A pony i bought years ago had it - he was REALLY itchy around his bottom - literally ruined his tail before i realised it wasn't sweetitch. Spoke to Vet who was out to do jabs for some of my others at the time and he suggested a particular wormer - i can't remember the name but pretty sure it was Ivermectin based? - cleared it up in days!!
I actually saw the worms before I noticed that he had been itching his bum (his tail didn't look like he had been). He did a poo when I was bringing him in from the field and noticed something moving!! eww
I wormed him with Strongid-P and then Panacur (the 5 day one) 10 days later. Seemed to do the job!
Ah!
My girl has a very itchy rear and has a lovely bald dock with sores. My friend had the vet this morning and just as the vet arrived he almost sucked his bum underneath him and so she looked and there was gooey stuff hanging out of his bum so she asked the vet what it was and she said pinworm. Now my mare has the same problem as him, and she also has been having yellow gunk around her anus (havent seem a worm), but I've kept wiping it off unaware of what it was. Does this sound like pinworm? I am going to the vets later so was going to ask them but just wanted to see if anyone has experienced it. I would of asked the vet but the gunk wasn't there to show them..
All the horses on your yard need to be treated for pin worm at the same time, and you will need to disinfect all the stables and grooming equipment or they will just keep coming back again.
Sounds exactly like pinworm. The adult migrates out of the anus and lays the eggs in a yellowish mucus-like goo. It's like a really stringy snot! Ivermectin is the most effective wormer for it (I use the Strongid-P sachets at double dose - for some reason the combination wormers don't do anything).
I think your vet is taking a bit of a gamble saying that it isn't catching. Some horses do seem more prone than others, but pin-worm can be picked up from contaminated pasture/sniffing other horses' poo ... etc, so all the horses are no less at risk than any other worm found in poo!