Molecular identification and genetic diversity of equine ocular setariasis in Thailand based on the COI, 12S rDNA, and ITS1 regions.

The research paper focuses on the improved detection and identification of a worm, Setaria digitata, that causes a common eye disease in equines in Thailand using molecular methods. It also ventures into the genetic diversity of this nematode, assessing the similarity, entropy, and diversity of the species within the country and compared to those in other countries.

Tools Used for Detection and Differentiation

• This study uses molecular detection methods instead of the traditional morphological characterization. The researchers express that morphology alone is insufficient to correctly identify and detect S. digitata.
• The researchers extend the identification methods by genetically characterizing the S. digitata filarial nematodes based on sequences derived from the mitochondrial cytochrome c oxidase subunit 1 (COI), mitochondrial small subunit ribosomal DNA (12S rDNA), nuclear internal transcribed spacer 1 (ITS1), and Wolbachia surface protein (wsp).

About the Sample Collection

• Five samples of S. digitata were characterized and submitted to the NCBI database for further analysis.
• These samples were used for a phylogenetic analysis to understand the genetic relationships and also for assessing similarity, entropy, and haplotype diversity of the species.

Findings of the Research

• The phylogenetic analysis showed that the Thai strain of S. digitata closely resembled strains found in China and Sri Lanka, with a 99-100% similarity.
• The entropy and haplotype diversity assessment showed that the S. digitata Thai isolate was conserved and very similar to S. digitata found globally, implying little genetic diversity.
• This indicates that despite geographical borders, the strains have conserved genetic components, which could be beneficial in understanding and tackling the disease universally.

Significance and Implications

• This study is significant because it is the first report on the molecular detection of equine ocular setariasis caused by S. digitata in Thailand.
• The findings could assist in the recognition of this species, which will help in the improved diagnosis and treatment of the eye disease in horses.
• This research can also help broaden the base of molecular databases, thereby increasing the efficiency and accuracy of future identifications of this species.