I was going to reply personally to keep the list length down but since two
people asked and it seems to be a recurring question lately:
 
Ferrets absolutely *are* susceptible to heartworm and should be on a
preventative.  The best is Ivermectin and the easiest way to dose it is to
give the bovine (cow) injectable form orally at a rate of .006 mg/kg -- your
vet will probably have to dilute the liquid to get this dose, and the best is
to dilute it with something that tastes nice (Drs.? -- I'm not familiar with
exactly how this is done).  It ends up being just one or two drops and it
need only be given monthly.  Some vets believe it is not necessary to give
heartworm preventative all year round and  so discontinue it during the
freezing months.  As almost every place these days tends to be prone to
sudden weird thaws and warm spells, I like to keep mine on all year round.
Ferrets don't tolerate heartworm treatment extraordinarily well so
preventative is very important.  Ferrets should be tested for heartworms
before preventative is started because if there are worms or larva in the
blood stream and they die from the preventative dose, they can get stuck in a
vessel and clog it up, causing kidney failure or other fatal outcomes -- this
is why your vet wants to test first.  Many vets recommend testing every two
years in dogs who are on year-round preventative just in case a dose was
accidentally missed or something.  I assume this recommendation would be the
same in ferrets.
 
I haven't heard of Lyme disease in ferrets, but I'm not in an endemic area.
I would say just use sensible precautions and there should be little danger --
 don't take your ferret into heavily wooded areas if you can help it and
regardless every time after you're outside check him over for ticks -- the
ones that transmit Lyme disease are *really* tiny so you'll have to look
pretty carefully.  This disease tends to be more of a problem in animals such
as hunting dogs who are in the woods and around wild animals a lot.
 
Laura
 
Laura L'Heureux Kupkee, U. of Illinois Vet Med Class of `96
[Posted in FML issue 1159]