Parasites of five vagrant Polar bears (Ursus maritimus) swimming to Iceland during 2008 to 2016

During 2008 to 2016, five polar bears (Ursus maritimus) swam from the East Greenland population to Iceland and were shot soon after walking ashore. Each bear was dissected. Ectoparasites were searched for in their ears and fur, helminths in the gastrointestinal tract and Trichinella larvae in muscles. Protozoan cysts, oocysts and helminth eggs were also searched for in faecal samples. No ectoparasites were detected. Two bears (40%) hosted fourth stage larvae of the nematode Contracaecum osculatum (strain B) in the stomach. Characteristic scars, noted as craters in the rectum wall, indicated previous acanthocephalan infection in one bear. Three polar bears were infected by the nematode Trichinella nativa. No protozoan parasites were detected in faecal samples, but cysts of the heterokontophyte Blastocystis sp. were found in faeces of two bears (40%). This is the first report of C. osculatum, Blastocystis sp. and an acanthocephalan infection in free-living polar bears.