The distribution and evolution of Blastocystis sp. in mammals and aves

Blastocystis sp. is a unicellular protozoan and one of the most common gastrointestinal eukaryotic parasites in humans and animals. It is distributed worldwide, but its pathogenic role is still controversial. Blastocystis sp. is subdivided into 33 subtypes, and existing different subtypes imply host specificity in various species. The study aimed to investigate in detail the host range of Blastocystis sp., given the limited studies. A total of 720 fecal samples from 132 animal species, 140 (19.44%) were PCR positive for Blastocystis sp., with 43.67% (31/71), 5.89% (7/119), 34.87% (53/152), 2.56% (1/39), 16.67% (2/12), 22.22% (4/18), 37.50% (3/8) and 12.96% (39/301) in Nonhuman primates, Carnivora, Artiodactyla, Perissodactyla, Proboscidea, Diprotodontia, Rodentia and aves, respectively. Sequence and phylogenetic analysis showed ten known subtypes (ST1, ST2, ST3, ST4, ST5, ST7, ST8, ST10, ST14, and ST23) of Blastocystis sp. in the present study, with ST10 as the predominant subtype in all animals. However, there were differences in dominant subtypes among the eight groups of animals, and ST2 of Non-human primates, ST3 of Carnivora, ST10 of Artiodactyla, ST23 of Proboscidea, ST1 of Diprotodontia, ST1 and ST4 of Rodentia and ST5 of aves, respectively. This is the first report of Blastocystis sp. infection in 48 species to the best of our knowledge. These results not only enriched the host range of Blastocystis sp. and filled the data of vacant animals but also provided a reference for preventing and controlling Blastocystis sp. infection between animals and humans.