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  Discussion on Mycotoxicosis (Mouldy Straw SynDrOme)
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Member:
Lesali

Posted on Thursday, Mar 11, 2004 - 4:44 pm:

I have recently had a very worrying experience with Ali, my 8 years old thoroughbred gelding. He has always been very well behaved whilst out hacking but his behaviour began to change over a period of several months.
He, like most horses would exhibit napping behaviour but, this began to progressively worsen and would happen for no apparent reason and to the point where he would absolutely panic at the thoughts of leaving his stable.

History

In May 2003 Ali developed oedema (swelling due to water retention) in his hind pasterns / cannons. I could press my thumb into the oedema and the impression would last for 15 minutes+. This was especially so when he was confined to his stable for more than a couple of days. There was also the appearance of “mud fever” scabs and “weeping” sores (unlikely in summer).

During the sunny summer months of July, his white pastern / cannon area became very infected and the flesh necrotized into open wounds almost to the bone. I called my vet out and he diagnosed “Photosensitivity”. He was put on a course of penicillin and I was advised to use a sunscreen on the affected area and to keep it covered during the summer season while he was “turned out”. Recovery took weeks & did eventually heal up but the oedema still remained when stabled for days or more.

In November the same year, Ali was moved with the other horses on the yard into the “winter” paddock, which is a “turnout” field with no grazing (yard rules!). Of course suddenly Ali was out most of the day with little or no grazing and would come in hungry. On many occasions he would on entering his stable, veraciously eat his wheat straw bedding since it was loose, in preference to eating hay from his hay net (a slower procedure). I would often keep spare bale in his stable and he would break them open and eat most of the bale. I thought nothing of it except that the straw contained little nutritional value.

I had noticed as I arrived one morning that Ali had eaten most of his straw bedding (not realising any connection at that point) and the normally whites of his eyes were bright orange (icterus). His gums were also very brown in colour (jaundice). He looked ill and held his head low. There was also a slight weight loss over the past weeks & diarrhoea/ loose watery stools (especially after exercise) & a general malaise.
I called the vet out immediately to check him over. My initial worry at that time was possible ragwort poisoning/ liver failure.
Blood tests were taken for assay but results were not indicative of liver failure or necrosis but showed an elevated Bilirubin count (160+) & increased Eosinophilia count possibly due to an allergic response. Eosinophils are special white blood cells, which are released in abundance in response to allergens. My vet suggested worming him, but Ali’s jaundice did not improve.

Ali became unridable / trainable and was kept mostly stabled. A few weeks late Ali suffered an acute “medical” colic episode, his jaundice very pronounced. Vet called out again. Rectal & general exam OK. Slight weight loss. Equipalazone injection needed. More “blood work” done.

Tests showed high Bilirubin levels but, otherwise, nothing specific. I pointed out to my vet that Ali’s jaundice level varied on a daily basis. He was surprised, but this observation was later to lead to an astonishing discovery. My vet declared that he did not know what was wrong with Ali and suggested giving him a vitamin supplement and see how he got on in the weeks to follow.

Over these weeks, I began to record and notice a pattern to Ali’s jaundice level. I found that his jaundice level (by observation) worsened 12 to 24 hrs after I added fresh straw to his stable. This he found surprisingly palatable & would eat large amounts. The following day, the straw became fouled and would leave it alone.

I suspected maybe a wheat allergy or a mould / fungus on the straw (“mouldy straw synDrOme”).
His wheat straw bedding was substituted with shavings and his jaundice symptoms improved markedly within 24-48hrs.

I have examined the straw microscopically & photographed specimens that have been incubated / cultured. During examination of cultures, extremely tiny amounts caused asthma attack, burning sensations in eyes & nose, sore throat, headaches just from breathing spores never mind ingesting!

I am no expert on mould varieties, but research has led me to believe that it may be Stachybotrys type and some Aspergillus variety, which is common in cereal straw. Mycotoxins produced by fungus / moulds were responsible for Ali’s symptoms! The mould was not immediately visible to the naked eye. It became just visible at X10 magnification.

Ali suffered bouts of acute colic & weight loss over the next few weeks, at times not able to eat or pass stools. My vet said he might have to refer Ali to a veterinary hospital. I had great difficulty convincing my vet of my finding / suspicions, since they had no previous experience of mycotoxicosis. Vets do not like being told their job do they?

I called the vets one final time for another acute colic episode. The practice sent out a different vet & although sceptical of my conclusions, she did take my comments “on board”. Ali was given penicillin in case there was a complication from internal infection & an ELISA allergy test was carried out on blood serum samples (very expensive).

Results of allergy test showed no response to wheat but a slight (level 1) response to barley & Aspergillus mould.
If it were not an allergy to wheat straw then it must be the mould infesting it! In any case, an allergy would not cause jaundice.


