Food Allergy - My Pet has WHAT?

By Loren W. Noblitt, DVM, MS

What:  Food allergy is one of the itchiest conditions known to cats and dogs. Animals eat a variety of processed food proteins, fillers, and colorings that are further processed inside their bodies and changed into substances recognized by the immune system as foreign invaders.  A battle then ensues between the food and the immune system resulting in lots of inflammation.  Many organs can be affected but usually it’s the skin and the gastrointestinal (GI) tract (including the mouth) that suffer.

Interestingly, many people erroneously assume itching from food allergy requires a recent diet change of some sort. In fact, the opposite is true.  Food allergy requires time to develop; most animals have been eating the offending food for years with no trouble.  At some point, there appears to be a “straw that breaks the camel’s back” type of event that ignites severe itching +/- diarrhea/vomiting.

The most common offending agents in dogs and cats are:

1. Chicken
2. Beef
3. Corn
4. Wheat
5. Egg
6. Soy
7. Casein
8. Fish

Why: Pruritus (itchy skin) in the small animal is often more than just a minor annoyance.  Red, oozing bald patches, rashes, and large areas of hair loss (“hot spots”) are classic markers of discomfort.  The skin is the “organ” most affected in pets because the skin has the densest mast cell distribution than anywhere in dogs’ and cats’ bodies.  Mast cells are allergic type cells that secrete histamine, which promotes itching and inflammation.  Same as in our own bodies.  These mast cells degranulate (releasing histamine into the blood) when the offending agent binds to receptors on its surface, causing runny eyes and sneezing in human beings affected with hay fever.  So why the difference?  Location, Location, Location!  Our mast cells are largely distributed in our upper and lower respiratory system, thus the primary difference between humans and small animals when it comes to manifestations of allergic reactions. 

Who & When:  Any age animal may be affected, but the majority of animals are older puppies/kittens (12-24 weeks) or in early adulthood.  Older animals (> 5 years old) that have no or little prior history of itching are good food allergy suspects. 

Where:  There is an old expression: “Ears and Rears (anal glands) and it (the itching) goes on all year.” Ear canals and anal glands are just extensions of the pet’s skin and are thus disproportionately affected with inflammation from a food allergy (based on mast cell distribution).  Other food allergic animals will present with “pseudoscabies,” meaning that they are itching all day long (“mad itch”) but either lack the classic hair loss pattern and skin irritation (redness) of animals with active scabies mite infestation OR they are still itching fiercely despite having been treated for sarcoptic mange already. 

Dogs with food allergies often have hair loss or redness around any or all of the following areas (see below):  chin, ears, belly, paws, around eyes and around the mouth.  Cats usually present with scabs on or around the head (mouth, neck, and ears).

Drawing borrowed from www.marvistavet.com

 

Other possibilities to explain the itching!:  Atopy (inhalant or environmental allergy), scabies mites, demodex mites, pyoderma (yeast/bacteria), flea bite allergy, or ringworm (fungus).  To complicate matters, some dogs and cats can have BOTH food and environmental allergies at the same time.  Dermatologic diligence needs to be performed to rule out the obvious (skin cytology, ringworm cultures, skin scrapes), thus, food allergy is often (not always) a diagnosis of exclusion.  It is sometimes a good idea to try a 7 day trial of low dose steroids, as most food allergic animals will have minimal response to steroids (vs. environmental allergies, where response should be drastic).

Diagnosis:  Unfortunately, there is no trustworthy blood test or intradermal skin test that can be run to diagnose a food allergy.  We have to perform strict food trials using 1 of 2 principles: Hydrolyzed protein and carbohydrate diet vs. Novel protein and carbohydrate diet.  Hydrolyzed protein is protein (often chicken or soy) that is broken down into small amino acid strands that shouldn’t trigger an immune response.  Novel protein is protein that your pet has never been fed before and, theoretically should be tolerated by the immune system and not elicit an allergic response.

Treatment:  The various options are Veterinary Prescription-only foods, however, if you are willing to cook homemade hypoallergenic foods for your pet (which can be prepared in bulk and frozen), there are many recipes available upon request.  The following are commercially available hydrolyzed and novel protein foods:

Hill’s Diets:
D/D canned/dry- salmon & potato/rice
D/D canned/dry- duck & potato/rice
D/D canned/dry-venison &potato/rice
D/D dry – egg & rice
D/D canned-lamb & rice

Low Antigen diets:
Z/D Ultra Allergen Free dry and canned-hydrolyzed chicken and refined starch
Z/D Low Antigen –dry and canned-hydrolyzed chicken and single source carbohydrate (potato)

Purina Diets:Low Antigen diets:
LA Limited Antigen dry-salmon and rice
HA hypoallergenic dry-hydrolyzed soy

Iams Diets:Prescription diets:
Response FP dry and canned-fish and potato
Response KO dry-kangaroo, canola meal, and oat flour

Royal Canin:Low Antigen diet:
Hypoallergenic HP 19 dry-hydrolyzed soy and rice

Potato and Duck dry and canned-duck protein and potato (also has light formula)
Potato and Rabbit dry and canned- rabbit protein and potato
Potato and Venison dry and canned- venison protein and potato (has large breed formula-dry)
Potato and Whitefish dry and canned-whitefish protein and potato

 

Regarding acceptable treats for food allergic dogs, I have consulted several Veterinary Dermatologists through the years and the consensus seems to be that the following items are OK to supplement your pet while on a strict food trial:

1. Marshmallows
2. Bananas
3. The wet form of your particular hypoallergenic food (meatballs as treats or meatballs baked in the oven)
4. Hill’s hypoallergenic treats (compatible with z/d, d/d, and i/d foods)

***Note:  All other treats have to be avoided, including rawhides, Greenies, carrots, green beans, etc.  Everyone in the household must be on the same page with a food trial!***

 Common Food Trial Pitfalls: 

     1.   The World Wide Web and Dr. Google

     2.   “PetStore Wisdom”
     3.   Grandma thinks its Ridiculous!!!

