First detection of Allobilharzia visceralis (Schistosomatidae, Trematoda) from Cygnus cygnus in Japan.

Adult schistosomes were detected in the veins or capillaries of the large intestine, mesentery, liver, and adrenal glands in eight of 13 whooper swans (Cygnus cygnus) examined in Iwate Prefecture, Japan. However, neither eggs nor severe tissue injuries were observed in any of the swans. The schistosomes were definitively identified as Allobilharzia visceralis based on the nucleotide sequences of the ribosomal internal transcribed spacer (ITS) region.