High Worm Count in 1 horse and zero in the other?!

[MochaDun]

Ester that link to the Vet Record comes up fine thank you.

We had some sheep escape onto our horses summer fields which the horses will return to on 1st May so I'm grateful for that

 

[soloequestrian]

granted it would follow that if you have low FECs over the summer months you are unlikely to have a problem with encysted redworm. However I would only not treat for this if I could be really happy that the FECs were accurate. I wouldn't say that benzimidazole is the most common treatment used nowadays I would guess that moxidectin as a single treatment has surpassed that.

But just how inaccurate can they be? If a horse has a huge burden, it will show up. If it doesn't, it doesn't need worming. I know our local vets still recommend Pancur.....

but yes I would agree we do have to use FECs but we have to use them, an I would say more importantly interpret their results accurately which I think is hard for the labs if they don't have full information on the horse's situation which would so much affect the interpretation.

Yes, I'm probably spoilt here. I do my own FEC's, and have total control over my horse's environment, so very lucky.

The thought of triple resistance is pretty terrifying. thanks for the article solo I will have a look, will make a change from microbiology . I do also think much of the problem is owners also worming inappropriately as most seem to have little knowledge of what wormer they are using when and why

Yes, I overheard someone buying a wormer in the vets the other day. She clearly had no idea what she needed, and wasn't offered any sort of advice by the receptionist. Aargh.

 

[FairyLights]

My take on it all:
Large redworm can kill horses - they migrate into intestinal blood vessels, and if numbers are large enough, block them, kill bits of gut and cause catastrophic colic. During the 1960's, and onwards, blanket worming was recommended to control these, and it worked - large redworm is an uncommon parasite now.
The parasites we do have now are much less of a threat. Small redworm are the most numerous, and they would very rarely cause life-threatening conditions. In large numbers, they will cause ill-thrift, and if they all erupt from their encysted state at once they can cause inflammation of the gut, so they do need to be controlled, but not with the same sort of urgency as the large redworm.
We are living with the hangover of the need to control large redworm, which we don't really need to do at the moment. The drug companies want to sell product. Most people fear worms, and like to feel they are doing something definite in terms of treating their horse. All this leads to massive overuse of wormers, and the development of resistance.
We also tend to ignore the fact that most horses can deal with most worms themselves, with very little help from us other than good management (low stocking density, good health etc). I'm very suspicious about treating horses specifically for encysted redworm. If they have low FEC's, where would all the encysted larvae come from? It seems to me that around the time large redworm became less of an issue, a product was launched that could control encysted small redworm larvae, and so the problem was also 'launched' on an already fearful horse owning population. In addition to this, there is widespread resistance to benzimidazole now, and encysted larvae are just as resistant as adult worms, so the most commonly used treatment for encysted larvae probably doesn't work much of the time.
To me, resistance is a far more worrying problem. What we need to do is lay off the chemical wormers, and manage worms in a much more specific manner. To do this we HAVE to use FEC's (and preferably tapeworm antibody testing too). If usage of chemical wormers was to decrease so that they were only used when absolutely and utterly necessary, they would gradually become more effective again as resistance genes in the worm population became diluted.
See http://onlinelibrary.wiley.com/doi/10.1111/j.2042-3292.2010.00084.x/abstract

Brilliant post, I agree 100%.

 

[ester]

'But just how inaccurate can they be?'

yes I do know what you mean and maybe I have just been too trained to question stuff. I think we have a spare microscope going which I might give a good home and get myself a McMaster slide

I can't remember what the treatment limit is for horses I know sheep was 300epg paper I linked to (using predictive modelling on results) reckon McMasters read 0 when there is 200epg 2% of the time, however I think that it was using samples obtained rectally which negates some of the owner collection issues. eta and the mcmaster technique did return a score of 0 when 20 separate tests indicated a mean of 300epg

 

[soloequestrian]

I can't remember what the treatment limit is for horses I know sheep was 300epg paper I linked to (using predictive modelling on results) reckon McMasters read 0 when there is 200epg 2% of the time, however I think that it was using samples obtained rectally which negates some of the owner collection issues. eta and the mcmaster technique did return a score of 0 when 20 separate tests indicated a mean of 300epg

Do you have a reference for that? Would be interested to read. The point I'm trying to make though is that if the horse had, say, 2000epg as with the OP horse, the McMaster would be very very unlikely to miss it.
The glass McMaster slides are expensive, but I got some plastic ones from a company abroad for a very good price. I just found them through Google. The slides have the huge advantage that they don't smash when you drop them.....