     4.   Dog or Cat is an escape artist

     5.   Not having other pets on the same food

     6.   Dog eats cat barf, or worse!

7. Neighbor kid(s) feed(s) the dog through the fence
8. Social Events:  How cute!  He is begging!
9. Oral Heartworm prevention – A recent study done at North Carolina State University (NCSU) found that giving Heartgard or other flavored once-a-month medications (these contain soy and beef) is enough to keep a soy or beef-allergic dog itchy despite appropriate dietary change.  Topical Revolution should be once monthly, or there is a non-chewable Heartgard option available through Merial. 

Long-term control and Re-challenging:  In the early stages of a food trial, once per month veterinary exams should be performed to make sure fleas are under control, the pet’s weight is maintaining and not considerably up or down, all is going well with the food trial (Q and A sessions about acceptable treats or other questions), and that there are no secondary bacterial or yeast infections present that will cause itching on their own. 

It is important to re-challenge (or at least discuss it) with old food for several reasons.  The first reason is to help confirm the diagnosis of food allergy.  It may be that when the food trial was started, the seasonal allergen picture was in flux or fleas may have been an issue and no longer are, etc.  Stranger things have happened!  The second reason to challenge is to help narrow down the offending agent so that a less expensive over-the-counter or home-cooked food can be used/prepared.  The re-challenge should be performed at a minimum of 8 weeks into the food trial and ideally after 2 weeks of being symptom (itch)-free.  The re-challenge should be done with a 50:50 mix of old food : new food.  Most pets will start itching within a few days, but some may take up to 2 weeks.  Steroid (either topical or oral, or both) and ear medication can be sent home to be used if needed to keep your pet comfortable during the re-challenge period.  It is important to cut out or write down the ingredient list of “the challenge food” or “old food” so that we can avoid all of the protein containing components listed, keeping in mind the most commonly implicated food allergens listed above.

That being said, many of our owners with food allergic pets find a special food that helps control the itching, and just keep their pets on this food for maintenance long-term control without re-challenging.  The “if aint broke, don’t fix it” principle.

Common Myths of Food Allergies:

There are many Misconceptions and Myths when it comes to considering food allergy for pets. The following excerpts are taken from VIN (Veterinary Information Network), and were originally posted by Veterinary Dermatologist, Carol Foil, DVM, DACVD.

MYTH:	“Food allergy ought to produce intestinal signs as it is the intestinal tract that is exposed to the allergen.”
FACT:	In pets, it is usually the skin that suffers with a food allergy. Food allergy is one of the itchiest conditions in veterinary dermatology. Making matters worse is the fact that food allergies tend to be resistant to cortisone therapies which makes itch control especially difficult.
MYTH:	“Food allergy is a less likely cause of my pet’s skin disease as we have been feeding the same food for years and the skin problem is a recent development.”
FACT:	It takes time to develop a food allergy, typically months to years. The immune system must be exposed and must develop enough antibodies to trigger an allergic reaction and this requires multiple exposures to the food in question. A reaction to a food that occurs on the first exposure to that food is not an allergic reaction. Such reactions are called “food intolerances” and involve toxins within the food but not an allergic reaction.
MYTH:	“Soy and corn are common food allergens and it is best to seek pet foods without these ingredients to avoid problems.”
FACT:	The most common food allergens for dogs are: beef, dairy, and wheat. These three ingredients account for 68% of canine food allergies. The most common food allergens in cats are: beef, dairy, and fish. These three ingredients account for 80% of feline food allergies.
MYTH:	“If it looks like my pet might have a food allergy, I should be able to manage the problem by switching to another diet.”
FACT:	Unfortunately for food allergic pets, most pet food diets contain some sort of mixture of beef, dairy, wheat, lamb, fish, and chicken. This means that simply changing foods is bound to lead to exposure to the same allergens. There are two ways to address food allergy: feeding a diet based on a truly novel protein source (this usually means an exotic diet like venison, duck, kangaroo, rabbit or even alligator) OR feeding a diet where the protein has been pre-digested into units too small to interest the immune system.
MYTH:	“My pet got only partly better after the food trial so that means it didn’t work.”
FACT:	Animals commonly have several allergies concurrently. A food allergy responding to a test diet at the same time an inhalant allergy is active will look like a partial response. On the other side of the coin, an inhalant allergy can become inactive should the weather change substantially during the diet trial. This would make a diet appear to be successful by coincidence. In order to determine if a response to a diet trial is real, at the end of the trial the patient is challenged with the original diet. If itching re-starts within feeding 2 weeks of the challenge, food allergy can be diagnosed.

Sources:

1.  Veterinary Information Network:  www.vin.com

2.  Veterinary Partner: http://www.veterinarypartner.com/Content.plx?S=0&C=0&A=652

3.  Veterinary Dermatology article on VIN: http://www.vin.com/Members/CMS/document/default.aspx?pid=38&catid=&objectid=7282&objecttypeid=10&redirectFromMiscDefault=1&calc

4.  Drawing of allergic dog and cat borrowed from:  http://www.marvistavet.com/html/body_food_allergies.html

 

 

 

Itch Much??? -- It Might be Mites!!!

By Loren W. Noblitt, D.V.M., M.S.

One of the most common reasons that a pet is brought in to the veterinary hospital is because of itching.  Allergies (environmental, flea, contact, bacteria/yeast, and food allergies) are probably the most common underlying problem in the majority of cases; however, this is not always the case.  

In addition to ear mites (which most people have heard of), there are two other types of mites that affect the skin of dogs and cats:  Demodex and Sarcoptes.  The lifecycles of these mites are very different, but the end result is often very similar:  A very itchy pet! 

