Internal parasites and associated histopathological changes in deceased white storks from Poland

The aim of this study was to analyze the parasitic fauna of dead white storks in nesting sites in different parts of Poland and the associated histopathological changes. Samples from thirty-eight white storks aged 3 weeks to 5 years were examined after their arrival at a stork sanctuary. The presence of Cathaemasia hians , Chaunocephalus ferox , Choanotaenia infundibulum , Railletina tetragona and Syngamus trachea was confirmed in 17 out of 38 (47.73 %) individuals. Cathaemasia hians and Chaunocephalus ferox flukes are not endemic to the studied area. The frequency of C. ferox was significantly higher in the youngest storks from group I (3–4 weeks old) compared to groups II (11–15 weeks old) and III (older than 2 years). Fluke eggs were only detected with sedimentation method in three samples (group III), while no adult flukes at all were found in the intestines. Chaunocephalus ferox was shown to be the most common pathogen in all storks studied when compared to other parasites. A histopathological examination of the jejunum and ileum revealed atherosclerotic changes in the muscular layer, lymphoid infiltration in the mucosa, the presence of adult flukes of C. hians and C. ferox in the intestinal lumen, and lymphoid infiltration in the muscular layer. Intense lymphoid infiltration in the mucosa was also observed in storks whose intestines were heavily infested with R. tetragona and C. infundibulum . Parasitic infections compromise the birds’ health status and affect the duration of flights, and they can increase the risk of other diseases.