Experimental Trypanosoma (Nannomonas) congolense infection in Microtus montanus

Seventy-two voles (Microtus montanus) were infected with a strain of Trypanosoma congolense of low virulence in mice to study their susceptibility and value as a tool for testing chemotherapeutic agents. The infection in Microtus was highly virulent. Parasitaemia was low to moderate. Significant spleen and body weight changes were observed. Blood capillaries of the heart, brain, kidneys and lungs were markedly dilated and numerous parasites were present in the dilatations, particularly in the heart. There was a generalized serous inflammation, often associated with histiocytic interstitial lesions (except in the brain), particularly in the heart. Treatment of voles with diamidines on cumulative mortality day 60% gave a complete cure.