Healing the Heart:
Shelter and Rescue Protocol for Heartworm-Positive Dogs
Marie Calabrasa, a widow in her early 70’s, saw Keni the hound’s photo on a local Pennsylvania rescue group’s website. His sweet face and floppy ears almost completely won her over, except for one thing. Rescued from an overcrowded shelter in North Carolina, Keni had been overlooked by potential adopters because he was heartworm positive.
“I’ll be honest—I was concerned because I thought he had a health issue. I’m on a fixed income and was worried about the cost of treatment,” said Marie. After careful thought, she decided to adopt him and took him for his continued treatments, paying for it out of her own pocket. “The rescue did not have the funds to treat him,” she said.
This is not an uncommon scenario that plays out with dogs that are rescued from an area of the country with a high stray animal population where heartworm disease is prevalent1. Sheldon Rubin, 2007-2010 president of the American Heartworm Society, says that “Heartworm disease has not only spread throughout the United States, but it’s also now found in areas where veterinarians used to say ‘Oh, we don’t have heartworm disease’ -- areas like Oregon, California, Arizona, and the desert, where irrigation and building are allowing mosquitoes to survive.”1
Heartworm Disease Prevention
Daily decisions must be made about the best allocation of resources for prevention and treatment of disease, spaying/neutering, and behavioral rehabilitation. Heartworm disease is among the most complex infectious diseases to detect, treat, and prevent. For that reason, it presents a special challenge to animal shelters.2
Challenges in the Shelter Setting
According to Martha Smith-Blackmore, DVM, research assistant professor at Cummings School of Veterinary Medicine at Tufts University, and author of “Managing Heartworm Disease in Shelter Animals” published by the American Heartworm Society (AHS), animal shelters face significant challenges in preventing, diagnosing, and treating many forms of infectious disease due to limited financial and organizational resources. In shelter animals, risk for heartworm infection is thought to be higher than in privately owned pets because stray and surrendered shelter animals are less likely to receive prior veterinary care.5
According to compliance data provided by Vetstreet in 2016, 64.31% of dogs do not receive any heartworm disease preventive medication.3,5 “Considering how difficult achieving compliance with veterinary recommendations is among the best clients, it is easy to understand how a surrendered animal is unlikely to have received good or consistent preventive veterinary care3”, stated Dr. Smith-Blackmore.
In 2014, The Association of Shelter Veterinarians (ASV) and the American Heartworm Society joined forces to discuss the prevention, treatment, and management of heartworm disease in animal shelters. In January 2015, the Heartworm Disease Resource Task Force was formed to formally address this issue.
Heartworm Disease Diagnosis2,4
Although funds may not be available for heartworm disease diagnostics in all shelters, an ideal goal is to perform a heartworm antigen and microfilaria test in all dogs at intake, as recommended by the American Heartworm Society in their current guidelines.
Shelters that evaluate dogs for heartworms should communicate to adopters that immediate, and annual testing is critical to detect infection and initiate treatment, if needed. Additionally, shelters should reinforce the importance of giving pets preventative medications as a safeguard, so heartworm disease does not become an issue.
Heartworm Disease Treatment2,5
The American Heartworm Society’s protocol is considered the gold standard for elimination of heartworms from dogs, based on current knowledge. This protocol for dogs entails a pre-treatment phase, which includes administration of doxycycline, and monthly heartworm preventive agents for 2 months before beginning a 3-injection treatment with an adulticide. Some shelters can implement this protocol while dogs are under their care or in foster homes, while others must leave treatment to adopting owners and their veterinarians to implement.
Use of Other Protocols4
If the shelter does not use, or recommend, the AHS’ recommended protocol for treatment, adopters need to be informed about the risks and responsibilities associated with the selected treatment method, including the following:
Not all shelters share the same level of expertise in heartworm treatment or client education. In the shelter setting, the decision to use a treatment protocol other than the AHS protocol can be a deliberate “war zone” approach to treating heartworm disease—in human medicine, treatment options in war zones or developing countries do not always reflect the best recommendation available but are better than no option.
According to Dr. Smith-Blackmore, shelter staff should inform adopters when dogs are being treated with a protocol that is less than the gold standard, and instruct them to consider following up with their veterinarians for further treatment. This is a rational approach given the limited time and resources in the shelter setting.2,5
Association of Shelter Veterinarians (ASV) Position Statement on Heartworm Disease Management6,7
The ASV supports the application of the American Heartworm Society guidelines for the prevention, diagnosis, and management of canine and feline heartworms in animal shelters.
Regardless of geographic location, sheltering organizations are urged to maintain all dogs and cats on monthly heartworm preventive medications year-round to protect individual animal health and welfare and limit disease transmission within the community.
The ASV encourages shelters to perform screening tests on all dogs to identify infected dogs and institute therapy to reduce pathology and infective potential. Alternatives to maintenance of infected dogs within the shelter population, such as foster care and transfer to partnering agencies, should be considered when possible.
Organizations choosing to treat and/or adopt out infected dogs should ensure that:
Resources and mission allow for the humane care of exercise restricted dogs with extended lengths of stay
Shelter staff, volunteers, and potential adopters are educated on the importance of adhering to each component of the management protocol
Potential adopters are encouraged to consult with their veterinarian for further guidance.
Shelter and Rescue Heartworm Disease Resources
In 2017, The American Heartworm Society and ASV published new 'best practices' to help stop heartworm transmission via transported dogs.
A Heartworm Disease Management for Animal Shelters Webinar is also available.