Category Archives: research

Quantifying Cognitive Decline in Dogs Could Help Humans With Alzheimer’s Disease

Researchers have found that a suite of complementary tests can quantify changes in dogs suspected of suffering from cognitive decline. The approach could not only aid owners in managing their elderly canine’s care, but could also serve as a model for evaluating cognitive decline progression in – and treatments for – humans with Alzheimer’s disease.

Photo by Ken Reid on Unsplash

Canine cognitive dysfunction syndrome (CCDS) is similar to Alzheimer’s disease in humans in that cognitive decline is associated with the development of amyloid plaques as well as cortical atrophy, a progressive degeneration of brain tissue. CCDS is also challenging to diagnose. Traditionally, CCDS is diagnosed based on ruling out any obvious physical conditions and an owner’s answers to a questionnaire.

“One problem with the current approach is that questionnaires only capture a constellation of home behaviors,” says Natasha Olby, the Dr. Kady M. Gjessing and Rahna M. Davidson Distinguished Chair in Gerontology at North Carolina State University and co-senior author of a paper describing the work. “There can be other reasons for what an owner may perceive as cognitive decline – anything from an undiagnosed infection to a brain tumor.”

Olby and co-senior author Margaret Gruen, assistant professor of behavioral medicine at NC State, wanted to determine whether cognitive function could be accurately quantified in dogs.

“Our goal was to bring together multiple tools in order to get a more complete picture of how CCDS presents in dogs,” Gruen says.

To that end, the researchers recruited 39 dogs from 15 breeds. All of them were in the senior and geriatric age range, but in good health overall. A dog is considered “senior” if it is in the last 25% of its expected life span based on breed and size, and geriatric beyond that.

The dogs underwent physical and orthopedic exams, as well as lab work that included a blood test that is a marker of neuronal death. Their owners filled out two commonly used diagnostic questionnaires, and then the dogs participated in a series of cognitive tests designed to assess executive function, memory and attention.

“The approach we took isn’t necessarily designed to be diagnostic; instead, we want to use these tools to be able to identify dogs at an early stage and be able to follow them as the disease progresses, quantifying the changes,” Olby says.

The team found that cognitive and blood test results correlated well with the questionnaire scores, suggesting that a multi-dimensional approach can be used to quantify cognitive decline in aging dogs.

“Being able to diagnose and quantify CCDS in a way that is clinically safe and relevant is a good first step toward being able to work with dogs as a model for Alzheimer’s disease in humans,” Olby says. “Many of the current models of Alzheimers disease – in rodents, for example – are good for understanding physiological changes, but not for testing treatments.”

“Dogs live in our homes and develop naturally occurring disease just like we do,” Gruen says. “These findings show promise for both dogs and humans in terms of improving our understanding of disease progression as well as for potentially testing treatments.”

The work appears in the Journal of Alzheimer’s Disease. NC State postdoctoral fellows Gilad Fefer and Wojciech K. Panek are co-first authors of the work.

Source: NC State News

Most US dog owners don’t follow FDA pet food handling guidelines

A new analysis suggests that most U.S. dog owners are unaware of—and do not follow—guidelines on safe pet food and dish handling from the Food and Drug Administration (FDA), but that better education and implementation of the guidelines could reduce contamination. Dr. Emily Luisana of North Carolina State University in Raleigh and colleagues present these findings in the open-access journal PLOS ONE on April 6, 2022.

Study mascot, Sally Star, at North Carolina State University College of Veterinary Medicine. Photo credit: Emily Luisana, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Pet food and dish handling involves potential health risks for both dogs and people, especially those with compromised immune systems. Multiple outbreaks of bacterial illness among dogs and humans have occurred as a result of contaminated dog food. The FDA has issued guidelines on protocols for safe pet food and dish handling, available online, but the information is limited, and the effects of the recommendations have been unclear.

To help clarify, Dr. Luisana and colleagues surveyed 417 dog owners. They found that less than 5 percent were aware of the guidelines, and many owners did not follow many of the recommendations. For instance, only one third reported washing their hands after feeding, and only two thirds reported preparing dog food on separate surfaces from those used for human food. The latter fact is of potential public health importance, but is not addressed in the FDA recommendations.

