Clinical spectrum of microsporidial keratoconjunctivitis

Microsporidial keratoconjunctivitis - first outbreak in Japan

BACKGROUND

Most cases of microsporidial keratoconjunctivitis are found in the Southern hemisphere. Our purpose was to investigate the first outbreak of microsporidial keratoconjunctivitis in Japan among healthy, immunocompetent soccer players from the same team during a 1-month period.

CASE PRESENTATION

This study is an observational case series. The medical records were analyzed for five cases with microsporidial keratoconjunctivitis who presented within September 2022. All five cases were males between 28 and 36 years old. These previously healthy individuals belonged to the same football team. Their eyes were considered susceptible to contaminated water or dirt from the turf at game and practice sites. All cases involved unilateral conjunctivitis, with scattered round white lesions that showed positive fluorescein staining in the corneal epithelium. All cases experienced diminution of vision in the affected eye. In three cases, direct smears showed spores of approximately 2-3 μm in diameter. Polymerase chain reaction (PCR) analysis of corneal scrapes revealed partial amplification of microsporidial 18 S ribosomal RNA gene in four cases. Sequences of PCR products from all four cases showed 100% identity with strains of Vittaforma corneae previously reported from an outbreak in Singapore. All cases were treated with topical therapy, including voriconazole, fluorometholone, and levofloxacin. Four eyes underwent corneal scraping. After treatment, all eyes healed without residual opacities.

CONCLUSIONS

Only a few sporadic case reports of this disease have previously been reported in Japan. We detected V. corneae in our case series, representing what appears to be the first outbreak of microsporidial keratoconjunctivitis in Japan. Exposure to contaminated water or soil, in addition to inadequate sanitary facilities, represents a potential source of infection. Further investigations to clarify the characteristics of microsporidia seem warranted.

Past, present, and prospects in microsporidial keratoconjunctivitis- A review

Ocular microsporidiosis comprises two entirely different spectra of disease as keratoconjunctivitis and stromal keratitis. Microsporidial keratoconjunctivitis (MKC) has been increasingly reported in the past two decades, probably due to raised awareness, simpler diagnostic procedures, and a better understanding of the clinical presentation. It is characterized by the presence of raised, coarse, punctate, multifocal, round to oval, greyish-white corneal epithelial lesions which usually evolve into nummular scars before resolution. Conjunctivitis seen is non-purulent and of mild-moderate intensity, with mixed papillary-follicular reaction. The mode of transmission and pathogenesis is poorly understood. Despite lack of inflammatory response, uncommon associations reported were- endotheliitis, corneal edema, limbitis, uveitis, and sub-epithelial infiltrates. There has been no consensus on the management of MKC. It varies from the use of multiple antimicrobial agents to simple lubricants. The majority of the disease goes underdiagnosed or misdiagnosed and treated as adenoviral keratoconjunctivitis, with topical steroids or anti-virals empirically. Changing trends have been noticed in the pattern of infection, possibly with increasing evidence of Vittaforma corneae as causative organisms, previously reported to cause stromal keratitis. An elaborate review of the past and present literature on MKC is provided in this review article, along with gaps in knowledge, and future directions of research.

Two parasites in one host: spatiotemporal dynamics and co-occurrence of Microsporidia and Rickettsia in an amphipod host

Biological interactions can greatly influence the abundance of species. This is also true for parasitic species that share the same host. Microsporidia and Rickettsia are widespread intracellular parasites in populations of Paracalliope fluviatilis, the most common freshwater amphipods in New Zealand. Although both parasites coexist in many populations, it is unclear whether they interact with each other. Here, we investigated spatial−temporal dynamics and co-occurrence of the two parasites, Microsporidia and Rickettsia in P. fluviatilis hosts, across one annual cycle and in three different locations. Prevalence of both Microsporidia and Rickettsia changed over time. However, while the prevalence of Rickettsia varied significantly between sampling times, that of Microsporidia did not change significantly and remained relatively low. The two parasites therefore followed different temporal patterns. Also, the prevalence of both parasites differed among locations, though the two species reached their highest prevalence in different locations. Lastly, there was no evidence for positive or negative associations between the two parasite species; the presence of one parasite in an individual host does not appear to influence the probability of infection by the other parasite. Their respective prevalence may follow different patterns among populations on a larger spatial scale due to environmental heterogeneity across locations.

