Comparison of Entamoeba histolytica DNA isolated from a cynomolgus monkey with human isolates.

Three protein-coding loci in DNA of an Entamoeba histolytica strain (EHMfas1) isolated from cynomolgus monkey (Macaca fascicularis) were sequenced; these loci corresponded to the genes for chitinase, the serine-rich E. histolytica protein (SREHP), and the 16 S-like small subunit ribosomal RNA (16S-like SSUrRNA). The nucleotide and deduced amino-acid sequences of chitinase and SREHP were compared with sequences from human isolates. EHMfas1 had several specific mutations in units in the polymorphic regions of the chitinase and SREHP loci, with some repetition of these mutated units. The sequence of the 16S-like SSUrRNA gene (16S-like SSUrDNA) was compared with other Entamoeba species. In phylogenetic analysis, EHMfas1 was not categorized in the E. histolytica cluster but between E. histolytica and E. dispar. To our knowledge, this is the first molecular characterization of E. histolytica isolated from cynomolgus monkey, and our results indicate that EHMfas1 may be a subspecies of E. histolytica that infects cynomolgus monkey.