To better understand the effects of the FDA recommendations, the researchers tested 68 household dog food dishes for bacterial contamination. After initial testing, they divided the owners into three groups with different instructions for implementing food handling guidelines, then tested the dishes again after 1 week. They found significantly reduced contamination of dishes from owners who instituted the FDA’s pet food handling guidelines, either alone or in combination with the FDA’s human food handling protocol, versus dishes from owners who were not asked to implement either protocol.

The researchers note that their study was small and that future research could clarify optimal hygiene strategies and ways to communicate them.

Nonetheless, on the basis of their findings, the researchers outline suggestions to reduce contamination in pet food dishes for owners, veterinarians, pet food sellers and manufacturers. These include ensuring household members who feed pets adhere to FDA guidelines and including written information on guidelines with pet food sales.

The authors add: “Most pet owners are unaware that pet food bowls can be a hidden source of bacteria in the household. Knowing how to mitigate this risk and practice proper pet food storage and hygiene may make for a happier, healthier household.”

To access the journal article in PLOS ONE: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0259478  

FDA’s Tips for Safe Handling of Pet Food and Treats

Source: EurekAlert!

Cannabis poisoning cases in pets have increased significantly, study finds

A survey of veterinarians in the U.S. and Canada highlights mounting cases of cannabis poisoning among pets and sheds new light on symptoms, treatments, and outcomes. Richard Quansah Amissah of the Ontario Veterinary College at the University of Guelph in Ontario, Canada, and colleagues present these findings in the open-access journal PLOS ONE on April 20, 2022.

Pets that are exposed to cannabis, most often by ingestion, may experience symptoms of cannabis poisoning — also known as cannabis-induced toxicosis — with varying degrees of severity. While prior evidence suggests that cases of cannabis poisoning among pets are increasing, the actual magnitude of the problem, including typical outcomes for pets, has been unclear.

To improve understanding of cannabis poisoning in pets, Amissah and colleagues analyzed survey data from 251 veterinarians based in Canada or the U.S. Conducted in 2021; the survey included questions about cannabis poisoning cases encountered by participants over several previous years.

Statistical analysis of the survey responses showed that the number of cannabis poisoning cases jumped significantly in both the U.S. and Canada following the 2018 legalization of cannabis in Canada. Unattended ingestion of cannabis edibles was the most frequent cause of poisoning, but it was unclear what proportion of cannabis products had been obtained for human consumption versus medicinal consumption by pets. The authors note that the post-legalization boost could be explained by increased cannabis use, but that increased reporting may have contributed as well.

Cannabis poisoning was most frequently seen in dogs, but cases were also reported in cats, iguanas, ferrets, horses, and cockatoos. While most cases were benign, observed symptoms — seen primarily in dogs — included urinary incontinence, disorientation, and abnormally slow heart rate. Most animals were treated with outpatient monitoring, and nearly all animals recovered completely.

In a small number of cases, veterinarians reported that pets had died due to cannabis poisoning, though the researchers note that other potential causes, such as underlying conditions, could not be ruled out in the study. With use of cannabis products continuing to rise, they call for additional research into the effects of cannabis on pets to help inform veterinary efforts and policies to keep pets healthy.

The authors add: “This is an important topic to study in the light of recent legalization of cannabis in Canada and across multiple states. In order to understand the mechanisms underlying cannabis-induced toxicosis in pets, and to develop treatments for it, we need to first understand what it looks like; this is what we had hoped to accomplish with this survey, and believe that these findings will help us get a better handle on this under-studied topic.”

Journal reference: Prevalence and characteristics of cannabis-induced toxicoses in pets: Results from a survey of veterinarians in North America

Cortisol in shelter dog hair shows signs of stress

In the Netherlands, thousands of dogs stay in a shelter every year. Despite the good care, a shelter can be a stressful environment for dogs. Researchers at Utrecht University investigated if the amount of the hormone cortisol in hair indicates the levels of stress that dogs experience before, during and after their stay in the shelter.

