A double antibody sandwich enzyme-linked immunosorbent assay for detection of secreted antigen 1 of Babesia microti using hamster model

► A sandwich ELISA targeting secreted antigen 1 of Babesia microti (BmSA1) was developed. ► The sandwich ELISA detected circulating BmSA1 earlier than antibody detection by indirect ELISA. ► The kinetics of circulating BmSA1 coincided with the profile of parasitemia. ► This assay was more sensitive than the microscopic examination of Giemsa-stained blood smears. ► BmSA1 could be a potential marker for surveillance of human babesiosis.