Corneal microsporidiosis. A case report including ultrastructural observations.
Stromal keratitis and iritis developed in the left eye of a healthy 45-year-old man with no history of ocular disease, trauma, or contact lens wear. The clinical course over a 2-year period was characterized by progressive central disciform keratitis, recurrent anterior stromal patchy infiltration, and iritis which was partially controlled with topical corticosteroids and broad-spectrum antibiotics. Results of bacterial, viral, fungal, and chlamydial cultures were negative. Results of histopathologic examination of a corneal biopsy specimen and, later, a penetrating keratoplasty specimen showed many extracellular and intracellular spores in degenerating keratocytes. By electron microscopy there were encapsulated oval structures measuring approximately 3.5 to 4 microns in length x 1.5 microns in width. Mature spores had well-developed cell walls that contained two abutted nuclei (diplokaryon) and a redundant polar tubule with six coils. These structures are characteristic of a protozoa in the genus Nosema.
Davis
R M
RM
Department of Ophthalmology, University of South Carolina, Columbia 29203.
Font
R L
RL
Keisler
M S
MS
Shadduck
J A
JA
D000818:Animals; D003316:Corneal Diseases / Q000175:diagnosis / Q000469:parasitology* / Q000473:pathology / Q000601:surgery; D056890:Eukaryota / Q000302:isolation & purification / Q000648:ultrastructure; D015822:Eye Infections, Parasitic / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D006801:Humans; D007500:Iritis / Q000469:parasitology; D007634:Keratitis / Q000469:parasitology; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D011528:Protozoan Infections / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery