Re: Worming

["Susan Garlinghouse" <suendavid@worldnet.att.net>]

> Why would you worm the horse again if you are not sure if it is wormy or
> not?  I can take a stool sample to my vet and have results in 15 minutes
for
> $10 as to whether my horse is wormy or not then I

Because the tests only come back positive (= "wormy") if the worms are
adults, shedding eggs in general, and also shedding eggs right that moment,
and enough eggs showed up in the fecal float  to be noticed and identified.

It won't show anything if the horse is infected but the worms are migrating
and not yet shedding eggs, or if the worm/egg load didn't happen to get
picked up, or they're encysted, etc etc etc.

In other words, it's *very* easy to get false negatives---a test that says
you don't have worms, when you do, including the big, nasty, bloodsucking
ones.

Susan G