Trypanosomes of small mammals in southern Ontario

Using the haematocrit centrifuge technique, 53 of 619 small mammals from seven areas in southern Ontario were found to be infected with three species of trypanosomes. Trypanosoma microti was found in 10 of 374 (2.7%) Microtus pennsylvanicus examined from two of five locations. Thirty-five of 102 (34%) of Tamias striatus from one area were infected with Trypanosoma tamiasi and over 94% (33 of 35) of the infected animals were juveniles. This would indicate that the trypanosome is primarily a parasite of juveniles. A trypanosome which was tentatively identified as Trypanosoma soricis was found in 8 of 36 (22%) Blarina brevicauda; it was recorded from two of four areas where the shrews were caught. A detailed description of the trypanosome was given because the original description was inadequate. No trypanosome was found in 74 Peromyscus maniculatus, 31 Mus musculus, and 2 Zapus hudsonius examined.