Canine Heartworm Treatment in Shelters

Treatment protocols for heartworm infection in shelter dogs may differ from the AHS best practices based on the shelter operational model, organizational philosophy, annual intake, and resources. Limited funding, staffing, housing, and technical expertise often make following the AHS Guidelines impractical.

A 2010 survey of heartworm treatment protocols in southeastern shelters found the following variations:

• • For shelters that performed heartworm testing, 39% treated all infected dogs, 4% treated some dogs, and 12% did not treat any dogs
  • Municipal shelters were more likely to euthanize infected dogs or release them without treatment
  • Municipal shelters were less likely to follow the AHS best practice treatment protocol than private nonprofit shelters

• 35% of shelters that treated heartworm-infected dogs used the 3-dose melarsomine protocol, 44% used the 2-dose melarsomine protocol, and 22% used the monthly heartworm preventive “slow-kill” protocol instead of melarosmine
• <50% of the shelters used doxycycline prior to adulticide treatment

A similar survey of shelter heartworm treatment practices in 2019 reported the following findings:

• 93% of the responding shelters treated at least some of their heartworm-infected dogs
• Municipal shelters were less likely to have treatment SOPs than private nonprofit shelters
• 43% of shelters that treated heartworm-infected dogs used the 3-dose melarsomine protocol, 38% used the 2-dose melarsomine protocol, and 17% used the monthly heartworm preventive “slow-kill” protocol instead of melarosmine
• 59% of treating shelters started infected dogs on macrocyclic lactone preventives
• 92% used doxycycline prior to melarsomine
• 71% gave prednisone with melarsomine injections
• 65% of the shelters housed dogs in foster homes during treatment or provided treatment for dogs after adoption
• 32% housed dogs in the shelter for the duration of treatment

These surveys revealed that shelters utilize a variety of heartworm treatment strategies ranging from full compliance with AHS guidelines to a complete lack of attention to heartworm infection. Many shelters develop their own protocols based on available resources and without the supervision of a veterinarian or support by evidence.

For both surveys, shelters reported that the biggest challenges for heartworm treatment were cost of treatment, long duration of treatment, housing during treatment, and managing activity restriction for ≥5 months during and after treatment without compromising the dog’s behavioral health and welfare. How to deal with these challenges is frequently discussed on shelter medicine practice listservs and discussion board and at continuing education conferences. Solutions will vary based on how shelter managers and veterinarians allocate their finite financial and staff resources to best serve a variety of competing needs for shelter operations and healthcare.

Think about the shelters you have worked in – what were their approaches to treating heartworm-infected dogs?

• Was the policy to transfer infected dogs to a rescue for treatment instead of being done by the shelter?
• Were infected dogs adopted out with the understanding that the new owner would seek treatment by their veterinarian?
• If the shelter provided treatment, did they treat all infected dogs or only those considered most adoptable?
• Did dogs stay in the shelter for the duration of treatment or were they in foster homes or new adopter homes?
• If the shelter provided treatment, who paid for this?

Let’s review the ASV position paper on heartworm management in shelters. This statement provides recommendations to guide shelters in making decisions on treatment protocols, including choosing protocols based on available resources and options for providing treatment outside of the shelter.

What are some of the canine heartworm treatment policies and protocols in Florida shelters?