Zionsville Animal Hospital has seen a definite increase in mites over the last several months, particularly in dogs diagnosed with Sarcoptic mange.  We have diagnosed it in 4 dogs and have had several other cases respond very favorably to the treatment without actual confirmation.  We think that this prevalence has to do, at least in part, to the increased number of foxes residing in Zionsville over the past year or so.  Foxes are a known reservoir of Sarcoptes scabei mites.



http://en.wikipedia.org/wiki/Dog_scabies

Sarcoptic Mange:These microscopic mites can invade the skin of healthy dogs or puppies and create a variety of skin problems, the most common of which is hair loss and severe itching (known as “Mad Itch”). While they will infect other animals and even humans, sarcoptic mites prefer to live their short lives on dogs and other members of the canid family (wolves, foxes, and coyotes).  Fortunately, there are several good treatments for sarcoptic mange and the disease can be easily controlled once diagnosed.  Canine scabies can infect all ages and breeds of dogs. While it prefers to live on dogs, this particular mite will also infect cats, ferrets, humans, and fox. Cats, fox, and humans all have their own particular species of mite within the Sarcoptes family.  Each species of mite prefers one specific kind of host, but may also infect others.  If your pet is suspected of having scabies or has been diagnosed with it, you should see a dermatologist if you have itchy skin or develop a skin rash abruptly.

Interestingly, the sarcoptic mites usually spend their entire life on a dog. The female mite burrows into the skin and lays eggs several times as she continues burrowing—this act is what is thought to incite the itch sensation. 

These mites “prefer” to live on the dog (or fox), but will live for several days off of the host in the environment.Because of the mite's ability to survive off of the host, dogs can become infected without ever coming into direct contact with an infected animal.Trees, decks, and other inanimate objects where foxes and coyotes may scratch themselves or have casual contact are thought to be the sources of infection for our unsuspecting pets.

The symptoms of canine scabies usually include hair loss and severe itching especially on the elbows, ears, armpits, hocks, chest, and belly. The mites prefer to live on areas of the skin that have less hair. As the infection worsens it can spread over the entire body.  Because of the severe itching and self-trauma to the skin, bacterial and yeast infection are common.  Trying to make a diagnosis of canine scabies can be very frustrating.  The standard method is to perform a skin scraping and then identify the mite under the microscope.  Unfortunately, on average, only ~20% of the infected dogs will show Sarcoptes mites on any given scraping. Therefore, if a dog has a positive skin scraping, the diagnosis is confirmed but a negative scraping DOES NOT rule out sarcoptic mange. Therefore, most diagnoses are made based on history and response to treatment for scabies.

The preferred treatment for scabies is with Revolution, a topical heartworm and flea preventative.  The active ingredient is called Selamectin (a derivative of Ivermectin).  The key is to apply the Revolution every 2 weeks for at least 6 weeks, and usually 12 weeks is recommended with confirmed cases.  I like to give a dose of injectable Ivermectin on Day 1 of a confirmed case of scabies to “get the ball rolling” and start killing these little buggers ASAP.  Because of the damage to the skin in sarcoptic mange, many dogs also have bacterial and or yeast infections and these obviously need to be treated as well.  Skin cultures are preferred, especially in severe cases, to make sure that the correct antibiotic or antibiotics are given.

Because your dog does not have to come into direct contact with an infected dog to contract scabies, it is difficult to completely protect him. Places where large numbers of dogs congregate are obviously more likely to harbor the mange mite.  Since foxes and the environment in which foxes may spend a large amount of time can transmit the mite to dogs, keep dogs away from fox and these areas.

Is Sarcoptic mange contagious to me or my other pets?  Yes, although when humans get Sarcoptes scabei from animals, the disease is generally self-limiting, causing only temporary itching. There is a human species of Sarcoptes, which is transmitted from person to person. This human species of sarcoptic mite causes a rash on the wrists, elbows, or between the fingers. In infants, the rash may appear on the head, neck, or body.  Other dogs in the house need not be isolated from each other, but because the treatment of scabies is relatively straightforward, it is recommended, however, to treat all pets in the household when there is a confirmed case.

Demodectic Mange:
Demodectic mange, also called demodicosis or “Red Mange,” is caused by a microscopic mite of the Demodex genus.  These mites are transmitted by mothers to their young through cuddling and nursing during the first few days of life.  Most live in harmony with their mites, never suffering any consequences from being parasitized.  However, if conditions change to upset the natural equilibrium, such as some kind of suppression of the dog's immune system (stress or long term/chronic use of steroids), the Demodex mites may gain the upper hand. The mites proliferate and can cause serious skin disease.  The mites burrow into the actual hair follicles, causing itching and hair loss, as well as secondary bacterial/yeast infections.

http://en.wikipedia.org/wiki/Dog_demodex

Demodectic mange is NOT considered a contagious disease (to people nor to other dogs or cats) and isolation of affected dogs is generally not considered necessary.  While there are still assorted theories about dog to dog transmission of Demodex mites, there is no question that mites cannot be transmitted to humans or to cats. 







Demodicosis has Three (3) Forms:  Localized, Generalized, and on the Feet (Demodectic Pododermatitis):
1)   Localized demodicosis occurs as isolated scaly bald patches, usually on the dog's face, creating a polka-dot appearance.  Localized demodicosis is considered a common puppyhood ailment and approximately 90% of cases resolve with no treatment of any kind. 

2)  Generalized demodicosis the entire dog is affected with patchy fur, skin infections, and bald, scaly skin.  The entire body is typically affected, and the secondary bacterial infections make this an itchy and often smelly skin disease.  Treatment is needed to facilitate recovery.
 
3)  Demodectic Pododermatitis is confined to the paws.  Bacterial infectious usually accompany this condition. Often as generalized demodicosis is treated, the foot is the last stronghold of the mite.  Old English Sheepdogs and the Shar Pei tend to get severe forms of this condition. The infection can be so deep that biopsy is needed to find the mites and make the diagnosis.  It is one of the most resistant forms of demodicosis.