On further research on the Internet in various countries (particularly USA), I discovered that such symptoms seem more commonly understood abroad.
This is perhaps due to higher incidences of mould problems, due to climate differences and a higher density of horse population.

The symptoms of mycotoxicosis caused by trichothecenes are identical to Ali’s. Plus the effect on humans from handling contaminated straw is identical to symptoms I have personally experienced, asthma, headaches, sore throat, nausea, depression / mood swings, abdominal pain, and general malaise / fatigue.


Extract /reference

The primary toxic mechanism of trichothecenes is the inhibition of protein synthesis causing weight loss. For the most part, their effects are known from instances in which humans or animals ate contaminated grain, or from laboratory animal or in vitro studies. The major effects observed include vomiting; inflammation; diarrhoea; cellular damage of the bone marrow, thymus, spleen and mucous membranes of the intestines; and depression of circulating white blood cells after an initial surge / increase.

Of course, horses cannot vomit and suffer colic!

Humans who have eaten contaminated grain develop "alimentary toxic aleukia," which begins with burning sensations of the mouth, throat, oesophagus and stomach, continues with vomiting, diarrhoea and gastric cramps, and finally progresses to severe leucopoenia (DrOp in white blood cell count), which renders the patient susceptible to infections. Death may result.
Skin contact with material laden with these trichothecenes induces contact dermatitis, and in stronger exposures lesions may be necrotizing (that is, may contain dead tissue, a significant risk factor for the development of bacterial infections).
_________


Ali is now making excellent recovery. I am riding/ training him now and he is responding normally and back to his normal character as prior to the onset of his illness. He is eating well, gaining weight & his stools are perfectly normal. The oedema in his hind legs has disappeared completely! At last I have my Ali “back” again.

I am convinced that toxic mould is responsible since substituting his wheat straw bedding with wood shavings made a significant difference to his symptoms. He also is now on haylage, which is “bought in” from a reliable source. His improvement continues.



Conclusions

Ali’s oedema was caused by contact dermatitis through exposure to the infected wheat straw bedding. The oedema worsened when stabled for long periods since the contact was longer. Ali’s hind legs were affected because his bed was at the rear of the stable and most of the time his hinds were in the straw and his front legs were on the concrete. The effect of sunlight during the summer months complicated the problem. Horses with liver problems often exhibit photosensitivity & oedema anyway.
The mycotoxins produced by the mould caused Ali’s jaundice by arresting liver & spleen function.

Ali is more of a “pet” and is used for general hacking. He is an “ex” flat racer and if he did still race I would have expected him to “run out of steam” part way round a track. This is because the horse’s spleen is a “storage” device, ready to release extra red blood cells (packed cell volume) in order to cope with the extra oxygen demands by muscles and tissues. If the spleen is compromised due to mycotoxins, then early exhaustion will occur.

Wheat straw appears most susceptible to mould especially on the leaves, which wilt and are in contact with the damp soil.

Straw is infected by mould in the field and although farmers spray their crops, understandably, their interest is mould prevention in the grain not the stalks & leaves.

Mould is much less of a problem with storage.

Ali’s panic attacks were due to behavioural changes caused by the mycotoxins.

Secondary internal infection due his immune system being compromised caused Ali’s colic / diarrhoea.

Arab breeds & thoroughbreds are more susceptible to toxins / allergens. Just because “one” has a horse that isn’t suffering does not mean that another cannot.


And finally

Ali came very close to being euthanised & I wouldn’t want anyone to go through the worry I have had to endure over these months. It’s not the financial cost that worries me (I had insurance cover). Moreover, Ali’s suffering was through no fault of his own and the ignorance of vets in the UK to symptoms of mycotoxicosis.

My vet now agrees with my diagnosis of Mycotoxicosis.




Dr Lesley J McCall PhD
(Medical researcher)




Member:
Liliana

Posted on Thursday, Mar 11, 2004 - 8:36 pm:

Hello Lesley

Reading your post I can not begin to imagine the worry that you must have gone through, however I am astonished about the practice at your yard of no grassing turnout area, horses have a very small stomach and most of the digestion is carried out in the sycom therefore they need constant grass (small meals but frequent). You are obviously a very caring person, but after what you have gone through I would change yards, and go some place where they can be turned on grass so that he does not have to starve for long periods again.

Mould is the worse thing for horses it does not matter what kind it is he could end up with chronic respiratory decease amongst other things.

Is the yard where you keep him the most convenient for you distance wise?, I used to live in Ealing West London and kept my horses in Chorley wood, but, it was a fantastic place, Sheila is and expert in horses so they were kept like kings.

