01933nas a2200229 4500008004100000245011500041210006900156300001200225490000800237520118700245653002501432653001801457653003301475653001401508653003201522100001901554700001901573700001901592700002101611700002301632856004801655 2012 eng d00aHaplosporidium raabei n. sp. (Haplosporidia): A Parasite of Zebra Mussels, Dreissena polymorpha (Pallas, 1771)0 aHaplosporidium raabei n sp Haplosporidia A Parasite of Zebra Mus a463-4770 v1393 a

Extensive connective tissue lysis is a common outcome of haplosporidian infection. Although such infections in marine invertebrates are well documented, they are relatively rarely observed in freshwater invertebrates. Herein, we report a field study using a comprehensive series of methodologies (histology, dissection, electron microscopy, gene sequence analysis, and molecular phylogenetics) to investigate the morphology, taxonomy, systematics, geographical distribution, pathogenicity, and seasonal and annual prevalence of a haplosporidian observed in zebra mussels, Dreissena polymorpha. Based on its genetic sequence, morphology, and host, we describe Haplosporidium raabei n. sp. from D. polymorpha – the first haplosporidian species from a freshwater bivalve. Haplosporidium raabei is rare as we observed it in histological sections in only 0·7% of the zebra mussels collected from 43 water bodies across 11 European countries and in none that were collected from 10 water bodies in the United States. In contrast to its low prevalences, disease intensities were quite high with 79·5% of infections advanced to sporogenesis.

10aDreissena polymorpha10aHaplosporidia10aHaplosporidium raabei n. sp.10aphylogeny10asmall subunit ribosomal DNA1 aMolloy, D., P.1 aGiamberini, L.1 aStokes, N., A.1 aBurreson, E., M.1 aOvcharenko, M., A. uhttp://dx.doi.org/10.1017/S0031182011002101