Heartworm disease occurs all over the world, with new and resistant strains developing more and more. Michigan's mosquito season is approximately 7 months long. Monthly preventives work by destroying early stages of the parasite after it enters your dog. The preventives will kill microfilaria that has been present for up to 30-45 days. This means, it will "flush out" any infection that may have occurred in the previous 30-45 days. Heartworm preventives when given on May 15th will cover from that day, backwards, to roughly April 1st, though we recommend for the safety and efficacy, your pets are given these products monthly.
These preventions are administered until mosquito season is over, and/or until the snow falls and the ground is frozen, typically around mid November. If mosquitos are still active after mid October, or your pet has exposure past this point i.e. trips to Florida for the winter, we recommend they continue prevention until exposure has halted.
So why do we test yearly if your pet is kept on a regimen of heartworm prevention? We understand that you may be right on time each month, or that your dog may love the once a month treat. So why test? As stated above, heartworm disease continues to evolve, as pets travel, strains mutate and become stronger. We test to ensure that in the event a dose was missed, or your pet was exposed to an unresponsive strain without your knowledge, we can stay on top of the infection and get a handle on it before it severely impacts your loved one.
The heartworm life cycle begins when a mosquito feeds on a heartworm positive host (dog, coyote, fox, wolf, ferret, or cat), and then feeds again, on a negative host, regurgitating infected blood from the infected host, back into its newest host. The regurgitation from the mosquito evolves into Microfilaria, then Larvae, into Juvenile heartworms, and shortly after that, mature into an adult heartworms.
The moment a dog is infected, it takes a full 6 months to mature into a "testable" stage. If that first test misses the stage by even a month, it may go undetected. With that said, keeping your pet on a prevention that works backwards, can help protect your pet in these situations, but that won't always be the case, which is why each spring, we ensure your pets are tested.
As far as felines are concerned, there is no approved treatment, only prevention. It is for this reason, that keeping your feline friend on heartworm prevention (Revolution Plus) is vital. So help us, help you, keep your kiddos safe and ask about our preventive options!