Guidance on the management of asymptomatic blood donors who test positive for Babesia

Evan M. Bloch, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Jeremy W. Jacobs, Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN, USA.
Edouard Vannier, Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA, USA.
Gary P. Wormser, Division of Infectious Diseases, New York Medical College, Valhalla, NY, USA.
Jeffrey A. Gelfand, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
Vijay K. Sikand, Department of Medicine, Tufts University School of Medicine, Boston, MA, USA.
Howard M. Heller, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
Sunil K. Sood, Northwell Cohen Children's, Infectious Diseases, Zucker School of Medicine, New Hyde Park, NY, USA.
Laura Kirkman, Department of Microbiology & Immunology, Weill Cornell Medicine, New York, NY, USA.
Jennie E. Johnson, Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA.
Luis A. Marcos, Department of Medicine, Division of Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA.
Jacob E. Lemieux, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, USA.
Robert P. Smith, Maine Medical Center, Maine Health Institute for Research, Scarborough, ME, USA.
Ann E. Woolley, Harvard Medical School, Boston, MA, USA.

Abstract

DESCRIPTION: Babesiosis is a tick-borne disease that is endemic in the United States (US). The major species, Babesia microti, is readily transmissible via blood transfusion. Since 2019, blood donors in 14 US states and Washington DC have been routinely screened for Babesia infection using highly sensitive and specific nucleic acid testing (NAT). Currently, there are no recommendations regarding the management of asymptomatic blood donors who test positive for Babesia. METHODS: A multidisciplinary expert panel was convened to develop guidance for the management of asymptomatic Babesia-infected blood donors. A survey was distributed through the Infectious Diseases Society of America (IDSA) Emerging Infections Network (EIN) to evaluate how a geographically diverse group of infectious diseases specialists would approach this problem. RESULTS: The expert panel recommends that all Babesia NAT positive blood donors should be referred for clinical evaluation and retested using peripheral blood smear (PBS) and B. microti PCR within two months of blood donation screening. The panel also recommends observation rather than treatment for a reactive molecular test alone. Antimicrobial therapy should be considered for PBS positive cases. Donors should be counseled regarding the typically self-limiting nature of this infection and instructed to seek medical care if symptoms develop. The EIN survey results are consistent with these recommendations. CONCLUSIONS: Several factors support these management recommendations. Blood donors typically comprise healthy, immunocompetent adults in whom most Babesia infections are self-limited based on studies showing that molecular evidence of infection clears in almost all asymptomatic blood donors without intervention.