Equine atypical myopathy (or Atypical Myoglobinuria) is an emerging disease in the UK and Europe that causes muscle damage. The cause of this disease is currently unknown, but there is speculation that it is linked to a toxin producing bacteria called Clostridium sordelii.
According to data from the Equine Atypical Myopathy Alert Group from Spring 2012, there were 23 new cases reported by 2nd May 2012. 18 of these were in France, 4 were in Great Britain and 1 was in New Zealand.

Risk Factors:
Although the exact cause is unknown, there have been several risk factors identified, that make a horse more susceptible to the disease. Some of these risk factors are listed below:
• Young horses, typically less than 3 years old
• Horses that are in poor body condition
• Unvaccinated and un-wormed horses
• Seasons – most cases are seen in the Spring and Autumn, following periods of heavy rain, warmth and humidity
• Low levels of Vitamin E and Selenium in a horse (important anti-oxidants) may increase the risk
• Dead leaves within the pasture, or a watercourse running through the pasture
• Previous history of aytypical myopathy on the pasture

Clinical Signs:
Most cases occur rapidly, with severe, generalised muscle weakness. Horses can be found lying on their side in the field, or found dead. The mild initial clinical signs listed below are not often seen:
• Lethargy
• Decreased appetite
• Lameness, especially of hindquarters
• Muscle tremors
• Signs of colic
• Dark coloured urine
• Dark red (congested) or purple (cyanotic) coloured gums
• Low temperature (hypothermia)

What to do if you suspect a case:
Equine Atypical myopathy has a high mortality rate, but the chances of recovery are increased with early intervention and treatment.
• Call the surgery to request a visit
• Minimal movement of the horse, as any movement will further aggravate the muscle damage.

Treatment:
There is no specific treatment available for Atypical Myopathy and current treatment is aimed at the symptoms and potential cause.
• Pain killers
• Fluids – can be given via a drip if needed
• Antibiotics – for potential Clostridium sordelli infection
• Supplement vitamin E/selenium

Prevention:
• Avoid grazing on affected pastures during Spring and Autumn, especially young horses
• Keep up to date with vaccinations and worming
• Assure your horse is in a good body condition (but not too fat)
• Remove excessive amounts of dead leaves from the pasture

Further information:
More information can be found at:
• http://www.simply-horses.net– under services, client information, equine health notes, medical conditions
• http://www.myopathieatypique.fr/en – where alerts from the Atypical Myopathy Alert Group (AMAG) are also posted.

