Wellness: Healthy Living
Arizona genetics researchers are taking the unusual step of asking for dog lovers’ help in fighting a mysterious, potentially lethal infection that plagues both dog and man.
They are looking for dogs to be registered and potentially to have their DNA collected to help combat valley fever, a fungus-based disease once confined to the Southwest desert but is now spreading across the country.
Valley fever can be triggered by inhalation of just a handful of spores of a particular fungus. People, dogs and cats are susceptible to the illness that was once believed to occur only in Arizona and California. The disease is not contagious and is not spread from species to species.
The risk for valley fever increases as climates get drier, say California State University, Bakersfield researchers. Warmer temperatures and less rain basically kill off the fungus’ competitors for nutrients and thereby creating an ideal growing environment for the infection-causing fungus.
Valley fever is now being reported in states such as Michigan, Ohio and Minnesota, which never used to see the condition. And the states that typically see the condition are reporting more and more cases: The number of Valley Fever reports is increasing in more than a third of California’s counties, putting more dogs at risk for a disease that can lead to lameness, extreme weight loss and coma.
When Charlie, a 75-pound Chocolate Lab, started coughing, it didn’t set off any alarms. But then he developed a fever and was diagnosed as having kennel cough, which can be easily treated by antibiotics and steroids. Then the symptoms returned and again it was misdiagnosed as pneumonia. More than two months passed before Charlie was given the correct medication; the delay in a correct diagnosis lessens his chances for a full recovery.
Charlie now spends most of his time sleeping off the effects of valley fever, instead of being his normal playful self.
There is no cure for valley fever. Currently treatments focus on helping dogs beat the symptoms. Vet bills can mount up since a dog may have to get medication for up to eighteen months; in some severe cases, a dog may be on medicine for the rest of his life. It is estimated that Arizona dog lovers spend $60 million per year in caring for dogs with valley fever.
Seeing the increase in valley fever cases across the U.S., Phoenix-based Translational Genomics Research Institute (TGen) researchers are now asking for dog people to take a brief online survey about their pet’s breed, health history and lifestyle. After the survey, the dog may be selected to give a saliva sample.
Then after the swabbing is done, researchers will look for differences in the genes of dogs who are sick compared to dogs who show signs of exposure to valley fever but who aren’t sick.
“In certain dogs, a minor infection can progress to severe disease, and the reasons for this are unknown,” said Dr. Bridget Barker, assistant professor and head of TGen’s Northern Arizona Center for Valley Fever Research in Flagstaff, Ariz.
This information would be used to help develop new therapies for both dogs and people, she said.
For more information about TGen’s Valley Fever PAWS (Prevention, Awareness, Working for Solutions), visit us on Facebook at www.facebook.com/vfpaws, and on Twitter at @ValleyFeverPAWS.
Wellness: Health Care
Intervertebral disc disease (IVDD)—what some call a “slipped disc”—can smolder or it can strike full-blown, leaving your dog in excruciating pain and unable to walk. Initially, signs that a dog is afflicted can be subtle: a hesitation about going up or down stairs, paws that knuckle under or cross over, nail scuffing, an arched back, a tense abdomen. Dogs may shy from their food bowls to avoid bending their necks, or cry when picked up.
IVDD causes compression of the spinal cord and leads to weakness, pain and sometimes paralysis, and is divided into two categories: Hansen Type I and II. Type I often swoops in suddenly, usually in younger, smaller dogs ages three to six. The center jelly of the vertebral disc, called the nucleus pulposus, degenerates, then ruptures and presses on the spinal cord. Not surprisingly, the chondrodystrophic breeds (dogs with short legs and longbacks)—Dachshunds, Corgis, Lhasa Apsos, Shih Tzus and Beagles—are predisposed to this type.
Type II, which is typically seen in large dogs like German Shepherds, Labradors and Dobermans ages eight to ten, progresses more slowly. Though the disc doesn’t burst its center, it bulges between the vertebrae and impinges on the spinal cord, causing chronic pain and weakness.
To rule out fractures, bone infections and cancers, your vet will start with X-rays, but a contrast myelogram, CT or MRI (all of which are often done at specialty centers) is needed to visualize the spinal cord and determine the nature and location of the problem.
In addition to type, IVDD is described by level of severity. Roughly, grade I involves pain; grade II, unsteadiness; grade III, weakness that prevents standing or walking; grade IV, paralysis but able to feel deep pain when the toes are pinched; and grade V, complete paralysis with loss of deep pain.
Dogs with grades 1 through IV will likely be managed with pain meds, muscle relaxants and strict rest for up to a month, and are often referred for physical therapy or Class IV laser treatments. Depending on the duration of neurological deficits and amount of pain, surgery may also be recommended for dogs with grades II, III and IV. Because the disease can change quickly, even dogs diagnosed with lower-grade IVDD need sequential exams to ensure that the condition is not progressing.
When a dog is completely unable to walk, decisions have to be made swiftly. Dogs who stay in the grade V stage longer than 48 hours often remain paralyzed despite intervention, while up to 50 percent of those who have surgery in the first 24 hours may regain their ability to walk.
IVDD surgery removes compromised discs, hemorrhage and adjacent bone compressing the spinal cord. With severe disease, it’s the best chance for a dog to walk again. It does, of course, also entail expenses and risks that not everyone is able or willing to undertake. What other options do we have?
Thankfully, veterinarians have been studying other modalities to treat IVDD, acupuncture among them. In 2007, a team lead by A.M. Hayashi found that dogs of all IVDD grades recovered more quickly with electroacupuncture (EAP) combined with a standard Western medical approach than Western treatment alone (JAVMA 231: 913–918).
In 2009, A. Laim et al. reported that dogs receiving EAP and pain medications after surgery for acute IVDD were less likely to need higher doses of pain meds during the first 12 hours than those who received meds alone. These patients also had significantly lower pain scores 36 hours after treatment (JAVMA 234: 1141–1146).
A 2010 study compared three options for IVDD dogs with severe neurologic deficits of greater than 48 hours’ duration: decompressive surgery (DSX), EAP, and DSX followed by EAP (DSX + EAP). The study, led by J.G.F. Joaquim, showed that EAP was more effective than DSX + EAP, and that DSX alone was the least successful. These dogs had severe, long-standing IVDD in the thoracic and lumbar (thoracolumbar) spine, and in the past, their prognosis would have been dismal. (JAVMA 236: 1225–1229).
How does acupuncture work? While there is some debate over definitions, it’s generally accepted that acupuncture points (acupoints) concentrate clusters of free nerve endings, small blood and lymphatic vessels, and mast cells, part of the immune system. A veterinarian certified in acupuncture inserts small, sterile needles into specific points to stimulate muscles, nerves, circulation and the immune system. For IVDD, one needle may be placed at the top of the spine by the shoulders, and a second above the pelvis, which moves the qi and stagnated energy caused by the disc disease.
Functional MRIs reveal that acupuncture activates pain-associated brain stem regions. The specific mechanism of acupuncture on IVDD has not yet been fully explained, but it’s surmised that it reduces local swelling, inflammation and pain; decreases cord compression, scar formation and tissue oxygen deprivation; and restores damaged nerves.
When compared to the use of needles alone, EAP has been found to increase the body’s response to acupuncture. In EAP, needles in the skin are connected by metal clips; electro-impulses move between the clips and into the needles, producing sensations that range from a tingling to a vibration. Frequency and intensity are determined by the type of condition being treated. Sessions usually last from 10 to 30 minutes, and dogs often fall asleep during treatment.
EAP has a cumulative effect and is typically prescribed as a series of treatments, every one to two weeks for at least a few months. Appropriate Chinese herbal formulas are often prescribed at the same time to reduce pain and enhance the effects of acupuncture. Dogs then proceed to maintenance acupuncture at one- to three-month intervals to prevent recurrence.
Ideally, your dog will never go through the pain of IVDD, and you won’t have the worry. But if you do find yourself up against a down dog, it’s good to know that adding acupuncture to the treatment repertoire may help your friend get back on all fours.
Good Dog: Behavior & Training
It’s now legal to break into cars to rescue pets and people
The governor of Florida just signed a law making it legal to break into a car to rescue a person or a pet who is “in imminent danger of suffering harm.” It applies to vulnerable people and pets (including cats and dogs), but does not apply to farm animals. Many people and pets die each year because they have been left in overheating cars, so this law could save many lives. It is especially important in a hot southern state like Florida with the summer months approaching.
The law specifies procedures that must be followed in order for a person breaking into a car to be protected from civil liability for damage to the vehicle. If you are trying to help someone in danger, here’s what you should know about the law. It is required that you check that the car is locked before breaking in. If you do break in, the law requires that you do so with the minimum force necessary. You are required to call 911 or law enforcement before or immediately after rescuing the person or pet from the car, and you must stay with the rescued pet or the person until first responders arrive.
I’m delighted to know that Floridians are now protected by this law if they see an individual in danger in a car and choose to act. Many people would rescue the pet or person regardless of the risk to themselves, but it’s far better to give legal protection to such potential heroes.
Wellness: Healthy Living
Winter not only keeps us inside, it’s also a time of food-centric holiday celebrations. How can we share the fun with our dogs without packing pounds on them? When you want to get the facts, you go to the pros, and for an answer to this question, we checked in with Julie Churchill, DVM, PhD, ACVN and associate professor of nutrition at the University of Minnesota Veterinary Medical Center. Her general advice is that we be mindful of our dogs’ daily caloric needs and their total intake. (More on this in a future issue.) Dr. Churchill also shared a few tips.
> Go for frequency, not volume, and choose either very small treats (pinkie fingernail-size) or ones that can be broken into small pieces.
> Look for tasty low-cal alternatives; if your dog likes likes raw fruit and veg —carrots, celery, green beans, cucumbers, apples, blueberries—keep a ready-to-eat supply on hand.
> Unsalted, unbuttered popcorn provides lots of bang for its caloric buck; there are only 20 calories in a popped cup, and a cup goes a long way, especially when scattered around for the dog to find.
We saved the really big question for last. How do we resist those soulful eyes as we eat our turkey sandwiches and our special holiday cookies? Dr. Churchill advises that if we’re going to cave, we should do it with the lowest-calorie treat. It’s also important to avoid reinforcing begging (do your best!) and to preserve our dog’s routine. Dr. Churchill’s final takeaway: Dogs choose joy, and the time we spend with our dogs means more to them than food. Carve out time to make some joyful memories.
Wellness: Healthy Living
Q&A with Dr. Robynne Chutkan
Dr. Robynne Chutkan, one of the leading gastroenterologists in the country, is the author of a new book, The Microbiome Solution, in which she takes us on an exploration of our guts’ ecosystems. Her rousing endorsement of “living dirty” includes the benefits of living with dogs. Bark’s editor speaks with her about just how helpful dogs are to our health, inside and out.
Is it true that there are similarities between our microbiome and those of our dogs, and that dog-owning families have more diverse microbial colonies than dogless households?
Although we share many of the same microbes, dogs in general have a more diverse microbiome than we do. Not surprisingly, some of their additional species are soil microbes (rolling in the dirt from time to time may be a habit worth copying!). Close contact with our dogs is hard to avoid, and that’s a good thing, because they end up passing on some of their unique microbes to their owners, giving dog-owning households a microbial boost.
Dog owners who have children share more mouth bacteria with their dogs than they do with their children. Is this a good thing?
The microbiome in children under the age of three is still developing and as a result, is very different from that of an adult, although there are still lots of shared species with household members (and pets), given the proclivity children have for [putting] everything in their mouths. So, most adults (not just dog owners) have a very different microbiome from their young children. As children get older, their microbiome starts to more closely resemble that of the other household members—not just parents, but pets, too. The vast majority of microbes our canines pass on to us are helpful or benign, not harmful, so keep those doggie kisses going.
So bacteria aren’t species-specific? Is that why, as you note, owning a dog is a highly effective way to replenish and revive bacteria that are basically under attack by modern-day living?
