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

Abstract

Microsporidia are protists close to the kingdom of fungi that may cause eye infections. Most cases are reported in Asia and affect both immunocompromised and immunocompetent patients. Here, we report a rare case of microsporidial keratoconjunctivitis in an immunocompetent French patient 3 weeks after returning from India. In our patient, Weber trichrome staining of conjunctival scrapings revealed rounded elements approximately 1-3 μm in size. Conventional polymerase chain reaction analysis by ribosomal RNA subunit sequencing showed 100% identity with . Treatment by corneal debridement combined with fluoroquinolone eye drops allowed complete resolution of the lesions. Although rare, ocular microsporidiosis should be investigated in a patient who is native to Asia or has returned from an endemic area and presents with keratoconjunctivitis of undetermined etiology.

Molecular identification of microsporidian species in patients with epithelial keratitis

“…Corneal findings and/or confocal microscopy may offer prompt and non-invasive options for diagnosis [17,18]. Recently, Vittaforma corneae, one of the pathogens causing microsporidial keratoconjunctivitis, has been identified by DNA sequencing of the nuclear small subunit (SSU) rRNA gene [8,9]. Here, we report microsporidial pathogens detected by staining and confirmation by DNA sequencing.…”

“…Cases of superficial keratoconjuntivitis caused by microsporidia such as Encephalitozoon intestinalis and Encephalitozoon hellem have been reported for many years [4]. However ocular keratitis cases caused by Microsporidium species have been recently reported in Asia including Thailand [5][6][7][8][9]. Clinical manifestations of human microsporidiasis, i.e.…”

“…gastrointestinal, hepatobiliary, urinary tract, muscular, systemic, and ocular infections, have been reported [10,11]. Prevalence of microsporidial epithelial keratitis (keratoconjunctivitis) due to Microsporidium infection has been markedly increasing in immunocompetent people throughout the world [12,13], with most cases reported in Asia [8,9]. Exposure to soil or mud, unsanitary contact lenses, steroid administration, refractive surgery and collagen cross-linking after surgery have been suggested as risk factors for the infection [12,13].…”

A Narrative Review of Microsporidial Infections of the Cornea

“…The characteristic feature of microsporidia is the intracellular spore, which confers resistance to adverse environmental conditions and promotes dissemination [9]. The spore length is typically between 2 and 8 lm but varies across species, ranging from 1 to 30 lm [10].…”

“…MKC There remains no consensus on medical treatment for MKC; as such, various therapeutic regimens have been attempted. Response to medical therapy is highly dependent upon the species involved and the immune status of the patient [9]. In most case, the visual prognosis is good with no loss of visual acuity after MKC resolution [56].…”