Anaplasma phagocytophilum presenting with orchitis in a renal transplant recipient

Human granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, is an emerging tick-borne disease. It is spread by the black-legged deer tick Ixodes scapularis that serves as the vector for six human pathogens. HGA is still rarely reported in solid organ transplant recipients. In solid organ transplant recipients, orchitis has been reported secondary to chickenpox, tuberculosis and infections due to Listeria monocytogenes and Nocardia asteroides. Orchitis as a presenting feature of HGA infection has only been reported in animals. We present a unique case of a renal transplant recipient with HGA that presented as orchitis. We also compare the clinical presentation and laboratory findings of our patient with other cases of HGA in transplant recipients. To the best of our knowledge, our patient is one of the first cases of A phagocytophilum mono-infection causing a classical presentation of orchitis in a transplant patient.