Some bacteria are species-specific, but many are shared by both humans and dogs. Most dogs are much more in touch with the natural world than their owners are, and that’s exactly where lots of the health-promoting microbes come from: soil; unfiltered, unchlorinated water; and, of course, the poo of other animals that our dogs are constantly checking out. Dogs tend to go easy on the hand sanitizer and antibiotics and eat a less processed diet (all habits worth emulating), so they haven’t super-sanitized away as many of their microbes as we have. Some of these canine microbes can be passed on to us, helping to replenish our lackluster microbiome.
The high-fat, low-fiber food we eat, attracts a different range of microbial types; do you know if that is the same for dogs?
I’m not aware of any specific studies looking at variations in canine diets and the effects on their microbiome, but certainly, dogs who eat more processed grains and other foods not natural to their diet tend to have more health problems, and the same is true for humans.
You mention that it’s okay to be a little dirty and sweaty. Why do you think Americans are so obsessed with being hyper-clean?
In the pre-antibiotic era, epidemics of the plague, cholera and other highly infectious diseases wiped out vast numbers of people. The advent of penicillin in the 1930s is still one of the most important contributions to modern medicine, and antibiotics have saved countless lives. But now the pendulum has swung the other way; we’re currently in an era of overdiagnosis and over-treatment, and we’re seeing the emergence of new “modern plagues,” not from infection, but from not enough microbes.
However, the public still sees antibiotics as the life-saving miracle workers they were in the first part of the last century, not as the overprescribed menace they’re becoming. Plus, 80 percent of all antibiotics sold in the U.S. are used in the livestock industry, mostly to fatten animals for slaughter. Clearly, that’s not a lifesaving endeavor.
I think the pharmaceutical and personal-product companies also have a lot to do with it. They’re responsible for many of the public-health campaigns that incorrectly equate cleanliness with health, and of course, they make billions of dollars selling hand sanitizer and other anti-bacterial products.
It’s not just okay to be a little sweaty and dirty, it’s great for your microbiome and your overall health. We need exposure to dirt and germs (bacteria, fungi, protozoa and so forth) to train our immune systems to recognize friend from foe. Not enough exposure to germs, especially when we’re young, leads to a confused immune system that tends to overreact. The result is allergies and autoimmune diseases.
In defense of less bathing and shampooing: your body is really good at concocting the exact formula needed to keep your skin and hair moisturized and healthy. But what do we do? We scrub away our natural oils with harmful antibacterial products and then try to revive our skin and hair with store-bought products full of chemicals. Live dirty for a healthier— and better looking—you!
Many studies have shown the benefits to children of having a dog, including a decrease in eczema and asthma. Why else would you recommend that a family get a dog?
Having a dog is great for reducing stress and anxiety and lowering blood pressure. And we already know they improve the microbiome of the entire household.
What’s your personal dog “biome”?
My mother’s bridge partner, Eva, worked for the Swedish embassy, and when she moved back to Sweden, she left her beloved German Shepherd, Trygg, with us. He’d been used to spending all his time with Eva, and became immediately attached to my mom. We had to be super vigilant in the bathroom because he loved to drink from toilets (all kinds of rewilding going on!).
Hugo, our German Shorthaired Pointer puppy, came into our lives about six months ago. Getting a dog forced me to slow down my too-busy lifestyle and spend more time sitting on my front steps, stroking Hugo and literally smelling the roses. He’s super active, so my husband and I take turns running with him in the mornings and evenings.
We live near Rock Creek Park in Washington, DC, so, thanks to Hugo, there’s a whole lot of dirt and sweat happening on a daily basis. Our daughter Sydney loves him so much that we really can’t imagine life without him.
Hugo slobbers over everyone he comes into contact with, and since I frequently have meetings with the Gutbliss team at our house, he’s become our CRO—Chief Rewilding Officer!
Rick Woodford, the man behind dogfooddude.com, is back with another highly informative, yet easy-to-use cookbook. His new, aptly titled Chow will enable even absolute beginners to try their hand at whipping up whole meals, or simple nutritious and delectable “toppers” (like the one here), for their dogs. Nothing says loving better.
Greyhound are known to reach speeds up to 45 miles per hour, making them one of the fastest breeds around. They’re perfect for running in a straight line or chasing prey, but as soon as the race is over, the greyhound is ready to take a nap. The Alaskan husky can achieve speeds about half that of the greyhound but can sustain the speed for much longer—all while pulling a sled. Both breeds are remarkable for their achievements, but are hardly interchangeable for the unique requirements needed in each racing environment.
Omega-3 fatty acids can be sourced from either plants or animals, and like the greyhound and husky, the different sources have different purposes and benefits. Flaxseeds, chia seeds, and pumpkin seeds contain alpha-linolenic acid (ALA), which can contribute to the fight against cancer and enhance brain function; but what your dog’s body really runs on is eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Although your dog can convert some of the ALA into EPA and DHA, it’s not enough to support the body’s entire requirement. Supplying EPA and DHA as part of the diet, by including fish or meat from grass-fed animals, is far better in reducing inflammation and furthering cognitive development. Such foods as mackerel can provide a healthy dose of EPA and DHA when fed as part of your dog’s diet two or three times a week.
Whenever possible, purchase mackerel without such additives as sugar and monosodium glutamate, a flavor enhancer that overstimulates neurotransmitters in the brain. Mackerel packed in water or tomato sauce is preferable over mackerel packed in oil, because your dog will already be receiving enough fats in his diet.
1 cup of canned mackerel has about 300 calories; equivalent to about ¾ cup of commercial dry food
Replace 10 percent of your dog’s regular meal with the following amounts:10-lb. dog: 2 tablespoons
20-lb. dog: 3 tablespoons
40-lb. dog: ¼ cup
60-lb. dog: ⅓ cup
80-lb. dog: ½ cup
100-lb. dog: ½ cup
KEY NUTRIENTS Calories 6% • Protein 30% • Total fats 15% • Omega-3 (DHA) 225% • Omega-3 (EPA) 123% • B3 (niacin) 46% • B12 (cyanocobalamin) 26% • D3 69% Mackerel Mix-In — Meal Topper Recipe
Mackerel can be used in place of salmon in salmon cakes for your plate, but it’s also beneficial for your dog and easy to prepare. With a wide variety of vegetables, fruits, and fish rich in omega-3 fatty acids, this meal topper is a must for any dog. Using canned mackerel and chopping the vegetables in a food processor enhances digestibility without your having to cook anything. Don’t worry about those tiny mackerel bones; they’re really soft and will break down even further in the food processor.