There is no difference between the cortisol levels of dogs when they enter the shelter and the control group of domestic dogs. After six weeks in the shelter, cortisol levels in the hair appear to have increased by one-third (on average from 16 pg/mg to 21.8 pg/mg). In measurements six weeks and six months after adoption, cortisol levels lowered, moving in the direction of the values at admission to the shelter. The results were published in the scientific journal Scientific Reports on 21 April 2022.

Cortisol in hair

The stress hormone cortisol accumulates in hair, in humans but also in animals. By measuring cortisol levels in hair, researchers can get an idea of the stress response and recovery over weeks or months – depending on the length of the hair examined. This technique has been used extensively in humans and other species, and some fifteen scientific studies have been carried out in dogs so far.

“In addition to the cortisol measurements in hair, we also measured cortisol values in the dogs’ urine. This gives a short-term picture while the hair measurements show the long term”, researcher Janneke van der Laan explains.

To the shelter every day

The researchers examined hair of 52 shelter dogs at four moments: just before admission, after six weeks in the shelter, six weeks after adoption and six months after adoption. They compared the cortisol values before admission with those of twenty domestic dogs, which were similar in terms of breed, age and sex. 

Van der Laan: “We took daily measurements in the shelter for over a year. After adoption, the new owners – after clear instructions – cut the dogs hair and sent it to us. They were helpful and enthusiastic, and were very interested in what their dog had experienced before adoption.” 
 

For the cortisol measurements, hair from the same location on the body was used every time. The researchers shaved the area and allowed new hair to grow during the period in which they wanted to measure the stress hormones. This is called a ‘shave-reshave method’. 

More cortisol in small dogs

A surprising result is that smaller dogs generally have higher cortisol levels than larger dogs. “We have also seen this pattern in previous studies, for example in a study on the resting pattern of shelter dogs. We don’t have a clear hypothesis about why that is, but it is interesting and is an area of focus for future research.”

Well-being in shelter

All the examined shelter dogs were in the same shelter, the largest in the Netherlands. Of course there are significant differences between shelters, not only within the Netherlands but also internationally. In The Netherlands, dogs are usually kept individually, while in other countries they are often kept in groups. 

“We know that a shelter is not a stress-free environment for dogs, even though staff members do their best to achieve the highest possible welfare,” Van der Laan says. “Even if you organise a shelter in the best possible way, there are still stress factors, such as crowds of other dogs and not being able to go outside as often as usual. And most important: the dog is gone from their old, familiar environment.”

The shelter in this study has a pioneering role in improving the welfare of dogs: they use glass walls instead of bars to reduce noise pollution for the dogs, for example. “The fact that we measured an increased amount of cortisol even in this shelter, suggests that this will also be the case in other shelters,” Van Der Laan said.

Source: Utrecht University

DCM Report: Incidence Rate Shows No Correlation to Grain-Free Growth

Veterinarians and scientists from BSM Partners, the largest pet care research and consulting firm, and the University of Missouri, published an analysis of a retrospective survey that evaluated the annual incidence of canine dilated cardiomyopathy (DCM) diagnosed by veterinary cardiologists across the United States, along with previously unknown information regarding the growth of grain-free pet food store sales.

The peer-reviewed article, which appears in Frontiers in Animal Science, includes data that did not indicate a significant increase nationally in DCM incidence over time, from 2000 to 2019, while grain-free pet food store sales grew 500 percent between 2011 and 2019. Researchers also found no significant correlation between the national DCM incidence rate in relation to the grain-free pet food sales.

Researchers received information on more than 68,000 total canine cardiology cases from veterinary cardiology referral hospitals, diagnosed between 2000 and 2019. The average incidence rate of DCM, amongst these referral cases seen in participating hospitals during the survey period, was 3.9 percent (range 2.53-5.65 percent). They also analyzed data regarding grain-free pet food store sales provided by the Nielsen Company, which showed a 500 percent increase in sales from 2011 to 2019.

“Based on the data we received from veterinary cardiologists across the United States, we did not observe a significant increase in DCM incidence rate over time, which included the recent period when grain-free pet food sales grew exponentially,” said Dr. Stephanie Clark, PhD, CVT, PAS, CFS, Dpl. ACAS of BSM Partners, an article co-author and a board-certified companion animal nutritionist. “The existing scientific literature indicates that nutritional factors can lead to the development of DCM, but we did not find a correlation in the DCM incidence rate to grain-free pet food sales.”

Dr. Stacey Leach DVM, DACVIM, an article co-author, and Chief of Cardiology and Associate Teaching Professor of Cardiology at the University of Missouri’s Veterinary Health Center, noted the following: “This work is unique because we only examined cases of canine DCM diagnosed by veterinary cardiologists and is a significant addition to our understanding of DCM.”

BSM Partners is the largest full-service pet care research, consulting and strategy-to-shelf product innovation firm. BSM Partners’ research professionals collaborate with hundreds of clients ranging from the largest companies to the smallest upstart companies to formulate, review and advise on the development of hundreds of new products each year, including grain-free and grain-inclusive dog foods, treats, and supplements.

Read the journal article here.

Source: Pet Age

Dogs can get a canine form of dementia — and it is very similar to the human version

If you have ever been close with a dog, the chances are that you have wondered what your canine companion might be thinking. As time goes on and your relationship grows — whether as a primary owner, a family member or an occasional visitor — you will probably ask yourself if the dog remembers you. Like our human friends and family, we would like to think that, even if we are not in the room, dogs still think about us.

Beagle Lies On The Floor In The House (Getty Images / Aleksandr Pobeda / EyeEm)

Scientists agree dogs are intelligent, emotional and capable of forming lasting relationships with humans. While there is robust debate about the extent to which this is true, animals like Bunny the “talking” sheepadoodle are able to communicate in such a sophisticated manner that they will even discuss their dreams.

The bad news is that, just like humans, dogs can develop degenerative nerve diseases which damage their minds. One illness in particular has a direct analogue in dogs: Alzheimer’s disease. Dogs, sadly, can develop a similar condition — and tragically, that might mean that your dog could suffer some of the same sad Alzheimer’s-like conditions, such as forgetting its close family, in its final days.

“Canine Cognitive Dysfunction [CCD] mirrors two key components of Alzheimer’s disease in humans,” Dr. Silvan Urfer of the Dog Aging Project and the University of Washington told Salon by email. It comes down to a peptide and a protein that will suddenly accumulate in your brain: Amyloid-beta 42 and hyperphosphorylated Tau (pTau). “While there are likely a few differences regarding the details of pTau pathology in particular, it is fair to say that CCD is the dog analog of Alzheimer’s Disease,” Urfer noted.

Dr. Elizabeth Head, a professor in the Department of Pathology & Laboratory Medicine at the University of California, Irvine, told Salon in writing that in addition to developing these beta-amyloid plaques — one of the hallmark features of Alzheimer disease — the dogs also suffer like humans, in that neurons die. The synapses, or connections between neurons, are lost, and these are observed in humans who as they age suffer from cognitive decline.

“From a psychological perspective dogs may show signs of disrupted sleep patterns (e.g. up pacing at night), more vocalizing, [being unable to] remember how to signal to go out and may have trouble recognizing family members,” Head explained. “This can lead to more anxiety. From a physical perspective, there may be more episodes of incontinence but oftentimes other physical problems are ruled out with the CCD diagnosis (e.g. deafness, blindness, systemic illness).”

Indeed, the similarities between CCD and human dementia are so striking that researchers believe man’s best friend could actually help him find a cure for the debilitating ailment. There is a nationwide study known as The Dog Aging Project — which was launched by Cornell University, the University of Washington and the University of Arizona and funded by the National Institute on Aging — which exists precisely because scientists are intrigued by those similarities. They believe that learning more about how to help dogs with the condition can, in the process, provide research data that helps fight human diseases related to senescence.

“What we’re trying to do is find a better understanding of the disease in dogs and translate those findings to humans,” Dr. Marta Castelhano, director of the Cornell Veterinary Biobank and one of the involved scientists, told Cornell News at the time.

Until a cure for CCD exists, the sad reality is that dogs and humans alike who experience cognitive decline will be left to manage their symptoms to the best of their ability. When speaking with Salon, Urfer stressed that he is “not providing veterinary advice on individual dogs, as there is no vet-patient-client relationship here.” People who are concerned about their dogs should consult a veterinarian. What we do know for sure, however, is that causal treatments do not exist for CCD. All we know is that there are certain physical characteristics that make dogs more or less likely to be at risk.

“We know that bigger dogs have a lower risk of developing CCD than small dogs, and there is also some evidence that intact males have a lower CCD risk than neutered males, and that existing CCD progresses faster in neutered than in intact males,” Urfer explained. “This is interesting in that it also mirrors findings from human medicine that taller people are less likely to get Alzheimer’s disease, and that men who undergo anti-androgen treatment for prostate cancer have an increased Alzheimer’s disease risk.”

If your dog is healthy now, then the best thing to do is make sure they stay healthy. That can prevent CCD from developing. It is the exact same as the approach for homo sapiens.

“The best approach is always prevention – ensure good physical health (e.g. keep up with dentals), exercise, lots of social and cognitive enrichment, and a good diet, manage co-occuring conditions (e.g. obesity)  – just like for people!” Head told Salon.

Source: Salon.com

Affection from a dog really is medicinal, according to a new study

Dogs may also be a doctor’s best friend.

For patients suffering from pain in the emergency room, just 10 minutes with a four-legged friend may help reduce pain, according to a study published Wednesday.

The results support what dog lovers everywhere have long suspected — canine affection cures all ills — as well as provides a bit of optimism for patients and health care providers frequently grappling with strapped hospital resources in the midst of the Covid-19 pandemic.

“There is research showing that pets are an important part of our health in different ways. They motivate us, they get us up, (give us) routines, the human-animal bond,” said lead study author Colleen Dell, the research chair in One Health and Wellness and professor at the University of Saskatchewan.

The study, published in the journal PLOS One, asked more than 200 patients in the emergency room to report their level of pain on a scale from 1 to 10 (with 10 as the highest level of pain). A control group had no intervention for their pain, while participants in the other group were given 10 minutes of time with a therapy dog, and patients rated their pain levels again, according to the study.

Those who got the visit from the dogs reported less pain.

The study has a strong methodology, said Jessica Chubak, senior investigator with the Kaiser Permanente Washington Health Research Institute. Chubak, who was not involved with the study, noted that there is still a lot to learn about therapy dogs.

“The results of the study are promising,” she said in an email. “Our current understanding of the effects of therapy dog visits in emergency department settings is fairly limited. So, it is particularly important to have more research in this area.”

Dell hopes that research like this study means we can stop asking if therapy dogs are helpful in a medical context and start asking how they help and how to integrate them better with health care teams.

In the hospital

The emergency room experience might actually contribute to patients’ pain.

The bright lights, long waits, anxiety and focus on immediate, acute conditions can make the feeling worse, said Erin Beckwell, a dog owner who has experienced chronic pain for much of her life.

“It’s not a place that you usually get escorted to a comfy room that’s quiet and gives us any sort of specific interventions,” she said. “It’s often suggestions of things you’ve already tried, and then they send you home after a long time of distressing and anxiety-provoking, pain-filled waiting.

You may not come out feeling like you were even really heard.”

Some people have a misperception that utilizing therapy dogs can transmit disease and risk hygiene in a hospital setting, but Dell said there are ways health care providers can utilize them in sanitary ways to make the whole system operate better.

Mike MacFadden, a nurse practitioner based in Canada, said he sees a lot of potential in incorporating therapy dogs as part of a holistic approach to pain treatment in the emergency room, and that it could help everyone involved.

