Transfusion-Transmitted Babesiosis

Area of Science:

• Medical Entomology
• Infectious Diseases
• Transfusion Medicine

Background:

• Babesiosis is primarily caused by Babesia microti and transmitted by Ixodes ticks.
• Transfusion-transmitted babesiosis is an emerging threat, with increasing incidence in the United States.
• Asymptomatic infected blood donors pose a significant risk to blood safety.

Purpose of the Study:

• To evaluate the effectiveness of current and emerging screening strategies for Babesia microti in blood donors.
• To inform regulatory guidance for reducing transfusion-transmitted babesiosis risk.

Main Methods:

• Review of historical data on transfusion-transmitted babesiosis.
• Analysis of the FDA-licensed DNA PCR and antibody assay for screening.
• Consideration of investigational nucleic acid testing (NAT) assays.
• Evaluation of FDA draft guidance for risk reduction.

Main Results:

• Current donor deferral methods are ineffective.
• FDA-licensed assays (DNA PCR and antibody) are used for screening in high-risk areas.
• Investigational NAT assays show promise for higher sensitivity.
• Final FDA guidance is pending comprehensive evaluation of screening strategies.

Conclusions:

• Effective blood donation screening is essential to mitigate transfusion-transmitted babesiosis.
• A combination of sensitive and specific assays is needed for robust screening.
• Ongoing evaluation and regulatory review are critical for blood supply safety.