[megansmomma]

Originally Posted by megansmomma

I'm pretty sure they test yearly for the simple reason that people are not always as compliant as they claim to be.


Here's a little more info:

https://www.vet.purdue.edu/vth/sacp/...nsonHWprev.pdf

Here is what Purdue had to say in the article that I posted:


[[

B]Why does my dog need to be tested for heartworms every year even though he’s been on heartworm prevention?[/B]


There are several reasons that dogs need to be tested every year for heartworm. Monthly administration of heartworm preventative is generally easy, however seldomly dogs can vomit up the chewable tablets or spit them out with out you noticing, leaving the dog unprotected. Dogs also need to be tested every year, because depending on which preventative your dog is on, it can be dangerous to give your dog preventative if he is infected with adult heartworms. Another great reason to test your dog is if there has been product failure (i.e. you have given heartworm preventative religiously and your dog is diagnosed with heartworm disease), most companies that produce heartworm preventatives have a guarantee on their product and will pay for any treatment necessary for your dog.