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something to kill adult Onchocerca? 19 CASE STUDIES POSTED-PAGE 58

Horse Care
#1581

I’m only about 5 years late to this party and just read through to Page 16 so far but major props to ChocoMare, little D and all the others contributing to and maintaining this extremely valuable thread.

I just completed the second DDEP on a training client’s 7 YO Arabian mare who has been plagued with NTWs for years. The bumps on her neck erupted after 3 days following the first dose. The itching has subsided dramatically but she’s so infected it may take several more treatments. I’ll follow up in another 2 weeks with a single dose of Equimax and then go back to a DDEP if necessary.

Considering I’m only on Page 16 and still reading my following observations may have already been duplicated. If so, I apologize.

It’s my understanding that a large majority of horses in NTW prone areas may be infected but show no outward symptoms. The horses that DO develop the bumps and welts associated with NTW’s are actually allergic to the parasites, thus presenting what simply appear to be normal allergy symptoms, diagnosed and treated as such instead of NTWs. My personal horses do not overtly display NTW symptoms but starting tomorrow they will also begin the DDEP as a precautionary measure.

My other observation concerns the lack of veterinary support or recommendation of the DDEP. There is a pharmaceutical definition of using medicines in a fashion for which they were not tested or intended. It’s called “off label use”. Although the DDEP appears to be extremely effective for treating NTW the results remain anecdotal and definitely “off label”. I can understand why a licensed vet would hesitate to recommend (read - prescribe) off label use of any medication. That could jeopardize their entire practice if such use had a detrimental effect, actual or perceived, on a client horse. It would be risky for them to even mention knowledge of it “off the record”.

Following at least 5 years of “anecdotal” DDEP success just here on COTH I have to wonder why Virbac AH Inc. (Equimax manufacturers) and others who produce the Ivermectin/Praziquantel cocktail dewormers have not commissioned double dose research on Onchocerca infected horses or rebranded an extra strength version of Equimax specifically for NTW treatment so it would no longer be an “off label use” of their products. That should certainly open it to endorsement from the veterinary community and get treatment to horses who are currently suffering without it.

I just may call Virbac and ask them.

Again, many thanks for all who have kept the DDEP torch burning in this thread for 5 years! ~FH

#1582

Let us know how the call to Virbac goes! :yes:

#1583

OK. I called Virbac and they only manufacture Equimax to the specifications provided by the parent company, Bimeda Equine. So, I called them too.

I could only get as far up the corporate food chain as Customer Service. The head honcho (Director of Technical Services) was out of the office traveling. The CS rep knew Equimax is being used in off label dosages for a number of things and said Bimeda does not endorse or condone such uses. She also said she is “not privy” to any information about any current or proposed clinical trials to test Equimax beyond its present suggested dosages. She did confirm Equimax has been tested safe for healthy horses up to NINE TIMES (9X) the suggested dosage and immediately said Bimeda does not endorse or condone treatment anywhere near those levels either. They can’t for the same reason a vet cannot suggest off label use. She also did not know what the lethal dose (LD-50) of Equimax was but if 9X is tested safe then LD-50 would probably be an astronomical one-time amount.

I pressed for more information about the possibility for future clinical trials and asked for a call back from the Director to discuss that. I’m not holding my breath…

One of the problems with getting Equimax or any other FDA approved medication certified for a different (off label) use is the time, expense and FDA application and oversight to establish a safe use-specific protocol just to extend its efficacy against a single parasite. It may not be profitable for Bimeda just for the derivative use of an existing product. So the corporate-think is most likely to continue turning a blind eye toward the DDEP for NTW since they’ve already established a 9X dosage safety margin and enjoy the legal protection against off label use.

My personal caveat to anyone who has a concern about the DDEP off label use for NTW is… make certain your horse is relatively healthy before double dosing. And follow up the DDEP with some pre and pro biotics to replace gut flora that may be killed off by the insecticide about a week after the second 2X dose. ~FH

#1584

UPDATE:

The Bimeda CSR called back and told me she forwarded my questions to the Director. He said they have no plans to change anything since they’ve already proven to the FDA Equimax is effective against Onchocerca at the label dosage.

