Skip to main content Accessibility help

A review on swimmer's itch and the occurrence of bird schistosomes in Iceland

  • K. Skírnisson (a1), J.A. Aldhoun (a2) and L. Kolářová (a3)


In the past decade, swimmer's itch (SI) has repeatedly occurred in people who have been wading or bathing in ponds or lakes in Iceland where water birds and snails are abundant. Some of the affected sites were warmed by geothermal activity, and others were not. A search for the causative agent of SI, ocellate furcocercariae that have been found in Iceland only in Radix peregra snails, revealed an average infection prevalence of 1.4% (n = 12,432). Locally, infection rates commonly exceeded 6%, the highest value observed being 24.5%. A search for adult schistosomes in visceral organs and the nasal cavities of 110 water birds belonging to the orders Gaviiformes, Podicipediformes and Anseriformes revealed eggs, miracidia or adult stages of at least seven previously identifiable schistosome species in four anseriform bird species. A previously unknown species of schistosome, Allobilharzia visceralis, was detected in whooper swans (Cygnus cygnus), and classified in a new genus. In mallards (Anas platyrhynchos) a nasal Trichobilharzia sp. and the visceral schistosome T. franki were identified. In red-breasted merganser (Mergus serrator), distinct egg types belonging to two species of the genus Trichobilharzia have been found. In grey-lag goose (Anser anser) two different egg types were also found – a large Trichobilharzia sp. and small eggs of a Dendritobilharzia sp. Additionally, unidentified cercariae, probably belonging to a previously undescribed genus were detected in R. peregra in Oslandsstjörn. Taken together, the data obtained by morphological examination of eggs and recent DNA sequencing results, indicate that at least eight species of bird schistosomes occur in Iceland.


Corresponding author

*Fax: +354 5673979 E-mail:


Hide All
Aldhoun, J.A., Kolářová, L., Skírnisson, K. & Horak, P. (2009) Bird schistosome diversity in Iceland: molecular evidence. Journal of Helminthology.
Anderson, R. (2005) An annotated list of the non-marine Mollusca of Britain and Ireland. Invertebrate Ireland Online, Ulster Museum, Belfast and National Museum of Ireland, Dublin.
Bargues, M.D., Vigo, M., Horák, P., Dvořák, J., Patzner, R.A., Pointier, J.P., Jackiewicz, M., Meier-Brook, C. & Mas-Coma, S. (2001) European Lymnaeidae (Mollusca: Gastropoda), intermediate hosts of trematodiases, based on nuclear ribosomal DNA ITS-2 sequences. Infection, Genetics and Evolution 1, 85107.
Brant, S.V. (2007) The occurrence of the avian schistosome Allobilharzia visceralis Kolářová, Rudolfová, Hampl et Skírnisson, 2006 (Schistosomatidae) in the tundra swan Cygnus columbianus (Anatidae), from North America. Folia Parasitologica 54, 99104.
de Gentile, L., Picot, H., Bourdeau, P., Bardet, R., Kerjan, A., Piriou, M., Le Guennic, A., Bayssade-Dufour, C., Chabasse, D. & Mott, K.E. (1996) Le dermatite cercarienne en Europe: un probleme de la santé publique nouveau? Bulletin de l'Organisation Mondiale de la Santé 74, 159163.
Galaktionov, K.V. & Skírnisson, K. (2000) Digeneans from intertidal molluscs of SW Iceland. Systematic Parasitology 47, 87101.
Glöer, P. (2002) Die Süβwassergastropoden Nord- und Mitteleuropas. Hackenheim, ConchBooks.
Glöer, P. & Zettler, P. (2005) Kommentierte Artenliste der Süßwassermollusken Deutschlands. Malakologische Abhandlungen 23, 326.
Horák, P. & Kolářová, L. (2005) Molluscan and vertebrate immune responses to bird schistosomes. Parasite Immunology 27, 247255.
Horák, P., Kolářová, L. & Adema, C.M. (2002) Biology of the schistosome genus Trichobilharzia. Advances of Parasitology 52, 155233.
Jouet, D., Ferté, H., Hologne, C. & Depaquit, J. (2009) Avian schistosomes in French aquatic birds: molecular approach. Journal of Helminthology.
Kolářová, L. (2007) Schistosomes causing cercarial dermatitis: a mini review of current trends in systematics and of host specificity and pathogenicity. Folia Parasitologica 54, 8187.
Kolářová, L., Skírnisson, K. & Horák, P. (1999) Schistosome cercariae as the causative agent of swimmer's itch in Iceland. Journal of Helminthology 73, 215220.
Kolářová, L., Rudolfová, J., Hampl, V. & Skírnisson, K. (2006) Allobilharzia visceralis gen. nov., sp. nov. (Schistosomatidae – Trematoda) from Cygnus cygnus (L.) (Anatidae). Parasitology International 55, 179186.
Kouřilová, P., Syrucek, M. & Kolářová, L. (2004) The severity of mouse pathologies caused by the bird schistosome Trichobilharzia regenti in relation to host immune status. Parasitology Research 93, 816.
Petersen, Æ. (1998) Icelandic birds. 312 pp. Reykjavík, Vaka-Helgafell (in Icelandic).
Pfenninger, M., Cordellier, M. & Streit, B. (2006) Comparing the efficacy of morphologic and DNA-based taxonomy in the freshwater gastropod genus Radix (Basommatophora, Pulmonata). BMC Evolutionary Biology 6, 100. Available at (accessed January 2008).
Skírnisson, K. & Galaktionov, K.V. (2002) Life cycles and transmission patterns of seabird digeneans in SW Iceland. Sarsia 87, 144151.
Skírnisson, K. & Kolářová, L. (2002) Are nasal Trichobilharzia cercariae potential threat to human health? The Icelandic Medical Journal 88, 739744(in Icelandic with an English summary).
Skírnisson, K. & Kolářová, L. (2005) Swimmer's itch in Landmannalaugar, Iceland. The Icelandic Medical Journal 91, 729736(in Icelandic with an English summary).
Skírnisson, K. & Kolářová, L. (2008) Diversity of bird schistosomes in anseriform birds in Iceland based on egg measurements and egg morphology. Parasitology Research 103, 4350.
Skírnisson, K., Magnússon, J., Kristjánsdóttir, Þ. & Kolářová, L. (1999) Swimmer's itch confirmed for the first time in Iceland. The Icelandic Medical Journal 84 (Suppl 37), 59(in Icelandic).
Skírnisson, K., Galaktionov, K.V. & Kozminsky, E.V. (2004) Factors influencing the distribution of digenetic trematode infections in a mudsnail (Hydrobia ventrosa) population inhibiting salt marsh ponds in Iceland. Journal of Parasitology 90, 5059.

A review on swimmer's itch and the occurrence of bird schistosomes in Iceland

  • K. Skírnisson (a1), J.A. Aldhoun (a2) and L. Kolářová (a3)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed