[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other parasites of interest](https://durgical.com/en/microbiology/groups/other-parasites-of-interest/) › Armillifer and Linguatula

# Armillifer and Linguatula

- Parasite
- For completeness

Worm-like parasites related to crustaceans that live in the airways of snakes and dogs. People are infected by eggs or by eating raw organs.

Updated Nov 13, 2026

Also called: tongue worms, pentastomids, Linguatula serrata, Armillifer armillatus

## Quick facts

**Type**
Parasite · [Other parasites of interest](https://durgical.com/en/microbiology/groups/other-parasites-of-interest/)

**Gram / shape**
Elongated

**Spread**
Visceral infection · Handling

**Causes**
Visceral pentastomiasis · Nasopharyngeal linguatulosis

**Treatment**
No antiparasitic drug is proven

On this page

- The basics Key points
- At a glance
- Morphology
- Transmission
- Life cycle
- Memory aid
- What the colours mean

- Clinical Virulence factors
- Diseases it causes
- Clinical picture
- Diagnosis

- Treatment Treatment
- Prevention

- Study Test yourself

- Connections Connections

## Key points

- Pentastomids are arthropods (crustacean relatives), not true worms.
- Armillifer: snake hosts; Linguatula serrata: dog hosts.
- Visceral form: incidental C-shaped calcifications on X-ray.
- Halzoun or marrara: throat swelling after eating raw offal.
- No drug: surgery only if needed.

## At a glance

**Shape**
Elongated, ringed, tongue-like body; Armillifer nymphs curl into a C shape

**Family**
Porocephalidae (Armillifer, Porocephalus); Linguatulidae (Linguatula)

**Type**
Pentastomids: highly modified crustaceans (arthropods), worm-like endoparasites

**Size**
Nymphs a few millimetres to over 1 cm; adults several centimetres

## Morphology

- Four hooks around the mouth, which explain the old name: five mouths (penta-stoma).
- Body ringed by annuli; Armillifer has prominent thick rings.
- Nymphs encyst in tissues and later calcify.

## Transmission

- Visceral infection: swallowing eggs from respiratory secretions or faeces of snakes or dogs, or from contaminated water, food or hands.
- Handling, cooking or eating snake meat is a major risk for Armillifer in Africa and Asia.
- Nasopharyngeal infection: eating raw or undercooked liver, lungs or trachea of sheep, goats or cattle with Linguatula nymphs.

**Reservoir:** Large snakes such as pythons and vipers (Armillifer, Porocephalus); Dogs and other canids (Linguatula); Rodents, sheep, goats and cattle as intermediate hosts

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Life cycle

- Adults live in the airways of the final host: lungs of snakes or nasal passages of dogs.
- Eggs leave in respiratory secretions or faeces and contaminate soil, water and food.
- An intermediate host swallows the eggs; larvae hatch in the gut and cross into the organs.
- Larvae moult into nymphs that encyst in liver, lungs, peritoneum and lymph nodes.
- The final host is infected by eating the intermediate host, and nymphs migrate to its airways.
- Humans are accidental intermediate hosts (eggs) or accidental final hosts (raw organs with nymphs).

## Virulence factors

- Most visceral infections are silent; the nymphs die and calcify.
- Heavy infections cause inflammation, abscesses, obstruction or bleeding in liver, peritoneum, lung and eye.
- Masses can mimic cancer or tuberculosis on imaging.
- Live nymphs attaching in the throat cause acute swelling, the halzoun or marrara syndrome.

## Diseases it causes

- Visceral pentastomiasis (Armillifer, Linguatula nymphs in liver, peritoneum, lungs)
- Nasopharyngeal linguatulosis (halzoun, marrara) after eating raw offal
- Ocular pentastomiasis: a nymph in the anterior chamber or orbit

## Clinical picture

- Usually an incidental finding: C- or horseshoe-shaped calcifications on an abdominal or chest X-ray.
- Abdominal pain, ascites or a liver mass in heavy infections.
- Halzoun: within hours of eating raw liver, throat pain, cough, sneezing and swelling of the pharynx and face.
- Eye: pain, reduced vision or a moving parasite seen inside the eye.

## Diagnosis

- Imaging: calcified C-shaped nymphs in liver and peritoneum.
- Histopathology or identification of nymphs removed at surgery or endoscopy.
- Serology is not widely available.

## Treatment

No antiparasitic drug is proven. Most cases need no treatment; surgical or endoscopic removal for symptomatic or heavy infections and for nymphs in the eye.

Drug class only; doses and regimens are set by the clinician from the current guideline.

## Prevention

- Handwashing after handling snakes or dogs; avoid eating or handling raw snake meat.
- Cook offal (liver, lungs) of sheep, goats and cattle thoroughly.
- Safe drinking water in areas with snakes or many dogs.

## Memory aid

Snake and dog keep the tongue worm in their nose; a person who swallows the egg gets a calcified C, one who eats raw liver gets a swollen throat.

## Test yourself

Think of the answer, then tap the question to see it.

## Which final hosts do Armillifer and Linguatula use?

Large snakes for Armillifer and dogs or other canids for Linguatula serrata.

## What is the classic imaging finding in visceral pentastomiasis?

C- or horseshoe-shaped calcified nymphs in the liver, peritoneum or lungs on X-ray.

## What causes halzoun or marrara syndrome?

Eating raw or undercooked offal with Linguatula nymphs, which attach in the pharynx and cause acute swelling.

## How is pentastomiasis treated?

There is no proven antiparasitic drug; most cases need nothing, and symptomatic nymphs are removed surgically.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/armillifer-and-linguatula/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

## Connections

## Related 3

- [Toxocara canis / Toxocara cati](https://durgical.com/en/microbiology/toxocara-canis-toxocara-cati/)
- [Echinococcus multilocularis and E. oligarthrus](https://durgical.com/en/microbiology/echinococcus-multilocularis-and-e-oligarthrus/)
- [Spirometra (sparganosis)](https://durgical.com/en/microbiology/spirometra/)

[← Back to the group: Other parasites of interest](https://durgical.com/en/microbiology/groups/other-parasites-of-interest/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Diagnosis of Human Visceral Pentastomiasis](https://journals.plos.org/plosntds/article?id=10.1371%2Fjournal.pntd.0000320) (PLoS Neglected Tropical Diseases, 2009); [Linguatula serrata Tongue Worm in Human Eye, Austria](https://wwwnc.cdc.gov/eid/article/17/5/10-0790_article) (Emerging Infectious Diseases (CDC), 2011).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/microbiology/armillifer-and-linguatula/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/armillifer-and-linguatula/