast majority of BGA associated dog deaths remain unreported and often unrecognized by owners and veterinarians.”
And the cases have surged along with the number of toxic blooms fueled by nutrients such as phosphorous and nitrogen washed into waterways from agriculture, lawns and other sources—and by climate change.
Reports of canine poisonings were sporadic until the mid-1970s, when dog deaths attributed to BGA were reported “almost yearly,” the study notes.
In 2007, as drought plagued much of the country, the Minnesota lake region alone saw as many as 40 cases of canine algae poisoning, and at least four deaths. Since 2001, eleven dog deaths have been blamed on BGA in California’s Humboldt and Mendocino Counties.
The earliest known case in the U.S. was in the late 1920s when a dog swam in California’s Clear Lake during an algal bloom. The dog reportedly became ill after licking “a thick coating of algae” from its fur. In 2013, another dog sickened after playing in the lake was less fortunate... this dog did not survive.
Spotting Blue-Green Algae
There are plenty of clues for telling BGA— the most primitive group of algae—from harmless green, brown, and other kinds. But according to a fact sheet from the Humboldt County Health department, while most BGA blooms don’t produce toxins, only tests can tell. “All blooms should be considered potentially toxic.” Only “a few mouthfuls of algae-contaminated water may result in fatal poisoning.”
For one thing, its color isn’t always blue-green. It can also be reddish-purple or brown, and other hues. And not all blue-green species produce toxins, while the dozens that do are only toxic at certain times. Normally, algae are equally distributed throughout the water. But excess nutrients, heat and drought make for large blooms, followed by large die offs. As it decays, toxins are released. These can still taint the water after it looks clear. Blooms may last for a week; their toxins may last three weeks.
Even when BGA isn’t floating on the surface, it may lurk below, moving up and down with available light and nutrients. At night it often floats to the top, forming scum. So blooms can appear overnight.
Wind and waves can then concentrate toxic blooms in shallow areas or at the water’s edge—right where dogs like to splash, wade or drink. The water doesn’t taste bad, vets say, so dogs will lap it up. Some like to gobble down dried algae mats.
After the sudden death of a dog last July—hours after swimming in an Oregon reservoir—officials issued an alert, as they did in Minnesota. But toxic blooms and dog deaths were nothing new. According to Minnesota Department of Natural Resources, from 2004 through 2007, the state had reports of eight algae-related dog deaths, while toxic blooms are a familiar scourge at the Oregon reservoir.
At least 18 states have monitoring programs to detect harmful blooms. But sometimes, even advisories aren’t enough. After two dogs died within hours of drinking water from a private lake in Nebraska in 2004, state agencies acted quickly. Two weeks later, monitoring and notification networks were in place. But by the end of the recreation season there were reports of three more dog deaths, wildlife and livestock deaths, and more than 50 cases of human effects at Nebraska lakes.
The Environmental Protection Agency hasn’t set national standards for BGA toxins in recreational or drinking water, though scientists and some politicians are calling for them. This summer, the agency is promoting safety and public awareness to help protect dogs and kids.
While most algal blooms just make the water unappealing, an EPA information sheet says, “there are some real risks if dogs swim in, wade, or drink from water” with harmful algal blooms. The toxins “can sicken pets, causing everything from mild eye irritations and diarrhea to extreme health problems, including liver poisoning and even death.”
The EPA recommends that outings with pets to lakes, rivers and streams include an algae check. Dogs should not drink, swim or wade in water that is discolored, smells bad, or where there are mats of algae, foam or scum. If dogs do get into scummy water, rinse it off with tap water immediately, making sure they don’t lick algae from their fur. The toxins can also be absorbed through their skin. If a dog shows signs of poisoning, seek veterinary treatment right away. And report incidents to the Public Health Department. To avoid adding to the algae problem at home, the agency advises not over fertilizing.
According to the study of canine incidents, BGA toxins can be inhaled and ingested, and exposure can induce “acute, sub-acute or chronic poisoning” in animals and people.
Most reported dog deaths involved swimming in or drinking from lakes, rivers and other fresh waters where slime was visible. In California, BGA from freshwater tributaries drained into Monterey Bay, killing sea otters in 2010. Scientists were baffled by the deaths. They hadn’t known the toxins could reach the ocean. One major clue: suspicious dog deaths at a lake tainted with BGA that drains to the sea.
Other dog incidents may have involved beach outings. The study of canine cases says that between 2007 and 2010, at least 8 dogs developed serious or fatal liver disease after visiting Monterey-area beaches. Two of the dogs belonged to local veterinarians, but weren’t tested for the toxin that was killing sea otters.
Blue Green Algae Toxins & Treatment
Are water-loving breeds more at risk? Researchers warn that diagnosing algae poisoning is hard enough—such assumptions can lead to the wrong diagnosis. But the study did find that the most incidents involved Labrador Retrievers.
However, the “wide range” of affected dogs included Poodles, Dachshunds and toy breeds, which also encountered BGA in urban and residential water bodies. These waters, often shallow and stagnant in warmer months, can have high levels of nutrients escaped from nearby yards and gardens, “providing ideal conditions for toxic blooms.”
The belief that small dogs or urban-dwelling dogs don’t encounter algae may influence the diagnoses considered. Also adding to the problem of detection and treatment, the study claims: the tests are expensive and can take weeks, access to testing may be limited, and diagnosis may not be a priority for the owner after the dog has died.
