Sweet Itch aka Queensland Itch aka Culicoides hypersensitivity is one of the most common skin problem in horses and is also the hardest to treat.  It is a horse owner's worst nightmare ! 

Sweet Itch is an allergy to insect bites. Mosquitos, black flies and no-see-ums have all been implicated as the cause of extreme itching and scratching which can lead to hair loss of at the mane,tail and belly, self trauma, and multiple open wounds with secondary bacterial infections. 

The saliva of these little blood suckers contains allergens that cause an intense itching. The horses will try to scratch on anything available to relieve the itch and in doing so can cause deep wounds and hair loss. Once the itching has begun, it is very difficult to control so preparation and prevention is key. The biological process is similar to hot spots in dogs which is caused by an allergy to flea bites. See my blog post about hot spots in dogs. 
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Why do some animals have allergies to certain things and some do not ? The answer is that allergies are cumulative. You may have a tolerance for pollen and cats and dust if exposed to any one of those things alone, however, if you encounter all 3 at once, your immune system will over react. You will be pushed beyond your allergy tolerance threshold, your body will release inflammatory mediators like histamine and cytokines that cause watery eyes, itchy skin, hives, sneezing, coughing and if severe, may constrict your airway.  The same is true in horses. They are exposed to lots of allergens in their daily life, mold, dust, pollen and bugs but when the swarms of biting flies emerge in the summer, they are pushed beyond their allergy threshold. 

​Recognizing the symptom is key. The photos below show advanced stage disease. ​

Let’s talk about prevention. Before the fly season begins you can prepare your horse and barn with some diet and lifestyle changes. 

1. Reduce contact with Insects

I know easy to say, hard to do. Most biting flies have a feeding pattern. Culicoides and gnats favor dusk and dawn while mosquitos are most active from dusk through early evening. Keeping your horse in the stable with a strong fan with plenty of fly spray may help. Fly sprays are short acting but can provide some relief. Some natural alternatives are Eco-vet and Repel which is made with Oil of Lemon Eucalypus. Gnats and no see ums are not strong fliers and will avoid the turbulence of a fan. When they do go out, fly sheets and face masks are a great help. 

To reduce the number of biting flies in your stable area you can reduce the breeding ground areas like stagnant water, long weeds and manure piles. A natural way to reduce emerging larvae is to treat ponds, streams and standing water with BTI aka mosquito dunks. Bacillus thuringiensis subspecies Isralensis, is a naturally occurring bacteria in soil. It produces toxins that only affect the larvae of mosquitos, blackflies and gnats. It is safe for all other animals, insects and plants and approved for pest control for organic farms. Spray BTI in ponds, use dunks in running water or drainage ditches. Make traps with bti in buckets of water with grass clippings or pulled weeds. Mosquitos and gnats will lay eggs there but they will never hatch. Goldfish and mosquito fish may be available from your county free. Dump water troughs every few days and some shell or gravel around the trough will prevent muddy puddles from becoming gnat nurseries. 

2. Reduce contact with other allergens

Mold and Dust are part of a horse's daily life. To reduce exposure, do not sweep or blow the barn aisle when horses are inside ! This is one of the worst things you can do to your horse's immune and respiratory system. Feed high quality hay and wet it down or soak it in a net for a few minutes before feeding. Do a full cleaning of the inside of the barn before allergy season. 
Inflammatory Foods processed foods and an unbalance ratio of omega 6 to omega 3 fatty acids tend to contribute to inflammation. Black oil sunflower seeds are high in vit E but have a high level of Omega 6. This ratio can be balanced to the ideal level of 1-4:1 (meaning approx 1-4 parts omega 6 to 1 part omega 3) by adding Chia seeds which are very high in Omega 3s.  

3. Increase your horse's allergy threshold
You can increase your horse's allergy threshold by increasing the levels of omega 3 fatty acids in the diet. As mentioned above, chia seeds are a great source of omega 3s and horses love them. Antioxidants can also help increase your horse's allergy threshold. Some foods therapy suggestions for horses are seaweed (kelp or spirulina), gogi berries, spinach, green tea, ginger and of course, Dr. Doug's favorite, turmeric. 

4. Avoid Immuno-stimulants
Vaccines stimulate the immune response to protect your horse from disease. Try to vaccinate early in the season before the emergence of biting flies. Killed vaccines and ultra purified vaccines do not cause as strong of an immune response as modified live and recombinant vaccines. 

So you have taken all the steps for prevention and your horse still has sweet itch. Now it is time to treat. Treat early in the course of the disease if possible when you first see the signs of hair loss and itching. 