1. Drain and rinse the mackerel.
Yield: 5½ cups
Serve the following amount once per day, replacing one-fifth of your dog’s normal meal.KEY NUTRIENTS 133 calories per cup • Protein 42% • Carbohydrate-to-protein ratio 0.4 to 1 • Total fats 40% • Antioxidants 38%
(In just an hour!)
This great kibble recipe is from the new cookbook, Dinner for Dogs by Henrietta Morrison. She is the founder of Lily’s Kitchen, a popular pet food company in the UK. She believes in proper food for dogs, and Lily, her Border Terrier, is her chief taster. See an interview with Henrietta as well.
Turkey is great as it’s very low in fat and very digestible, which makes it useful for dogs who are allergic to the usual protein sources—lamb, beef and chicken. Turkey is also handy as it’s readily available ground.
This is also a good hypoallergenic recipe that is free of wheat. You’ll notice I haven’t included peas, which always seem to be part of a dog’s menu these days. Peas can be hard to digest for some dogs and therefore can make them gassy.
Put the rice and lentils into a saucepan and cover with the water. Bring to a boil, then reduce the heat to medium and cook for 20 minutes.
Once the rice and lentils are cooked, add the chopped carrots, sweet potato and apple to the saucepan. Stir in the oats and chopped herbs and gently simmer for 20 minutes more. Add an extra cup of water if the mixture is too dry. Preheat the oven to 350°F/180°C.
Meanwhile, brown the ground turkey in a separate frying pan. You will need to keep stirring it while it is cooking to prevent it from sticking to the pan as it is very low in fat. It will take about 10 minutes to cook through.
Put half the cooked vegetable and grain mixture into a food processor with half the cooked turkey, add half the oil and pulse until the mixture resembles a thick purée.
Grease 2 cookie sheets and spread the mixture onto one of the sheets so that it is about ¼ inch (5 mm) thick. The mixture will spread slightly so leave a bit of room for this. It is important that the mixture is not too thick because it will prohibit the kibble from cooking through.
Repeat as above using the second cookie sheet and the remaining ingredients.
Place both cookie sheets into the preheated oven and bake for 45 minutes. Turn the kibble over so that it dries through, and cook for another 30 to 45 minutes. You should have what looks like two very large cookies. Make sure the kibble is completely cooked through, as any moist bits will get moldy after a couple of days. If it is not fully dried out, leave it in the oven for 20 minutes more.
Reduce the oven temperature to 325°F/160°C. Remove the “kibble cookies” from the oven, cool slightly and cut them into small pieces. Place the pieces back onto the cookie sheets and bake for an additional hour, or until the kibble is completely dried (but not burnt).
Remove the kibble from the oven and let cool completely. It should resemble pieces of broken pita bread.
It will keep in the fridge for 10 days.
Valentine Liver Nibbles
This delicious recipe is nutritious and tasty, and the loaf can be sliced up into any size. What better way to make your pup feel truly special this Valentine’s Day than with homemade treats richly infused with love. The added bonus is that Valentine Liver Nibbles are completely wheat-free, making them ideal for sensitive pets.
What to Do
Note: We've omitted the garlic originally in this recipe.
Wellness: Healthy Living
Medical marijuana shows promise for ailing companion animals.
A Bulldog who spent two years either lying down or throwing up plays like a puppy thanks to a daily dose of medical marijuana. A Boxer’s skin cancer begins to disappear following topical applications of cannabis oil. A 12-year-old Lab mix diagnosed with liver and lung cancer regains his appetite and becomes more himself after his owner gives him a cannabis tincture purchased from a licensed medical marijuana dispensary.
These stories offer hope to those of us who live with aging and/or infirm dogs, hope that we can improve the quality of their lives and perhaps even extend them.
Even more hopeful is the fact that these aren’t isolated incidents, but rather, three in an ever-increasing narrative of companion animals and cannabis- assisted healing. Yet, veterinarians played little to no official role in them. Why? Because Cannabis sativa (aka marijuana, grass, pot, hash, ganja, et al.)— a plant cultivated for literally thousands of years for its seeds, fibers and medicinal value—is a federally designated Schedule 1 controlled substance, a “drug with no currently accepted medical use and a high potential for abuse.”
So, even if vets believe that medical marijuana could or would relieve a dog’s pain, nausea or seizures, their hands are tied, including in the 23 states and the District of Columbia where cannabis is legal for human medical use. Physicians in those states are exempt from prosecution, but veterinarians don’t have the same protection. Prescribing, or even recommending, cannabis for medicinal use exposes them to the loss of their license to practice.
It’s a difficult place for a vet to find him- or herself: to have a remedy that has been shown to have very real benefits but not be able to use it, or even mention it, without career-ending consequences. Nonetheless, some have put their livelihoods at risk by challenging that prohibition, usually for the same reasons given by the late Doug Kramer, DVM, of Chatsworth, Calif., in a 2013 interview with Julia Szabo: compassion, and to prevent owners from accidentally overdosing their animals in well-intentioned efforts to relieve their pain.
And that’s part of the veterinary quandary. Medical marijuana has been described as the new “dot.com” boom, fueled by a growing body of research that seems to be validating cannabis’s beneficial effects for people. When people are helped by a particular treatment, they tend to want to share it with their ailing companion animals.
With medical marijuana, they’re doing this in increasing numbers, acting on the belief that if it works for them, it can also work for their dog or cat … or horse, for that matter. In doing so, they’re not necessarily curing incurable conditions but rather, are helping their animals enjoy daily life with better appetite and less pain until age or disease ultimately catches up.The Backstory
The plant world has given us some of our oldest and most trusted—and, it’s true, sometimes abused—remedies. Pain relievers like codeine and morphine (poppy); colchicine, an antitumor drug (autumn crocus); the cardiac drug digitalin (purple foxglove); antimalarial quinine (quinine tree); and salicin, the chemical precursor to aspirin (white willow). The list is long.
