The State(s) of Heartworm Incidence: What does the latest AHS Survey Show? | VETgirl Veterinary Continuing Education Podcasts

And I'm actually really excited to speak to you because we're going to be talking about the latest Heartworm Society survey.

And the American Heartworm Society conducted its first US heartworm incident survey back when I had just finished my residency.

So this was 2001 and has repeated this veterinary survey every three years since then.

So if you guys don't know about it, you definitely want to check it out.

But you guys are using the information to also produce a map that shows veterinarians and their pet-owning clients where heartworms can be found and where the greatest density of heartworm infections can occur.

So let's start by talking about the survey itself.

How does the AHS obtain data in this survey?

Every three years, we send out a call.

And so this year, in early 2026, A call went out to veterinarians in private practices and shelters in all 50 states.

And we asked them to report the number of heartworm tests that they had performed in the 2025 calendar year, and also to report the number of positive results.

And veterinarians were also given some questions regarding their perception of heartworm incidents.

And we were really excited.

We received over a thousand responses and this represents over 1 million canine heartworm tests.

And we take this incidence and report it as the number of heartworm cases per clinic and put them into these ordinal bins of cases per clinic.

And this is then color coded on the map.

So less than one case is that white color.

lower incidents such as one to five cases, kind of a peach color, and then it grows more and more red as we go from six to 25 cases per clinic, 26 to 50 cases per clinic, and then the higher incidents of 51 to 99 cases per clinic, or even 100 plus cases per clinic.

And so this survey is conducted the same way every year.

And many of the responding clinics have been responders for years, if not decades.

And this really allows us to evaluate the incidence of heartworm infection from year to year.

And again, so there's a nice visual representation regarding heartworm incidents nationwide.

And your listeners can navigate to heartwormsociety.org and see these maps.

And we've got all of them there so they can scroll through year to year and show their clients the changes year to year.

And it really gives you a visual cue as to what the incidence is in your area.

And the bottom line is, yes, there are some white areas, but that is more in the unpopulated regions of the U.S. where there just aren't many veterinary clinics or even people.