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  Discussion on Darnit a possum....link to epm?
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Member:
Jojo15

Posted on Sunday, Nov 13, 2005 - 11:06 pm:

I'm curious do all possums carry this disease? anything that screams infected? etc....I got a pretty good look at him. Not pleasant in a corner situation.

Do all horses carry the positive titer to EPM? or did i read the article wrong. I haven't done the testing yet, but think i am dealing with an IR horse, would that be considered more of a concern than a healthier horse?

I have lived here two years and never saw a possum and last night one showed up. IN my feed shed. of course i was looking for any feces out of place but heck does anyone know what possum feces look like? Hopefully i just have this one time visit. But is that enough to be concerned?

thanks all who are possum savvy....
Moderator:
DrO

Posted on Monday, Nov 14, 2005 - 8:37 am:

I have not seen a survey of the incidence of this disease in possums so am uncertain what the risk of exposure to your horse is but if you are greatly concerned you could just replace all the exposed feed. The incidence of positive titers to EPM does vary from area to area. Lastly I don't think IR horses would be more susceptible.
DrO
Member:
Ginger1

Posted on Monday, Nov 14, 2005 - 9:51 am:

Opossum DrOppings look a lot like dog DrOppings and it was my understanding that they had to eat another animal that was infected with the parasites before they became infected themselves. A multi cycle process.

Gigi
Member:
Vickiann

Posted on Monday, Nov 14, 2005 - 10:03 am:

The University of Florida has done a study on this and you could probably get an answer to your question by calling the Veterinary School. There are tons of articles available on the internet by asking for possums and EPM and some with adding University of Florida to the request. My computer recently crashed so I have to reinstall the programs to open some of those articles. Possums are nocturnal so even if you do not see them they are probably out there in fair numbers here in Florida. I wish I could recall what percentage of horses my Vet. told me test positive for exposure here in the State, but am sure it (perhaps substantially) exceeds 50%. Though I never see possums around my farm, I did have reason to test one of my horses for exposure and indeed he was positive, though he did not turn out to be suffering from EPM. It seems the possibility for exposure is very high in our pastures and paddocks.
Member:
Jojo15

Posted on Monday, Nov 14, 2005 - 10:19 am:

what i am learning that even cats can carry the protozoa for EPM and they are a transit host for the opossum. possum eats cat. Cat eats bird. and mostly the birds are the main transit host. Can't micromanage them...

So, I guess the problem is more rampant than just one little ole possum. Not to mention someone said rats can be a carrier, too. And they never rattled me... Their DrOppings, etc. Though i am finding them around more too...

Vicki that seems a bit high that 50% of horses down here could carry it. How many actually come down with it. Thanks for the lead i will look up UF site and see if i can learn more. I bet its our weather, like always, keeps things just right for hosting all these things. you'd think we'd get a break by now. Its 84 degrees. In november....

Thanks DrO the feedstuff is closed tightly. hay hopefully wasn't walked on. I had just had 30 bales delivered and they were to the rafters. Since finding him on the ground i don't think that was a problem.

Its never ending the things you need to worry about, huh?
Member:
Ryle

Posted on Monday, Nov 14, 2005 - 6:37 pm:

Generally, it is believed that about 50% of the horses in the US will test positive for exposure to the protozoa while only a very small percentage of those will actually develop EPM.

How likely a horse is to be positive for exposure depends on location in the US, too.
In March of this year there were some statistics reported in The Horse magazine...

"Although complete results are not yet available, Reed discussed an ongoing study of EPM exposure being conducted by OSU and Equine Biodiagnostics/IDEXX. The researchers evaluated serum WBT results in neurological patients presented for diagnosis from 2000-2003. They found that the incidence of seropositive (exposed) horses was as follows: California 35%, Oklahoma 80%, Texas 65%, Kentucky 66%, Florida 56%, New York 57%. In most cases, these numbers are far from supporting any assumption that nearly all horses are exposed to EPM.In addition, "The actual seropositives in the general population may be much lower," Reed commented. In other words, since most of the study horses were tested because they already exhibited neurologic signs, they don't represent a random sample and might be expected to have a much higher incidence of any pathogens causing neurologic signs than the general horse population. "Seropositive rates of horses with CNS disease are about twice as high as the general horse population," he added.

I wouldn't be too certain that the hay didn't get messed on just because the possum was on the ground when you found him. It's very possible he has been there before or had been in the rafters before you saw him.

Keeping all the food up so that it isn't a temptation for him to come around and keep the barn closed up at night is the best thing you can do to deter possums from coming around.
Member:
Vickiann

Posted on Monday, Nov 14, 2005 - 7:35 pm:

It is extremely frightening to realize our beloved horses could become ill due to EPM. In some states our chance for exposure is quite high, and believe we must try to control the things we CAN and do everything possible to have healthy horses whose immune systems are functioning well and hope for the best. We must also realize that horses should be allowed to be horses and that is going to expose them to risks we wish they did not have to experience. Most horses exposed will not actually become ill. And if the worst happens, there are horses I know who have EPM that do well in spite of it.
Member:
Jojo15

Posted on Monday, Nov 14, 2005 - 11:50 pm:

I am happy to report no opossum sitings this evening.

I did take Dr. O's advice to heart about getting rid of feedstuff. But i think that is a bit much. The hay is in a shed not barn. and filled to the top of it is what i meant when its filled to the rafters. I think its pretty ok.

I will be tossing the dog food it got into. Funny how all my researching this last day or so, nothing was ever mentioned about dogs being a carrier. My dogs eat birds, and rats, and all those nasty things. Anyone know why cats can be carriers, but not dogs? or does it present itself as a different disease in dogs?

Did you take a look at the Percentage in Oklahoma? Even if that is off a bit. why so high?

Thanks everyone for your help.. and gigi i did find smaller looking feces, thanks for the headsup.
Moderator:
DrO

Posted on Tuesday, Nov 15, 2005 - 10:18 am:

The life cycle, known intermediate hosts, prevalence, etc... are all in our article on EPM. The article can be found at, Equine Diseases » Nervous System » Incoordination, Weakness, Spasticity, Tremors » EPM, Equine Protozoal Myeloencephalitis. To get the list of new intermediate hosts (dogs and horses are currently added to the list) hit the Scientific and clinical topics on the Nat. Library of Medicine at the bottom. It is as current as what has been published today in the scientific literature.
DrO
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