Treatment:  Ivermectin (Ivomec 1%) is a broad spectrum anti-parasite medication with a number of uses, including killing demodex mites.  Ivermectin is inexpensive and involves no labor-intensive bathing.  It DOES, however, taste terrible if given orally.  It requires daily treatment in most cases and should be continued for a minimum of 3 months, or 2 negative skin scrapes 1 month apart.  There is, unfortunately, an important occasional problem that keeps other treatment options listed: drug sensitivity.  Some individual dogs are sensitive to ivermectin and can die if subjected to a typical therapeutic dose for demodicosis.  Benzoyl Peroxide Shampoos (e.g., Pyoben) are great to use with affected animals because it penetrates and flushes out the hair follicles, deep where these mites live on the animal’s skin.  Amitraz dips on a weekly basis are effective, but labor-intensive, and are usually reserved for dogs that don’t tolerate the oral Ivermectin.

Relapse?
When relapse occurs it is often because the dog appeared to be normal and the owner did not return for the appropriate re-scrapings. Relapse is always a possibility with generalized demodicosis as there is no easy way to confirm that every mite has been killed, but most dogs that relapse do so within a 6 to 12 month period from the time they appear to have achieved cure.

Sources:

1.  Veterinary Partner (www.veterinarypartner.com)

2.  Wikipedia (http://en.wikipedia.org/wiki/Dog_scabies)

3.  Wikipedia  (http://en.wikipedia.org/wiki/Dog_demodex)

4.  Dr. Fosters and Smith (http://www.peteducation.com/article.cfm?c=2+2111&aid=764)

 

 

 

Why Do Dogs Eat Grass?

By:  Loren W. Noblitt, D.V.M, M.S.

 

A lot of dogs (and some cats) eat grass.  I am commonly asked, "Why does [ENTER PET'S NAME] eat grass?" - I file this question under my "if I knew the answer and how to stop it, I'd have a million dollars", category of questions.  There seems to be multiple acceptable answers to this question - no one knows for sure in all cases. There are some very interesting theories to help explain our pets' 'fondness for forage', and they are as follows:

 www.thepetcentral.com

• Boredom behavior
• Dietary deficiency
• To induce vomiting
• Biologic/Ancestral influence

Let’s take a look at each of these individually now.

1)  Boredom behavior   
Some dogs flat out, just like to eat grass.  They like the taste and they like the texture.  Some particularly like certain types of grass, like fescue grass.  In these dogs there is no underlying pathology or illness causing them to eat grass.  This is not true of most dogs, and, for the most part eating grass is an inappropriate behavior and justifies some looking deeper to try to see why this habit is occurring.  Lack of stimulation during confinement in a particular environment, such as the back yard, can motivate a dog to eat grass or other various environmental substances. This condition, called pica is characterized by the consumption of non-nutritive material such as mulch, cat litter, grass, rocks, clothing, dirt, even feces.  Pica leads to vomiting, diarrhea, and intestinal obstruction or perforation.  Pica behavior can be reduced by providing your pet with stimulating and appropriate chew toys, more attention, and as a last resort: a basket muzzle. 

Try not to make it a “big production” if your pet puts an inappropriate item in their mouth, as this can eventually lead to attention-seeking behavior and can fuel a pica disorder.  Calmly walk over and remove the item from your pet’s mouth and replace it with an appropriate item, such as a Kong (available for both dogs and cats), Tartar Shield sticks, and Greenies.  Pica can be caused by underlying medical abnormalities, therefore veterinary examination, laboratory testing (blood/urine/fecal tests, radiographs, etc.) and dietary evaluation should be explored.  If your dog is eating his/her own feces (a subset of pica known as copraphagia) there are a wide array of anecdotal suggestions your veterinarian will likely have for you.  Contact the veterinarians at Zionsville Animal Hospital if your dog displays this unfortunate habit!

2) Dietary Deficiency

Veterinary behaviorists and nutritionists speculate that dogs eat grass to compensate for nutritional deficiencies, iron and fiber are among the most commonly sited suspected deficiencies.   A reduction in your dog’s grazing may be achieved by simply adding fresh greens and/or fibrous vegetables or fruits to their diets.  Leafy greens like kale, broccoli, and parsley and pineapple have all been reported to yield favorable results.  It should be noted that vegetables are most palatable (and digestible) when steamed and pureed or finely chopped before being incorporated into a dog’s meal.  Additionally, dogs that eat a diet based in whole foods (which requires owners to cook meals at home) instead of commercially available, processed, non whole-food based dry (kibble) or canned foods tend to exhibit less foraging behavior.

3)  To Induce Vomiting

Plant material is composed of insoluble fiber that is not readily digestible and irritates/inflames the stomach wall.  Dogs seem to “know” this instinctively.  Grass accumulates in the stomach instead of moving into the small intestine, like food normally would.  It also can pass through, undigested, and you'll see green blades in the feces (if you look carefully enough).  Underlying illnesses like Inflammatory Bowel Disease (IBD), stomach or intestinal parasite infestation, metabolic diseases of the kidneys, liver, or pancreas, and pica (discussed above) can stimulate the physiologic urge to vomit.  Therefore, dogs can eat grass as a means of facilitating their own vomiting and for reducing nausea.

4)  Biological/Ancestral Influence

Grass eating is a behavior exhibited by wolves.  An article in the Journal of Veterinary Behavior suggests that the grass eating traits of a nursing mother can influence similar behavior in her puppies. Your dog’s mother, grandmother, and so on may be partly responsible for imparting modern-day grass eating tendencies.   Conversely, another study looked at grass-eating dogs and no link was found to diet or history of gastrointestinal disease. Some dogs were reported to only eat grass if they already had an "upset stomach", and needed to vomit.  Most dogs seemed to eat grass because they liked it!

As a veterinarian, I see grass-eating dogs inadvertently ingesting toxins such as fertilizer, pesticide, and other unhealthy environmental debris (particularly rocks!).  Recently pesticides and some fertilizers have been linked to cancer in dogs and can cause temporary neurological problems (http://www.vet.purdue.edu/pcop/files/docs/CanineUrinaryBladderCancer.pdf). 

