how often should a dog be checked for heartworm
Dogs should be tested for heartworms before beginning a heartworm prevention program, or when changing from one heartworm preventive to another. Dogs that are already on heartworm preventive medication should also be tested periodically.The âprepatent periodâ for heartworm disease (the amount of time it takes for microfilariae to be produced) is approximately 6 months in a dog.During this time, heartworm tests will be negative even if a dog is actually infected. Therefore, puppies younger than 7 months old are generally not tested for heartworms.ogs should be tested for heartworms before beginning a heartworm prevention program, or when changing from one heartworm preventive to another. Dogs that are already on heartworm preventive medication should also be tested periodically.