When that plant has a cultural backstory like marijuana’s, however— “demon weed” in the ’50s, counterculture toke of choice in the ’60s, DEA Schedule 1 drug in the ’70s and onward —empirical evidence is harder to come by. Many barriers are placed in the path of those who want to find answers to questions about marijuana’s potential healing powers. Consequently, there’s a scarcity of rigorous research on the topic, particularly for veterinary application.
Determining whether or not to bring medical marijuana into general and legal use nationwide for humans and animals alike—and how to do it in a way that maximizes its benefits and minimizes its risks—requires this research. Stories, no matter how compelling and promising, are not science, and anecdotal evidence isn’t evidence in the scientific sense. Rather, hypotheses need to be tested in randomized, placebo-controlled studies, the results analyzed and conclusions drawn. The results are then retested and found to be replicable (or not) by others.
Until relatively recently, claims for cannabis’s medicinal values haven’t been supported in this way. As Hampton Sides notes in “High Science,” the June 2015 National Geographic cover story, “for nearly 70 years, the plant went into hiding, and medical research largely stopped … In America, most people expanding knowledge about cannabis were, by definition, criminals.”The Science
Now for the more technical aspects of the topic, greatly simplified and synthesized.
The first published research related to cannabis and companion animals appeared in 1899 in the British Medical Journal. Written by English physician and pharmacologist Walter E. Dixon, the article included Dixon’s observations on dogs’ response to cannabis. However, it would be almost 100 years before we understood where the response originated: in the endocannabinoid system (ECS).
All vertebrates, from sea squirts to humans, have an endocannabinoid system, which scientists estimate evolved more than 600 million years ago. This ancient system, unknown until the late 20th century, is named for the botanical that most dramatically affects it, Cannabis sativa. Cannabinoids are the ECS’s messengers. The system’s purpose is to maintain internal balance— to “Relax, Eat, Sleep, Forget and Protect.”
Marijuana, a complex botanical with more than 400 known natural compounds, contains at least 64 phytocannabinoids (plant-based cannabinoids). The two produced in greatest abundance are cannabidiol (CBD) and tetrahydrocannabinol (THC).
How do they work? According to the National Cancer Society, cannabinoids “activate specific receptors found throughout the body to produce pharmacologic effects, particularly in the central nervous system and the immune system.” The effects depend on the receptors to which they bind.
Robert J. Silver, DVM and veterinary herbalist of Boulder, Colo., provides another way to look at it. “Receptors are like locks, and cannabinoids are like keys. They fit together perfectly. Once the cannabinoid connects to the receptor and ‘turns that lock,’ a series of actions in the cell membrane occur; these actions are responsible for some of the cannabinoid’s effects.”
In his forthcoming book, Medical Marijuana and Your Pet, Dr. Silver notes that the ECS is unique in the world of neurotransmitters. Instead of releasing signals across a synapse (gap) in a forward direction, “the body’s naturally occurring endocannabinoids travel backward from the post- to the presynaptic nerve cell, inhibiting its ability to fire a signal. This is one way the ECS helps modulate and influence the nervous system.”
Research has revealed two distinct cannabinoid receptors, CB1 and CB2. As in other vertebrates, canine CB1 receptors are primarily found in the brain, but also appear in dogs’ salivary glands and hair follicles, while CB2 receptors are localized in canine skin, immune system, peripheral nervous system and some organs, such as the liver and kidneys.
Of the currently known cannabinoids, only one—THC—provokes a “mind-bending” response. CBD, on the other hand, has several well-documented biological effects, including antianxiety, anticonvulsive, antinausea, anti-inf lammatory and antitumor properties.
Terpenoids, components that give plants their distinctive odors, also play a role, helping cannabis cross the bloodbrain barrier and work synergistically. Ethan B. Russo, MD, associated with GW Pharmaceuticals in the UK, calls this the “entourage effect.” In an article in the British Journal of Pharmacology, Russo notes that terpenoids may make a meaningful contribution to cannabisbased medicinal extracts “with respect to treatment of pain, inf lammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus [MRSA]).” The entourage effect also suggests that in general, the whole plant, with all of its phytocannabinoids, is likely to be most effective for medicinal purposes.
Those who choose to treat their companion animals with medical marijuana generally give it to them in one of two ways: as an oil or as an edible —a food item made with marijuana or infused with its oil. While edibles intended for human consumption usually contain THC, those for dogs and cats more commonly use CBD from industrial hemp, strains of cannabis cultivated for non-drug use, which has almost no THC.
In 1996, California became the first state in the nation to legalize medical marijuana. It now has the largest legal medical marijuana market in the U.S. —not to mention an almost clichéd historical relationship with the herb— so it’s no surprise that many who are pushing the boundaries of its use with companion animals are based there.
Constance Finley, founder of Constance Pure Botanical Extracts (a Northern California legal medical cannabis collective) became involved in cannabis use with dogs when her 10-year-old service dog was diagnosed with hemangiosarcoma and given six weeks to six months to live.
Finley had been using cannabis oil herself to treat the effects of a debilitating autoimmune disease that began when she was in her mid-40s. The prescription medication she took almost killed her, she says, an experience that inspired her to set aside her long-held bias against marijuana and give it a try. The oil provided both pain- and symptom relief, and Finley went on to study cannabis cultivation and the complicated laws around its use. She eventually developed proprietary blends of highly concentrated oils from multiple strains of cannabis, extracted with organic, food-grade solvents.
So, when her much-loved dog was struggling with cancer, she says she dithered, then began giving the dog small amounts of cannabis oil, wiping it on her gums. Within days, the dog started to move around normally and eat; after three weeks of treatment with the oil, her vet could find no signs of the cancer. Unfortunately, she didn’t completely understand how cannabis worked; she figured her dog was cured and stopped using the oil. Within six months, the cancer was back, and ultimately it claimed her dog’s life.
However, the experience made her a believer in its value for companion animals. While to date, there’s been no dog-specific research on its medical use, Finley is confident that cannabis oil has a place in the veterinary toolbox.
In her work with human clients, Finley says she has yet to see a conflict between conventional medications and cannabis, although anyone using it with dogs needs to be aware of the dog’s entire situation. It’s critically important, she says, that the dose be correctly titrated so the dog’s system isn’t hit with too much THC too quickly. She also notes that the effectiveness of an individual dog’s endocannabinoid system, not the dog’s weight, determines the dose. To establish the correct dose, it’s necessary to work with and observe the dog.
