Epidemiologic Notes and Reports
Microsporidian Keratoconjunctivitis in Patients with AIDS
From November 1989 through January 1990, five cases of ocular
infections with microsporidia in patients with acquired
immunodeficiency syndrome (AIDS) were reported. Three cases were
identified in New York City (1), one in San Antonio, and one in
Cleveland (2). All five patients were homosexual men aged 29-46
years. The most common presenting manifestations were
conjunctivitis or scleritis (all patients), foreign-body
sensation (four patients), blurred vision (three patients), and
photophobia (three patients). Ophthalmologic examinations found
conjunctival inflammation (all patients), decreased visual acuity
(four patients), and diffuse punctate keratopathy (four
patients). One patient had corneal inflammation, and one patient
had corneal ulceration. Pathologic findings were bilateral in all
patients. Concomitant, unilateral cytomegalovirus retinitis was
noted in two patients. After routine bacterial and fungal
cultures failed to identify plausible etiologic agents, corneal
or conjunctival scrapings and/or biopsy specimens were obtained
from all patients. Sections from these specimens prepared with
Giemsa and other routine histologic stains contained numerous
oval, dark-staining organisms consistent in morphology with
microsporidian spores. Visualization of characteristic
ultrastructure with transmission electron microscopy confirmed
the diagnosis in all cases.
Two of the five patients have died of other AIDS-related
complications. No improvement in their ocular infections was
noted before death despite attempted treatment with various
topical antimicrobial (tobramycin, chloramphenicol, and
sulfisoxazole), lubricating, and anti-inflammatory agents (1).
Two other patients did not respond to therapy with topical
antimicrobial agents (neomycin, propamidine isethionate,
amphotericin, sulfacetamide, and trimethoprim/sulfamethoxazole);
however, several weeks after therapy was discontinued the
symptoms resolved. The reason for these improvements is unknown,
but both patients coincidentally began systemic therapy with
fluconozole or itraconazole for concomitant cryptococcal
meningitis. Infection in the fifth patient failed to respond to
topical preparations (cefazolin, propamidine isethionate, and
clotrimazole); one cornea perforated, and the patient underwent
emergency corneal grafting.
One patient wore contact lenses; none had histories of ocular
trauma. Use of other eye medications by patients is unknown. Two
patients had histories of foreign travel. Four patients were
exposed to domestic animals: one had cared for a friend's pet
cat, two others kept pet birds (parrot and parakeets) in their
homes, and one had both a pet cat and a pet bird. The exact
source of infection in all five cases remains unknown.
Reported by: JM Orenstein, MD, George Washington Univ Medical
Center, District of Columbia. J Seedor, MD, New York Eye and Ear
Infirmary; DN Friedberg, MD, SM Stenson, MD, PM Tierno, PhD, NC
Charles, MD, New York Univ Medical Center, New York City, New
York. DM Meisler, MD, CY Lowder, MD, JT McMahon, PhD, DL
Longworth, MD, I Rutherford, MD, Cleveland Clinic Foundation,
Cleveland, Ohio. RW Yee, MD, A Martinez, MD, F Tio, MD, K Held,
MD, Univ of Texas Health Sciences Center, San Antonio, Texas.
Parasitic Diseases Br, Div of Parasitic Diseases, Center for
Infectious Diseases, CDC.
Editorial Note
Editorial Note: Microsporidia are ubiquitous, spore-forming,
intracellular protozoal parasites that cause disease in a wide
range of vertebrate and invertebrate animals. Manifestations of
disease in humans range from asymptomatic infections to fulminant
cerebritis and/or nephritis; ocular infections are recognized
infrequently (3,4).
Since 1987, microsporidia have been increasingly recognized as
a human pathogen (5,6). From 1959 through 1989, only eight cases
of microsporidiosis were documented in immunocompetent (six
cases) or immunosuppressed (two cases) patients without AIDS;
four of these were ocular infections. Since 1985, enteric
microsporidial infections have been reported with increasing
frequency in AIDS patients with chronic diarrhea; hepatic and
peritoneal infections have also been documented. Through 1989,
more than 50 cases of intra-abdominal infections were reported in
AIDS patients (7). Because reliable serologic tests are
unavailable, the diagnosis of microsporidiosis requires biopsy of
the infected tissue. Although routine histopathologic studies can
provide presumptive identification, diagnostic confirmation
requires electron microscopic visualization of the organisms'
characteristic ultrastructure. There is no known effective
antimicrobial therapy; data on the outcome of surgical
procedures, such as keratoplasty and corneal transplantation, are
insufficient to permit recommendations.
The occurrence of five cases of ocular microsporidiosis within
such a brief time from three diverse geographic areas suggests
that this problem (like intestinal microsporidiosis) may be more
widespread than previously recognized. Knowledge of the
epidemiologic characteristics and clinical features of
microsporidial infection is limited. Infections with
microsporidia have been documented in immunocompetent and
immunosuppressed patients with varied cultural and socioeconomic
backgrounds from at least five continents (Africa, Asia, Europe,
North America, and South America). However, common epidemiologic
characteristics have not been identified (7) and the mode of
transmission in humans is unknown. In animals, transmission
occurs by ingestion of microsporidian spores shed into the
environment through the skin, urine, or feces of infected hosts
(3). Although fecal-oral transmission is the likely route of
infection in humans with intestinal microsporidiosis, the source
of ocular infections is not clear. The relatively superficial
location of conjunctival and corneal tissues suggests that direct
inoculation of the eye may occur.
To better characterize the epidemiology, public health impact,
and clinical features of microsporidial infections, CDC's
Parasitic Diseases Branch (PDB), Division of Parasitic Diseases,
Center for Infectious Diseases, is interested in obtaining
information and specimens from physicians who suspect this
condition in their patients. Physicians are encouraged to report
such cases to CDC through their state health departments.
Consultation and information regarding specimen processing are
available through PDB; telephone (404) 488-4050.
References
Friedberg DN, Stenson SM, Orenstein JM, Tierno PM, Charles NC.
Microsporidial keratoconjunctivitis in acquired immunodeficiency
syndrome. Arch Ophthalmol (in press).
Lowder CY, Meisler DM, McMahon JT, Longworth DL, Rutherford I.
Microsporidia infection of the cornea in an HIV-positive man. Am
J Ophthalmol 1990;109:242-4.
Canning EU, Lom J. The microsporidia of vertebrates. New York:
Academic Press, 1986.
Cali A, Owen R. Microsporidiosis. In: Balows A, Hausler WJ Jr,
Lennette EH, eds. The lab oratory diagnosis of infectious
diseases: principles and practice. Vol 1. New York:
Springer-Verlag, 1988:929-50.
Bryan RT. Microsporidia. In: Mandell GL, Douglas RG, Bennett
JE, eds. Principles and practice of infectious diseases. 3rd ed.
New York: Churchill Livingstone, 1990:2130-4.
Shadduck JA. Human microsporidiosis and AIDS. Rev Infect Dis
1989;11:203-7.
Bryan RT, Cali A, Owen RL, Spencer HC. Microsporidia:
opportunistic pathogens in patients with AIDS. Prog Clin
Parasitol (in press).
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