Summer Buzz

Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Babesia microti Infection, Eastern Pennsylvania, USA

Marcela E. Perez Acosta

, Peter T. Ender, Erin M. Smith, and Jeffrey A. Jahre

Author affiliations: St. Luke’s University Hospital and Health Network, Bethlehem, Pennsylvania, USA

Abstract

Infection with Babesia microti has not been well-described in eastern Pennsylvania, USA, despite the vector of this organism being prevalent. We report 3 cases of babesiosis in eastern Pennsylvania in persons without recent travel outside the region or history of blood transfusions, suggesting emergence of this infection.

Babesiosis is an intraerythrocytic infection caused by protozoan parasites of the genus Babesia. In the United States, Babesia microti is the most common species that causes human babesiosis. Disease-endemic areas include specific regions in the northeast and upper Midwest United States. Infection with this organism can be asymptomatic to life-threatening. Signs and symptoms include high fever, diaphoresis, chills, headaches, and anorexia. Patients can also have hemolytic anemia and thrombocytopenia (1).
B. microti is transmitted by the Ixodes scapularis tick, which is also the vector of Borrelia burgdorferi and Anaplasma phagocytophilum (2). Although B. burgdorferi is endemic to Pennsylvania (3), B. microti is not considered endemic to this region (4,5). We report 3 cases of human babesiosis in patients from Northampton County in eastern Pennsylvania, USA, who had not recently traveled outside the region or had blood transfusions. None of the patients had risk factors for severe babesiosis, such as asplenia.

The Patients

Patient 1 was a 68-year-old man who was hospitalized on August 18, 2011, because of 6 days of fever, arthralgias, generalized weakness, and confusion. He was given doxycycline for treatment of presumptive Lyme disease but showed no improvement. He had not traveled outside eastern Pennsylvania for >3 years. He had never received any blood transfusions. Although he did not recall any tick attachments, he enjoyed gardening and other outdoor activities.