The TCVM diagnosis is Wind (Itching) and Damp Heat (red crusty inflamed and infected skin) 

Acupuncture and Chiropractic Care can help reduce the itching and rebalance the immune system. To find a veterinarian trained in TCVM near you, search by your zip code at the Chi Institute page www.tcvm.com.

Herbal Therapy includes formulas to Tonify the Blood to stop itching and Clear Heat.

For Topical Treatment we recommend Dr. Ying's Sweet Itch Cream, a soothing blend of coconut oil, Chinese herbs and essential oils to relieve itching, soothe irritated skin, prevent secondary bacterial infection and repel biting insects.

We also have 2 herbal formulas to be given orally for Sweet Itch. The TCVM diagnosis from your veterinarian will help determine which is the right choice for your horse. 

Damp Heat Skin Formula or External Wind Formula can help relieve the itching and inflammation in the skin. 

Food therapy is a very important part of the treatment. As mentioned above, omega 3 fatty acids and antioxidants need to be included in the diet. Foods that Tonify Blood and Cooling foods can be beneficial. Apricots and dates Tonify Blood, Barley, cucumber and green tea can Drain Damp and are Cooling. 

So as you can see, sweet itch can turn into a mid summer nightmare for you and your horse. Do your best to prepare for the season and change the things you can control. You don't need to do them all. If you live next to a creek or if the barn manager refuses to turn the horses out before they blow the barn, well ok you have to live with it but at least you can add some food therapy treats or some herbs or sneak some BTI into your neighbor's pond to get you one step closer to a happier, healthier summer. 

In Episode 294 : GMHA and Dr. Coggin's Test
We talk to Dr. Oscar Fletcher who was the Dean of NCSU-CVM from 1992-2004 (my Dean from way back in the 90s) to share his memories of Dr. Coggins and his insights on the history and importance of Dr. Coggins' Test.

TCVM segment starts at 29:35

In our practice, we sometimes have clients ask... 

"Why does my old retired horse need a coggins, he doesn’t go anywhere ?"
or they say, " Have you ever seen a positive ?"  

Well thankfully no, I have never seen a positive and I hope from routine testing, I never will. With our ever increasing urbanization of the USA, even horses who don’t travel, live in close proximity to others so we have to think about herd health on a large scale. 

To understand the necessity of the Coggins Test, let's look at the history of Equine Infectious Anemia and the man who's pioneering work developed the test, Dr. Leroy Coggins.  

What is the Coggins Test ?

The coggins test looks for antibodies for equine infectious anemia in the horse's blood by using the Agar Gel Immunodiffusion (AGID) test. Equine Infectious anemia is a lentivirus in the same family as HIV and FIV. These are retroviruses meaning they insert themselves into the host cell's DNA to replicate. Because of this, horses are infected for life and there is no cure and any horse with antibodies to EIA is infectious to other horses. 

The virus is spread by biting flies such as horse flies or deer flies. Because the bite is so painful, a fly may bite one horse and then be swatted off only to come back immediately to finish their meal. EIA can also be spread by contaminated needles, blood products and dental equipment. In 2015, an outbreak in racing quarter horses in California resulted in 34 horses being infected. 250 more horses on 19 farms were exposed and had to undergo 60 days of quarantine and testing.

The 3 phases of infection

The acute phase begins within 3 days to 2 weeks after infection. Horses will have a high fever, edema, be lethargic and anemic. 30 % of horses will die. These horses carry a high viremic load and 1 ml of their blood can infect 1 million horses ! A horse during the acute phase may test negative on the coggins test because he has not made antibodies to the virus yet. 
The 70 % who survive can be chronically infected or become inapparent carriers. 

Chronically infected horses may show general signs of weakness, weight loss, depression and a recurring fever. Very general signs right ? These horses will test positive on a coggins test and 1 ml of their blood can infect 10,000 horses !

The inapparent carrier state as the name implies shows little if any sign of infection. In these cases only 1 horsefly in 6 million will transmit EIA.  However stress or another illness can cause a relapse and these horses can revert back to the chronic or acute phase and their viral load will increase. 

History

I bet you didn't know that there really was a Dr. Coggins behind this test.

Dr. Leroy Coggins was one of the founding administrators of NCSU College of Veterinary Medicine. He was the head of the department of Microbiology, Pathology and Parasitology. He was a well loved and respected researcher, professor and mentor. Read more about Dr. Coggins at the NCSU-CVM site

EIA has been reported in all parts of the world and was 1st recognized in the US in 1890. Outbreaks were usually noted at racetracks because infected horses were brought into close quarters with other young, stressed horses. There were states designated as "hot zones" which included the southeast. At the time, the vector had yet to be determined but horses who were infected seemed to live or come from hot, damp climates and EIA was given the common name of “swamp fever”.

