How effective is heartworm prevention?

When given every month, year-round heartworm prevention is very effective. Again, it kills the larval stages before they can develop into adult heartworms, and adult heartworms are really what cause the problem in dogs. The American Heartworm Society recommends monthly, year-round heartworm prevention for all dogs, especially in coastal and hot areas. We're sort of borderline here, but I don't think that we can count on mosquitoes that transmit heartworm disease to die reliably, so I don't think that there should be any break in heartworm prevention, and that's how it's going to be most effective.

No prevention is 100%, but the ones prescribed by your veterinarian give you your best chance of preventing something like heartworm disease. And a lot of those are actually backed by multimillion-dollar companies that really believe in research and their products.

Most, if not all, FDA-approved heartworm preventions are incredibly effective—in fact, over 99% effective. That's very fortunate because, again, in Texas, heartworm disease is such a big deal. Having prevention that we can be very confident in is a very good thing.

The heartworm preventatives are 95% effective, if not more. There are a few cases of resistant heartworms that have become more recent. They used to be 100% effective. Now, they're about 95%, I would say. And that's still pretty good.

Also, some people are under the misconception that they don't have to give preventives in the winter. That's not true. Especially here in North Carolina, we have temperatures where mosquitoes can replicate and infect dogs all year. We recommend year-round treatment in most places in the United States now.

Extremely effective. There are cases where dogs can spit out a heartworm preventative treat or where a topical preventative doesn't actually hit the skin. In those cases, if the preventative was purchased through a veterinary source, the heartworm preventative company will guarantee the product and cover treatment. However, almost all of the time, it is very effective.

Heartworm preventatives are very effective for preventing heartworm disease. However, there has been a new resistant strain of heartworm disease, particularly in Louisiana and Mississippi. The injectable heartworm preventatives are considered the most effective at this time.

Heartworm prevention is very effective. As long as the heartworms aren't resistant to the medications, then it will kill all of them.