Morulae in neutrophils: A diagnostic clue for human granulocytic anaplasmosis

Although there was no specific finding in peripheral blood smears performed on the second day after doxycycline administration in clinically suspected human granulocytic anaplasmosis (HGA) patients, we re-examed the peripheral blood smears performed at the time of admission and found morulaes in neutrophils. This case shows that the detection of morulae in a blood smear can be helpful in the diagnosis of HGA, especially in the acute phase of illness, prior to empirical antibiotic administration.