 

[ester]

that was this one

http://www.innovis.org.uk/Resources/The_Veterinary_Record_February_12_2005.pdf

and yup agree with you re the 2000epg, I think its just more if the other horse is not being identified as a contributory factor when it is.. or it might not be!

ahh might google plastic ones thanks!

 

[Zuzzie]

Can I say a big 'thank you' to all those who have contributed to this topic. Its so informative - a real eye opener.

 

[Jasper65]

hey guys

my boy is due for worming at the end of the month but last time he had a wormer he coliced quite badly and im worried the same is going to happen again. His weight has been fluctuating alot more than usual recently and he has no energy. I was advised to get a worm count done and then worm accordingly but have never done a worm count and as he came from a field that had over 30 horses and 2 donkeys, none of which were wormed and the field was never poo picked im not sure what to do for the best?

any help would be greatly appreiciated.

 

[paddy555]

can I ask a question of the experts here please? It is concerning roundworm rather than red. It is my understanding from the Liverpool uni site that FEC's also show up roundworms. I started worm counting about 6 years ago. The redworm counts were always low never more than 100 and usually less than 50 and so I relied on the FECs and did not worm. There was no mention in the report of a roundworm problem. I did not worm one horse for about 2 years. He was frequently egg counted. (I did not want to worm as I was trying to locate his low grade laminitis problem and did not want to complicate his problems with wormer)
Eventually I wormed, probably with eqvalan. It was difficult to locate his dung under a massive pile of "spaghetti" There were far more worms than dung. He was about 8yo. It was horrendous. Surely all the worm counts I had done (which were about 6 or 7) would have suggested some problem? After that I gave up FEC's as I had no confidence in them. Was I correct to be sceptical or are roundworm eggs unlikely to show up?
I asked my vet at the time I went onto an FEC based programme what he thought and he was horrified at what I was doing ie relying on egg counts.
Last week I asked how to plan my foals worming programme and was told to egg count. I did not get the feeling of any great confidence from the vet and it seemed more a case of him repeating what had obviously come out in vet journals.

I have had a second occurance of lack of confidence in FEC. I bought a 4yo from what I thought was a knowledgible owner. Turned out the knowledge didn't extend to worming. I wormed with ivermectin and there were masses of redworm in the droppings. (May) I took advice from the vet who said to FEC in 8 weeks. This time the vet organised the worm count so a different lab. It came back clear. By now it was around begining of July. I wormed in Sept with eqvalan duo. Looked in the dung and it was crawling with red worms. Masses of them. In hindsight I realise my horse had been poorly dealt with both by the previous owner and myself who had not appreciated the severity of it's redworm problems. However if a FEC comes back clear at the beginning of July surely there should not be such a mass of redworm 2 months later if the results were accurate.
As you will see I am struggling to have confidence in the new method of FEC's although I understand the resistance problem fully.

 

[soloequestrian]

Paddy and Jasper, I'm interested to see what others say about your situations. They seem very unusual, and I'm not well placed to comment on extraordinary worm things! As far as I know, FEC should pick up roundworm eggs. It would be unusual for a horse of that age to have a roundworm burden, but I don't know why it would be missed.
In the case of the horse with redworm in the droppings, the only things I can think of are 1) some sort of mix-up in the testing lab, 2) some reason why the horse was delayed in becoming reinfected with redworm after the first worming, which would mean that although there may have been a large population of worms, they may not have been producing eggs at the time of the second FEC. In all the time I've been around horses, I've never seen an adult worm in faeces. I'm sure they've been there, just not in high enough numbers to notice.
In both these cases, I think I would be badgering the experts - your vets, your local equine specific practice, the parasitologists and vets who are employed by the wormer companies (Virbac etc), researchers at universities (Liverpool especially) to see what they all recommend.
These unusual situations kind of highlight why everyone does need to think more carefully about strategic worming - obviously use of chemical wormers is required here and at the moment the wormers will be effective. Imagine the situation where a wormer is desperately needed, but all the chemicals available have become ineffective due to resistance. The drugs need to be preserved for when they are really needed.
I wonder if more owners should start doing their own FEC's - it's a really straightforward thing to do, all you need is a microscope that can magnify x100, which I would think one from a decent kids science kit would be able to do, and a McMaster slide. After the initial investment, people could repeat tests as often as they wanted to, to guard against false positives and odd patterns of worm infection. Any college that runs an equine course should be able to teach people how to do the test.

