Microsporidial Keratitis: Need for Increased Awareness

Microsporidial Keratitis in Patients with Hot Springs Exposure

“…This phenomenon could be explained as the result of a secondary change to infection. It could also be due to a preexisting defect of the host epithelium that facilitates parasite invasion (17,29). None of our patients, however, had a history of previous recurrent corneal erosions.…”

Vittaforma corneae keratitis in southern India: role of a novel duplex PCR

“…Diagnoses of microsporidial infections are primarily based on the identification of microsporidial spores in clinical samples using light microscopy, but genus and species differentiation are uncertain (Sharma et al, 2011). In the present analysis, of the 12 clinically suspected microsporidial keratitis samples, corneal scrapes from 6 cases showed positive results for microsporidia by smear-based light microscopy examinations revealing a uniform oval shape, and a non-budding sporulant nature, which helped to differentiate them from bacteria and yeasts.…”

“…The genus-specific or pan-microsporidial primers amplified the region between sequence positions 1 and~1205 of the SSU-rRNA gene of microsporidial species, producing 1200 bp products from the DNA of nine study subjects, whereas, the species-specific primers for V. corneae, which were novel and primers designed by us, amplified the region between sequence positions 191 and 662 of the SSU-rRNA gene of V. corneae, [which was complementary with the reference sequence of V. corneae (GenBank accession no. L39112)] and produced 472 bp amplicons from the DNA of six study subjects, as well as showing a positive amplification with genus-specific (pan-microsporidial) primer sets.Diagnoses of microsporidial infections are primarily based on the identification of microsporidial spores in clinical samples using light microscopy, but genus and species differentiation are uncertain (Sharma et al, 2011). In the present analysis, of the 12 clinically suspected microsporidial keratitis samples, corneal scrapes from 6 cases showed positive results for microsporidia by smear-based light microscopy examinations revealing a uniform oval shape, and a non-budding sporulant nature, which helped to differentiate them from bacteria and yeasts.…”

“…Over 1300 species of microsporidia belonging to 160 genera have been described, of which, Nosema and Encephalitozoon are well-known ocular pathogens (Witner & Weiss, 1999;Sharma et al, 2011). Ocular microsporidiosis has been classified pathologically as either stromal or epithelial, and its pathogenesis varies according to the immune status of the patients (Cali et al 1991;Schwartz et al, 1993).…”

“…Although an enormous amount of literature is available on microsporidiosis, knowledge of ocular manifestations is still minimal. In spite of the fact that a variety of diagnostic techniques have been described, laboratory diagnosis still remains difficult, and reports on ocular manifestations, especially in India remain scant (Sharma et al, 2011;Joseph et al, 2006a, b). Hence, a concerted approach was needed to overcome the shortcomings to allow accurate identification, which has led of late to molecular methods (Fedorko & Hijazi, 1996;Reddy et al, 2011;Joseph et al, 2006c).…”