“Emergency service teams can feel conflicted and experience moral distress resulting from their inability to meet their own expectations for optimal care. With people’s experience of pain being multifaceted, we know that a multifacetedapproach is most beneficial to meet the needs of patients,” McFadden said. “The presence of a therapy dog not only has the benefits of supporting the patient’s experience, but I think it also serves as a comfort to the care providers.”

Hunter, a therapy dog, and his handler, Amanda Woelk, sit with Tyler Regier, 2, and his mother, Tina Regier, both of Overland Park, Kan., on Oct. 2, 2015, at Children’s Mercy Hospital in Kansas City, Mo. (Allison Long/Kansas City Star/TNS)

In the home

Pain can be thought of as both a physical and social experience, said Michelle Gagnon, assistant professor of psychology and health studies at the University of Saskatchewan. Gagnon was not involved with the study.

Anxiety, depression, having support or being dismissed can all have an impact on how we experience pain, she said. It makes sense that spending time with a creature that brings you joy and doesn’t invalidate your feelings can help you feel better.

“The things that you can gain from pets and some of the positive emotions that could be elicited from having the pet around you I think could have an impact on the pain experience itself,” she said.

Beckwell said she has experienced it personally with her 10-year-old cocker spaniel, Reilly, as she has experienced arthritis and autoimmune disorders.

“I feel more in control of the situation and less panicked or anxious about the severity of my pain, the duration of my pain, those sorts of things when I have that unconditional support from my dog,” Beckwell said. “She will come in, and she has learned over the years when I’m in pain she can’t sit on my lap.

“I don’t need to tell her — she knows,” Beckwell said.

Source: CNN

Core strength could help dogs avoid knee injuries

Photo by Angel Luciano on UnSplash

Agility dogs lacking core strength from routine physical exercise and those participating in activities like flyball may be more susceptible to one of the most common canine knee injuries.

That knee injury is a cranial cruciate ligament rupture, which is equivalent to an anterior cruciate ligament (ACL) tear in humans.

According to a research survey documenting activity and injury odds of more than 1,200 agility dogs, just about any physical exercise seems to lower the risk of rupturing the ligament, but some exercises seem to increase the risk. In addition, the size and shape of the dog — and thereby certain breeds — were also found to be at higher risk.

“Balance exercises, wobble boards, anything that improves the core strength of the dog seemed to lower the odds of a ligament tear,” said Deb Sellon, a Washington State University veterinarian and lead author on the study published in BMC Veterinary Research. “We found fitness matters for dogs just like it does for people, and we haven’t shown that before.”

Sellon is also the founder of the university’s Agility Dog Health Network, which was accessed in the study. By using odds ratios, which is essentially a statistical risk assessment, Sellon and Denis Marcellin-Little, a veterinary orthopedic specialist with University of California, Davis, looked for trends in 1,262 agility dogs — 260 that tore the ligament and 1,002 dogs that did not.

In addition to balance and core strengthening exercises activities like dock diving, barn hunt and scent work are associated with a decreased rate of ligament rupture, too.

While regular activity, like swimming, playing fetch or frisbee, walking or running didn’t increase the risk of injury, it didn’t lower the odds either.

Surprisingly, dogs that competed more frequently in agility events and competed at a higher level on more technically rigorous types of courses were less likely to rupture their cruciate ligaments.

The only physical activities that increased the odds of injury were short walks or runs over hilly or flat terrain on a weekly basis, and many of those injuries were in dogs early in their agility career that lacked core strength from routine physical exercise or at times, rest days.

Training or competing in the new and popular dog sport flyball was found to be the riskiest activity of all activities evaluated in the survey. Agility dogs that also engaged in the sport of flyball were nearly twice as likely to rupture the ligament as compared to other dogs. Nearly 12% of dogs reported to play flyball ruptured the ligament.

The survey confirmed some long-standing and well-accepted risk factors as well. In particular, female dogs spayed before the age of one were almost twice as likely to rupture the ligament compared to dogs that were spayed after their first birthday. Sellon said this is believed to reflect the importance of hormones in developing strong ligaments in young animals.

