heartworm

noun

heart·​worm ˈhärt-ˌwərm 

: 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

Also, as part of their annual exams, shots and heartworm tests, the younger dog did test positive for Lyme Disease with a 4DX test. —Dr. John De Jong, Boston Herald, 10 Aug. 2025

Fees include vaccinations, spaying/neutering, microchips, heartworm test for dogs 7 months and older, feline leukemia test for cats, 14 days of limited health care from VCA Animal Hospitals and a bag of free food. —Lois K. Solomon, Sun Sentinel, 8 Aug. 2025

She was diagnosed with aspiration pneumonia, or fluid on the lungs, that was a complication of her heartworm treatment. —Alyce Collins, MSNBC Newsweek, 4 Aug. 2025

In addition to her dental issues, S'mores also tested positive for heartworm disease, a condition transmitted by mosquitoes that can be fatal if left untreated. —Melissa Fleur Afshar, MSNBC Newsweek, 1 Aug. 2025

Word History

First Known Use

1877, in the meaning defined above

Rhymes for heartworm

• affirm
• bookworm
• confirm
• cutworm
• earthworm
• infirm
• midterm
• tapeworm
• wireworm
• angiosperm
• echinoderm
• berm

Medical Definition

heartworm

noun

heart·​worm -ˌwərm 

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