In a perfect world, any dog diagnosed with heartworms would undergo treatment and recovery prior to travel with their owner or, in the case of shelter dogs, being transported for adoption purposes.

But in a world fraught with a pandemic, hurricanes, and wildfires, delaying travel isn’t always possible for heartworm-positive dogs, especially for rescue dogs in need of rehoming.

That’s why the American Heartworm Society (AHS) and the Association of Shelter Veterinarians (ASV) have issued updated joint recommendations to safeguard the health of heartworm-positive dogs while ensuring that infected animals don’t become vectors for heartworm transmission.

The AHS and ASV originally issued their joint recommendations for the transport of heartworm-positive dogs in 2017 after a season of devastating hurricanes in the southern US left thousands of homeless pets needing to be rehomed. The recommendations provided critical information for veterinarians and rescue organizations working to saving the lives of abandoned and homeless pets.

NEWStat reached out to Brian DiGangi, DVM, DABVP, to find out more. DiGangi, a past president of the ASV who currently serves as an officer on the board of directors for the AHS, also serves as the senior director of shelter medicine for the American Society for the Prevention of Cruelty to Animals (ASPCA).

NEWStat: How do the new recommendations differ from the recommendations issued in 2017?

Brian DiGangi: The recommendations have been expanded and clarified in a few key areas—specifically the revisions are intended to better address a few specific points. First, the revised recommendations clarify that testing should occur within 30 days of transport to maximize the chances of the test accurately reflecting the dog’s current status. Since the recommendations also consider what to do in the event that test results are not available, we have also clarified that doxycycline use should be limited to cases where a diagnosis of heartworm infection has been confirmed through microfilarial or antigen testing. A third key update is an option to include an isoxazoline in the pre-transport protocol to kill any mosquitoes that may feed on the dog along the journey and ensure they do not contribute to further transmission.

NEWStat: How has the situation regarding the relocation of heartworm-positive dogs changed since the original guidelines were issued in 2017?

BD: There’s still a tremendous need throughout the country for increased access to care for dogs infected with heartworms in both shelter and community animal populations. In some regions of the country, up to 85% of dogs admitted to shelters are infected with heartworms. Relocation remains a critical tool to ensuring these dogs, and many others, get the care they need to improve their own health and welfare, and to ensure that they don’t continue to serve as reservoirs for further transmission.

NEWStat: Do the guidelines reflect an increase in dogs being relocated from one part of the country to another to accommodate the increase in pandemic-related pet adoptions?

BD: While I’m sure there are individual shelters that have seen changes like this, nationwide data from Shelter Animals Count suggests that, for a variety of reasons, shelter animal intake [is] down compared to 2019. While the COVID-19 pandemic has shown the importance of animal relocation for shelters and animals in their care, animal relocation has been a vital program for animal welfare organizations, and a priority program for the ASPCA in particular, over the past decade as a lifesaving tool to help pets find homes in areas where there is greater opportunity for adoption.

NEWStat: Roughly what percentage of relocated dogs are, or are suspected to be, heartworm positive?

BD: Unfortunately, we don’t have the answer to that since there is no central database of animal shelters or relocation programs. Professional guidelines for animal relocation call for testing of dogs older than six months of age prior to transport and full disclosure of test results so that receiving organizations can ready the resources to meet those dogs’ needs upon arrival. And from our 2019 nationwide survey of heartworm-management practices in animal shelters, we know that more than 80% of shelters test all eligible dogs after admission. The reports that do exist regarding relocation of heartworm-positive dogs do not take into account whether the disease status was known prior to relocation, and, indeed, many of these dogs are relocated precisely so they can get lifesaving treatment at the receiving shelter.

NEWStat: Have you noticed an increase in the spread of heartworm since the pandemic began?

BD: We don’t have data specifically on pre- and postpandemic incidence of heartworm disease, and likely won’t know the answer to that question for quite some time. Whether the incidence of infection increases will be directly linked to whether pets continued to be tested and, most importantly, stay on prevention. That’s why AHS has taken steps during the pandemic to provide guidance that prioritizes year-round prevention and encourage veterinarians and staff members to continue stressing prevention and finding alternative ways to educate owners if—like most veterinarians—they’re not seeing clients across the exam table these days.

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