Trends were also identified among certain breeds.

Survey results indicated Australian shepherds and Labrador retrievers were more than twice as likely to rupture the ligament. Rottweilers and Australian cattle dogs were more than four times as likely to tear the ligament.

Marcellin-Little speculates that could have something to do with the shape of the dog, and maybe its tail.

“Larger dogs doing agility tend to be less balanced, so it is not surprising a Rottweiler or Australian Shepherd may be at a higher risk of a rupture compared to smaller breeds,” he said. “The tail could also be a factor; the tail has been proven very important for cheetahs and you can imagine it has a role to play in the overall balance of the dog.”

Marcellin-Little said there is still a great deal of research that needs to be completed, but the survey gives veterinarians a place to start. 

“This research decreases uncertainty; it doesn’t bring certainty, but this one study could provoke thoughts and help us look at potential research areas to target moving forward,” he said. “That is the type of research that the Agility Dog Health Network is planning to support.”

Source: Washington State University

Dog faeces and urine could be harming nature reserves, according to new study

New research finds that dogs being walked in nature reserves contribute a significant amount of nutrients to the environment through their faeces and urine, which researchers warn could negatively impact local biodiversity. The research is published in the British Ecological Society journal, Ecological Solutions and Evidence.

Sign prohibiting dogs at one of the nature reserves. Credit: Pieter De Frenne

Significant levels of fertilisation

Researchers at Ghent University have estimated that each year dog faeces and urine add an average of 11kg of nitrogen and 5kg of phosphorous per hectare to nature reserves near the Belgian city of Ghent. The researchers say that the nutrients added through this neglected form of fertilisation are substantial and could be detrimental to biodiversity and ecosystem functioning.

The estimates for the amount of nitrogen being added by this previously unrecorded source are particularly significant when compared to the total levels of nitrogen being added across most of Europe through fossil fuel emissions and agriculture, which range from 5 to 25kg of nitrogen per hectare.

Professor Pieter De Frenne of Ghent University and lead author of the research said: “We were surprised by how high nutrient inputs from dogs could be. Atmospheric nitrogen inputs from agriculture, industry and traffic rightfully receive a lot of policy attention, but dogs are entirely neglected in this respect.

The researchers call for land managers, especially in low nutrient ecosystems, to emphasise the negative fertilisation effects of dogs to visitors, encouraging them to remove their dogs’ faeces. They also call for leash use to be enforced more stringently and the establishment of more off-leash dog parks to reduce the pressure on nature reserves.

Dogs on leashes and owners removing faeces have big impacts

In the experiment, which calculated the amount of nutrients dogs were adding to the environment by recording the number of dogs present in four nature reserves, the researchers modelled different scenarios including if the dogs were on or off leashes and if owners picked up dog faeces.

When the researchers modelled a scenario where all dogs were kept on leashes (legally required in all these reserves) they found that this reduced the fertilisation rates in the largest part of the reserves but strongly increased fertilisation rates in the small areas around paths. Over a year this input was as high as 175 kg of nitrogen and 73 kg of phosphorus per hectare.

Professor De Frenne said: “In our scenario where all dogs were kept on leashes, we found that in these concentrated areas around paths, nutrient inputs of both nitrogen and phosphorus exceeded legal limits for fertilization of agricultural land. Which is quite staggering as our study concerned nature reserves!”

In a scenario where dogs were on leashes, but all owners picked up their dogs’ faeces, the researchers found that this reduced fertilisation levels by 56% for nitrogen and 97% for phosphorus. This is due to dog faeces accounting for nearly all phosphorous being deposited whereas nitrogen is deposited equally by both faeces and urine.

Dog being walked on lead
In models where all dogs were kept on leashes, the researchers found that this reduced fertilisation rates in most of the reserves but strongly increased fertilisation rates in the areas around paths.

Increased nutrients a problem for nature reserves

The addition of nutrients to nature reserves might sound beneficial as these lead to increased plant growth, however, this mostly occurs in a limited number of nutrient demanding species that outcompete rarer specialists, reducing biodiversity.