A dosage protocol for dogs is one of the areas in need of study and standardization. In the mid-1970s, researchers found that dogs have a high concentration of CB1 endocannabinoid receptors in their hindbrain and medulla as well as other areas of the brain. This suggests that, in terms of compounds that include THC, dogs require less to get the desired effect. (One of the diagnostic signs of THC overdose is something called “static ataxia,” first described in the 19th century and unique to dogs. Dogs in this condition rock rigidly back and forth and drool, their muscles tense up, and their pupils dilate.) According to Dr. Silver, when it comes to dogs and medical marijuana, “The ratio of brain weight—and by extension, receptors— to body weight is not linear.”
Finley also observes that there are at least two myths about medical marijuana that need to be dispelled. First, that CBD is good and THC is bad; each has its uses, but for cancer in particular, she says, THC is the workhorse. Second, that hemp and cannabis are the same; they are different varieties or sub-species, and while CBD can be refined from hemp, she feels that cannabis provides oil that is more easily used by the body.
In Oakland, Calif., Auntie Dolores has been making cannabis-infused edibles for California’s medical marijuana users since 2008. It recently launched Treatibles, a new, locally manufactured product for dogs and cats. The active ingredients are CBD, CBN (cannabinol) and CBG (cannabigerol) distilled from European industrial hemp, which, founder and CEO Julianna Carella notes, is “non-toxic, 100 percent safe and non-psychoactive. Even dogs who do not have health problems can use the product as a preventive measure.”
Each bag of Treatibles, about 40 pieces, contains 54.6 mg of CBD; each t reat contains about 1 mg. Carella says that the company guarantees 40 mg per bag, but often the consumer gets a bit more. “We feel that all products purporting the health benefits of CBD should have at least enough of the material in the product to warrant the price, as well as to provide a medicinal dose. Even so, dogs are more sensitive to cannabinoids and generally need less than humans.”
Carella says that she was inspired to develop edibles for companion animals by cannabinoid science and research into the endocannabinoid system as it relates to all animals. Like others in the field, she is dismayed by cannabis’s current federal legal status. “Unfortunately, research on cannabinoids and animals is delayed due to the status of cannabis and the Controlled Substance Act, which has disallowed research into its medicinal value. CBD has become part of this controversy, even when derived from hemp.”
Initially, Treatibles was sold only through the company’s Treatibles website, but Auntie Dolores has recently been making it available in California medical cannabis dispensaries and local pet retail outlets. Holistic Hound in Berkeley, Calif., is one of the first stores to carry the product. While its name includes the word “treats,” store owner Heidi Hill considers Treatibles to be more closely aligned with supplements— i.e., to have health benefits. She says her customers have given Treatibles an enthusiastic reception, with most reportedly using the edible to alleviate their dogs’ anxiety and, in some cases, pain.
Hill says she gives Treatibles to Pearl, her aging, arthritic Siberian Husky, and has observed an improvement in her appetite and energy level. The quality of its other ingredients—among them, organic, gluten-free oat flour; pumpkin; peanut butter; organic coconut oil and coconut nectar; organic brown rice flour; applesauce; turmeric; and cinnamon— also recommends it, she says.Change Is Coming
While many have seen positive outcomes, some veterinary professionals worry about people extrapolating from their own experiences with medical cannabis to their dogs’ health problems and giving dogs inappropriate amounts. “Sometimes public sentiment and activity get ahead of the scientific background, and that can be dangerous,” Barry Kellogg, senior veterinary adviser to the Humane Society of the United States, has said.
To date, the American Veterinary Medical Association has not taken an official position on the use of medical marijuana with animals. The American Holistic VMA is the first, and so far only, veterinary organization to officially encourage research into the safety, dosing and uses of cannabis in animals. In 2014, the group released a statement that said in part, “There is a growing body of veterinary evidence that cannabis can reduce pain and nausea in chronically ill or suffering animals, often without the dulling effects of narcotics. This herb may be able to improve the quality of life for many patients, even in the face of life-threatening illnesses.”
Other developments are on the way. In March of this year, Nevada state senator Tick Segerblom (D-District 3) introduced Senate Bill 372, which makes a variety of changes related to medical marijuana in the state. Among its provisions is one that would allow officials to issue medical marijuana cards to companion animals whose owners are Nevada residents and whose vet is willing to certify that the animal has an illness that might be helped by marijuana (the illness does not need to be fatal).
California is also in the process of creating a structured regulatory system. In the June 4, 2015, edition of the Sacramento Bee, reporter Jeremy White summarized Assembly Bill 266: “[It] would create what’s called a dual-licensure system, with cannabis entrepreneurs needing to secure permits both from local authorities and from one of a few state agencies. The Department of Public Health would oversee testing, the Department of Food and Agriculture would deal with cultivation and the Board of Equalization would handle sales and transportation—all under the auspices of a new Governor’s Office of Marijuana Regulation.”
According to Constance Finley, the fact that the marijuana industry is unregulated has been part of the problem regarding access. But next year may be the tipping point. If California’s AB 266 is passed and the marijuana industry comes out of the shadows into effective regulation, particularly in terms of verifiable cannabinoid content and freedom from contaminants, the rest of the nation could follow. The state’s size, market potential, and trailblazing environmental and technology industries have historically inf luenced trends nationwide, and that dynamic is likely to drive the discussion in this case as well.
Veterinary professionals are generally in agreement that more study is needed. In a 2013 interview with R. Scott Nolen, Dawn Boothe, DVM and director of the Clinical Pharmacology Laboratory at Auburn University’s College of Veterinary Medicine, commented: “Veterinarians do need to be part of the dialogue. I can see a welldesigned, controlled clinical trial looking at the use of marijuana to treat cancer pain in animals. That would be a wonderful translational study, with relevance to both pets and their people.” (In translational research, laboratory science and clinical medicine combine their efforts to develop new treatments and bring them to market.)
