Screening of patient blood samples for babesiosis using enzymatic assays.

Human babesiosis is an emerging tick-borne disease in the United States and Europe. Transmitted by Ixodes ticks, the causative agent Babesia microti is an intraerythrocytic parasite that causes mild to deadly disease. Transmission of B. microti can also occur by transfusion of infected blood and blood products resulting in transfusion-transmitted babesiosis (TTB), which carries a high risk of fatality. To effectively manage this rise in B. microti infections, better screening tools are needed, which require minimal manipulation of the samples before testing. To this end, we tested two enzymatic assays, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), for efficacy in diagnosis of babesiosis. The results show that AST and ALT activity is significantly higher in the plasma of B. microti-infected patients. Moreover, statistical analysis revealed that these assays have high sensitivity and positive predictive values, which highlights their usefulness as diagnostics for babesiosis. These standardized enzymatic assays can be used to perform high-throughput, large-scale screens of blood and blood products before they are certified safe for transfusion.