Midges are to blame – Sweet itch is most often an allergic reaction of horses to the bites of midges, which occur in almost every country in the world where horses are kept. Midges are small, only a couple of millimetres in length and like many insects that feed on blood, only the females do so as they need the high protein meal to enable them to lay their eggs.
Although the disease has been known for centuries, the first scientific description of the link with midge bites was made in Australia in the 1950s by a vet called Riek. Riek first noticed that the disease occurred only in areas where midges were abundant, then showed that when an extract of midges was injected into the skin of the affected horses, a small swelling appeared within a few minutes.
This type of “acute” reaction is typically seen in certain types of immune “hypersensitivity” or allergy and so Reik concluded that sweet itch was an allergy to midge bites.
Why do midges spit? – I was out in the field checking our ponies. It was a calm sunny evening and as I watched I could see large numbers of midges, which are most active around dawn and dusk or on overcast days when there is less risk of them drying out in the hot sun. After alighting they crawl down the hair shafts to the skin surface. Their mouthparts are too short to probe for a blood vessel like their larger cousins the mosquitoes, so they have to chew their way through the tough outer layers of skin. To assist their efforts they secrete saliva containing a mixture of enzymes that digest and soften the skin tissue as well as “vasodilators” to encourage extra blood to flow to the site of the bite and several factors that will prevent the blood clotting. A small pool of blood forms just under the skin surface and is then sucked up by the midges.
Once full they make their way back to the ends of the hairs from where, laden with blood and weighing twice as much as when they arrived, they launch themselves into the air. The whole process takes about 15-20 minutes and over the course of an evening a horse may be bitten by hundreds or even thousands of midges, each one injecting a small amount of saliva containing foreign proteins into the horse.
The response of the immune system to midge saliva – When an animal is injected with something foreign like midge saliva, its immune system responds by making antibodies that can bind on to the foreign proteins. The action of antibodies is often compared to that of a key for a lock, in that one end is like the key’s handle, while the other end has a unique shape that fits the lock or in the case of antibodies allows them to bind their target.
Antibodies are made by specialised cells called B-cells. Each individual B-cell is programmed to make a unique antibody. An animal like a horse (or human) has millions of B-cells which between them can make millions of different antibodies. But one B-cell on its own will not make very much antibody, so when a B-cell encounters a foreign substance that binds its own unique antibody it is stimulated to grow and divide so that in a few days there are thousands of them and lots of antibodies can be made.
This is how your horses vaccination works; your horse is injected with a small amount of the influenza virus and those B-cells which make antibodies that can bind to the virus increase in number. Then when a real flu virus turns up there are lots of B-cells primed and ready to immediately make antibodies that bind onto the virus and “neutralise it”, preventing the infection spreading, without your horse having to go to the trouble of getting ill and waiting several days for its immune system to catch up.
So, if the immune system of horses with sweet itch is reacting to the saliva of midges, the horses should have antibodies that will bind specifically to the proteins in midge saliva. The first stage in our research was to identify which midge proteins are important.
There was no problem getting some midges – all that was needed was to catch them in a suction trap as they landed on the horse to feed. The first approach we used to look for the antibodies that bind to midge saliva proteins, was a technique called immuno-histochemistry. First the midges are sliced into very thin sections then placed on a glass slide. The slides are exposed to serum from horses so that any antibodies in the serum will bind to their target. We then detect the bound horse antibody using a label that produces a red colour.
However, we found that all British horses had antibodies that bound midge saliva; perhaps this is not surprising as all horses living in Britain will be bitten by midges. Fortunately we were able to get some serum from horses living in Iceland, one of the few places in the world where there are no midges. The serum from Icelandic horses that had never encountered a midge did not stain the midge saliva glands, confirming that their serum contained no antibodies to midge saliva.
A special kind of antibody – But if all British horses have antibodies to midges, why do only some develop sweet itch? The answer lies in understanding more about the immune system and about antibodies. Think again of the antibody being like a key, with one end specially shaped to bind a foreign substance and a handle at the other end.
The B-cell can attach a different handle to its antibody for different purposes, for example, one type of antibody handle is best for binding to an influenza virus and preventing it from infecting its host. A different type of antibody handle is needed to deal with a bacteria like the one that causes strangles, in this case the antibodies bind to the bacteria’s surface and their handle enables white blood cells to catch hold of the bacteria then ingest and destroy them.
The kind of antibody that is important in allergies like sweet itch is called Immunoglobulin E or IgE for short. Its role is in immune responses to parasites such as worms. Adult worms of course are very common in the horse’s digestive systems but many of the larval stages of worms invade the tissues of the horse and some types of worm actually live just under the skin.
To help protect against worms the immune system has to use one of its most powerful weapons, known as the “mast cell”. These mast cells coat themselves in IgE antibodies and lie in wait just under the skin or in the lining of the intestine. When the IgE binds its target, the mast cell releases a cocktail of chemicals that cause a severe inflammatory reaction and attract other immune cells which can injure or kill the parasite.
Unfortunately mast cells, like other weapons of mass destruction, can cause a lot of collateral damage. Allergies occur when the immune system makes a mistake and mounts an anti parasite response to the wrong thing. For example, in people this could be a food like peanuts, or in hay fever it is often pollen, and in some cases people even develop an allergy to horse hair. But in horses themselves the commonest allergy is to midge saliva.
