Article ID: JJID.2020.013
We report the case of a 76-year-old woman whose infection was rapidly diagnosed as human granulocytic anaplasmosis (HGA) through a peripheral blood smear that showed characteristic intragranulocytic morulae. The smear was prepared on the day of hospitalization, which was 1–2 weeks before results were available from serology or the polymerase chain reaction (PCR). On the basis of the blood smear test, we started timely and appropriate antimicrobial treatment. The peripheral blood smear is known to have the lowest sensitivity when compared with serological or PCR tests for the diagnosis of HGA, but we suggest that the sensitivity of peripheral blood smear tests could be increased by employing experienced staff. The patient was confirmed as having HGA by PCR 7 days after the positive peripheral blood smear test, and 14 days later by serology. Morulae in neutrophils are an important diagnostic indicator of HGA, especially in febrile patients with a history of tick-bites or outdoor activities in rural areas.
