Pentastomid Biology and Host Interaction

Pentastomids, commonly known as tongue worms, are obligate crustacean-related endoparasites with a complex life cycle involving both invertebrate and vertebrate hosts. Adult worms inhabit the respiratory tracts of definitive hosts—most often reptiles or canids—where they mature and reproduce, shedding eggs into the environment. Intermediate hosts, typically small mammals or amphibians, ingest these eggs, which give rise to motile nymphs that migrate to visceral tissues and form encapsulated lesions. Host–parasite interactions are marked by tissue invasion, granulomatous inflammation and varying degrees of fibrosis, reflecting both parasite virulence factors and host immune responses. Molecular and morphological tools have refined species delineation, revealing cryptic diversity and plasticity in hook morphology related to host physiology. Evolutionary studies suggest an origin of pentastomids as ectoparasites on marine invertebrates, followed by independent terrestrial transitions coinciding with vertebrate land colonisation. Zoonotic transmission arises primarily through consumption of undercooked meat from infected definitive hosts or accidental ingestion of embryonated ova, leading to incidental human infection with a wide spectrum of clinical manifestations. Emerging reports of geographical range expansions and invasive pentastome species underscore the importance of One Health approaches. Advances in imaging, histopathology and genomic sequencing continue to unravel host specificity, life-cycle dynamics and the molecular basis of host tissue tropism, opening avenues for targeted control measures and improved diagnostics in both human and veterinary contexts.

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Pentastomid Biology and Host Interaction publication trend

The graph below shows the total number of articles in pentastomid biology and host interaction across all publications each year (not limited to Nature Index journals).

Technical terms

Pentastomid: A subclass of parasitic crustacean-related arthropods known as tongue worms, which live inside vertebrate hosts.

Definitive host: The organism in which a parasite reaches sexual maturity and reproduces.

Intermediate host: A host that harbours the larval or asexual stages of a parasite before transmission to the definitive host.

Nymph: A juvenile developmental stage of pentastomids that migrates in host tissues and forms encysted lesions.

Zoonosis: A disease or infection that is naturally transmissible between vertebrate animals and humans.

References

1. Characterization of the Tongue Worm, Linguatula serrata (Pentastomida), Identified from Hares (Lepus europaeus) in Romania. International Journal of Molecular Sciences (2023).
2. A 425-Million-Year-Old Silurian Pentastomid Parasitic on Ostracods. Current Biology (2015).
3. Using Combined Morphological, Allometric and Molecular Approaches to Identify Species of the Genus Raillietiella (Pentastomida). PLOS ONE (2011).
4. Case Report: Invasive Pentastomes, Raillietiella orientalis (Sambon, 1922), in a Free-Ranging Banded Water Snake (Nerodia fasciata) in North Central Florida, USA. Frontiers in Veterinary Science (2020).
5. Armillifer Infections in Humans: A Systematic Review. Tropical Medicine and Infectious Disease (2019).