Heartworm prevention message shifts from awareness to adherence
Bottom line
CURRENT BRIEF VERSION: A new dvm360 video commentary is putting the communication side of heartworm prevention in focus. In the April 29, 2026 piece, cardiologist Marisa Ames, DVM, DACVIM, who is also president of the American Heartworm Society, argues that better client conversations, supported by a well-informed veterinary team, can improve adherence to preventive therapy and help reduce transmission risk. The message lands as the American Heartworm Society’s latest incidence map shows heartworm continuing to spread beyond traditional hot spots, with the 2026 survey identifying rising case density in parts of Texas, the Florida Panhandle, the Carolinas, southern Illinois, and other emerging regions. (dvm360.com)
Why it matters: For veterinary professionals, this is less about new medicine than better execution. Recent JAVMA viewpoint articles argue that most heartworm infections in established canine patients are driven by noncompliance rather than preventive failure, and one analysis found only 24.4% of dogs under care achieved full-year purchase compliance with monthly macrocyclic lactones. At the same time, consumer research from Banfield found nearly 40% of pet parents don’t believe their pet is at risk, and nearly 30% said their pet is not on heartworm prevention. That perception gap is not limited to dogs: feline experts have also warned that “indoor” is often a misleading risk category, since mosquitoes and other parasite exposures still reach cats in apartments and homes, making indoor-only status a weak reason to skip prevention. In that environment, consistent messaging from the entire care team, paired with practical tools like the American Heartworm Society’s Heartworm Toolkit, may be one of the most actionable levers practices have. (pubmed.ncbi.nlm.nih.gov)
What to watch: Expect more emphasis on staff training, adherence tracking, and prevention-first workflows as practices respond to expanding geographic risk, persistent compliance gaps, and ongoing client assumptions that indoor or “low-risk” pets do not need year-round protection. (capcvet.org)
CURRENT FULL VERSION: A dvm360 commentary published April 29, 2026, is sharpening attention on a familiar but unresolved problem in companion animal medicine: how to communicate the value of heartworm prevention in a way that actually changes behavior. In the video, Marisa Ames, DVM, DACVIM, president of the American Heartworm Society, says stronger client communication and better team-wide education can improve adherence to preventives and help reduce heartworm transmission. (dvm360.com)
The timing matters. The American Heartworm Society’s 2026 incidence map, built from 2025 testing data, shows heartworm cases continuing to shift beyond long-recognized endemic areas. According to AAHA’s coverage of the map, Texas led the nation for incidence for the first time, while parts of east Texas, the Florida Panhandle, southwest Florida, the central Carolinas, and southern Illinois posted more than 100 cases diagnosed per clinic. AAHA and CAPC both describe a broader pattern of northward and westward spread, driven by mosquito ecology, climate conditions, dog movement, and prevention gaps in places still perceived as low risk. (aaha.org)
That backdrop helps explain why communication has become a strategic issue, not just a client education issue. Ames’ core point is that the whole veterinary team should be able to explain heartworm disease clearly and consistently. The American Heartworm Society has been building infrastructure around that need, including Heartworms Unraveled staff-training modules and the Heartworm Toolkit, which offers a treatment dosage calculator, life-cycle visuals, and client-facing educational materials. Those resources suggest the profession increasingly sees prevention messaging as something that needs systems, not just individual clinician effort. (dvm360.com)
New literature adds urgency. A recent JAVMA viewpoint by Matt Horvath argues that owner noncompliance, not preventive failure, drives most canine Dirofilaria immitis infections in established patients. The paper reports that only 24.4% of dogs under veterinary care achieve full-year purchase compliance with monthly macrocyclic lactones, and it questions whether common workflows overemphasize annual detection reminders over ongoing prevention support. A second Horvath viewpoint applies a number-needed-to-screen framework to annual antigen testing at preventive renewal in documented-compliant dogs, challenging whether current testing expectations are proportionate to residual risk in every case. Together, the articles push clinics to think harder about whether their protocols are optimized to catch failures after the fact, or to prevent them in the first place. (pubmed.ncbi.nlm.nih.gov)
Industry and consumer data point to the same disconnect. Banfield reported in April 2024 that nearly 40% of surveyed pet parents did not believe their dog or cat was at risk for heartworm disease, nearly 30% said their pet was not on prevention, and 21% did not believe mosquitoes in their state carry the parasite, despite heartworm being diagnosed in all 50 states. That misconception also shows up in feline medicine. In a VetGirl podcast, feline practitioner and American Heartworm Society board member Mark Cousins, DVM, DABVP, argued that “indoor” is one of the profession’s most misleading risk labels because owners and veterinarians often define it differently, while mosquitoes and other parasite exposures still enter homes, apartments, and high-rises. His point reinforces a broader communication challenge: when clients equate indoor living with no exposure, prevention conversations can fail before they start. More recently, Today’s Veterinary Business reported that Embrace Pet Insurance claim data showed heartworm diagnosis claims rising by more than 200% between 2020 and 2025, with notable increases in northern states including Illinois, Michigan, Rhode Island, and Maine. (banfield.com)
Why it matters: For veterinary teams, the practical takeaway is that heartworm prevention may need to be framed less as a seasonal recommendation and more as a continuity-of-care challenge. If risk is widening geographically and the biggest failure point is missed or delayed dosing, then every touchpoint matters: reception scripts, technician education, refill reminders, renewal policies, and how clinicians answer common objections about indoor pets, colder climates, or “low-risk” regions. This also has workforce implications. When every team member can explain why year-round prevention matters—and why “indoor only” is not the same as “no mosquito exposure,” especially for cats—practices are less dependent on a single doctor-client conversation to drive adherence. (aaha.org)
There’s also a broader public health and practice-management angle. CAPC notes that a single heartworm-positive dog can increase local transmission risk where competent mosquito vectors exist, which turns individual nonadherence into a community concern. For practices, better compliance may also reduce the downstream burden of managing complex adulticide cases, treatment cost conversations, and exercise-restriction counseling. In other words, communicating prevention well is not just about selling a product; it’s about reducing avoidable disease, preserving client trust, and making caseloads more manageable. (capcvet.org)
What to watch: The next signal will be whether practices start operationalizing this prevention-first approach through measurable adherence programs, broader use of AHS training tools, and more intentional reminder systems as heartworm surveillance continues to document spread into emerging regions. Just as important will be whether teams get more explicit and consistent in addressing one of the most durable client myths in parasite medicine: that indoor pets, especially cats, are automatically protected by lifestyle alone. (aaha.org)