Ocular Microsporidiosis—Our Experience in a Tertiary Care Centre in North India

Abstract

Microsporidia are obligate intracellular protozoal parasites. They are eukaryotic and spore forming. Increasing interest in this parasite as a pathogen in the ocular tissues in recent times is due to increasing awareness of microsporidia as an ocular pathogen and better methods of identification of the organism. It also can cause intestinal, sinus, pulmonary, muscular and renal diseases, in both immunocompetent and immunosuppressed patients. Ocular microsporidiosis can occur in isolation or as a part of systemic infections. In earlier published literature, ocular involvement in immunocompetent individuals was more in the form of stromal keratitis and immunocompromised individuals were seen to have keratoconjunctivitis. However, later studies show that this pattern has many variations. Occurrence in rainy season with exposure to muddy water and history of minor trauma is now a known factor. Identification by light microscopy from scrapings with KOH, Gram, Giemsa staining is possible. Growth of the organisms, however, is possible only by cell culture. Species identification is done by polymerase chain reaction and by electron microscopy. Immunofluorescent staining techniques are also available in advanced laboratories for species differentiation of microsporidia. Till date, treatment of ocular microsporidia has not been standardized and varies from simple debridement to use of various antibiotics, antiseptics antifungals and antiviral agents.

Case Report: Ocular Microsporidiosis: Case in a Patient Returning from India and Review of the Literature

“…21,46 As reported previously for our immunocompetent case, clinical symptoms include unilateral pain, conjunctival redness, photophobia, the sensation of a foreign body in the eye, and blurred vision. 35,45 Progressive and significant decrease in visual acuity complicated by a perforated corneal ulcer in stromal keratitis was also reported. 47 The clinical features of our case may mimic adenovirus or herpes keratoconjunctivitis.…”

“…44 It was only in the 1990s, during the acquired immune deficiency syndrome epidemic, that a much larger number of cases of keratoconjunctivitis were reported. 45 Since early 2000, an increase in stromal keratitis and keratoconjunctivitis cases has been described in immunocompetent patients. 21,46 As reported previously for our immunocompetent case, clinical symptoms include unilateral pain, conjunctival redness, photophobia, the sensation of a foreign body in the eye, and blurred vision.…”

“…However, it appears that the infection is deeper and more extensive in ocular microsporidiosis. 21,45,47 Recently, Herpes virus and microsporidia have been reported to coexist in granulomatous inflammation. 48 Electron microscopy was formerly the reference technique for the identification of species based on studying the structural characteristics of the spore.…”

Diagnostic Utility of CDC DPDx for an Atypical Presentation of Infectious Crystalline Keratopathy-Like Infiltrate Secondary to Microsporidia

“…[3][4][5][6] Microsporidia are ubiquitous, spore-forming, obligate intracellular protozoan parasites found both in the environment and systemically in human beings. 5 Microsporidial ocular infections have previously been reported in both immunocompromised and immunocompetent individuals. 3,5,6 Epidemiological risk factors include soil contamination, exposure to muddy water, poor contact lens hygiene, and topical steroids.…”

“…3,5,6 Epidemiological risk factors include soil contamination, exposure to muddy water, poor contact lens hygiene, and topical steroids. 5,7 Microsporidial keratitis may present as 1 of 3 clinical patterns: superficial punctate keratitis, stromal keratitis (including both a nummular and crystalline-like appearance), and endotheliitis. 6 Nonspecific and cyclical symptoms of photophobia and blurred vision are common.…”