A Case of Human Granulocytic Anaplasmosis Suspected to Be Complicated by Cholangitis

Human granulocytic anaplasmosis is a febrile illness caused by Anaplasma phagocytophilum, an intracellular bacterium transmitted by ticks that is mainly prevalent in the United States and Europe. Five cases have been reported from Japan. A 63-year-old man was admitted to our hospital with a 5-day history of high fever. The patient frequently worked in mountainous areas and reported having felt an insect bite or thorn stick in his right leg some days earlier. Laboratory investigations showed increased serum levels of C-reactive protein, total bilirubin and the hepatobiliary enzymes. The patient was immediately started on treatment and received minocycline 200 mg/day for 8 days and ceftriaxone sodium 2 g/day for 6 days for a suspected diagnosis of rickettsiosis and acute cholangitis, and recovered by eight days. Eventually, on the basis of the results of serum tests for antibodies to tick-borne pathogens, which revealed increase in antibody titers to A. phagocytophilum in paired sera, the patient was diagnosed as having anaplasmosis. Different from the 5 previously reported cases from Japan, this patient was a habitual drinker and cholangitis was suspected as a complication of anaplasmosis in him. Herein, we report an unusual presentation and severe disease complications of human granulocytic anaplasmosis in a habitual drinker.