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

Vectors means the insects spread diseases such as West Nile virus, encephalitis, malaria, dengue fever and chikungunya in humans, or heartworm parasites in dogs. —Janet Loehrke, USA Today, 25 May 2025

Besides being nuisances, many types carry diseases including West Nile virus, encephalitis, and canine heartworm. —Arricca Elin Sansone, Southern Living, 11 May 2025

In a Facebook post shared on Tuesday, Brother Wolf Animal Rescue shared the story of Alicia, a 1-year-old pup who was found chained outside and severely underweight by a local shelter, and then surrendered to them after testing positive for heartworm. —Maria Azzurra Volpe, MSNBC Newsweek, 24 May 2025

In dogs and cats, it is licensed as a preventive medication against heartworm. —Katia Hetter, CNN Money, 24 Apr. 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