First report of the isolation and phylogenetic characterization of equine Setaria digitata from India based on mitochondrial COI, 12S rDNA, and nuclear ITS2 sequence data

• Published in: Parasitology research (1987) Vol. 119; no. 2; pp. 473 - 481
• Main Authors: Maharana, B. R., Potliya, S., Ganguly, A., Bisla, R. S., Mishra, C., Ganguly, I.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2020; Springer; Springer Nature B.V
• Subjects: Analysis; Animals; Biomedical and Life Sciences; Biomedicine; Congeners; Cytochrome oxidase; Cytochrome-c oxidase; DNA, Intergenic - genetics; DNA, Ribosomal - genetics; Electron Transport Complex IV - genetics; Ethylenediaminetetraacetic acid; Evolution; Eye Diseases - parasitology; Eye Diseases - veterinary; Filarioidea - genetics; Filarioidea - isolation & purification; Genetics; Horse Diseases - parasitology; Horses - parasitology; Immunology; India; Medical Microbiology; Microbiology; Mitochondria; Mitochondrial DNA; Nematoda; Phylogenetics; Phylogeny; Phylogeny - Original Paper; Polymerase Chain Reaction - veterinary; Ribosomal DNA; RNA, Ribosomal - genetics; Sequence Analysis, DNA; Setaria digitata; Setaria Nematode - genetics; Setaria Nematode - isolation & purification; Setariasis - parasitology; Sibling species; India; Sri Lanka; ITS2; 12S rDNA; Equine; Setaria; COI; PCR
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-019-06587-1

Equine ocular setariasis arising mainly from ectopic infestation of
Setaria digitata
is a common vision impairing ophthalmic disease in India, and the identification of this filarial nematode is based solely on morphology. However, morphological characters alone are inadequate to detect and differentiate
S. digitata
from its congeners. The present communication reports the first phylogenetic characterization of equine
S. digitata
from India based on sequences derived from the mitochondrial cytochrome
c
oxidase subunit 1 (COI), the mitochondrial small subunit ribosomal DNA (12S rDNA), and the nuclear internal transcribed spacer 2 (ITS2). Three isolates were characterized for each gene, and respective sequences were submitted to NCBI database (MN078131, MN078132, and MN095798). The sequences were also compared with the other related sequences available from PubMed around the globe, and phylogenetic analysis was carried out in conjunction with nucleotide homologies. There was no intraspecific variation among the Indian isolates. The phylogenetic analysis of
S. digitata
, inferred from these genes, showed that the isolate sequences obtained from different host species created a separate monophyletic clade within the genus
Setaria
with minor sequence variations revealing similar molecular characteristics of
S. digitata
isolates throughout the globe. In addition, the studied Indian isolates were found closer to Sri Lankan isolates. The
S. digitata
and
S. labiatopapillosa
appeared as sister species.