Molecular Characterization of Blastocystis in Captive and Free-Ranging New World Primates, Platyrrhini.

PURPOSE: Blastocystis species are widely distributed micro-eukaryote parasites found in both human and nonhuman primates. Despite having a global distribution, descriptions of Blastocystis subtype diversity in neotropical primates is largely limited to captive animals. The aim of this study was to molecularly characterize the presence of Blastocystis in free-ranging black-headed night monkeys, Aotus nigriceps, and to analyze Blastocystis heterogeneity in primates of the Parvorder Platyrrhini.
METHODS: We analyzed Blastocystis small sub-unit ribosomal DNA (SSUrDNA) from both A. nigriceps and Azara's night monkey, A. azarae boliviensis, in Southeastern Peru. We also included additional Blastocystis sequence from other neotropical primate studies to explore the distribution and host specificity of Blastocystis subtypes (ST) throughout the neotropics.
RESULTS: Thirteen percent of A. nigriceps samples were Blastocystis positive. Only ST8 was amplified in A. nigriceps and this partial DNA sequence was highly similar to ST8 sequence previously obtained from a human in Brazil. In our analysis of all available Blastocystis SSU sequences from primates of the Parvorder Platyrrhini, we found 15 monophyletic lineages corresponding to previously described subtypes ST1-ST10, ST12-15, and ST17.
CONCLUSIONS: Blastocystis SSU sequences amplified from A. nigriceps fecal samples shared high sequence similarity to isolates found in several other neotropical primates, Alouatta palliata, A. caraya, Ateles fusciceps, and Lagothrix. Similar subtypes have been found in human and captive primates which supports the possibility of transmission when in close contact. Expanded sampling of sympatric neotropical primates in the wild will establish whether subtypes and clades are limited to taxonomic group or whether transmission occurs between overlapping species.