Detection of morulae in peripheral blood neutrophils from two dogs with Anaplasma phagocytophilum infection in Japan

Abstract

Morulae are cytoplasmic inclusions found in granulocytes of mammals infected by Anaplasma phagocytophilum. Two dogs presented with acute anorexia and lethargy in 2018, and both exhibited fever and thrombocytopenia as clinicopathological findings. Hematological examination of blood smears revealed cytoplasmic inclusions in neutrophils, which were confirmed as A. phagocytophilum infection with serological and molecular methods. Sequencing of partial 16S rRNA genes revealed highest homologies to the A. phagocytophilum sequence from a case of canine granulocytic anaplasmosis in Japan. This is the first report of morulae appearance with canine granulocytic anaplasmosis in Japan