That’s their story and they’re stickin’ to it. ~FH

#1585

I did the first DD last Friday on my gelding… so far, he seems to be doing much better (substantially less itchy and welts on his neck, face and midline seem to be healing. Fingers crossed!

Thank you all so much for sharing this information!

#1586

[QUOTE=Halt Square;7073222]
I’m aware that I’m replying well after the fact, but I’ve been going through each post from the start, and this one especially spoke to me. I’m not even yet sure if anyone else responded to this, or could relate at all.
My girl stocks up just a few hours after even a single dose of Equimax, but not ivermectin knock on wood. This is why I did my first double dose with the iver. I had no problem with that and she has been noticeably less itchy, though one of the stall walls had to be repaired a few days after. I’m eager to give her the second DD of iver this coming Monday. I won’t be doing anything other than DDing with iver, then single dosing it, as needed. Can’t touch the Equimax.
She is a three year old Clydesdale and this is dramatically helping. Less bum, mane, body itching and feather issues. FINALLY!!! THANK GOD!!! I had tried everything!
This thread is such a blessing. I can’t wait to read the rest and report on our experience. Callie and I thank you all! So happy! :applause:[/QUOTE]

An update … At about the one week mark, after the first DD, I was dying hit the girl again with the iver - just a single dose. Although she wasn’t (and hasn’t been) as intensely itchy at feeding times anymore, at some point she rubbed out more mane than ever before. I ended up single dosing the girl with iver after just over a week. I couldn’t stand to see her lose anymore mane and have to explain myself to my farrier, who was due any day. He also has Clydes and seems to think I’m radical enough, simply because I feed alfalfa instead of oats. Had he seen her at the peak of her symptoms, I would’ve been pressed for an explanation, which he likely would’ve pooh-poohed before spreading the word. I’d prefer he see the results before I discuss it with him. I also don’t want the girl literally taking the stall wall down again because she’s suffering so much. I’m glad I hit her with the single dose when I did because she started feeling better almost right away. I’ll consider DD’ing again in a few days …

I’ve just gotten up to the case studies. I could especially relate to case 16. My horse has this frog problem, too. Oddly, one of hers is “normal”. It would be great if this treatment could make a difference. I’ll pay close attention so I can report …

#1587

Yet ANOTHER update:

I’m still working my way through this thread’s history and once again beg your indulgence if this has already been addressed

Additional info regarding NTW infestation. Even if your horse doesn’t SHOW any symptoms you should read these links. Make notice of the overall percentage of horses found to be infected with ADULT Onchocerca worms. Breakdowns are by both age and sometimes region:

http://www.ncbi.nlm…/pubmed/4008301

http://www.ncbi.nlm…/pubmed/3963592

Since the original title of this 5 year old thread was the question “something to kill adult Onchocerca?” the following abstract indicates NO amount of Ivermectin based product kills adult Onchocerca. And the adult worms are suspected of thriving in an infected horse for life cycles of 15 years or more! It’s only during their 21 day larvae stage they CAN be killed with multiple dose Ivermectin. This abstract also states adult Onchocerca found in the cited horse necropsies were still alive and capable of producing microfilariae (larvae). That means once an infected horse is identified and treated for NTW larvae, to be effective that treatment needs to be repeated at 21 day or monthly intervals for the rest of its life to hold the non-treatable adult reproduction at bay! The black fly (worm vector) season may only be during the warmer months. But once the horse is infected NTW reproduction occurs all year long. Not exactly the news many of us want to hear.

http://www.ncbi.nlm…/pubmed/3421544

Adult Onchocerca were found numbered in the tens of thousands in some older individual infected horses necropsied in these studies. There is no breakdown of how many studied horses presented the outward symptoms (allergic bumps and weals) or if they were all just a general sample population culled at random, other than the ones cited in the Ivermectin efficacy study where control groups were in place.

