Heartworm
Dirofilaria immitis (Leidy, 1856) Railliet & Henry, 1911
Status not recordedworms
Heartworm (Dirofilaria immitis) is a worm in the phylum Nematoda, classed in the subfamily Dirofilariinae of the order Rhabditida. It belongs to the class Chromadorea and the suborder Spirurina, within the genus Dirofilaria.
Quick facts about the heartworm
Other English names for it are Cruel worm, Dog heartworm and Dog Cardiac worm. The scientific name carries the authority (Leidy, 1856) Railliet & Henry, 1911.
- Weight
- Not recorded
- Length
- Not recorded
- Lifespan
- Not recorded
- Main food
- Not recorded
- Habitat
- Not recorded
- Young per litter or clutch
- Not recorded
- Conservation status
- Not recorded
- Countries on record
- Not recorded
Where does the heartworm live?
Not recorded
Where has it been introduced?
The Global Register of Introduced and Invasive Species lists the heartworm as introduced in 3 countries.
- Canary Islands
- Ecuador
- South Africa
Introduced means brought by people and now present; invasive means the country's checklist records an impact. A species can be native to one part of a country and introduced in another. Source: Global Register of Introduced and Invasive Species (CC BY 4.0).
What is the heartworm?
Dirofilaria immitis, also known as heartworm or dog heartworm, is a parasitic roundworm that is a type of filarial worm, a small thread-like worm, and which causes dirofilariasis. It is spread from host to host through the bites of mosquitoes. Four genera of mosquitoes transmit dirofilariasis, Aedes, Culex, Anopheles, and Mansonia. The definitive host is the dog, but it can also infect cats, wolves, coyotes, jackals, foxes, ferrets, bears, seals, sea lions, and, under rare circumstances, humans.
Adult heartworms often reside in the pulmonary arterial system (lung arteries) as well as the heart, and a major health effect in the infected animal host is damage to its lung vessels and tissues. Heartworm infection may result in serious complications for the infected host if left untreated, eventually leading to death, most often as a result of secondary congestive heart failure.
From the Wikipedia article “Dirofilaria immitis” (en.wikipedia.org/w/index.php?title=Dirofilaria_immitis&oldid=1373899714), by Wikipedia contributors, licensed under CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0). This block is kept separate from our own text.
Is the heartworm endangered?
No conservation assessment is recorded for this species in our sources. That is not the same as being safe: it has not been matched to an assessment.
How is the heartworm classified?
- kingdomAnimalia
- phylumNematoda
- classChromadorea
- orderRhabditida
- genusDirofilaria
- SpeciesDirofilaria immitis (Leidy, 1856) Railliet & Henry, 1911
Synonyms Filaria immitis, Filaria papillicauda
Other names and names in other languages (7)
- Cruel wormEnglish
- Dog Cardiac wormEnglish
- Dog heartwormEnglish
- 심장사상충Korean
- 개심장사상충Korean
- HartwormDutch
- Vlasovec psíSlovak
Relatives of the heartworm
Other species in the same genus Dirofilaria.
CompareHeartworm vs Dirofilaria acutiusculaHeartworm vs Dirofilaria asiaticaHeartworm vs Dirofilaria incrassataHeartworm vs Dirofilaria repens
Common questions
Each answer is written from the sourced facts on this page, and only where they hold the answer.
What kind of animal is the heartworm?
The heartworm is a worm in the phylum Nematoda. It is placed in the order Rhabditida and the subfamily Dirofilariinae.
What is the scientific name of the heartworm?
The scientific name of the heartworm is Dirofilaria immitis, in the genus Dirofilaria.
What other names does the heartworm have?
The heartworm is also called Cruel worm, Dog heartworm and Dog Cardiac worm.
Who named Dirofilaria immitis?
The authority for Dirofilaria immitis is written as (Leidy, 1856) Railliet & Henry, 1911.
What class and suborder does the heartworm belong to?
The heartworm belongs to the class Chromadorea and the suborder Spirurina.
Is the heartworm an invasive species?
The Global Register of Introduced and Invasive Species lists the heartworm as introduced in 3 countries: Canary Islands, Ecuador and South Africa, but does not flag it as invasive in any of them.
Sources and how to cite this page
Data as of 2026-11-14. How this page is put together.
- Catalogue of Life eXtended Release · CC BY 4.0 · 2026-10-16 XR
Catalogue of Life (2026). Catalogue of Life eXtended Release, version 2026-10-16 XR. Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgzlf - Wikimedia Commons · per file (CC0 / public domain / CC BY green, CC BY-SA amber, anything else not displayed) · 2026-11-11
Wikimedia Commons contributors. Wikimedia Commons. https://commons.wikimedia.org (each file credited to its author under its own licence). - Global Register of Introduced and Invasive Species (GRIIS) · CC BY 4.0 · 2026-11-13
Pagad, S., Genovesi, P., Carnevali, L., Schigel, D. & McGeoch, M.A. (2018) Introducing the Global Register of Introduced and Invasive Species. Scientific Data 5: 170202. https://doi.org/10.1038/sdata.2017.202. Country checklists published through GBIF by the IUCN SSC Invasive Species Specialist Group. - Wikidata · CC0 1.0 · 2026-11-11
Wikidata contributors. Wikidata. https://www.wikidata.org (data retrieved via the Wikidata Query Service). - Wikipedia (English) · CC BY-SA 4.0 · 2026-11-11
Wikipedia contributors. Wikipedia, The Free Encyclopedia. https://en.wikipedia.org (text under CC BY-SA 4.0; each block names its article and revision).
Embed a card for this animal on your own site
Copy this code. The card shows the photo with its credit, key facts and a link back to this page.
CreatureData. (2026). Heartworm (Dirofilaria immitis). Retrieved from https://creaturedata.com/animals/heartworm
“Heartworm (Dirofilaria immitis).” CreatureData, 2026, https://creaturedata.com/animals/heartworm.
@misc{heartworm_2026,
title = {Heartworm (Dirofilaria immitis)},
author = {{CreatureData}},
year = {2026},
url = {https://creaturedata.com/animals/heartworm},
note = {Data as of 2026-11-14}
}