When we looked for IgE antibodies that bound to midge saliva glands we only found them in the serum taken from horses with sweet itch, confirming that this disease is an allergic response to midge bites.
What is it in midge saliva that the horse’s immune system reacts to?-The next task in our research, which was funded by The Horse Trust, was to identify all the different proteins in midge saliva. One way of doing this is to isolate the relevant genes that contain the instructions for making the proteins in midge saliva. In animals, every cell contains DNA that carries the code for making an entire animal, but only those genes that are needed by a particular cell are switched on.
From midge saliva glands, we isolated the switched-on genes which code for the saliva proteins and put them into a special type of bacteria in the laboratory. When grown overnight on a dish of agar gel each individual bacteria forms a colony that will contain only one extra gene from midge saliva. We can then pick each colony of bacteria, isolate the midge gene and read its coded message. By reading lots of coded messages we can work out which ones are most common in midge saliva and are most likely to be the genes of the proteins that cause sweet itch.
The second approach is to look at the proteins themselves. Using a combination of methods, proteins can be separated in a polyacrilamide gel according to their size and acidity. The individual proteins form spots and each spot is then punched out of the gel and digested into fragments. The sizes of the fragments are then measured by a mass spectrometer. To identify the proteins a computer program is used that compares the pattern of the fragment sizes with those that we would expect to find based on the genetic codes. After putting all this information together we can work out what the commonest proteins in midge saliva are. We can also investigate which of the spots bind IgE antibodies in the serum of allergic horses. All horses with sweet itch have IgE antibodies that bind midge saliva proteins but individual horses will recognise a different pattern of spots.
Once the genes or the relevant proteins have been isolated we can put them into cultures of insect cells which will make the protein in an identical way to a midge saliva gland. Each culture can be over a litre in size and makes only one midge protein so we can produce a pure protein equivalent to the contents of several million midges’ saliva glands.
What are we planning to do with all that protein from midge saliva?- We can in theory use it to re-programme the immune system of an allergic horse to act like that of healthy horses. First we need to better understand why the immune systems of only some horses react with an allergic response. Although Icelandic horses do not get sweet itch in Iceland where there are no midges, when brought to mainland Europe, more than one in four Icelandic horses may eventually develop the condition.
So are Icelandic horses as a breed genetically more likely to get sweet itch? Scientists and vets from Iceland and European countries have looked at this in detail and the answer is no. Although there are genes in some horses that make them more likely to get sweet itch, these are not more common in Icelandic horses compared to other breeds, and Icelandic horses born on mainland Europe do not get sweet itch any more often than other horse breeds.
Other studies on the development of the foal’s immune system have shown that they do not make IgE antibodies until they are about six months old. We think that when foals are exposed to midges before this age their immune system usually becomes programmed not to make IgE antibodies to midge bites. But Icelandic horses first exposed to midge bites as adults are very susceptible to developing sweet itch because as foals their immune system was not programmed to ignore midge bites.
A case of mistaken identity – Remember how the B-cell attaches a different handle to its antibodies – how does it know what kind of handle it needs to use? Well, the B-cell is told what kind of handle to use by chemical messages sent by another group of immune cells called T-cells. So how do the T-cells know what chemical messages to send? The T-cells are told what to do by yet another type of cell called a dendritic cell which detects foreign substances and can tell if they are from bacteria, from viruses or are of parasite origin. This seems to be the root of the problem – the dendritic cells recognise bacteria because they are made of different materials, and when cells are infected by viruses they send out distress calls that alert the dendritic cells to the virus’s presence. But what about parasites?
A migrating parasite has to break down the tissue. To do this it secretes enzymes similar to those the midge uses to break down the skin, and like midges, the migrating parasites also release factors that can interfere with blood clotting. The horse’s immune system “detects” these effects and interprets them as an invading parasite when in fact it is only a midge bite. So it looks like sweet itch is a case of mistaken identity leading to the wrong messages being sent down the chain of command to the B-cell which responds by making IgE antibodies which trigger an allergic reaction.
Scientists at the Veterinary School in Berne analysed the chemical signals made by the immune system of horses with sweet itch, and showed a clear difference in the messages made by the T-cells from healthy horses responding to midge saliva and the T-cells from horses with sweet itch.
Can we re-program the immune system of horses with sweet itch to be like that of healthy horses? – The term immunotherapy is used to describe treatments that can be used to re-program the immune system of people (or animals) with allergies; usually this involves repeatedly exposing the immune system to small amounts of the allergen. Originally this was done by daily injections but it is unlikely that this method would be suitable for use in horses. There are several newer ways that re-programming could be attempted but it will take some time to carefully work out how this can be safely done. For example, would mixing the midge proteins with some parts of bacteria fool the immune system’s chain of command into giving orders that divert the B-cells from making IgE? Or could feeding midge protein convince the immune systems that this is really a harmless food? Should all foals be inoculated with midge proteins at an early age?
We don’t yet know. It has taken almost 10 years to get this far but we are making progress. In research, there are always new surprises that await, but one thing is certain in science – it always take longer that you think. Yet if everyone works together, one day we will indeed be able to “do something about sweet itch” and develop an effective cure.