As I noted in an earlier post, the absence of symptoms apparently does not mean the absence of NTW. But infection rates in some regions and age groups has been documented as high as 80%. Does that mean we should do DDEP on ALL of our horses at least once per month after the initial two week period? Or should we just treat the ones who experience the torment of itching and scratching from allergic reaction. I don’t know the answer to that.

NTW and associated treatment protocols may have to be divided into two categories; 1) the treatment of a KNOWN NTW health issue that causes overt agitation, open sores and increased bacterial infection, and 2) experimental treatment to address possible performance and secondary health issues that may or may not be NTW related.

At current average pricing for Equimax of $10 per tube, continuous DDEP on a once per month basis after the initial two weeks apart treatment adds about $250 a year per horse. To some that may not seem like much but others may not find that amount sustainable.

Decisions, decisions…

One thing appears to be certain. The answer to the problem of treating NTW infestation and its related effects is not very simple or straightforward. While the information in the above links is not very encouraging, I hope it adds to our collective understanding of NTW/Onchocerca, both big and small, treatable and non-treatable. ~FH

#1588

[QUOTE=Halt Square;7077600]
An update … At about the one week mark, after the first DD, I was dying hit the girl again with the iver - just a single dose. Although she wasn’t (and hasn’t been) as intensely itchy at feeding times anymore, at some point she rubbed out more mane than ever before. I ended up single dosing the girl with iver after just over a week. I couldn’t stand to see her lose anymore mane and have to explain myself to my farrier, who was due any day. He also has Clydes and seems to think I’m radical enough, simply because I feed alfalfa instead of oats. Had he seen her at the peak of her symptoms, I would’ve been pressed for an explanation, which he likely would’ve pooh-poohed before spreading the word. I’d prefer he see the results before I discuss it with him. I also don’t want the girl literally taking the stall wall down again because she’s suffering so much. I’m glad I hit her with the single dose when I did because she started feeling better almost right away. I’ll consider DD’ing again in a few days …

I’ve just gotten up to the case studies. I could especially relate to case 16. My horse has this frog problem, too. Oddly, one of hers is “normal”. It would be great if this treatment could make a difference. I’ll pay close attention so I can report …[/QUOTE]

Finally got through the entire thread. Took days! Very informative. I took lots of notes.
Also, my farrier mentioned that my girl looks overall better, even before I told him what I was doing. I think the best is yet to come.
Even though she’s a complete brat about it, I’m really looking forward to hitting her again this Wednesday! I never thought I’d actually look forward to deworming her before this. Now it’s all worth it. :slight_smile:

#1589

For someone who doesn’t have time to get through the whole thread, is there a specific post that is a synopsis or can someone post one? Pretty please…

#1590

Ok, I’m going to bump this back up as it was on page 3, and hopefully(selfishly thinking) get an answer to my questions: I did read through this thread a bit more, basically what I’m coming up with is that we DD according to weight with Equimax and then 2 weeks later, we do it again. Is that correct? Does anyone do this for a horse that doesn’t look horrible? I have one that every spring/summer starts rubbing his tail and recently has gotten these little bumps on him (only a few) that then kinda open up and leave a bare spot. Most problematic was one on the side of his back (1" diameter) where the saddle goes (NOT from the saddle!) and then another 3" patch on the side of his face. A couple other smaller ones on his body, but overall he looks GREAT! He is very itchy, though, when I groom him. We’re definitely not “in the area” where this is supposed to be a problem. I’ve been following the new deworming protocols, so I’m hesitant to stray from that. BUT vet is at his wits’ end with the tail thing and doesn’t know what to think of the other spots although they are all healing well now with Entederm. Sooooooo, should I do it???