During the 1960s, Dr. Leroy Coggins was working on his PhD in virology at Cornell University when a major outbreak occurred on Standardbred Farms in New York. By 1970, Dr. Coggins had developed a test using the AGID method to detect antibodies to Equine Infectious Anemia. Previously, a donor horse inoculation test was the only test available to screen chronically infected or exposed horses which took 4 to 8 weeks and was very expensive both monetarily and morally.

In 1973, the USDA made the Coggins test the gold standard for determining exposure and prohibited any “positive reactor” from moving across state lines. Individual states determine the requirements for entry and that same year, Florida was the 1st state that required any horse being sold, moved, raced or shown to be tested and for positive horses to be quarantined or euthanized. Of course this was a shock to many horse owners who had inapparent carriers. Their horses did not look sick and there was little educational material for the general horse owner about Equine Infectious Anemia. 

Thankfully the Florida Department of Agriculture had the foresight to enforce these regulations to attempt to control the spread of EIA using Dr. Coggins’ Test. In 1970, 12 % of horses tested in Florida were positive. By 2000, this number dropped to 0.016% and there were zero cases of EIA in Florida in 2016 !

Nation wide, the value of the Coggins test was similar. In 1972 about 4% of horses tested nationwide were positive. By 1980, this number dropped to less than 1%. There are still occasional outbreaks reported. However mandatory routine testing seems to be keeping the prevalence to a minimum. 

Now that you know some details about EIA are you rethinking the importance of your coggins test ?

For more info about EIA check out these links

USDA-APHIS Federal Guidelines
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USDA-APHIS EIA discussion group notes 2015 

Florida Department of Agriculture

In Episode 253 : Vaccine Induced Lyme Syndrome, Artist and Horse Trainer, Aeron Mack of Middleburg, VA tells us about her Vaccine induced Lyme Syndrome research and shares her story of bringing her horses back to health. You can also find great resources about Lyme disease and Vaccine Induced Lyme Syndrome on Aeron's blog page. 

The TCVM segment starts at 40:30.

What is Lyme Disease
Lyme disease is caused by the bacteria, Borrelia Burgdorferi and is transmitted to horses, dogs and people by the deer tick (Ixodes scapularis). For more tick info, visit the "Tick Guy", Thomas Mather at the University of Rhode Island's Tick Encounter Resource Center.

Lyme is often classified as a syndrome because many general symptoms of malaise like weakness, behavior changes, body pain, joint pain and swelling and heart problems lead us to suspect Lyme on our differential list. Signs can be mild at first and you may not have seen or remember a tick bite on your horse or dog. As the disease progresses, the most common presentation in horses is pain and sensitivity over the large muscles of the back and limbs, swelling of multiple joins and lethargy. A horse who normally looks forward to riding time with his person will gradually become more resistant to work and may even avoid grooming time. In dogs we will see shifting limb lameness or a lameness that comes and goes. They may have a low grade fever and may lose their appetite. 

B.burgdorferi is a corkscrew shaped bacteria (spirochete) and is in the same family as Leptospira, implicated in abortions, moon blindness and kidney disease and Treponema responsible for Syphilis in humans. These bacteria do not produce toxins and are usually found in low numbers in the blood and tissues. They cause such wide ranging symptoms because they can evade the immune system and cause autoimmune symptoms many months and even years after infection. 

The Lifecycle of the deer tick shows when your chances of encountering tick bites and exposure to Lyme's is highest. ​

How is it Diagnosed

Some of the things we consider when diagnosing Lyme disease is if the horse or dog was living or traveled to an area endemic for Lyme, did they have a tick bite, clinical signs and ruling out other diseases. A blood test we can run in the clinic can tell us if they have antibodies to Lyme and a more quantitative test can be run at Cornell's veterinary diagnostic lab to tell us if the disease is chronic, acute and/or the vaccination status. For more info about Cornell's veterinary research, click here. 

​TCVM Diagnosis and Treatment

The TCVM diagnosis of the acute stage is a mixed pattern of Wind-Heat Toxin (infection/fever) with Qi and Blood Stagnation (pain).

In the chronic stage, the Zheng Qi (immune system) is damaged and we see Qi and Yin Deficiency (weak immune system, lethargy, pain, intolerance to warm weather, panting, anxiety)

In most Lyme cases, dry needle acupuncture is painful so these animals will be treated with a Chiropractic adjustment followed by laser acupuncture and a course of Herbal Therapy. 

