I will try to answer your questions about heartworms in ferrets.  Yes,
ferrets can get heartworms just like dogs and cats (and even seals) can.
They all get heartworms from mosquito bites.  As for prevention, there
are several products that can be given to prevent heartworms.
 
Heartgard for cats 0-5 lbs. (ivermectin), Interceptor for dogs 0-10 lbs.
(milbemycin oxime), Revolution for cats 5-15 lbs, and diluted ivomec can
all be used on a monthly basis.  All 4 meds should work just fine.
 
The test that is recommended to detect heartworms is the Idexx ELISA snap
test.  Ultrasound can also be used to actually see the worms in the heart.
 
As for treatment options, ferrets can be treated with Immiticide (using the
3 dose schedule) with pediapred.  Pediapred helps prevent blood clots and
to reduce the damage to the lungs.  The other option is to start them on
diluted ivomec (50 mcg/kg per month) with pediapred.  The ivomec will cause
a slow kill of the heartworms over many months, and the pediapred helps
with blood clots and lung damage.  Heart failure can be treated with lasix
and diltiazem.  Treatment is not as successful in ferrets, so prevention is
the best way to go.
 
Hope that helps,
Jerry Murray, DVM
 
PS Yes, you can just start them on prevention without a test, or you can
use the Idexx ELISA snap test first.
[Posted in FML issue 3461]