One Touch Heartworm Research
A new study starting in August 2025 has the potential to change treatment of heartworm infected dogs. The study is a partnership between Toronto Humane Society, the Shelter Medicine Program at the University of Florida, and The Inner Pup and is made possible by a grant from Maddie’s Fund.
Heartworm disease – A challenge for shelters and low-income pet owners
Canine heartworm is present in all 50 states in the US (as well as Canada and many other countries) but is most prevalent where mosquitoes capable of transmitting infection thrive in the warm and humid climate of the South. Since heartworm disease occurs most frequently in dogs with poor access to preventive healthcare, it is most common in shelter dogs and dogs in low-income communities.
The longer dogs carry heartworms, the more damage to the lungs and heart occurs. Disease may be undetected in the early stages, but progresses to cough, exercise intolerance, and in some cases, heart failure and death. Heartworms are transmitted to other dogs via mosquitoes. Adopters often shy away from adopting heartworm positive dogs due to the cost and difficulty of managing a dog through heartworm treatment. And dogs with heartworm disease may be surrendered when owners are unable to provide the treatment they need.
The Consequences
Timely treatment improves quality of life and decreases the likelihood of life-long heart and lung damage caused by heartworm disease. The American Heartworm Society recommends a melarsomine based treatment protocol often considered the safest and most successful. However, this treatment course is expensive, requires multiple veterinary visits, and demands months of strict exercise restriction.
Alternative evidence-based treatments, (so-called “slow-kill”) can be used when melarsomine is not a viable option. Our study aims to provide more data on this type of treatment, with the goal of making heartworm treatment simpler and more accessible.
Current Treatment Options
and Challenges
Can a new condensed heartworm treatment plan measure up to traditional protocols?
Our research team developed a prospective clinical trial comparing the safety and efficacy of two treatment protocols. The three year study, “One Touch Heartworm Treatment,” is made possible by a grant from Maddie’s Fund, which supports research to increase access to veterinary care. In developing the protocol, the researchers kept some key goals in mind:
- Match the safety of traditional protocols
- Achieve high treatment success
- Minimize the number of medical treatments for staff to carry out
- Contain treatment costs as much as possible
- Potentially identify an effective treatment that could be delivered in one veterinary visit
Dogs are randomly assigned to a heartworm treatment protocol. Both protocols include the same medications but with different timing and frequency. During treatment, dogs receive either one month of doxycycline and one Proheart12 injection per year or 2 courses of doxycycline and 2 ProHeart12 injections per year. Heartworm tests begin in month six and continue periodically until the dog is heartworm negative. Following two negative tests, the dog is considered heartworm free and no longer in the study. If the dog is still heartworm positive in month 18, the dog is referred for traditional melarsomine treatment. Throughout the study, dogs are monitored by the study staff at The Inner Pup.
Meet the Team
Dr. Hannah Hegwood
Research Associate
Dr. Mike Greenberg
Veterinary Supervisor
Dr. Linda Jacobson
Toronto Humane Society
Dr. Julie Levy
Shelter Medicine Program at UF
Gene Goldring
The Inner Pup
Roni Murphy
The Inner Pup