heart·​worm | \ ˈhärt-ˌwərm How to pronounce heartworm (audio) \

Definition of heartworm

: a filarial worm (Dirofilaria immitis) that is a parasite especially in the right heart of dogs and is transmitted by mosquitoes also : infestation or disease caused by the heartworm

Examples of heartworm in a Sentence

Recent Examples on the Web But don't go out and buy heartworm medication for dogs just yet — ivermectin, the panel added, is not FDA-approved for the treatment of any viral infection. Elinor Aspegren, USA TODAY, "Coronavirus updates: Disneyland to end Annual Passports program; President-elect Joe Biden vows 100M shots in first 100 days; 388K US deaths," 15 Jan. 2021 Teddy is receiving treatment for a heartworm infection and will remain at the humane society during treatment. Megan Becka, cleveland, "Humane Society of Summit County seeks adopters for dogs rescued from South Korea, Lebanon," 3 Dec. 2020 Canine vaccines will also include a heartworm test, and for the kitties, the price also includes deworming at the Humane Society offices in Covington. NOLA.com, "No-kill shelter continues discounted vaccinations in Covington," 9 Nov. 2020 Some are being treated for heartworm, a potentially fatal disease spread by infected mosquitoes, and will need special attention with medical needs. San Diego Union-Tribune, "Dogs rescued before recent hurricanes still need forever homes," 31 Oct. 2020 Cost is $75 for canines or felines at the clinic; includes a heartworm test for dogs and a deworming for kitties. Staff Reports, NOLA.com, "Friends need volunteers, Halloween events are afoot, vintner dinners continue," 19 Oct. 2020 During these house calls, Louderback offers vaccines, wellness care and a range of services — trimming claws or toenails, cleaning ears, testing for heartworm and treating for parasites. Kevyn Burger Special To The Star Tribune, Star Tribune, "'That pet is their lifeline': Low-cost vet makes house calls for older Minnesotans," 16 Oct. 2020 Simparica Trio medicine, which protects animals against heartworm and other diseases, help justify the valuation. Veronica Dagher, WSJ, "Pandemic Pets Push Industry Stocks to Pricey Valuations," 14 Oct. 2020 Cooler weather does not mean it’s time to stop the heartworm, flea or tick preventatives. Traci Howerton, NOLA.com, "With fall here, keep up pest preventatives for your pets and watch for seasonal allergies," 22 Sep. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'heartworm.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of heartworm

1877, in the meaning defined above

Keep scrolling for more

Learn More about heartworm

Time Traveler for heartworm

Time Traveler

The first known use of heartworm was in 1877

See more words from the same year

Statistics for heartworm

Last Updated

26 Jan 2021

Cite this Entry

“Heartworm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/heartworm. Accessed 27 Jan. 2021.

Keep scrolling for more

More Definitions for heartworm


heart·​worm | \ -ˌwərm How to pronounce heartworm (audio) \

Medical Definition of heartworm

1 : a filarial worm of the genus Dirofilaria (D. immitis) that is especially common in warm regions, lives as an adult in the right heart especially of dogs, and discharges active larvae into the circulating blood whence they may be picked up by mosquitoes and transmitted to other hosts and that may infect humans causing local pulmonary infarction but does not achieve sexual maturity in the human organism
2 : infestation with or disease especially of dogs caused by the heartworm, resulting typically in gasping, coughing, and nervous disorder, and when severe commonly leading to death

More from Merriam-Webster on heartworm

Britannica.com: Encyclopedia article about heartworm

Comments on heartworm

What made you want to look up heartworm? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Slippery Words Quiz—Changing with the Times

  • ducreux self portrait yawning
  • What is an earlier meaning of nice?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!


Anagram puzzles meet word search.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!