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AbstractDuring the years 2002?2007, Icelandic freshwater snails and birds from different orders were examined for bird schistosomes. Only the snail Radix peregraand anatid birds proved to be infected. In total, 32 samples of bird schistosome cercariae from seven localities and four samples of adults of Anas platyrhynchosand Mergus serratorfrom two localities were used for sequencing of the internal transcibed spacer (ITS) region of rDNA. Based on the sequence and position in the phylogenetic tree, five species/genotypes of bird schistosomes were identified. Three of them correspond to the sequences in GenBank for Trichobilharzia franki, Trichobilharziasp. JR-2007 from Anas penelope(isolates Pl7 and Pl10) and schistosomatid sp. JR-2004 from Physa fontinalis. The other two species/genotypes belong to the genus Trichobilharzia, but their further determination was not possible due to lack of data. All of these species/genotypes develop in R. peregra, probably the only suitable intermediate host species in Iceland. As T. frankiand schistosomatid sp. JR-2004 were previously reported from other snail species, the findings from Iceland proved that, under some circumstances, bird schistosomes are able to adapt to a different snail species; some of them can even adapt to a snail belonging to a different gastropod family. High diversity of bird schistosomes in Iceland is probably linked with migratory flyways of birds, as several bird species from Iceland overwinter in western Europe as well as in North America. [ABSTRACT FROM AUTHOR]

AbstractIn 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 peregrasnails, 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 Trichobilharziasp. and the visceral schistosome T. frankiwere identified. In red-breasted merganser (Mergus serrator), distinct egg types belonging to two species of the genus Trichobilharziahave been found. In grey-lag goose (Anser anser) two different egg types were also found ? a large Trichobilharziasp. and small eggs of a Dendritobilharziasp. Additionally, unidentified cercariae, probably belonging to a previously undescribed genus were detected in R. peregrain Oslandsstj?rn. 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. [ABSTRACT FROM AUTHOR]