We report the first results of parasitological study of Dreissena polymorpha (zebra mussels) from Sweden. The samples of Dreissena were collected from Lake Erken in July 2007. The most common endosymbionts found in the mantle cavity of the mussels were the commensal ciliate Conchophthirus acuminatus and free-living nematodes Chromadorina bioculata and Laimydorus sp. Unidentified chironomid larvae and aquatic mites were also occasionally observed in the mantle cavity. The finding of host-specific ciliate C. acuminatus suggests that zebra mussels invaded Lake Erken at the juvenile or adult stage.
Aquatic Invasions (2008) 3(1): 83-86

We report the results of a two-year study in the Svisloch River (Minsk, Belarus) on the dynamics of infection in Dreissena polymorpha by nematodes and three ciliate species Conchophthirus acuminatus, Ophryoglena sp., and Ancistrumina limnica. Although these endosymbionts were present in most of the samples, their prevalence and infection intensity differed significantly. C. acuminatus and A. limnica infection intensities in both years of the study had a maximum in summer and were positively correlated with water temperature. In contrast, Ophryoglena sp. and nematode infection intensities were considerably lower in summer versus winter and were negatively correlated with temperature. In the first long-term study to monitor the size and reproductive rate of C. acuminatus, we found that mean length was negatively correlated with temperature and that temperature was positively correlated with asexual reproduction, with a peak of cell division in April as water temperatures increased.
Journal of Invertebrate Pathology (2003) Volume 83: 73–82