L. serrata Tongue Worm | CDC EID

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Volume 17, Number 5–May 2011
Dispatch
Linguatula serrata Tongue Worm in Human Eye, Austria
Martina Koehsler, Julia Walochnik, Michael Georgopoulos, Christian Pruente, Wolfgang Boeckeler, Herbert Auer, and Talin Barisani-Asenbauer

Author affiliations: Medical University of Vienna, Vienna, Austria (M. Koehsler, J. Walochnik, M. Georgopoulos, C. Pruente, H. Auer, T. Barisani-Asenbauer); and University of Kiel, Kiel, Germany (W. Boeckeler)

Suggested citation for this article

Abstract
Linguatula serrata, the so-called tongue worm, is a worm-like, bloodsucking parasite belonging to the Pentastomida group. Infections with L. serrata tongue worms are rare in Europe. We describe a case of ocular linguatulosis in central Europe and provide molecular data on L. serrata tongue worms.

The species Linguatula serrata belongs to the Pentastomida, a still-enigmatic group of worm-like, bloodsucking parasites that inhabit the upper respiratory tract of terrestrial, carnivorous vertebrates, mostly reptiles and birds; L. serrata, commonly called tongue worms, typically inhabit canids and felids. The intermediate hosts of these parasites are usually sheep, cattle, or rodents. The hosts ingest the eggs, and the first instar larva hatches within their intestines, penetrates the mucosa, and retreats into the tissue, where it encysts and molts to the third larval stage. Humans can serve as aberrant final hosts after ingesting raw or poorly cooked viscera (i.e., liver, lungs, and trachea) of intermediate hosts. This nasopharyngeal infection is known as Halzoun syndrome in the Middle East or as Marrara in Sudan (1,2). Humans can also serve as accidental intermediate hosts, when ingesting the eggs (visceral infection) (3). Intraocular infection is extremely rare; only 5 cases caused by L. serrata tongue worms have been described: 2 from the southern United States (4–5), 1 from Portugal (6), 1 from Israel (7), and 1 from Ecuador (8).

The phylogenetic position of the pentastomids is still not fully resolved. A position as the sister group of branchiurian crustaceans (Maxillopoda) is supported by molecular data and sperm morphology (9–11) and is widely accepted today; however, sound evidence also exists for other classifications (12). The group itself is divided into 2 orders, the more primitive Cephalobaenida and the more advanced Porocephalida. All species infecting humans are currently classified as Porocephalida; the species L. serrata and Armillifer armillatus are responsible for most human cases of infection.

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Suggested Citation for this Article
Koehsler M, Walochnik J, Georgopoulos M, Pruente C, Boeckeler W, Auer H, et al. Linguatula serrata tongue worm in human eye, Austria. Emerg Infect Dis [serial on the Internet]. 2011 May [date cited].
http://www.cdc.gov/EID/content/17/5/870.htm

DOI: 10.3201/eid1705.100790


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Julia Walochnik, Molecular Parasitology, Institute for Specific Prophylaxis and Tropical Medicine, Centre for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria; email: julia.walochnik@meduniwien.ac.at