• Ensure your mares vaccinations are up to date
• Know your mare well so that you will have the best chance of knowing when will foal
• Have a clean, quiet and dry place for your mare to foal
• Once the mares waters have broken she should give birth within about 20 minutes
• Keep an eye on the mare once she has foaled the foal should stand and suckle within a
  couple of hours and the mare should pass her placenta
• If you are getting concerned or there are obvious problems then call your Vet immediately

Even if your mare has a very straight forward birth and you think the foal is happy and well don’t presume all is now going to be okay you will need to keep a close eye on the mare and newborn. When the foal is born don’t be impatient, let nature take its cause. Some foals can take up to an hour to stand and two hours to suckle. If the foal hasn’t been able to suckle within four hours we recommend that you call your Vet.

The first 12 hours of suckling provides the foal with the colostrum they need to give them a good immune system and strength. The foals umbilicus should be treated with some antibiotic spray to help avoid any infection. Within the first 3 hours after birth the mare will pass her placenta this should be kept for your vet to examine. The next step should be the foal passing there first faeces (meconium) and urinating all within eight hours of birth. Failure to pass the meconium is the most common cause of colic in new born foals so veterinary advice should be sought if this is not observed. If everything has gone according to plan it is then recommended that the vet checks the mare and foal from 12 to 18 hours after birth.

Keeping a close eye on the mare and foal as often as possible will reduce the chance of anything major going wrong. You should make sure the foal is suckling often without any problems and that the mare is accepting it. If the foal goes lame that would be a big concern as they can get septic arthritis from bacteria in the blood stream and left untreated even for a few hours can lead to irreparable damage. If you are worried about anything it is advised to call the team at Simply Horses as soon as possible, the Vet will also advise you on the next steps for the mare and foal.

The majority of laminitic horses start when the horses are turned out to grass in the spring. The weather becomes warmer and horses are allowed out 24/7. Although this seems like the kindest thing for a horse it can cause laminitis or colic leaving you with a very lame or ill horse.

The horse is usually in the stable for the majority of the winter then suddenly turned out onto the spring grass. This means that the horse’s digestive system is not acclimatised to the grass. Therefore the horse needs to be slowly introduced to the grass but some horses will not be able to handle being turned out for many hours especially if they are prone to colic or laminitis. The fructans in the grass are a type of sugar that occur from photosynthesis and is used to aid plant growth. The fructans are stored in a blade of grass and particularly like the cooler weather such as in the spring. Below are a few points to help keep your horse healthy:

• Gradually increase the time the horse is turned out by about 15 minutes daily
• Avoid the afternoons where the sun has been on the grass as the fructans are at the highest levels
• Rotate the grazing as the fructans are higher on mature or overgrazed grass
• Watch your horses weight otherwise they can suddenly balloon when turned out to pasture
• If your horse is fat or prone to laminitis make sure they are in a small paddock or have a muzzle on
• Feeding little and often is best for the horse as it keeps the hindgut moving therefore reducing the chance of colic
• Keep your horse exercised as this burns off some calories and helps to keep weight down

What are the clinical signs for the start of laminitis?

