A congress report of the new Emerging Pathogens and Parasitology Subgroup within the ISBT Working Party on Transfusion-Transmitted Infectious Diseases.

In 2025, the Parasitology Subgroup of the International Society of Blood Transfusion (ISBT) Transfusion-Transmitted Infectious Diseases (TTID) Working Party (WP) transitioned into the Emerging Pathogens and Parasitology (EPP) Subgroup (referred to here as the EPP). This followed recognition that the parasitology subgroup's relevance was limited in scope given the small number of transfusion-transmissible parasites that still lacked effective mitigation. The EPP was proposed to address themes that are not adequately covered by existent subgroups of the TTID WP. In addition to maintaining a focus on transfusion-transmissible parasitic infections, a major objective of the EPP is horizon scanning for emerging pathogens. Horizon scanning refers to a systematic and proactive approach of information gathering and evaluation to identify early-and often subtle-signals of possible threats, which in this case pertain to blood safety. The EPP will characterize those risks to guide decision making and preparedness, pertaining to the safety and sufficiency of the blood supply. We describe the scope, structure and functioning of the EPP, within the broader TTID WP. We include examples of projects that may be pursued and outputs from horizon scanning a contemporary emerging pathogen. This collectively highlights the strategic relevance and objectives of the EPP.