It's not surprising that the veterinarians at Zionsville Animal Hospital recommend dog owners take appropriate measures to deter grass munching, during all stages of life, and encourage owners to explore the possibility that there is an underlying reason for it.  However, there is a good possibility that the answer will be, “ Because he likes it," or, "Because the grass can't outrun him."

Nutraceuticals: The Good, The Bad, and the Worthless

        By:  Loren W. Noblitt, D.V.M., M.S.

     A question that I am asked very frequently (almost daily it seems), is, "Can I (safely) give my dog or cat the same over-the-counter (OTC) supplements that I take?" The answer is, "it's complicated." I mean, seriously -- EFAs, PUFAs, EFA, EPA, DHA, GLA, LPO -- What do all these letters and abbreviations mean? What do essential fatty acids do anyway? How should you use them? What dosage? What brands are available? Are they all the same? What about probiotics, cranberry extract, and appropriate liver support?

     Ok, Ok, Ok - it's REALLY complicated.
    
The term "nutraceutical" is defined as "a food or a part of a food that provides medical or health benefits."  Nutraceuticals and dietary supplements are commonly used in both veterinary and human medicine.
     
Since there is no regulatory body for the manufacturing of nutraceuticals, it becomes difficult to assess product quality.  Drugs regulated by the FDA must meet specific manufacturing standards. Nutraceuticals...not so much.  Studies have shown that nutraceuticals are commonly mislabeled; may contain impurities, such as heavy metals, toxins, bacteria, molds; may have variable quantities of active ingredients; may fail to dissolve (thereby remaining ineffective).  Though the label may say "X mg", it is possible that some capsules have less (even zero) and some may have more.

That's the clear advantage of Nutramax products:  What they say is in each capsule, really is. 

     Case in point:  Many of the OTC glucosamine and chondroitin products are made from shark cartilage or other hard-to-metabolize products.  They often pass through the gastrointestinal tract without reaching significant levels in the joints, largely because of stomach acid degradation.  Some of these products come from other countries (i.e., Mexico, China, Brazil, Malaysia, etc) and are not proven to be toxic free or even effective, at all.  It is for all of these reasons that the Veterinarians at Zionsville Animal Hospital consistently recommend products like Dasuquin, Cosequin, Proviable probiotics, Denosyl, and Welactin fish oils -- all of which are made by the Nutramax company.

     To date, the Nutramax company has done virtually all of the available Veterinary studies in terms of effectiveness, batch variance, and bioavailability.  They have the research around their Cosequin product to prove it works, and better yet, the NEW! Dasuquin has added soybean and avocado extract, which has been found to reduce pain and inflammation, as well.  Does this mean that only their products are effective?  Likely not, but we can't say for sure.  The same holds true for the Omega 3's, probiotics, cranberry extract, and liver support (to name just a few). 

     Welactin has been extensively studied and remains the top additive of omega 3 essential fatty acid available to pets in the form of a supplement.  Of note here is the Hill's Pet food company and their j/d (Joint Diet) fortified with serious omega 3 fatty acids.  Hill's veterinary nutritionists say that you'd need to give ~two (2) dozen fish oil capsules to a large dog to approximate the omega 3's in a serving of Hill's j/d food.  These products are all promoted and sold at Zionsville Animal Hospital for these reasons.  Hill's j/d food is available upon request.

What's the BIG DEAL about Fish Oil (Omega-3 and 6 fatty acids) anyway?
Omega-3 and 6 fatty acids are classified as "essential"-- hence the term Essential Fatty Acids, or EFAs -- because humans and other animals are unable to synthesize them naturally.  Omega 3's have received much attention lately, and the important thing to know about them is they come in two varieties EPA and DHA, both are good!. 

Most EFAs are obtained from fish, crustaceans, and vegetables.  It was once thought that omega 3's were the better of the two because they were more anti-inflammatory than the omega-6's; however, this is no longer considered to be the case by Veterinary Dermatologists.  There is evidence that fish oil works to decrease the itching threshold, or "pruritic threshold", in dogs and cats with allergic skin disease (pollen allergy or atopy) and a recent clinical trial demonstrated a steroid-sparing effect of fatty acids due most likely in part to suppression of histamine and prostaglandin release.  Welactin fish oil is free of any proteins, which are the allergens in diets. Thus, theoretically, it should be safe to feed fish oils to animals with dietary allergies, so long as they're produced by reputable companies (i.e., Nutramax) that have repeatable quality control measures.  Your veterinarian may opt to withold fatty acids in the early stages of a dietary food trial (if a food allergy is suspected in your pet) in attempts to not "muddy the waters" in trying to arrive at a diagnosis. 

Fish oil is often used in cases of joint disease and osteoarthritis because of these inherent anti-inflammatory effects, and also a joint lubrication effect.

     When fatty acid supplementation is needed, it should be done at 180 - 200 mg of combined EPA and DHA fatty acids per 10 pounds of you pet's bodyweight.  The table below lists some of the preferred veterinary supplements on the market, and provides an omega-3 EFA dose per capsule or pump.  Zionsville Animal Hospital carries all 3 of these products and will be available via our online pharmacy coming soon:
            
        Product                                Omega-3 EFA Concentration/Dose         Amount per Pet
1)  Nutramaxlabs Wellactin                        270mg/capsule                             1 capsule per 20lbs
Omega3 Canine Gel-caps

2)  Nutramaxlabs Wellactin                        250mg/capsule                              1 capsule per cat
Omega3 Feline Gel-caps

3)  Nutramaxlabs Wellactin                      1300mg/5ml (1 tspn)                        5ml per 35kg
Omega3 Canine Liquid

     Ultimately, studies demonstrating the clinical benefits of a nutraceutical should be evaluated.  For example, several peer-reviewed studies exist documenting improvement in clinical signs with chronic osteoarthritis in dogs or horses given glucosamine or chondroitin sulfate (or combinations of these compounds). However, clinicians should examine how the studies were conducted, to determine their likely validity, because many studies are poorly designed or executed.
    
