I give it every year, for 6 months, and test every 2 years. Mind you, we're always told quebec province has a low occurence, but I've always done it anyway.
Since last spring, when a coworker brought home a pregnant dog brought to the clinic (found as a stray in the city) and we found out that she's heartworm positive, it's been a bit more in my face. Juno, the dog, was mildly symptomatic - slightly intolerant to exercise, coughing mildly. We also ended up finding out that she was from Ste-Agathe, a very small city up north (so technically more mosquitoes, but less chances of getting heartworm since the more north you go, the less common it is). She's undergone a few months of the "slow treatment" which hasn't worked well for her. Now she's started the Immiticide (melarsonine - the "hard treatment) where they get intramuscular injections (super painful) and have to be crates/kept super quiet to minimize the chance of pulmonary embolism due to dead heartworms (if they're in good quantity in the heart) moving to the lungs, potentially fatal.
This gives me no doubt about being right doing the preventative treatment - I wouldn't want to have either of my boys go through the immiticide tx. Then again that's my opinion, not telling people what to do!!
Edited cause I can't spell!
“Your birth is a mistake you'll spend your whole life trying to correct.” Chuck Palahniuk
I love pus but I hate people.
I can say words like undifferentiated gonads now!