Dolley Madison R.I.P. 5-29-2019
Every year at this time, I start to see pictures of opossums, big possums, hissing possums, baby possums, smiling possums, possums playing dead ... linked to articles, blogs, and posts about saving them, encouraging them in your neighborhood. How these are our only national marsupial, and all the wonderful things they can do, and are good for. And that is all true. The Virginia Opossum (often referred to as a "Possum") is our only North American marsupial, they are resistant to rabies. They are omnivorous, and particularly enjoy ticks, grubs, lizards, small reptiles & rodents, and will actively hunt them, will eat carrion and often scavenge roadkill and other remains (clean up in aisle 3). They are primarily nocturnal, so do not often interfere with typical daytime activities. They are fairly shy, if you bump into one they may hiss, growl, but often fall over playing "dead", allowing you to simply leave the area unharmed. All in all, they are a wonderful little creature, cute despite their odd appearance, endearing in their somewhat bizarre behavior, harmless, innocuous, and primarily beneficial for the world in which we live, and an important player in our local ecosystems.
Every year, when I see those articles, I want to cry. I want to shout "Beware!!" If you are a horse person, or someone you know is one, please pass this on. Where I board my horses, I have a friend, and Dolley Madison was her girl, friend, companion, confidante, rock of Gibraltar, co-conspirator of antics, trailblazer, she was cherished and beloved. A gaited Missouri Fox Trotter, a strawberry roan with all the chrome you could want. Gentle and kind, tho no dead-head, and she certainly had an attitude (and a bit of mare-itude), but it came from being loved, secure, and well-taken care of, Dolley knew she was someone important. Then one day she suddenly, altered, and it was so odd, that at first no one realized it. She was fine one day, trail rode out like always, brave and steady. The next day she inexplicably bit her owner, and of course, bc it was so out of character, we all ohhh'd and ahhh'd and searched for excuses, she was jealous because another horse was in a nearby stall, she was talking to a fellow boarder and wasn't paying attention, and so on. But that wasn't where it ended.
A few days after that, she came up to the gate when called for dinner like always, but there was something obviously wrong, those lovely, long, solid legs weren't carrying her straight to the barn where her stall was, she was sort of Weeble's wobble but they don't fall down, meandering, as though incapable of walking a straight line for a few steps, then collecting herself and forging forward, only to start to weave a bit drunkenly again. So the vet was called, and an hour of intense diagnostics, and questions, and answers, left us all shocked, too shocked to grieve, almost too shocked to ask the right questions. EPM was the major suspect (I remember standing there wondering what the heck EPM really was) and blood drawn, medications administered, a course of treatment to start immediately, more treatment pending the test results, were discussed. We knew she might never be 100%, but not once was any word of her NOT recovering mentioned or questioned. As the days turned from one to the next while we waited for signs of improvement, for the test results to return, more symptoms arose, leading to more questions. We all searched for answers like scurrying little ants, swarming about the anthill. The test results came back, 92% and we were told that the increase in symptoms was expected as a side effect of the progression of the disease and response to treatment. By then she could barely stand upright, could hardly walk in a straight line, but circled, her head no longer in control of, or in sync with, her hindquarters.
Dolley was a fighter, she had spirit, she had heart...the day came when she was found down in the pasture, unable to right herself in the mud from a rainstorm the night before, unable to get to her feet unaided, the ranch owner managed to get her up again, and brought her up to the barn, turned her out in the grassy arena behind it, the vet was called, they said continue the course of medications. Dolley was cleaned up as best we could, we could have just hung a sign on her that said "Gone Mudding", and it wasn't easy to clean her up, we needed a pressure washer, and all we had was a bucket and a hose to use while trying to minimize the stress on this already exhausted mare. She had mud ground into every inch of one side, including her eye and ear. She had trouble eating, chewing, swallowing, by then, great streams and globs of green mucous was coming out of her nostrils (that was supposedly her body expressing the protozoan infection thanks to the medication and we were told it was a good sign. I get it, but it was horrible to see.) Her eye was swollen, and it swelled shut over night, she had other scrapes, cuts, and bruises too, and the best we could do was to coat things with protective dressings to keep the flies away and reduce the swelling.