All the best
Liliana


Moderator:
DrO

Posted on Friday, Mar 12, 2004 - 8:09 am:

Hello Leslie Jayne,
Did you ever come to a conclusion as to whether the jaundice was do to increased RBC destruction or do to liver dysfunction? Also did you ever follow up how the straw had been grown and processed to see if there was anything odd? It does sound like the straw but I am not sure your cultures results are unusual. Of course we could surmise a particularly toxic variety or some sort of immune reaction (allergy) perhaps better understanding the nature of the jaundice would help flesh this out better.
DrO
Member:
Lesali

Posted on Saturday, Mar 13, 2004 - 2:39 pm:

Hi Liliana,

I fully agree with you and have challenged practices on the yard causing much friction between the yard owners and myself. Ali is a cribber / windsucker but much less than he was. The lifestyle and eating habits of a racehorse are less than ideal, plus lack of continuous foraging is not good either. I have asked if I may put hay in the field during turnout. The answer was “no, they have tried it and the horses fight over it”. They know their job; they have been doing it for years! That’s what they tell me anyway.

The horses get terribly bored when turned out all day with no grazing and tend to play fight very rough sometimes. It’s not the best situation liliana.

We have a high equestrian density in my area and places are hard to come by.
Some yards don’t even have a winter turnout at all, so it could be worse. At least they get some exercise and freedom between hacks out. And of course it gives important time for social interaction with other horses. As you know, it is important for horses to be horses sometimes (it’s what they are best at, being themselves). It gives them time to play and run around. A quote from a book called” Think Like Your Horse” by Michael Peace & Lesley Bayley,

“Only happy horses play”

I have my name down for two other yards at the moment. There are long waiting lists for the “good yards” since they are in demand. I am DIY at the moment. The yard has excellent security (recorded CCTV) and excellent summer grazing. It is excellent value for money and is close to home. It also has an on-site shop, we just write down what we want and it is put in a bunker aside the stable.

It was unreasonable to move Ali during his illness (he doesn’t travel well anyway), plus I needed to find out the cause of his illness, so it was necessary to be at the source. Other yard owners might have been concerned that Ali’s mysterious illness might be contagious. So until I knew for sure, I had to “stay put”.


Thank you for your concern & comments,

Best regards,


Lesley (& Ali)
Member:
Lesali

Posted on Saturday, Mar 13, 2004 - 3:01 pm:

Dear Dr O

When my vet declared that Ali’s symptoms were none typical of any malfunction or disease, I made many suggestions to him as to how we might uncover the root problem with the illness. I suggested a BSP clearance assay that might point to a liver malfunction. I asked him if he ought to perform a PCV test “at rest” & after exercise that might point to spleen dysfunction.

These were greeted with a “doubting” response. I would liked to have known, but I was trying to tread carefully without the appearance of telling him his job.

I asked him to send me a copy of the liver function results. The bilirubin count was only a total bilirubin & I really would have expected both direct & indirect values. This would have been a useful tool in the liver/spleen debate.

I decide to call the labs that carried out the blood work. They told me that they didn’t deal with the general public. They insisted that any further blood tests must go via my vet (they have arrangement/accounts with each other I presume).
So, without my vet on my side I was stuck.

By this time I was already on the MOULD trail and it didn’t really matter any more.

So, back to your question.

I suggested to my vet that if Ali’s jaundice was due to excessive RBC breakdown then he might exhibit anaemia. He answered that Ali did not look anaemic yet still did not carry out a blood test to check the RBC count. I have to trust his word to some extent since I have no idea how “one” would visually check for equine anaemia.

All I can say is my “gut” feeling on the matter. All other liver parameters were within normal ranges. There was no evidence of bilirubin in Ali’s urine and it was normal in colouration. So therefore, I don’t think it was due to excessive RBC breakdown. I think that the toxins “target” was either the liver, or re-absorption of bilirubin through his inflamed and damaged mucosal intestinal wall.

In hindsight I cannot prove it one way or another. I have questioned several visiting vets on the yard. None had any personal experience of mycotoxicosis.
I have “bust a gut” to cure Ali’s illness against ridicule from those around me who claimed I had not enough experience with horses to know what is wrong. I have put my research at the hospital “on hold” & there have been many times I have felt alone
due to lack of support & broke down in tears.

I have talked to everyone concerned with processing & handling the straw, which has caused a great deal of “friction”. Everyone feels that they are not to blame for this episode. I am not looking to blame anyone. I look only for answers. It’s no one’s fault…just circumstance & I was unlucky that MY horse was affected.

Regards,

Lesley.





Member:
Lesali

Posted on Saturday, Mar 13, 2004 - 3:11 pm:

If anyone is interested, I have uploaded pictures of the mould/anomolies found on the straw.

There is also a htm. document about mould.

view pictures
Moderator:
DrO

Posted on Saturday, Mar 13, 2004 - 7:31 pm:

Well I guess we will have to be content with things are going much better now.
DrO
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