“In many nature reserves, the management is specifically directed towards lowering soil nutrient levels to enhance plant and animal biodiversity. This can be done through methods like mowing and hay removal.” Explains Professor De Frenne. “Our findings suggest that the currently neglected inputs of dogs in nature reserves could delay restoration goals.”

Calculating nutrient levels

To estimate the amount of nutrients dogs were adding to the environment, the researchers first calculated dog abundance per hectare, per year, by counting dogs in four nature reserves close to the city of Ghent, Belgium. These counts were performed on 487 occasions over 18 months. They then performed a literature search of nutrient concentrations in dog urine and faeces to model different scenarios.

While this method meant that researchers could accurately calculate the abundance of dogs in the nature reserves, estimations had to be made based on the average dog and average volumes of urine and mass of faeces, as well as estimates of nitrogen and phosphorus concentrations.

The researchers say that their data could be improved by recording breeds of dogs, as well as their size, weight and the number of urine and faecal deposits, for instance, by asking owners. The researchers also suggest that georeferencing dog faeces and urine locations could further help to detect fertilisation ‘hot spots’.

Source: British Ecological Society

Paw hygiene no reason to ban assistance dogs from hospitals

Over 10,000 people in Europe use an assistance dog; think of guide dogs for the blind and visually impaired, hearing or signal dogs for the deaf and hard of hearing, medical response dogs and psychiatric service dogs.

Assistance dog user Iris and her dog Sandy in the recovery room after surgery. After a severe epileptic seizure, Iris was not doing well and Sandy was brought to the hospital in the hopes she could help improve Iris’ condition, which was indeed the case. Sandy even accompanied Iris to the OR, where Iris had to undergo a major surgery. One year earlier, bringing Sandy along was not negotiable in this particular hospital. Photo: private photo of Iris and Sandy.

According to European law, these dogs are welcome in stores, hospitals and other public places. However, in practice, many assistance dog users and their dogs are regularly refused entry. In the Netherlands, four out of five assistance dog users indicate that they regularly experience problems with this.

Often, hygiene reasons are given as the main argument for refusing entry to assistance dogs. Research by Utrecht University now shows that the paws of assistance dogs are cleaner than the shoe soles of their users, and thus, paw hygiene is no reason to ban assistance dogs from hospitals.

To investigate this, Jasmijn Vos, Joris Wijnker and Paul Overgaauw of Utrecht University’s Faculty of Veterinary Medicine took samples from the paws of 50 assistance dogs and the shoe soles of their users. For comparison, they also investigated an equally large group of pet dogs and their owners. Vos and her colleagues examined the samples for poop bacteria (Enterobacteriaceae), which are very common outdoors, and for an important diarrhoeal bacteria (Clostridium difficile).

“The dogs’ paws turned out to be cleaner than the soles of their shoes,” says Jasmijn Vos, Masters student at Utrecht University. “This makes the hygiene argument that is often used to ban assistance dogs from public locations invalid.” Moreover, the diarrhoeal bacteria did not occur on the dogs’ paws whatsoever, and only once on a shoe sole.

81% of assistance dogs are refused

Dutch assistance dog users were also surveyed about their experiences. 81% are still regularly refused entry to public places with their dog, even though this is prohibited by law. This is mainly down to lack of knowledge on the part of the person refusing entry: lack of knowledge on what an assistance dog is, how it can be recognised, and about the rules of law.

The study also shows that assistance dog users constitute only a small fraction of the total number of patients in Dutch hospitals. Should they decide to bring their assistance dog to the hospital, or elsewhere, this should be made possible; assistance dogs are usually well behaved and are no more of a hygiene hazard than people!

Research publication
Vos SJ, Wijnker JJ, Overgaauw PAM. A pilot study on the contamination of assistance dogs’ paws and their users’ shoe soles in relation to admittance to hospitals and (in)visible disability. Int. J. Environ. Res. Public Health. 2021; 18(2): 513.
Full text: https://www.mdpi.com/1660-4601/18/2/513

Source: Utrecht University