Hematological, splenic and adrenal changes associated with natural and experimental infections of Trypanosoma lemmi in the Norwegian lemming, Lemmus lemmus (L.).

Both natural and experimental Trypanosoma lemmi infections in Norwegian lemmings caused slight anemias and hypoglycemia. Leucocyte counts remained the same. Adrenal and splenic hypertrophy were associated with natural infections whereas only splenic hypertrophy was present in the experimental infection. Grahamella sp. infections were also associated with adrenal and splenic hypertrophy in wild lemmings. It is suggested that blood parasites which are associated with anemia, hypoglycemia and adrenal hypertrophy might also interfere with both male and female reproduction, and should be considered in the interpretation of the population regulation of small rodents.