Narda G. Robinson, DVM, director of Colorado State University’s Center for Comparative and Integrative Pain Medicine, agrees. In an email exchange, Dr. Robinson said, “There is a big gap that needs to be addressed between those who are already using hemp products and finding value for their animal and science-based practitioners who want to make sure that their patients are receiving safe and effective treatment. Research will help bridge that gap.”Next Steps
Clearly, veterinarians—our partners in keeping our animals healthy—need a voice in this debate. While interested in the herb’s potential, many are leery about trying it, not only because of the legal consequences but also, because there’s so little evidence-based information. On the other hand, dog owners who have found it useful for themselves feel that not including it in the vet-med repertoire is a missed opportunity.
Although the tide is slowly turning in its favor, the debate about the utility of medical marijuana and its related components for both people and their pets is often mired in personal bias and opinion. Regardless of what position we take, it would seem that the best way to come to a resolution is to focus on the science. Controlled studies that determine cannabis’s therapeutic and toxic ranges in veterinary use and standardization of THC and/or CBD content have the potential to make a potent natural ally legally and safely available to our four-legged companions.
In transforming anecdote to evidence, we can move from what we think, what we believe and what we imagine to what we actually know. That would be a very good thing for us and for our co-pilots as well.
Wellness: Health Care
On the trail of canine cancer
In Dog Diseases Treated by Homeopathy (first published in 1863, before chemotherapy, radiation, biopsies and blood panels), author James Moore advised concerned dog owners on treating cancer: “An operation cannot remove the cancer, but it can remove the tumor, which causes much suffering; the knife is, therefore, merely palliative in its effect. Still, the disease, even then, is likely to return at a period more or less remote.”
Today, the diagnosis isn’t as bleak. Indeed, 50 percent of all canine cancers are curable if caught early enough. Moreover, the disease is mostly an aff liction of old age (tragically, some cancers strike dogs as young as two). It may seem like more dogs get cancer than ever before, but it’s presumably because they enjoy a longer life span, thanks to vaccinations against infectious diseases like parvovirus and distemper, and new treatments for congenital, degenerative and metabolic disorders.
“Cancer” is the broad term for a complex cluster of more than a hundred diseases. Although there are many causes, each type of cancer starts with alterations in genes that tell cells how to function, which triggers accelerated and uncontrolled cell growth. The defective signal may hide in abnormal genes inherited from parents, or germinate when normal genes are exposed to harmful environmental influences.
Some breeds are predisposed to certain types of cancer, and in those cases, a strong inherited genetic component is suspected. It is thought that a small number of genes account for cancer risk, but, although they are directly related to the development of individual cancers, rarely is a single gene the sole cause.
By the time people and dogs pass 70 and 10 years of age, respectively, about 50 percent will have been diagnosed with some type of cancer. The malady accounts for approximately 23 percent of all deaths in people. In dogs, cancer mortality varies across breeds, from under 10 percent to higher than 60 percent.
In general, small dogs weighing less than 20 pounds are at very low risk. (Small dogs have lower levels of IGF-1, a hormone that is related to bone and tissue growth. Researchers suspect this may be one reason they have a lower incidence of cancer.) For instance, the chance that a Chihuahua, Dachshund, Maltese, Miniature Pinscher or Pomeranian will get cancer is less than 10 percent. Breeds with the highest risk include the Bernese Mountain Dog, Bouvier des Flandres, Boxer, Bullmastiff and Golden Retriever (Fleming et al. 2011).
Goldens as Case Studies
Interestingly, cancer risk in Europeanbred Goldens appears to be significantly lower. A 2010 study put the mortality figure at 38.8 percent (Dobson 2012, Adams et al. 2010). Although much higher than average, the incidence is substantially lower than that found in North American Goldens.
Goldens in Europe and the U.S. may look similar, but there are enough DNA differences to separate the dogs into two distinct populations corresponding to their geographic regions. Gene pools on both continents are large, so breeding between the two populations is rare.
When studied in the lab, genomic differences suggest that risk for some types of cancer is related to recent genetic mutations in North American Golden Retrievers. And this could be good news: genetic differences between European and North American Golden Retrievers may be key to understanding the etiology of canine cancer overall.
Population, Popularity and Popular Sires
Registration agencies impose strict standards on pedigreed dogs, requiring that the ancestors of each dog be registered as well. This, combined with widespread use of popular sires, means that each breed is a closed population, with no gene flow. The “popular-sire” effect occurs when an animal with desirable attributes is bred repeatedly. Descendants share specific genetic mutations, both good and bad, and those mutations spread rapidly throughout the gene pool, where they may become permanently established, or fixed. (“Fixation” is a change in a gene pool in which at least two variants of a particular gene are reduced to only one.)
When the 1998 GRCA study confirmed that a high number of Goldens were dying of cancer, club members realized they had both a problem and an opportunity. The club’s nonprofit 501(c)(3) fundraising offshoot, the Golden Retriever Foundation (GRF), got off the ground about the same time the survey results were being analyzed.
It started by funding a few cancer studies, including some managed by Morris Animal Foundation (MAF), a nonprofit that invests in science to advance animal health worldwide. Eventually, GRF contributed $1 million and asked MAF to match it if both could agree on a project.
In the meantime, at a MAF canine cancer summit in Chicago, three goals were promulgated: build a tumor archive, fund more canine cancer studies and devise prevention strategies. In response to this collaborative effort, a team of scientists, epidemiologists, veterinary oncologists and surgeons, nutritionists, toxicologists, geneticists, breeders, and donors spent three-anda- half years designing the ideal study. Not an easy task.
Animal epidemiology studies (which deal with the incidence, distribution and possible control of diseases) are few in number, largely because they face so many obstacles. Among them are limited funding, participating private practices using non-standardized methods to record data, pedigrees that are difficult to confirm, and grieving owners who aren’t eager to authorize post-mortem tests. Some cancers are silent killers, so a sudden death may not be attributed to cancer. And, due to attrition, studies are difficult to adequately enroll and don’t last long enough to develop statistically significant patterns.
However, after almost four years of stops and starts, the Morris Animal Foundation Golden Retriever Lifetime Study, the first breed-specific, life-todeath research project of its kind, was launched on August 30, 2012.