Herbal Therapy

In the acute stage, if we have a red tongue and surging pulse, a fever, hot swollen joints we recommend  Jing Tang's Ba Wei Yu Peng San (Jade Screen Eight formula). This formula comes from the combination of 3 formulas used to treat acute febrile diseases, Yin Qiao San, Huo Xiang Zheng Qi San and Yu Ping Feng San. This formula was used extensively to treat and control the SARS (severe acute respiratory syndrome) epidemic in China in 2002. We would use this for 30 - 60 days to balance the immune system and kill the bacteria.  

The majority of the damage to the body from an autoimmune disease is sometimes referred to as a "cytokine storm". The pathogen stimulates the immune system's white blood cells and cytokines (pro and anti inflammatory mediators like interleukins and free radicals) to respond but the reaction gets out of control. Just think about when you have the flu and your body hurts, you are sweaty then freezing, you have so much mucous in your nose and lungs you can barely breathe. This is your body trying to get rid of the virus. Many of the deaths we see from influenza, bird flu, SARS, Ebola and even graft vs host disease are due to the body not being strong enough to tolerate the immune system battle or becoming confused and attacking itself. 

In the chronic stage when we are treating the pain and restoring the immune system, we use Dr. Xie's Lyme formula which is a combination of Du Hou Ji Sheng Tang (Angelica and Loranthus Powder) and Yu Ping Feng San. Du Hou Ji Sheng Tang is one of the most popular formulas for treating arthritis in people and animals. It is for Wind-Cold-Damp arthritis so for chronic whole body pain and stiffness that is worse in the cold weather. Yu Ping Feng San is a formula for cold and flu and has recently been shown to block the expression of iNOS and COX-2 so has NSAID like activity in addition to stimulating the immune system. 

Food Therapy

In the acute stage, you want cooling foods that tonify Qi.

For horses, this can include alfalfa, dandelion, pear, sweet potato, figs, goji berries and chia.

For dogs, foods like turkey and barley with eggs, string bean, spinach and shiitake mushrooms made into a congee with bone broth can stimulate the appetite and tonify the Qi. 

In the chronic stage you want to keep building the immune system and relieve the aches and pains but can add some warmer foods. 

For horses add some Turmeric, orange peel, ginger and garlic to the recommendations above.

For dogs, add some Turmeric and ginger plus a sardine which is high in omega 3 fatty acids.

Homework
Get Guineas ! 
https://www.youtube.com/watch?v=PXfEEf8B5j8

What is Vaccine induced Lyme Syndrome

Lyme disease has become so prevalent in some areas of the country that veterinarians have been using the dog lyme's vaccine in horses as common practice. I did this myself when I lived in Virginia. I had to retire a horse with Lyme and at the time, given the research available to me, I thought I was protecting my horses and my clients horses. For dogs, there are a few FDA approved vaccines that are considered to be safe and the AVMA recommends vaccination in endemic areas. 

Aeron Mack a horse trainer in Middleburg, VA, had an experience with her horses last year that has changed my mind about the Lyme vaccine. Evidence in humans implies that vaccination may be implicated in causing a "Lyme like Syndrome". If what we know about spirochetes and the immune response is true, this makes a lot of sense however, there is currently no research indicating this is the case in horses and dogs.

TCVM Diagnosis and Treatment
is similar to what we discussed above.  Presentation may be acute or chronic and we would treat what we find with an emphasis on relieving pain and controlling the immune response.
 
If you suspect your dog or horse has Lyme disease or vaccine induce Lyme syndrome, contact your veterinarian for an exam and consultation. Do not make this diagnosis on your own or begin treatment without veterinary advice.

If you are looking for a TCVM trained veterinarian in your area, go to http://www.tcvm.com/Resources/FindaTCVMPractitioner.aspx and enter your zip code to find veterinarians from the Chi Institute of Traditional Chinese Veterinary Medicine. 

Listen to Aeron's story on the TCVM segment on the Driving Radio show on the Horse Radio Network.

Listen in to the Traditional Chinese Veterinary Medicine segment of the Driving Radio Show.

We have 2 shows about EPM.

In Episode 253 : EPM part 1, Dr. Ellison of Pathogenes, Inc in Ocala Florida tells us about her EPM research and novel treatment strategy. The TCVM segment starts at 36:22.

In Episode 288 : EPM part 2, Dressage trainer, Karen Abbattista shares her rehab protocol for horses post therapy. The TCVM segment starts at 49:04.