     In summary, neutraceuticals are not regulated by the FDA, as they are not considered to be "drugs." This means that they can be sold without scientific proof of effectiveness, without assuredness of safety and consistency from batch to batch, and without mandatory testing to determine the optimal dosage in target animals.  There are numerous anecdotal reports of these medications helping numerous individuals (both human and animal) but one should keep in mind that scientific investigation is continuing. 

     The best thing to do for your pet is to follow your veterinarian's advice and use reputable products when it comes to fish oil, glucosamine/chondroitin, or other supplementation, when possible.  If this cannot be done for whatever reason, try to keep the following suggestions in mind to help weed out inferior OTC nutraceutical products.

1.   Price.  Cheaper compounds are less likely to be of high quality. This has been the general observation with chondroitin sulfate.

2.   Pay attention to whether or not the product has a lot number and an expiration date.

3.  There is a general USP veterinary page (for veterinary drugs, requires free registration) and the USP Dietary Supplement Verification Program page, which provides a list of suppliers that have voluntarily submitted their products for USP verification and approval. These products carry the following mark:
                                                      
4. Claims of safety or efficacy.  If a nutraceutical claims a medical benefit on the label, there should be a New Animal Drug Application (NADA) number accompanying the product. While this is "mandated" by law, it is often ignored.  A NADA tends to suggest higher quality, because the manufacturer has bothered to abide by FDA regulations for drug manufacture.

5. Ingredient list. All ingredients should be listed by order of magnitude based on weight.

6. Scientific evidence supporting manufacturer's claims. Some manufacturers have begun providing data for their specific products through independent scientific studies. These studies should ideally be peer-reviewed and published. Importantly, they should be clinical studies, not in vitro studies. There are institutes, affiliated with universities and medical schools, who are beginning to investigate nutraceutical claims scientifically. These include The Nutraceuticals Institute, The Institute of Nutraceutical Research, and others.

7.   Testimonials in place of valid research.  Many companies provide testimonials from "satisfied clients".  These should be ignored, and companies that promote these instead of scientific research supporting their claims, should be viewed skeptically.

8.   Membership in National Animal Supplement Council (www.nasc.cc). This industry group has a close relationship with FDA and strict guidelines for member companies regarding quality control and adverse event recording. Member companies are likely to have better quality products.

Several websites exist that may help you investigate specific nutraceuticals:
1. www.quackwatch.com
2. www.herbalgram.org
3. http://nccam.nih.gov
4. www.navigator.tufts.edu/index.html
5. www.consumerlab.com
6. www.biovalidity.com

Photos coutesy of:  www.nutramaxlabs.com

Feline Diarrhea: Tritrichomonas and Giardia

                                          By:  Loren W. Noblitt, DVM, MS

Few conditions are more frustrating for veterinarians (and owners) than feline diarrhea.  I know that I always cringe a little inside when I'm confronted with these cases.  Primary causes of diarrhea, like gastrointestinal inflammation, infection, dietary changes, and cancer should all be considered, as well as secondary causes like liver, metabolic, and pancreatic disease.  The first diagnostic step (if the answer isn't obvious) is to obtain baseline blood work (CBC/Chemistry/Thyroid level), a fecal sample, and a urine sample.  Sometimes, a gastrointestinal (GI) blood profile test is indicated on a case-by-case basis.

In the infectious category, usually the cause will be related to bacterial infection, either from stress (immunosuppression that allows low level anaerobic, "bad" bacteria to thrive), dietary indiscretion (introduction of "bad", foreign bacteria either from human food, trash, feces, or an animal carcass), or a very recent food change (malabsorption, food intolerance, or digestive problems).  When treatment for these more common causes fails to yield resolution of diarrhea, or if the diarrhea has been a chronic longterm issue for your cat, the veterinarian likely will discuss Tritrichomonas foetus (T. foetus) and Giardia.

T. foetus and Giardia are both protozoal diseases, meaning that they are neither bacteria nor virus, but rather a life-form in-between (so to speak); they are both transmitted by the fecal-oral route (through direct contact with feces), and Giardia can be found in unclean water.  Let's now discuss the salient features of each of these pathogens, focusing on risk factors, diagnosis, and treatment.

T. foetus is an emerging parasite in the feline world, however, it was first discovered in cattle as a cause of abortion (thus the species name: 'foetus'), and is spread as a venereal disease amongst cattle. Surveys have suggested that approximately 1/3 of all purebred cats are infected. It is rarely tested for and may be responsible for many of the cases of chronic diarrhea (e.g. inflammatory bowel disease) in cats.  A T. foetus organism looks very similar to Giardia so if viewed by in a fecal smear a misdiagnosis of Giardia is common. Fecal floats and Giardia snap tests are insensitive to it. T. foetus is a fragile organism whose life span out of the body is normally less than an hour. This lack of hardiness is due to the fact that T. foetus cannot form a cyst.  If T. foetus dries out, if it is refrigerated, or if it experiences temperatures above 105°F, it will die.  Good News!!! 

The protozoan lives in the intestinal lining of the large bowel.  It causes "cow pie" like stool that is often gassy and malodorous. The health of the cat is not usually adversely affected.  Cat breeders have commented that in symptomatic cats that the smell of the stool is a significant clue of an infection. It is important to note that an infected cat may or may not have clinical signs of tritrichomoniasis.

