Heartworms

Part of speech: noun

Definitions

1. A type of parasitic roundworm that infects the heart and lungs of animals, particularly dogs, causing severe health issues and requiring medical treatment
2. Parasitic organisms primarily affecting canine cardiovascular systems, leading to serious conditions like congestive heart failure if left untreated
3. Infestations by these worms can result in lethargy and respiratory problems in affected animals, with transmission occurring through mosquito bites

Etymology: "Heartworms" is the plural of "heartworm," a compound of "heart" and "worm." The name describes exactly where the parasite lives: in the heart and the large blood vessels around it, usually in dogs, cats and other mammals. The adult worms are long, thin roundworms (the species most often named is Dirofilaria immitis), and the infection is spread by mosquito bites rather than by contact with the animal. The plural form simply counts more than one of these worms, so the word needs no further grammatical explanation. Its two parts are plain English words that were combined to name a specific parasite, one whose location, not its appearance or behavior, gave it the name.