To listen to other episodes of our podcast visit ​The Driving Radio Show and you can find even more equine, pet and health shows on The Horse Radio Network, the voice of the horse world ! 

What is Equine Protozoal Myeloencephalitis - EPM ?

EPM is a syndrome caused by single celled organisms (protozoa) that infect the horse and cause inflammation and pain in the brain, spinal cord and muscles. This inflammation can cause clinical signs like lameness, weakness, a behavior change, stumbling, muscle atrophy.

The definitive host, the opossum is infected by eating infected muscle tissue from his prey or road kill that happens to be an intermediate host. Intermediate hosts have been identified as armadillos, cats, skunks, racoons, sea otters and harbor seals. The parasite then replicates inside the opossum to an infective stage and is released upon the world in opossum poop. The horse becomes infected when he ingests sporocysts from food or water that has been contaminated with opossum droppings.

The horse is a dead end host for the parasite, meaning the horse's body is not the right environment for the protozoa and it eventually dies off before completing its life cycle. These dead parasites can cause damage to any part of the nervous system so any neurologic sign is possible. Symptoms can be acute or chronic, severe or mild so it is a very difficult disease to identify and diagnose.

How is it Diagnosed ?

Owners usually notice a change in behavior as the first sign, maybe the horse is now all of a sudden spooky on trails or has started bucking. Sometimes the signs can be as subtle as muscle atrophy and/or poor performance. In these cases we will typically be called in a few months later when many common issues are ruled out and the neuro signs start to become more evident.

EPM can sometimes present very suddenly with a downed horse and diseases like neurologic rhino or Eastern Encephalitis or West Nile need to be ruled out and aggressive supportive care needs to be started immediately. These cases will go into a clinic and diagnostic test may include a spinal tap which is the gold standard for diagnosis for EPM. In the early stages with mild symptoms, conventional diagnosis can be a positive response to treatment such as Rebalance or Marquis.

TCVM Diagnosis and Treatment

In our practice each exam starts with tongue and pulse diagnosis plus an acupuncture point scan follow by standing and moving evaluations. A horse with EPM will usually be very painful in his whole body and have some level of neurologic abnormality. The scan may reveal other concurrent diseases such as ulcers or arthritis.

The TCVM diagnosis is a mixed pattern of Qi Stagnation (pain) and Qi Deficiency (weakness).

If we suspect EPM we take a blood sample and send it to Dr. Ellison at Pathogenes to screen for EPM and Lyme's Disease. Dr. Ellison has developed some novel tests and protocols to diagnose and treat EPM. You can read more about it on her website and listen to her interview on the TCVM seg of the driving radio show ....scroll down for the player. *** Many Thanks to Kate McCaffery for encouraging us to participate in Dr. Ellison's program****

Acupuncture and Chiropractic Care would focus on relieving the pain, tonifying the Qi and supporting the immune system. The points I use will be based on the exam but because there is an autoimmune component to these cases I always include hemo-acupuncture which involves injecting some of the horse's own blood into certain points.

Herbal Therapy
Herbal Therapy is very helpful in these cases for 3-6 months after the initial diagnosis and treatment.
Qing Hao San - "Artemisia Powder"
Tonifies the Qi, strengthens the immune system and eliminate the parasites.

Dr. Xie developed Qing Hao San based on Dr. Tu's nobel prize winning research using Artemisia to treat Malaria (also a protozoa like Sarcocystis), combined with of 2 traditional formulas, Guan Zhong San (Dryopteris Root powder) and Si Jun Zi Tang (4 Gentleman). Read more about Dr. Tu's research here.

To Order Qing Hao San, follow this link

Food Therapy
Our food therapy recommendation include foods that are high in vitamin E and antioxidants.

Black Sunflower seeds - high in Vit E and omega fatty acids
Chia Seeds - High in Vit B and omega 3s, Black sunflower seeds have an imbalance of omega 6 to omega 3, the chia can help balance that ratio.
Lyceum berries (goji berries) high in Vit C and antioxidants
Spirulina immune booster by stimulating IgG antibody production

My favorite sources are
Sunflower seeds - TSC
​Chia - US Chia
Lyceum berries and Spirulina - nuts.com

Homework
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What can you do to help your horse recover and reduce the chance of reinfection.

• Do not leave feed tubs in stalls or in the pasture overnight and wash feed and water buckets daily.
• Avoid leaving pet food in the barn your barn cats can eat mice !
• Review your wellness program with your vet to make sure you are helping and not harming your horse's immune system

Coming soon - rehab exercise videos