 

[soloequestrian]

Posted twice by mistake - site went all weird

 

[paddy555]

further to my posting last night about not trusting FEC's I just wanted to add that the lab was NOT Westgate as I know Gill posts on here and I was hoping she may comment. I have no reason to believe the company I used (which appears to be a commonly used one that people think is reputable) was poor in any way. I just think perhaps that my small and very limited samples of dung did not reflect the whole story.

Thanks for your reply Solo. If Westgate spin dung samples how effective it doing home worm counts?

 

[ester]

paddy that's interesting to hear,

I would say that the 4yo on during those summer 4 weeks could have had an increase in burden that much.

I can add that roundworm definitely come up on FECs, basically if it is nematode you cannot tell any difference between the eggs really under the microscope you have to grow them into larvae. This does cause its own problems if the pasture you take your sample from is not that clean as there are non parasitic nematode worms too, though this would be false positive so not so much of a problem.

I do think FEC have their place, I just think that most people, including vets in many cases (or due to the possible amount of variation) do not really know how to use them optimally. Not helped by all the drug companies trying to advise use of their wormer, SQPs with not enough knowledge of PML products etc.

I agree solo I think that within reason people doing their own under advise/supervision would be an excellent idea.

And yes, just so people know once, as in Mexico you have worms on a property which are have resistance to all known drugs (not necessarily all resistance genes in one worm but in the population) that's kind of it and no horses can then be kept on that land for a lenghty period of time. The same has already happened with sheep in this country.

 

[soloequestrian]

Thanks for your reply Solo. If Westgate spin dung samples how effective it doing home worm counts?

If you look at methods for using the flotation technique, only about half of them include centrifugation. It makes things neater, but I'm not sure it changes the results. Having said that I've never actually tested that theory. The centrifuge fractionates the liquid, so you end up with all the rubbish as a pellet, and the worm eggs suspended in a reasonably clear solution. Without the centrifuge, the worm eggs are mixed with faecal material on the slide BUT the point of the technique is that the eggs float in the saturated salt solution, and anything else in there sinks, so you can see them clearly even if there is faecal material present.

 

[ester]

having done both it is much quicker to centrifuge and you do get a clearer slide making it a bit easier to see the eggs.

Having done it the proper accredited lab way with various sieves, centrifuges and glass mixing balls.

But seem to get equally good results with a pestle and mortar, a tea strainer and waiting for half an hour!

 

[paddy555]

thank you for your helpful comments Esther. I will accept the 4yo's count was clear and he did acquire more. I decided to give up on worm counts for him and to worm him in the hope that when he was older he would become more resistant. He seems to be the one "bad" one out of my herd of "good" ones.
I am also in the situation that I clean the fields daily in summer but in the winter there is no way as they are river meadows and we can barely walk on them.

I would like to try and pestle and mortar method or indeed any basic simple method that I can to regularly to give me an idea what is going on to back up FEC's.
Sorry to be a pain but please could you outline exactly what I do with this method. Presumably mush up the dung with water and strain it, wait and then???
anyone with other "home methods" of detecting worms I would love to hear from you,
From reading this thread I guess the sales of tea strainers are going to boom!

 

[ester]

paddy have a look at this thread a from a while ago, I included a link from the RVC in it which hopefully still works. If you get stuck though do give me a shout

http://www.horseandhound.co.uk/forums/showthread.php?t=363223&highlight=worm+count

 

[Borderreiver]

There is no reason at all why you shouldn't have a go at doing your own counts. Most people can't be bothered and for the small cost of testing decide to send off samples. Of course they then access proper qualified worming advice too.

I certainly don't think you should 'give up on worm counts'. They are more essential than ever with a horse where there are problems. You will obviously need to worm him, but using the correct products and monitoring as you go with tests. This will be the best way forward. It's really not a case of either worming or testing as the two can compliment each other. You will definitely need to treat encysted redworm, rather than only the adult egg laying stages which you have so far covered.

To the other poster, ascarids, roundworm should come up in worm counts. They are far less common than strongyles (roundworm) and usually only a problem with foals, youngsters and neglected animals from markets. Mature horses develop an immunity to them.
When you saw your horrible spaghetti after worming, are you sure they were roundworm and not pinworm? There are many problems with pinworm at present even in very well wormed horses. Just a thought.

 

[paddy555]

thank you Esther, the link works so that is tonight's reading
thanks to Gill. I hadn't considered they could be pinworms. Am away to find pictures of pinworms to see if I made a mistake.

Haven't been on this forum for long but this thread has made it so worthwhile.