Abstract

Scuticociliates are facultative parasitic ciliates of the subclass Scuticociliatia Small, 1967 which cause scuticociliatosis, one of the most important parasitological problems in marine aquaculture worldwide. In this study, we report, for the first time, the presence of Pseudocohnilembus sp. in Algeria. The unexpected discovery of Scuticociliate DNA during our research on protozoan parasites in bird faeces, led to the parasite’s molecular and phylogenic characterization. BLAST analysis of the partial small subunit ribosomal DNA sequence (SSU rDNA) showed sequence similarity value of 99.64% with an uncultured Pseudocohnilembus clone. The alignment of this sequence with other Pseudocohnilembus sequences gives a separated sub-clade among the same uncultured Pseudocohnilembus sequences isolated from stool. The distance between our Pseudocohnilembus sp. and the uncultured Pseudocohnilembus sequences isolated from stool does not exceed 1% when computed using Kimura 2-parameter model, however, it greatly exceeds 1.5% with the other species included in the dataset. These distances, and the phylogenic tree, clearly indicates that Pseudocohnilembus sp. isolated from different animal stools corresponds to a new species, and our present sequence of Pseudocohnilembus sp. forms an original Algerian haplotype.

Keywords: Animal feces; Birds; Genotype; Protozoa; SSU rDNA; Scuticociliates