1. Life Science Research Centre; Faculty of Science; University of Ostrava; 710 00 Ostrava Czech Republic
2. Biology Centre; Institute of Parasitology; Czech Academy of Sciences; 370 05 České Budějovice (Budweis) Czech Republic
3. Zoological Institute; Russian Academy of Sciences; 199034 St. Petersburg Russia
4. Department of Parasitology; Faculty of Science; Charles University; 128 44 Prague Czech Republic
5. Faculty of Sciences; University of South Bohemia; 370 05 České Budějovice (Budweis) Czech Republic
6. Canadian Institute for Advanced Research; Toronto Ontorio M5G 1Z8 Canada
7. Department of Biology and Ecology; Faculty of Science; University of Ostrava; 710 00 Ostrava Czech Republic