Preliminary studies on trypanospmes from the dogfish, Scyliorhinus canicula L.

In a sample of 83 dogfish, Scyliorhinus canicula, 30% were found to be infected with trypanosomes during the summer of 1981 at Plymouth. Infected fish were over 53.0 cm total length and slightly anaemic, reflected in a 4.6% reduction in circulating erythrocytes with a small (0.6%) increase in leucocytes. Individual differences in serum proteins did not correlate with infection, although spleens from infected fish showed lymphoid aggregations around blood vessels. Parasitaemias were consistently low, ranging between 1.5×l03 and 6.O×103ml−1. No dividing forms were found in the peripheral blood or lymphomyeloid tissues, although two size forms were found in the peripheral blood. The trypanosome, Trypanosoma scyllii, is described from living and stained preparations and has been successfully maintained in laboratory culture.