Novel Etiological Agent: Molecular Evidence for Trematode-Induced Anterior Uveitis in Children

Figure 1. Clinical and histopathological findings and snails with cercarial larvae. A, Anterior chamber granuloma in a 9-year-old boy. B, Aqueous fluid showing numerous eosinophils (E), neutrophil (N), lymphocyte (L), and a single macrophage (M) (hematoxylin-eosin, original magnification ×200). C, Melanoides tuberculata snails collected from the pond thought to be the focus of infection. D, Light microscopic image of the cercaria larval stage recovered from the snails (original magnification ×200).

Figure 2. Molecular confirmation of trematode etiology. A, Real-time polymerase chain reaction amplification plot of ribosomal DNA from the internal transcribed spacer 2 region, showing the positive control (Fasciola gigantica DNA, 100 pg) (a), granuloma DNA from the patient (b), cercarial DNA (c), and the negative control (nuclease-free water) (d). Rn indicates normalized reporter. B, Dissociation curve, showing the positive control (F gigantica DNA, 100 pg) (a), granuloma DNA from the patient (b), cercarial DNA (c), and the negative control (nuclease-free water) (d). C, Gel electrophoresis of the amplified DNA checked on 2% agarose gel. Lane 1 indicates a 100–base pair (bp) DNA ladder marker; lane 2, negative control; lane 3, positive control; lane 4, granuloma DNA; and lane 5, cercarial DNA. D, Representative electropherogram confirming the sequence of the trematode Procerovum varium. The numbers above the bases indicate the nucleotide sequence of the internal transcribed spacer 2 region of the trematode.