With each passing day there was the roller coaster of "hurrah! there is improvement" and the crash of "oh no! why is she doing this or that or something". You look so hard for signs of good and bad, You wait with bated breathe for a sign, any sign, no matter how minuscule, that you have turned that invisible corner and are on the road to recovery. Not quite three weeks along, and the holiday weekend, Memorial Day dawned sunny, hot, muggy, the bugs were maddening, but early in the morning there was still a small window of cool tranquility, usually with enough breeze to keep the bugs at bay, an opportunity we couldn't resist. As we tacked up for a short, early Memorial Day ride, my phone rang. Dread. Horse Down. Dolley. I untacked, let my sweet girl loose in the pasture again with an extra hug, hiding my face in her mane for a moment, breathing in her warm wonderful smell, leaning against her to draw a tiny bit of borrowed strength from her warm, solid presence. Said a pray for the courage to face what I knew was to come, for the strength I wanted to have for my friend, and of thanks for the knowledge that the sweet soul I hugged so hard was safe and healthy, of course that got me one of "those" looks, and I could tell she was wondering what the heck I was doing getting her neck wet clinging like a limpet, sniffling into her mane, when I should be either giving her treats now or telling her to "go be a horse", which of course made me laugh. So I collected myself up and headed to the barn.
Dolley died in the grassy greenness of the arena, she had suffered from a seizure that dropped her flat, most likely gone before she hit the ground, but the body's reactions are odd at times, and she apparently "ran" in a single circle her legs moving hard enough to pull one shoe off a hind hoof ... the epitome of the fright & flight reaction, running from the one foe no one outruns, Death. We searched for the better part of half an hour looking for that shoe bc her owner requested our help, wanting to keep her 4 nearly new shoes as a tangible memory. Those last 3 weeks of Dolley's life were both blessed and agonizing. It was one of the most terrible deaths I have ever personally seen and I have seen my fair share, and too many. Her case was extreme, her levels nearly off the chart, there were complications along the way, and most people will only experience a mild version of this with their horses. Exposure had likely come some time ago, and it had lain dormant bc she was young, healthy, well-cared for. The cost of treating an EPM event is a major issue, the medications & requisite vetcare is expensive, the main medication alone typically runs $1200 or more for a 28 day treatment and many horses require a second 3 week dose or more. It doesn't end with the initial treatment either, rehabilitation is essential, and can not be rushed. No one is prepared for an event like this where there horses are concerned, even when you know its possible, and have planned for contingencies.
The best you can do under these circumstances is be stoic. Address the issues, be strong for the friend who is grieving, help make the arrangements for the horse, notify those who need to know, remember to ask if they want a snip of hair. Try to arrange things neatly as possible & give them a moment alone to say a final farewell. Then you try to create a supportive group as one after another friend, co-boarder, fellow horseman, shows up to say how sorry they are, and ask if the owner is okay, if there is anything they can do, anything you need, and all the time it is obvious that the person, while appreciative, wants to shout to the Heavens "WHY?? Why my horse, why now, HOW?? How does this happen, how could it be prevented?? What else should I, could I, have done??" The answer is simple...nothing. 20/20 hindsight is golden, but you can only do what you can, with the information you have to work with at the time, and it does no good beating yourself up after the fact. Over the next week, and in the time since, we all managed to learn a lot more about EPM, how it works, what causes it, little things you can do to prevent contamination of the barn and pasture areas, that its the younger, healthier horses that are often hit hardest, that the best prevention is to avoid anything that attracts opossums, and to make certain to clean anything that a possum may come in contact with where your horses are. We learned how the disease progresses, and that there is a surprisingly high mortality rate under certain circumstances, and an even higher rate of relapse even though they originally recover because you don't really cure it, it simply goes into remission in most cases. That after 30 years they are still researching it, and struggling to find answers, effective treatment, a cure and a workable vaccine.
If you own a horse, possums are NOT your friend. At least not in the areas in which you pasture, stable, or work with your horses. They, alone, are the sole transmitter of the parasites that can infect your horse with the organisms that are the single cause of equine protozoal myeloencephalitis (EPM). Caused by the single-celled protozoan parasites Sarcocystis neurona and Neospora hughesi. Contamination occurs via the feces of infected possums, in the pastures, water sources, grass, barns, hay, stalls, grain buckets on your farm. Once believed that the two-host life cycle of S. neurona, included domestic cats, raccoons, skunks, armadillos and passerine birds, researchers have discovered that the only host to pass this disease onto horses is the opossum. Although the possum most likely becomes infected by scavenger behavior with those other animals. The horse itself is a "dead-end host", in other words, it isn't capable of communicating the disease to other horses or anyone else. Having been infected by ingesting contaminated feed, water, hay, grass etc, the sporocysts migrate from the gastrointestinal tract into the bloodstream to cross the blood-brain barrier. Neurological symptoms often occur soon after infection, some horses have immune systems that ward off the infection and it never gets to the CNS, and others harbor the organism and only develop symptoms at a later time usually after a traumatic stressor. To date, EPM is one of the most debilitating neurological disorders known in the equine world.
