PARSIPPANY, N.J.--(BUSINESS WIRE)---- $ZTS #animalhealth--Drug-resistant heartworm is a growing concern for veterinarians and pet owners as resistant heartworm populations emerge. New research shows that not all heartworm preventives perform equally against these resistant isolates. Macrocyclic lactone (ML) resistance means some heartworm isolates are less sensitive to the drug class used in today's heartworm disease preventives. As ML resistance continues to challenge heartworm prevention, veterinarians need data th.