#1591

[QUOTE=Dune;7089159]
Ok, I’m going to bump this back up as it was on page 3, and hopefully(selfishly thinking) get an answer to my questions: I did read through this thread a bit more, basically what I’m coming up with is that we DD according to weight with Equimax and then 2 weeks later, we do it again. Is that correct? Does anyone do this for a horse that doesn’t look horrible? I have one that every spring/summer starts rubbing his tail and recently has gotten these little bumps on him (only a few) that then kinda open up and leave a bare spot. Most problematic was one on the side of his back (1" diameter) where the saddle goes (NOT from the saddle!) and then another 3" patch on the side of his face. A couple other smaller ones on his body, but overall he looks GREAT! He is very itchy, though, when I groom him. We’re definitely not “in the area” where this is supposed to be a problem. I’ve been following the new deworming protocols, so I’m hesitant to stray from that. BUT vet is at his wits’ end with the tail thing and doesn’t know what to think of the other spots although they are all healing well now with Entederm. Sooooooo, should I do it???[/QUOTE]

I would do it. My mare wasn’t bad. Just the same itchy tail you have and she did start rubbing off a tiny section of mane, which I wanted to stop before it got out of control.
Not sure if you’ve read far enough to see that the poster “little D” is the farrier that advised ChocoMare to do this in the first place. I’d at least read all her posts, which you can pull up in the advanced search section.

#1592

Unless you’ve got a very small or young horse I’d use the full tube X2, regardless of weight. Equimax is tested safe at 9X the regular dosage and using the full tube would just bump you a little over the 2X by weight.

As for the tail and other areas where NTW might not be responsible for the hair loss and itching you may want to try a topical application of 1.87% Ivermectin rubbed into the affected area followed by DMSO applied on top of it. DMSO will help the insecticide penetrate the tissue and possibly get at parasites a blood borne dose doesn’t normally reach. I suspect using Equimax applied topically on the neck and crest in the same fashion might also be effective against the NTW larvae that live in the soft tissue there but I haven’t tried that method yet. I may give it a go if the bumps return again on my infected horse.

If you’re seeing improvement with the Entederm treatments I’d stick with it. But the DDEP done in concurrence with that shouldn’t hurt your horse. ~FH

Forgot to add… USE RUBBER GLOVES applying Ivermectin and DMSO. And don’t spray DMSO. You risk inhaling it that way.

#1593

So, it’s been a week since I last single dosed with Iver. I was going to dose her again today, but … I’ve been thinking more and more about this … I’ve decided to do a single dose every two weeks, instead.
If these buggers can only be killed during their 21 day larvae stage, then why wouldn’t two doses within that time frame be sufficient? By spacing it apart, and only doing the singles, you don’t have to have such a big die-off reaction. Risking a uveitis flare up over a large die-off is just quite … risky.
So this is how I intend to proceed until the first freeze and then I’ll consider single dosing every 3-4 weeks, at least until next spring. If she’s having symptoms again next spring, I’ll likely step it up again to a single dose every two weeks. My horse will definitely continue to be on prebios, among other things, to make this easier on her system.
If I could do this over, I’d probably start her off this way, instead of DDing right out of the gate. I’m not sure the risks that come with such a large initial die-off are necessary.
Wasn’t the reason for the double dosing just to be sure you’re not underdosing, anyway? I don’t think you’d be underdosing, if you were giving two biweekly singles within the 21 day period.
Am I missing something, or does this sound reasonable?
I would think even single dosing every week would be less risky than doing the doubles, while still being just as effective …

#1594

As I’ve come to understand the NTW problem the double dose is necessary because the larvae live in soft body tissue and not the gut. Therefore NTW don’t get as much contact with the insecticide because it has to penetrate deeper into the horse’s system to reach them.

Quite frankly, I think you may be more at risk creating a resistance to Ivermectin with weekly single doses rather than a bi-weekly double dose. And not just for the NTW but other parasites as well.

