Subconjunctival setariasis due to Setaria equina infection; a case report and a literature review.

A rare case of human subconjunctival setariasis due to Setaria equina infection is reported herein. A 15-years old girl was referred with a 24h history of edema and redness in her left eye. On slit lamp examination, a thread-like cylindrical worm was moving in the subconjunctival area. The worm was extracted, stained and measured 110mm in length 510μm in width. The isolated worm was identified as adult female S. equina based on morphometric criteria. Identification of the species of the worm was confirmed using molecular methods. For this purpose, the 12S rRNA gene was PCR-amplified and the purified amplicon was directly sequenced. After alignment, phylogenetic analysis revealed that the 12S rRNA sequence of this worm (Accession no.: KU291446) showed 100% identity with that of S. equina. This is the first case in Iran and provides evidence that S. equina can be an etiological agent of subconjunctival infection was isolated and diagnosed as where it located Middle East.