Molecular characterization and genetic diversity of Blastocystis sp. in animals from four zoos in China

Blastocystis sp. is a widespread unicellular protozoan that is a gastrointestinal eukaryotic parasite of humans and animals. At present, Blastocystis sp. is subdivided into 42 subtypes (STs), and the different STs suggest different host specificities. The study aimed to investigate in detail the host range and genetic diversity of Blastocystis sp., given the limited studies.

A total of 863 stools were taken from 135 animal species. Among these, 135 (15.64 %) were positive for Blastocystis sp., with 42.25 % (30/71), 5.04 % (6/119), 27.63 % (42/152), 2.56 % (1/39), 16.67 % (2/12), 22.22 % (4/18), 25.00 % (2/8), 12.62 % (38/301) and 8.62 % (10/116) in non-human primates (NHPs), Carnivora, Artiodactyla, Perissodactyla, Proboscidea, Diprotodontia, Rodentia, Aves and Amphibian, respectively. All Chiroptera and Reptilia samples were negative. Sequence and STs analysis showed ten known STs (ST1-ST5, ST7, ST8, ST10, ST11 and ST14), but there were differences in dominant STs among the eight animal groups. These included ST2 of NHPs, ST3 of Carnivora, ST10 of Artiodactyla, ST11 of Proboscidea, ST1 of Diprotodontia, ST1 and ST4 of Rodentia, ST5 of Aves and ST3 of Amphibian. This is the first report of Blastocystis sp. infection in 19 animal species. Sequences analysis using MEGA 11.0 and DnaSP 6.12.03 showed a parasite nucleotide diversity index of 0.11607 and a haplotype diversity index of 0.981.

These data demonstrate that Blastocystis sp. has high genetic variation. The data are consistent with the wide distribution and rapid transmission of Blastocystis sp. among hosts. The results increase the known host range of Blastocystis sp. and may help to prevent and control Blastocystis sp. infection transmitted from animals to humans.