Abstract
Purpose: :
Subconjunctival and anterior chamber granulomatous uveitis is one of the newly recognized sight threatening ocular disorder in children from South India. Histopathological analysis, revealed a possibility of parasitic cause; however, the exact etiology was unknown. Aim of this study is to confirm the etiology of the disease in context with environmental source using molecular techniques.
Methods: :
Twelve subconjunctival and twenty three anterior chamber granulomas were collected from the suspected granulomatous uveitis patients. A total 850 Snails of five different species were collected from 18 different muddy ponds in southern districts of Tamil Nadu, India. Trematode cercariae were isolated from the snails. Subsequently DNA extraction was carried out from the granulomas and from the cercarie by Qiagen kit tissue lysis methods. The conventional and Real-Time polymerase chain reaction assay was carried out targeting the ITS2 & 28S rDNA region of trematode genome using universal primer. Bi-directional sequencing and BLAST analysis were done for the identification of trematode at species level.
Results: :
Five subconjunctival and three anterior chamber granulomas out of thirty five were found confirmatory for trematode. Out of five different species of snails which were collected from the infected ponds, only one (Melanoides tuberculata) released the cercariae in the laboratory. The sequence analysis of patient’s granulomas DNA and environmental cercariae DNA collected from the snails revealed maximum similarity with Procerovum varium family Heterophyidae of trematode.
Conclusions: :
The present study confirmed the etiology of parasitic granulomatous uveitis in children of South India as a trematode, Procerovum varium.The possible source of infection identified as the snail infested water bodies.
Keywords: uvea • inflammation • anterior chamber