Laminitis is inflammation of the sensitive laminae of the foot. Overweight ponies and horses kept on grass are in the highest risk category. Usually it is the forefeet that show signs of laminitis but it can be the hind feet as well. The horse will react by rocking back on their feet to take the pressure off their toes. The feet will have heat in them and the pulses in the foot will be pounding.

What are the signs of colic?

Horses get colic through either just bad luck or because of change in diet or routine. Hence suddenly turning a horse out to grass can bring on signs. Symtoms will depend greatly on the severity and type of the colic; these may include some or all of the following:

• Changes in eating habits, including a loss of appetite
• Continuously getting down to roll and then getting back up again
• Pawing the ground
• Pacing the stable
• Limited or no passage of faeces
• Straining to excrete faeces
• Turning round and looking at their flanks
• Kicking at their abdomen
• Anxious and shivering
• Sweating
• Abnormal temperature, respiratory rate and heart rate
• Excessive urination

All cases of laminitis and colic should be treated as serious and the quicker the vet gets to the horse the more likely it will be a positive outcome. If you are concerned do not hesitate to contact the staff at Simply Horses.

Owning and caring for a horse can be a source of great enjoyment but is also a big responsibility with a long-term caring and financial commitment. The Animal Welfare Act 2006 (“the Act”) requires you to ensure that any horse, pony, donkey or mule for which you are responsible, whether on a permanent or a temporary basis:

• has a suitable environment to live in;
• has a healthy diet;
• is able to behave normally;
• has appropriate company; and
• is protected from pain, suffering, injury and disease.

Breach of a provision of the Code is not an offence in itself, but if proceedings are brought against you for a welfare offence the Court will look at whether or not you have complied with the Code in deciding whether you have committed an offence.

http://www.defra.gov.uk/publications/2011/03/26/code-of-practice-horses-pb13334/

The worm count is a small sample of your horse’s faeces that are viewed under the microscope to see if any worm eggs exist. This way it means that the horse is only getting the necessary worming therefore; it is not creating resistance to any wormer’s. For you it is very straight forward all you need to do is provide us with a small sample of the horses faeces we will then do the rest for you. It will only cost £11 and the results should be through within the week.
Why do a worm count?

Primarily, the reason for having a worm count done is to check one aspect of the internal health of your horse or pony. Overlooking a worm problem can lead to the development of a heavy worm burden and the typically described “Poor do-er” which may show diarrhoea, colic, loss in weight, lethargy and, in the worst cases, death. A worm count can help to recognise that there is a potential problem so that you, the owner, can take steps to prevent things progressing. Other reasons for getting a count done are:

1.To give you peace of mind that your horse is not shedding eggs onto the grazing area and so contaminating the pasture and creating recurring problems for you and other owners.

2. To give confidence that the worming and pasture management strategy which you and/or your livery yard are using is successfully controlling the parasites.

3.To check newly acquired horses and ponies upon arrival at a yard before turning them out onto communal grazing so that pasture contamination is kept to a minimum.

4. To make sure that your animal is not carrying worms which are resistant to (i.e. not controlled by) current worming chemicals.

5. To monitor horses which are travelling to different venues as part of their routine, and grazing on potentially contaminated grassland.

6. As part of a pre-sales or pre-loan health check.

Many of our clients , in conjunction with specific veterinary advice, are adopting a strategy which aims to decrease the quantity of chemicals given to their horses. In these cases, regular worm counts are done and worming chemicals are given only if the count reaches a threshold level. This technique not only reduces costs, but is also considered helpful in combating the problems of resistant worms developing (see below).

For any further help Please do not hesitate to contact the team at Simply Horses.