Preventing and treating heartworm disease in shelters

The American Heartworm Society (AHS) recently released an updated map of heartworm incidence in the US, along with results of the organization’s triennial survey of veterinary practices around the country.¹ In an interview with dvm360, Marisa Ames, DVM, DACVIM (Cardiology), president of the AHS and an associate professor of cardiology at the University of California, Davis, Weill School of Veterinary Medicine, discussed the survey results, shifting hot spots, and prevention methods for individual patients and the greater community.

In this video, Ames discusses how animal welfare care providers can help reduce the transmission of heartworm infestation in shelters, which includes the use of drug therapies. The following is a transcript of the video:

dvm360: How can heartworm disease be prevented or treated in shelter situations?

Marisa Ames, DVM, DACVIM (Cardiology): There's a lot more information lately from the Association of Shelter Veterinarians and the American Heartworm Society about how we manage dogs with heartworm infection in a shelter situation, since we do see more movement of those dogs—and that's a good thing. Dogs are moving to get new homes, and so sometimes the necessity is that dogs with an infection have to move, but there are ways to prevent them from being infective to other dogs staying, of course, to understand if the dog is infected with heartworm disease, and prioritizing testing to confirm that diagnosis.

And then there the initiation of a simple drug like doxycycline. Even if the dog has heartworm infection and if they have circulating microfilaria, starting a course of doxycycline can reduce the risk for that dog—say he were to be bitten by a mosquito. It makes it less likely, and after an adequate course of doxycycline, it eliminates the risk that that dog will then be the source of heartworm, picked up by mosquitoes and transferred to another dog.

There are also other ectoparasite options and insecticide options that you can treat a dog so that you know they can kill the insect before it has a chance to pick up the heartworm. So fairly simple methods to kind of protect that dog and keep that dog from infecting others as he goes on his journey, hopefully towards his next home.

RELATED VIDEO: Mitigating heartworm disease in communities

Reference

Crossley KC. New heartworm incidence map shows shifting hot spots. dvm360. April 13, 2026. Accessed April 24, 2026. https://www.dvm360.com/view/new-heartworm-incidence-map-shows-shifting-hotspots