T. foetus is typically transmitted by an infected cat to other cats sharing the same litter box. Currently, the preferred and most reliable test to confirm diagnosis is a PCR test using the cat's stool sample.  Follow this link to see video of T. foetus and Giardia in action (Quicktime required): http://www.ncsu.edu/project/cvm_gookin/Tfoetusvideo.mov

Treatment of the T. foetus  infection is difficult due to drug resistance. Traditional antiprotozoal drugs such as Panacur and Metronidazole do not alleviate the symptoms, and as mentioned above, often is the first indicator that T. foetus infection may be present. Some antimicrobial drugs have been shown to improve symptoms but do not eradicate the parasite.  Ronidazole has had good efficacy in eradiation of the parasite in cats but has the potential for a variety of side effects, most notably, neurological side effects.  During treatment, the cat should be engaged in play activity regularly to ensure they are not experiencing neurological side effects, or motor skills impairment.  Two weeks of ronidazole, dosed at 30 mg/kg, once daily, is currently the recommended dosage. Care should be exercised (wearing gloves) while handling ronidazole, which can be toxic to humans.

During treatment, the cat should be keep isolated from other cats as to prevent the spread of T. foetus to another cat. Your cat should be fed a prescription high fiber food to help clear the organisms from the colon and to help heal the colon cells.  A common GI diet remedy in cats (boiled chicken breast and white rice) may be highly beneficial during and after treatment.

Treatment with ronidazole has shown good efficacy, and some positive results may be achieved after just two to three days of treatment, but completion of the two week cycle of drugs to avoid the risk of recurrence.  It is essential that a PCR test be conducted after treatment to verify that the organism has been completely eradicated.  It is also recommended that a follow-up test be performed a few months after the first.  Interestingly, cats that carry T. foetus and are not treated, usually cure themselves of the parasite within 2 years.

                                                                   
                                                    Giardia, in its motile Trophozoite form (above and below)

Photos courtesy of:  http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/Giardiasis_il.htm

 

Giardia is a single-celled protozoan that affects the intestinal tract of mammals and usually causes diarrhea and can cause vomiting.  Definitive diagnosis comes from an enzyme-linked immunosorbant assay (ELISA) test using a stool sample.  Dogs and cats can become infected when they swallow Giardia that may be present in stagnant puddles of water or unclean drinking water. It is primarily contracted from the stool of infected animals, both wild and domestic.  Having giardiasis for a long time can cause weight loss, generally poor condition, and even death when the disease is serious. You might notice blood in your cat's stool from irritation that the Giardia parasite causes to the lining of the small and large intestines; however, many cats infected with Giardia do not show any signs of disease. The best way to prevent Giardia infection is to make sure that your cat has a safe, clean drinking water supply.  It is important not to allow cats to drink water from areas where other animals have left their feces.  Pick up soiled litter left by your cat or cats daily and place it in the trash.  Take care not to track animal feces into your house or environment where the cat will be.

The best treatment for Giardia is a six day course of an antiparasitic medication called Panacur (Fenbendazole), and on days #3 and #6 of the treatment, use wet wipes or soap and water to thoroughly clean your cat's rear end and tail.  This will cut down on the number of Giardia cysts that stick to the hair and will help prevent your cat from re-infection by normal cat grooming behaviors.  Bleach (diluted 1:20) or Lysol spray should be used to clean the litter boxes (allowing 10 minutes of good contact time before wiping), as these are both quaternary amines that are able to destroy the Giardia cyst lifeforms.  Importantly, a stool sample should again be checked in 1 month after the treatment was started to make sure the giardiasis is cured. 

As a veterinarian, I am often asked the question, "Can my cat (or dog) get Giardia from my dog (or cat)?"  The answer is Yes.  Either.  We typically recommend treating all the animals in the household when one animal is identified as being a Giardia carrier. 

Also of note, there is a chance that humans can be harmed by the same Giardia that affects their pets, but zoonotic infection (infection passed from animal to human) is extremely rare in this particular case.  It is likely that most people become infected with Giardia passed by other people rather than Giardia from pets.  Be sure to avoid contact with feces by using gloves, a bag over your hand, or a scooping device.  Also, be sure to thoroughly wash your hands after picking up feces.

Heartworm Disease: An Ounce of Prevention is Worth a Pound of Cure

By:  Loren W. Noblitt, DVM, MS

     Heartworm disease is a serious and potentially fatal condition caused by parasitic worms called Dirofilaria immitis.  These worms-heartworms-live in the arteries of the lungs and occasionally in the right side of the heart of dogs, cats and other species of mammals including wolves, foxes, ferrets, sea lions and, in rare instances, human beings!  Heartworms are classified as nematodes (roundworms) and are filarids, one of many species of roundworms. Dogs and cats of any age or breed are susceptible to infection.
    
     Naturally acquired heartworm infection in dogs and cats is identified as a worldwide clinical problem in veterinary medicine today. Despite improved diagnostic methods, effective preventives, and increasing awareness among veterinary professionals and pet owners, cases of heartworm infection continue to appear in pets around the world.  It occurs wherever the following four factors are found: i) a susceptible host population, ii) a stable reservoir of the disease, iii) a stable population of vector species, iv) a climate that supports the parasite's life cycle.
    
     Dogs are considered to be the definitive and "susceptible host" for the heartworm parasite, meaning that even though the disease is not transmitted directly from one dog to another, untreated dogs provide a "stable reservoir" for the disease for mosquitoes. Mosquitoes of several different species are the "stable vectors" and are considered to be intermediate hosts for the developing microfilariae (baby heartworms).  Development of the microfilariae in the mosquito requires a temperature at or above 80 degrees F for about two weeks.  Interestingly, no larval development takes place in the mosquito below 57 degrees F.
    
     In the United States, heartworm disease continues to be a problem.  It has been reported in all 50 states, all countries, and all continents except Antarctica. The map below shows particularly endemic areas in the United States based on the number of cases reported by clinics.  Note that Indiana is in the "26-50 cases" of Heartworm disease reported per Veterinary clinic, and that on average, the Zionsville Animal Hospital treats 10-15 cases of heartworm disease per year.


