[Host and site-specific pattern of occurrence of digenetic trematodes in rodent communities from Lower Silesia,...

Trematodes of the class Digenea are parasites with complex life cycles and often use small mammals as definitive hosts; however, they are usually not highly prevalent in this group of mammals. In our work the patterns of occurrence of digeneans parasitizing small mammals were analyzed. The surveys were conducted at four locations, i.e., irrigation fields (Osobowice), a water distribution area (Mokry Dwor), recreational grounds (Redzin forest), and Nature Reserve "Stawy Milickie". Overall 894 rodents were examined. During investigation we identified flukes representing the following species and groups: Brachylaima recurva, Brachylecithum glareoli, Echinostomatinae sp., and Plagiorchis elegans. The digeneans were reported from all studied locations and were present in Apodemus agrarius, A. flavicollis and Myodes glareolus. The statistical analysis showed significant qualitative and quantitative differences in infections with digeneans among examined animals. The highest prevalence of infection with flukes was reported in A. agrarius (28.8%) with the maximum value--78.2% in the Nature Reserve "Stawy Milickie"; only at this location the co-infection with three and two trematode species were found. The differences in occurrence of Brachylaima sp., Echinostomatinae sp., and Plagiorchis sp. found in ,,Stawy Milickie" were not statistically significant; the flukes occupied the small intestine of A. agrarius at the same frequency. For comparison, digenetic trematode infection in the yellow necked mouse Apodemus flavicollis was dramatically lower (overall prevalence 2.8%) than in the striped field mouse A. agrarius, and flukes were reported only in Mokry Dwor (5.1%) and Milicz (5.9%). The bank voles Myodes glareolus were infected with two trematode species, i.e., Plagiorchis elegans (1.3%), and Brachylecithum glareoli (19.2%), and these parasites were reported only in the water distribution area. Aside from two accidental reports of dicrocoeliid trematodes found in Osobowice, Brachylecithum glareoli was reported mainly in bank voles M. glareolus collected from Mokry Dwor, which could indicate both host and site specificity for this species. Our results showed that the food habits of hosts species and site-specific conditions could be taken into consideration as potential factors affecting the trematode fauna of rodents.