Abstract

Eperythrozoon coccoides and Haemobartonella muris produced in mice and rats respectively, essentially the same disease, characterized by anaemia, splenomegaly and in severe cases, haemoglobinuria with death. In both infections anaemia was associated with phagocytosis of erythrocytes by monocytes of the spleen, and with the presence of cold-active haema-glutinin for trypsinized red cells (CAH). An antigen similar to the serum antigen (SA) associated with acute malaria and babesiosis was also found in the blood of the anaemic animals. One or two days later antibody to SA (ABSA) was detected and for several days thereafter, both SA and ABSA could be detected in plasma samples. Anaemia crisis with haemoglobinuria was better correlated with the appearance of ABSA than with the presence of CAH. It is suggested that CAH, and complexes of SA and ABSA could have acted as anaemia factors and were in part causal in the sequestration or haemolysis of erythrocytes during acute infection.