FIG. 4.

Alignment of the deduced amino acid sequences of 51-kDa major antigen gene fragments amplified from E. risticii strains from seven horses and three snails (the snail designations are underlined). The sequences of an equine E. risticii strain (from a horse in Maryland; GenBank accession no. U24396), the SRC agent (GenBank accession no. AF037217), and two snail-derived E. risticii strains (SHSN-1 and SHSN-2; GenBank accession nos. AF037215 and AF037216, respectively) are included for comparison. Identical amino acids are represented by periods, differences in sequence relative to the sequence of the strain from the horse in Maryland are indicated by capital letters; insertions are shown by underlined italics.