According to an algae fact sheet from Humboldt County health department, the toxins of concern are nervous system poisons (neurotoxins) and liver poisons (hepatotoxins). The neurotoxins can kill animals within minutes by paralyzing respiratory muscles, while hepatotoxins can cause death within hours by causing blood to pool in the liver.
The canine study mentions the many reports of animals drinking algae-tainted water “and dying within hours from neurotoxicity or hepatotoxicity, or developing sublethal chronic liver disease.”
Another less dangerous compound causes allergic responses. But initial, low-level exposure to any of these toxins may cause skin irritation and stomach upset, the study says. So those symptoms alone may not help identify the toxin.
Both nervous system toxins and liver toxins can be fatal. Liver toxins cause weakness, vomiting, pale mucous membranes and diarrhea. Common signs of neurotoxins are muscle tremors, seizures, labored breathing and difficulty moving.
Often implicated in poisonings are anatoxins (neurotoxins) and microcystins (liver toxins, considered more common and possibly carcinogenic, research suggests). Dogs are especially susceptible to anatoxins, according to the North Carolina Department of Health’s website; these poisons can be fatal within minutes – or hours. Quick veterinary care with anti-seizure medication and oxygen may help.
The consensus is that there is no antidote for BGA toxins. But the review of dog poisonings says that most exposed animals aren’t given specific treatment, even though “simple, cost-effective treatments may improve their chances.” In the case of microcystin exposure, since many believe that no therapies exist, owners and vets “might euthanize suspect cases or provide limited supportive care.”
After several days of veterinary treatment, a Miniature Australian shepherd sickened by algae at a Montana lake was only getting worse. On the fifth day, her vets tried a new therapy not readily available. Last year, a report described what happened next as possibly the “first successful treatment of microcystin poisoning.”
Over the next few days the little Aussie made a surprising comeback.
After eight long days, that dog went home.
News: Karen B. London
What do you want to know about dogs?
What’s hot on the research frontier can change quickly. Years ago in the environmental world, acid rain was all the rage, then it was mercury pollution and now big bucks are going to fund issues related to climate change. In the animal behavior world, copious studies on foraging behavior gave way to the popularity of parasitism, followed by a fascination with sexual selection and mating strategies.
Right now, studies of domestic animals, including dogs, are big, and a variety of topics are hot within the canine research community. I would love to see the funding that supports this research continue, and I think that will happen if people continue to see the value of the research. We’re learning about our best friends at a faster rate than ever, and it’s an exciting time to be interested in dogs.
Canine cognition research is a hugely popular area of study right now, as is the role of oxytocin in a variety of canine social behaviors. Interactions with people and the way dogs’ brains respond to various stimuli have also both been studied a lot lately. Play behavior has been popular for quite a long time, though we are perhaps past the main peak of the wave of studies on this topic for now. Receiving far less attention are some other areas of dog behavior. It’s currently far less common to study courtship and mating behavior, communication, aggression or feeding strategies.
Where would you like to see the studies of dogs go next? That is, what questions do you want answered in order to understand dogs better?
News: Karen B. London
It bonds people and dogs
You gaze into your dog’s eyes. Your dog gazes back at you. It’s true love, right? Yes, absolutely! And it’s not just any kind of love, but perhaps one of the most powerful kinds of love that exists—the love between mother and child.
So says a new study published in the prestigious journal Science called ”Oxytocin-gaze positive loop and the co-evolution of human-dog bonds.” This research provides evidence that our feelings of love for dogs are mutual and are in part a result of looking into one another’s eyes, just like mothers and babies do to form their strong attachment.
In humans, it has been shown that mothers who spend more time in mutual gazing with their babies have higher levels of oxytocin. (Oxytocin is a hormone that plays a large role in the formation of social bonds as well as feelings of love.) Additionally, there is a positive feedback loop in humans. Mothers with higher oxytocin levels engage in more mothering behavior, which affects oxytocin levels in their babies. That in turn leads to higher levels of attachment, which increases oxytocin levels in mothers, leading to more maternal behavior, and so on.
The purpose of this new research was to investigate whether humans and dogs also have a positive-feedback loop in which oxytocin plays a role, and if so to learn whether gazing is a part of the process. In one part of the study, researchers measured levels of oxytocin in the urine of people and their dogs both before and after they interacted. They found that in pairs in which the dogs gazed at their guardians for a long time, levels of oxytocin rose in both the people and the dogs.
In the second part of the study, experimenters examined whether giving oxytocin to dogs affected their gazing behavior or the oxytocin levels of their guardians. Researchers gave oxytocin to dogs (intranasally) and observed that female dogs given this chemical gazed at their owners for longer periods of time than female dogs given saline as a control. (It didn’t affect male dogs the same way.) Even though they were not given oxytocin, guardians’ levels of this hormone increased after interacting with female dogs who had received it. Researchers are not sure why the behavior of female, but not male, dogs was affected by the oxytocin.
This research suggests that the bond we feel with our dogs is not only similar to the bond between mothers and children, but that the mechanism behind the connection is the same. This type of attachment between different species is rare and continues to interest scientists and dog lovers alike. It’s possible that the process of domestication of the dog was possible in part because dogs co-opted the social communication and social bonding process of babies.
Do you feel the love when you and your dog gaze into one another’s eyes?
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