FHSS systems at all, because instead of using pure frequency-hopping, they also use DSSS spreading techniques to ensure that they also create distributed a spread spectrum (DSSS) output. However, for the purposes of this article and to avoid confusion, I'll use the term FHSS for these systems.
Dogs that are already on heartworm preventive medication should also be tested periodically. The âprepatent 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. Instead, puppies should be started on heartworm preventive medication (usually during their puppy checkup visits) and tested when they are older than 7 months.
Antigens for the heartworm cannot be detected until seven months after initial infection. For this reason, testing animals less than 7 months of age is not indicated. Annual re-testing is recommended for dogs not receiving heartworm preventative year round.