EPM is seen any time of year, with an estimated 50 percent of horses exposed to S. neurona, though less than 1 percent develop clinical symptoms of EPM. Although there's a low incidence of EPM in the general horse population, 14 cases per 10,000 horses per year (23 percent of the horses that died with neurologic signs showed S. neurona antibodies in their CNS, according to studies done at the University of California-Davis (UC Davis). It's been found in most horse breeds, including Thoroughbreds, Quarter Horses, Standardbreds. It has also been found in ponies, but not in mules, donkeys or other non-horse equids. A few diagnostic tests are available—the older Western blot test, the indirect fluorescent antibody test (IFAT) and a quantitative ELISA based on S. neurona surface antigens (SnSAGs) SAG1 ELISA as well as the newer SAG 2,3,4 ELISA.
EPM can show up in a myriad of ways, each horse may present differently, onset can be acute or chronic. EPM often mimics symptoms of other diseases (ie: Wobbler's Syndrome, EHV-1, etc) or lameness issues (ie: stringhalt, asymmetric gaits, stumbling, dragging hind toes, etc), atrophy of facial muscles, trouble swallowing, changes in behavior, muscle atrophy, etc. may be present, so testing is crucial. Use of the Modified Mayhew Scale Neurological Examination is a common diagnostic tool employed. Early diagnosis and immediate treatment to reduce the titre count for the protozoan parasite is also critical. Without treatment, the progression of EPM is somewhat unpredictable, as the neurologic signs in untreated horses usually get worse—from the more mild signs to ataxia, recumbency or death in hours to years, with periods of severe exacerbation possible after prolonged periods of quiescence.
Four drugs have been approved by the FDA for treatment of EPM: pyrimethamine, sulfadiazine, ponazuril and diclazuril. The recommendation for treatment with pyrimethamine-sulfadiazine is three to six months, so it has a longer treatment period. Both ponazuril and diclazuril are given for 28 days. With either drug, at least 60 percent of horses improve. There's no information on how many of the treated EPM horses completely recover, but it's believed to be a factor of how bad they were to start with. Along with antiprotozoal drug treatment, anti-inflammatories and immunostimulants have been used. Immune support & other supplements including natural-source vitamin E at 10,000 IU/day are typically employed. It is recommended to de-worm regularly, treat as needed for gastric ulcers, and consider therapeutic daily use of probiotics in horses prone to intestinal upsets. Feed a balanced diet with generous optimal levels of important minerals and vitamins.
Less than 30% of horses will recover to a pre-EPM condition. A horse that has once been infected with EPM, whether its immune system fought it off unassisted or it is now in remission thru treatment, is never truly "cured". Like cancer, it is exactly that, remission. Stressors of many types from pregnancy, to injury, to trailering, and so much more, can trigger a new episode of EPM, and each episode must be treated like a new event, rediagnosed, and remedicated. Some horses never relapse, some relapse on an intermittent basis. Rehabilitation is a crucial element of recovery. Rehabilitating the EPM horse is a long term process. While the horse may learn to compensate for the loss of feeling in a few weeks, allow at least one year for the damaged nerves to regenerate. When the horse is unable or unwilling to perform a movement or desired behavior, the owner must consider three reasons why the horse is not performing at pre-EPM levels. First, that the horse has been out of work for months, and is not accustomed to requests by the owner. Second, that the horse has physical deficits in weak muscles, or limited muscle control. Third, that lesions in the brain have caused mental behavior changes. If the horse shows many uncoordinated movements, trips often, or has other deficits that make him unsafe to ride, continue to ground work the horse, adding new tasks only when they are ready for it. Consistently asking the horse for more than what it can physically deliver can create stress and promote a relapse.
Common issues during rehabilitation - asymmetrical ataxia (uncoordinated) movement of the rear legs, changes in eyesight, deficits to the jaw, lips, tongue, or cheeks, his reaction to his usual bit may change. He may not be able to feel it, or it may cause unaccustomed pain. Problems with the farrier and changes in behavior during trims and shoeing are most often related to the loss of pre-EPM abilities, such as balance, or inability to feel their feet the same as before. Locking stifles (try exercises using backing up). Downward transitions can often be extremely difficult for the recovering EPM horse, due to hindquarter issues and muscle loss.