I certainly respect the concern for your horse’s well being. If you suspect NTW infestation has moved to your horse’s eye a close veterinary eye inspection might be in order to evaluate that possibility before DDEP treatment. But based upon the huge amount of anecdotal evidence presented in this thread and elsewhere I don’t think you would have much success against NTW with single dose Ivermectin. That being said…

… you might try slathering Iver paste topically directly upon the infected area and then applying DMSO to carry the insecticide only into the suspect area to get stronger direct contact with the larvae than oral administration that will circulate weaker through the entire system. I haven’t yet personally tried this method to judge its effectiveness. The horse I’m treating now is responding well to oral DDEP and she’s got a massive infestation. But I do plan to try the topical Iver/DMSO method when the next opportunity presents itself. ~FH

#1595

I really appreciate your input. I’ll consider another DD in a week. Hopefully my next batch of iver arrives by then.
I’ve just been spooked by some threads I’ve seen of people having done the DD and then battling uveitis. Freaks me right out. Heart is literally racing right now.
I should try the paste topically, too. She seems to especially need it at the one week point, which is why I’ve caved and given weekly singles before being able to do a second DD.
I’ve been extremely worried about resistance, too. It would absolutely kill me if, by trying to help her, I made the situation worse.
Oh, this is stressing me right out. Really need a drink. :cry:

#1596

OK, I did it! I dd w/Equimax a couple of days ago when I came out and found that said horsie had rubbed his tail yet again! No adverse reactions so far, bumps that had opened into small wounds look drier/“quieter”. We shall see…will dd again 2 weeks from 1st dose.

#1597

[QUOTE=Dune;7095867]
OK, I did it! I dd w/Equimax a couple of days ago when I came out and found that said horsie had rubbed his tail yet again! No adverse reactions so far, bumps that had opened into small wounds look drier/“quieter”. We shall see…will dd again 2 weeks from 1st dose.[/QUOTE]Good for you… and your horse! The erruptions are sure indicative of NTW infestation. You may want to spray some Vetericyn on open sores until they dry and scab over.

The itchy reaction to dying larvae seems to be normal. But you might want to try some Ivermectin applied topically to the tail with some DMSO to penetrate the tissue. Even if it’s not a NTW related itch the insecticide should kill suspected parasites too far from the bloodstream to reach orally. If that has no effect try a little squirt of WD40 on that area. My old country vet directed me to do that for rain rot fungus and it worked. ~FH

#1598

I am new to this forum and just sort of getting a grip on what is actually going on with my horse. Just really in the last few days really getting that the severe sweet itch could well be related to the NTW. I had read about single dosing wormer three times, three weeks apart…and I have done that. In two days it will be the third of three weeks. But I am now really realizing that it is going to need to be double dose. What I am unclear about…and it may be in there somewhere but I have not been able to read all 80 pages…is do I DD with Ivermectin or Equimax??? I am not clear what the difference is when dealing specifically with the NTW.

And it may be of interest to some. I am a member of a yahoo horse keeping group and a woman there is researching the effects of Neem oil on the NTW. There may be some interesting results come out of that. It appears it may be that the adult worm is killed by need oil applied topically or by neem leaf added to the diet. If anyone here has an interest in knowing more about that as it comes available let me know.

#1599

Double Dose (by weight) with Equimax Day 1
Double Dose (by weight) with Equimax Day 14

-if necessary-

Double Dose (by weight) with Equimax Day 28

#1600

That would be me working with neem. I have seven horses, Warmblood, Arabian and Icelandics. I care fora 35 y.o. Quarter horse mare and a 15 y.o. Arab/standardbred. One Icelandic mare had a symptom beyond itchy neck/rectal area that lasted l winter. She had a quarter-sized amber disc under her forelock. Searching that this Spring, I found onchocerca cervalis and realized that my horses were not just itchy from gnats. Two old horses, now deceased, had uveitis.

Can someone tell me how much ivermectin you use topically with DMSO. I have the liquid. I don’t want to use more than I need. My Icelandic mare looks great except the rear-rubbing. Neem oil worked for rear-rubbing and other itchy spots on one horse. Two still rub. They need more. Mostly, neem oil keeps gnats away. There are indications it kills the microfilae.

Thanks,

Sue
Montana

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