Based on observations summarized in questionnaires, researchers hope to identify potentially modifiable risk factors that may account for the high incidence of cancer and other diseases in Golden Retrievers and, eventually, in all dogs. Funded and managed by MAF, the study will investigate the effects of genetics, nutrition and exposure to environmental factors.
Although other breeds are at higher risk for cancer, Golden Retrievers were chosen because their population exceeds that of most other breeds by a large margin: the larger the sample size, the more accurate the data. Additionally, because these versatile dogs perform multiple jobs—from assistance and search-and-rescue work to field, performance and companion tasks—they are subject to a broad range of environmental exposures.
Rodney Page, veterinary oncologist and director of Colorado State University’s Flint Animal Cancer Center and the project’s principal investigator, describes some of the factors underlying the study. “Within the estimates that we currently have, we know that 50 percent of canine cancers are curable with surgery and other treatments. Our study is addressing the ones you can’t cut out: the 15 percent of mast cell tumors that aren’t operable; lymphoma, a whole-body cancer; osteosarcoma and hemangiosarcoma, because they spread rapidly before they’re discovered. These four types of cancer cause approximately 80 percent of cancer deaths in Golden Retriever dogs.” These fatal cancers begin to increase in incidence around five to six years and peak about age nine or ten. However, they may also develop in dogs age two and younger.
More than 2,050 veterinarians are providing health care for enrolled dogs. Annually, they conduct physical exams and report findings online; collect samples of blood, urine, feces, hair and toenail clippings and send them to participating laboratories; submit health information from additional heath visits; collect tumor tissue samples when applicable; and provide owners with information and guidance to help them make a choice about necropsy (an autopsy performed on an animal) after the dog dies.
Participating veterinarian Stephanie Ensley of Bentonville, Ark., who enrolled her own Golden in the program, elaborated on the study’s intent. “The information we’ll gather looks at areas of potential exposure by air, contact and feeding. Owners are expected to provide information as detailed as chemicals used in the home, yard and on the dog, and drinking water sources, to name just a few. When all this information is put together and analyzed, we’ll have an opportunity to find commonalities that may be related to cancer and other diseases. The more data available, the more opportunity to find a connection. On the flip side, we’ll also find commonalities in dogs who live to be 15 and over.”
Among the study’s other expected outcomes are insights into how dog-breeding practices and lifestyle choices might be modified to reduce the prevalence of myriad diseases, and the creation of a repository of biological samples that may be made available to researchers working to develop genetic tests.
As GRCA research facilitator and breeder Rhonda Hovan, who has been a Golden Retriever advocate for 45 years, notes, “Breeders play a special role in the success of the study because they can recruit multiple siblings who share the same genetic heritage. Data from littermates who experience different environmental factors and diets during their lifetimes may provide unique scientific insights that could make a significant impact on the long-term health of dogs.”
One immediate benefit is that veterinarians, dog owners and dogs won’t have to wait until the study is complete to see results that may help influence and improve veterinary medicine. The questionnaire responses are analyzed quarterly, so information is continually streaming into the study, and trends, once validated, will be published as they emerge.
Genetic testing to eliminate dogs from the breeding pool may not be the panacea it first appears. Dogs share more the 300 inherited diseases with humans, from narcolepsy and hemophilia to diabetes and lupus. It’s unlikely that all of these can be bred away from while still maintaining healthy genetic diversity. Reducing diversity increases risk for other diseases to surface in the future, especially in a breed like the Golden Retriever, one that has already experienced diversity loss caused by widespread use of popular sires.
In an article published in Golden Retriever News (Nov/Dec 2014), Hovan cautioned Golden Retriever breeders: “Keep in mind that when we remove a dog from breeding due to a failed health test or for any other reason, we are removing all of that dog’s genes from the gene pool, not just the genes associated with disease or unwanted traits …” She also observed that rigorously removing dogs affected with minor conditions has far more potential to damage future generations than occasionally and carefully breeding them. Breeding away from targeted conditions, she says, is part of an inescapable loop that presents subsequent generations with an elevated risk of having some other problem arise. “When conditions are targeted without good cause, there’s an all-too-real possibility that the ‘something else’ will be worse than whatever it is we tried to breed away from to begin with.”
Eliminating dogs based on genetic tests is not a sustainable way to control disease. A better approach, Hovan explained, is to “test and replace” as opposed to “test and eliminate.” For diseases with a recessive mode of inheritance, breeders can avoid risk by breeding carrier and affected dogs to normal dogs. That way, the genetic variety represented by the line can be maintained for as many generations as it takes to arrive at genetically normal offspring.
As Hovan went on to say, “To make good decisions as caretakers of our breed, we need to know what we’re working with. You can’t change what you don’t measure.” To this end, GRCA is working with a research team from University of California, Davis, to survey the breed’s genetic diversity across types and geographic location, collecting samples from the U.S. and Canada. Referencing this survey, Hovan added, “We want to approach this in a scientific manner. This study will help to clarify what we need to do and provide a road map so we can move forward.”
Could one solution be as straightforward as avoiding environmental triggers that trip biological switches and activate uncontrolled cell growth? Maybe. Researchers expect to collect enough biological samples to accurately define the incidence of each cancer being studied. When the study ends, researchers will also have a detailed life story of every enrolled dog. The hope is that in the long run, data will show relationships between cancers and exposures.
The population-based study is creating a baseline for future research in all sorts of health-related issues. According to Page, “The samples and data we are collecting now will be used by scientists in the future to answer their own questions about health and wellness issues in dogs. Studies will be encouraged that access these assets for analyses of everything from toxic exposures to microbial populations in the gut as they might influence health outcomes.”
Cohort studies like the Golden Retriever Lifetime Study are costly, susceptible to attrition and take a long time to produce statistically useful information. Their value depends on an organization’s capacity to stay in touch and engage all participants. DVM, PhD and CEO of Morris Animal Foundation David Haworth, who also enrolled his dog in the program, summarizes it most concisely: “A study like this can only happen through the active participation of an extended community of dog owners, dogs, veterinarians and study sponsors. I think I can say with absolute certainty that we have one of the most active groups of study subjects of any longitudinal health study ever initiated. After all, they are Golden Retrievers.”
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