Prevention - It's essential that all food stores be secure and any animal carcasses are buried promptly. Clean up any spilled feed promptly. If opossums live on your property they should be humanely trapped and removed, you may want to hire a pest control company for this as simply dropping them outside their normal territory is neither sufficient or ethical. Fencing has been designed to prevent entrance of these animals and should be considered if opossums are a nuisance. https://www.thesprucepets.com/equine-protozoal-myeloencephalitis-1886437
Possum Facts:
1) The only known North American Marsupial:
a) How the Possum got its name: The opossum received its name in the early 1600s from Captain John Smith of the Jamestown colony in Virginia. The name is derived from aposoum, a Virginia Algonquian word meaning “white beast.” The first recorded reference to the opossum in literature came in 1610 in the following passage from A True Declaration of the Estate of the Colonie in Virginia: “There are … Apossouns, in shape like to pigges.” In the late 1700s, Sir Joseph Banks, a naturalist who accompanied Captain James Cook on his first great voyage, likened a furry creature he saw in Australia to “an animal of the Opossum tribe.” The term for the ringtail marsupial that he spotted was shortened to possum. This truncation of the original term may explain why many people are surprised to learn that opossum and possum are in fact two very different marsupial species of the arboreal kind. ~ https://www.dictionary.com/e/possum-opossum/
b) A marsupial of the order Didelphimorphia (/daɪˌdɛlfɪˈmɔːrfiə/) endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 103 or more species in 19 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of the two continents. Their unspecialized biology, flexible diet, and reproductive habits make them successful colonizers and survivors in diverse locations and conditions.[3] Although the animal is often called a possum in North America,[4] which would refer to the Virginia opossum species, it should not be confused with the suborder Phalangeriformes, which are arboreal marsupials in the Eastern Hemisphere also called "possums" because of their resemblance to Didelphimorphia. ~ https://www.farmersalmanac.com/opossum-facts-27732
2) Omnivore: Opportunistic and voracious ... Dead animals, insects, rodents and birds are eaten by opossums. They also feed on eggs, frogs, worms, grubs, small rodents, tubers, plants, fruits and grain. One source notes their need for high amounts of calcium. Thus possums eat the skeletal remains of rodents and roadkill animals. Opossums also eat dog food, cat food and human food waste. They don't just scavenge, but will actively hunt small birds and animals, and vigorously dig up insects they detect below ground or in hollow logs. They will use their strong claws and dexterous front paws to rip open burrows, have been known to hunt and eat rats, "Opossums are voracious eaters that will try anything they find, something you know quite well if you’ve ever found one pawing through your garbage bins. Ticks, particularly the black-legged ticks like deer ticks that are responsible for the spread of Lyme disease, appear to be a top item on the opossum’s menu. Several years ago, biologists from the Cary Institute put opossums and other species, like chipmunks, squirrels, mice, and catbirds to the test, giving each animal 100 ticks to eat. Opossums ate far more ticks than any other animal, leading scientists to estimate that just one opossum eats, on average, 5,000 ticks each year. ~ https://www.farmersalmanac.com/opossum-facts-27732"
Rabies & Other Diseases:
a) Rabies - Rabies is a terrible virus that attacks brain function. It is considered very rare for the common opossum to contract, carry or transmit rabies. It seems the rabies virus thrives in animals with higher body temperatures than that of the possum. For instance, the normal body temperature of a raccoon is 102.8, while the opossums average body temperature is about 95 degrees, sometimes less. This does not mean they are immune from rabies however, and a handful of opossum rabies cases are reported pretty much annually, although the CDC reports that the majority of animal rabies cases comes from raccoons, skunks, foxes, and bats.
b) Leptospirosis - But, the common possum is a carrier of leptospirosis, a bacterial disease that appears to be a simple flu, but, If left untreated, can cause kidney damage, liver failure, respiratory complications and even meningitis. Leptospirosis is spread through the opossums urine and excrement, so keeping outside surfaces they may frequent clean, and making sure your pets are protected from exposure is a good idea.
Leptospirosis in horses can cause a) Equine Recurrent Uveitis (ERU) The chronic disease of the globe may cause cataracts, retinal degeneration, or even glaucoma. corneal, anterior chamber, and posterior chamber disease, corneal edema, clinically quiet retinal lesions observed on funduscopic examination, and most dramatically recurrent and progressive painful uveitis often leading to blindness. b) up to 13% of the known bacterial abortions in mares c) fever d) renal failure. https://www.merckvetmanual.com/generalized-conditions/leptospirosis/leptospirosis-in-horses
EPM is one of my missions, I pray to never see another horse suffer through this terrible disease, or another owner share their suffering ... Dolley is my poster child, I can still close my eyes and clearly see her during those agonizing weeks. She is the beacon that guides my driving desire to educate about, and protect against, this disease. She is never forgotten, Sonja.
Farmer's Almanac - https://www.farmersalmanac.com/opossum-facts-27732