The Life Cycle

     Adult female heartworms bear live young - thousands of microfilariae in a day-released into an animal's bloodstream. Then, while taking a blood meal from the infected animal, mosquitoes become infected with these microfilariae.  During the next 10 to 14 days, the microfilariae mature to the infective larval stage within the mosquito. After that, the mosquito bites another dog, cat or other susceptible animal (see above), and the infective larvae actually burrow into the animal through the mosquito's bite wound and undergo several changes to reach adult form.  They then travel to the right side of the heart through a vein and await the opportunity to reproduce.
    

Heartworms in the Pulmonary Artery of a dog

    
    
     Microfilariae cannot mature into adult heartworms WITHOUT first passing through a mosquito.  It then takes a little over six months for the infective larvae to mature into adult worms. In dogs, the worms may live for up to seven years if there is no treatment given.  Adult heartworms can reach twelve inches in length and can remain in the dog's heart for years.  In cats, by contrast, heartworms live only several years.  In both cases, there can be tremendous, long-term damage to the lungs as a result of heartworms.

What Are the Signs of Heartworm Disease?

     For both dogs and cats, clinical signs of heartworm disease may not be recognized in the early stages, as the number of heartworms in an animal tends to accumulate gradually over a period of months and sometimes years and after repeated mosquito bites.  The first sign of heartworm infestation is often a soft cough that increases with exercise, and commonly may be dismissed as being trivial or unimportant by the owner.  But often the cough worsens and the dog may actually faint from exertion, tires easily, becomes weak and listless, loses weight, and may cough up blood.  Breathing becomes more difficult as the disease progresses because the worms are multiplying in the lungs and heart. The progression is traumatic: the dog's quality of life diminishes drastically and he/she can no longer retrieve a ball or Frisbee; can no longer take a nice walk in the park without respiratory distress.  Congestive heart failure ensues, and the once-active family pet is in grave danger.
    
     Cats may exhibit clinical signs that are very non-specific, mimicking many other feline diseases.  Chronic clinical signs include vomiting, gagging, difficulty or rapid breathing, lethargy and weight loss.  Signs associated with the first stage of heartworm disease, when the heartworms enter a blood vessel and are carried to the pulmonary arteries, are often mistaken for feline asthma or allergic bronchitis, when in fact they are actually due to a syndrome defined as Heartworm Associated Respiratory Disease (HARD).  Chest x-rays and objectively measuring the cat's heart, in conjunction with heartworm blood testing, should be done to look for heartworm disease.  These tests are recommended even if a cat has been on heartworm prevention reliably.
Detecting Heartworm Disease
    
     Heartworm infection is usually detected with blood tests for a heartworm substance called an "antigen" (found only on the adult female's body) or actually seeing the microfilariae under the microscope on a routine blood smear.  Neither test is consistently positive until about seven months after infection has occurred.  An antibody test is the preferred blood test for cats because the worm burden is usually smaller in cats versus dogs and there may not be significant antigen (e.g. significant number of female worms) in an affected animal's blood to make the test positive. Heartworm infection may also occasionally be detected through ultrasound and/or x-ray images of the heart and lungs, although these tests are usually used in animals already known to be infected.
Prevention
    
     Because heartworm disease is preventable, the American Heartworm Society (AHS) recommends that pet owners take steps now to talk to their veterinarian about how to best protect their pets from this dangerous disease.  Heartworm prevention is safe, easy, and inexpensive; however, treatment for heartworm disease is a complicated and expensive process, taking weeks for infected animals to recover and, during the recovery period, STRICT exercise restriction is mandatory. Recently the drug used to treat heartworms in dogs, Immiticide (melarsomine), has become increasingly hard to obtain, resulting in some animals with heartworm disease having to wait for treatment to be available. Thus, the expression, "an ounce of prevention is worth a pound of cure" is truly apropos. There is currently no effective treatment for heartworm disease in cats, so it is imperative that disease prevention measures be taken for cats, especially for at-risk, outdoor cats in particular.  For more information on this, please ask your veterinarian.
    
     There are a variety of options for preventing heartworm infection in both dogs and cats, including monthly tablets (Interceptor, Sentinel, and Trifexis) and chewables (Heartgard Plus), monthly topicals (Revolution and Advantage Multi) and a recently re-released, six-month injectable product called ProHeart available only for dogs.  Some of these preventives also kill gastrointestinal parasitic worms and fleas, as well.  All of these methods are extremely effective, and when administered properly and on a timely schedule, heartworm infection can be completely prevented. These medications interrupt heartworm development before adult worms reach the lungs and cause disease.  Veterinarians recommend a year-round heartworm prevention program to guard against the occasional mosquito flying about in areas with mild winters, such as Indiana.

Treatment

     The first step is to evaluate the dog and treat any secondary problems of heart failure, liver or kidney insufficiency, so that he/she can withstand the treatment. The next step is to kill the adult worms with Immiticide (an arsenic compound).  This compound is carefully injected deep into the muscles adjacent to the lower spine through a series of treatments. Treatment may be administered on an outpatient basis, but hospitalization is sometimes recommended, depending on a number of variables such as energy level, attitude, home environment, other pets or not, etc.  When the dog returns home, strict exercise restriction must be enforced to decrease the risk of partial or complete blockage of blood flow through the lungs by dead worms ("worm plugs" or "worm mats").  Importantly, re-infection during treatment is prevented by administration of a heartworm preventive, as described above.  Usually, all but the most advanced cases of heartworm disease can be successfully treated in dogs.  Again, there are no products in the United States currently approved for the treatment of heartworm infection in cats-the disease just has to run its course.  Veterinarians will often attempt to treat an infected cat with supportive therapy measures to minimize immune reaction; however it is always best to prevent the disease.

     For more information on heartworm disease or if you have specific questions about this disease or specific preventives for your dog or cat, please contact the veterinarians or staff at the Zionsville Animal Hospital.

Photos Courtesy of:  The American Heartworm Society
http://www.heartwormsociety.org/pet-owner-resources/heartworm.html