The Battle Against Heartworms Is Getting Tougher!

Despite preventives that are nearly 100% effective, veterinarians continue to report increasing numbers of canine heartworm disease cases.  Some owners blame the heartworm preventives for failing their pets, but the reality of the situation is much different. Every month, lots of dog owners, and a few cat owners, give their pets some form of heartworm prevention.  But recent studies are showing increasing numbers of heartworm positive pets across the country.  Some people believe the worms now have the upper hand.  Has our trusted protection failed us?

Dog owners, and a growing number of cat owners understand that once -a-month heartworm preventives keep their pets safe from a very serious cardiovascular parasitic disease.  Despite consistent use of preventive medications, a significant number of dogs are testing positive for heartworms, especially in the mosquito heavy Southeastern US.  Are we seeing the beginnings of a resistance movement?

In some cases, careful questioning of the clients reveals some monthly doses of medication were not given, opening the door for potential infection.  In other cases, medical records and client compliance appear to be complete, yet the pet is positive on the annual heartworm blood test.

Heartworm preventive works by killing immature heartworm larvae that are spread by mosquitoes.  In theory, a pet who receives medication each month should be protected and never have a positive heartworm test.  Why then, do some dogs test positive?