Temporal trend of microsporidial keratoconjunctivitis and correlation with environmental and air pollution factors in India

Purpose:

The aim of this study was to describe the correlation between the temporal pattern of presentation of acute microsporidial keratoconjunctivitis (MKC) with meteorological parameters such as environmental temperature, rainfall, humidity, windspeed, and air pollution.

Methods:

This cross-sectional hospital-based study included 182,789 patients presenting between January 2016 and December 2019 hailing from the district of Hyderabad. Patients with a clinical diagnosis of MKC in at least one eye with an acute onset (≤1 week) of presentation were included as cases. Correlation analysis was performed with the local environmental temperature, rainfall, humidity, and windspeed (Telangana State Development and Planning Society) and air pollution (Central Pollution Control Board, Government of India).

Results:

Overall, 84 (0.05%) patients were diagnosed with acute onset MKC from the district of Hyderabad. The mean monthly prevalence in this cohort was 0.05% with peak prevalence in the months of July (0.08%), August (0.09%), September (0.12%), and October (0.08%). The environmental parameters of rainfall (r² = 0.87/P = < 0.0001), humidity (r² = 0.78/P = 0.0001), windspeed (r² = 0.38/P = 0.0321) were significantly positively correlated and the air pollution parameters such as ground level ozone (r² = 0.89/P = < 0.0001), particulate matter PM₁₀ (r² = 0.65/P = 0.0013), PM_2.5 (r² = 0.50/P = 0.0095), nitrogen dioxide (r² = 0.53/P = 0.0071), and carbon monoxide (r² = 0.69/P = 0.0008) were significantly negatively correlated with the temporal pattern of MKC in the population.

Conclusion:

Parasitic infections like MKC show a distinct temporal trend peaking during the monsoon season in the population. An increase in humidity, wind speed, and especially rainfall contributes to a higher prevalence of MKC cases during the year. An increase in ground-level ozone seems to be protective against infection.

A Narrative Review of Microsporidial Infections of the Cornea

Microsporidia are a rare and commonly misdiagnosed cause of corneal infection, accounting for approximately 0.4% of cases of microbial keratitis in some populations. Ocular microsporidiosis most often presents as either microsporidial keratoconjunctivitis (MKC) or microsporidial stromal keratitis (MSK). Though these two clinical entities exhibit similar symptomology, they are distinguished from one another by the time course for disease progression, findings on slit-lamp examination, and response to medical therapy. This review summarizes the current literature on the etiology and clinical presentation of microsporidial infections of the cornea and highlights ongoing developments in available diagnostic modalities and treatment regimens.

Demographic and clinical profile of microspodial keratitis in North India: an underreported entity

Ocular microsporidiosis was first described in immunocompromised subjects but recent reports have also shown cases in immunocompetent hosts. The database of existing clinical studies is very limited. The aim of present study was to analyse demographic profile, clinical features, microbiological profile, treatment and outcome of ocular microsporidiosis in northern India. The present study was carried out in the Department of Medical Parasitology, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, and Bharat Vikas Parishad Charitable trust, Chandigarh. A total of 250 patients during year 2013-17 and suspected of microsporidial keratitis (either clinically or after exclusion of bacterial, viral or fungal agents). Corneal scraping were taken and subjected for various staining methods and PCR. 8 patients of microsporidial keratitis were confirmed, based on positivity by at least any two of the above mentioned techniques. None of the patients had history of contact lens wear or exposure to swimming pool. All these patients were systemically healthy and HIV serology was negative except one had history of diabetes mellitus. This study is a reminder to clinicians that when multifocal diffuse epithelial keratitis and culture-negative keratoconjunctivitis not responding to medical therapy, regardless of immune status are found in patients with symptoms suggesting an infectious keratitis, microsporidial keratoconjunctivitis should be included in the differential diagnosis.

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

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 Vittaforma corneae. 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.

Microsporidial Stromal Keratitis: Successful Treatment with Topical Voriconazole and Oral Itraconazole

We report a case of microsporidial stromal keratitis successfully treated with topical voriconazole and oral itraconazole. A 30-year-old Hispanic male construction worker who wears contacts lenses presented with left eye erythematous, epiphora, and mild pain increasing over few days after failing previous antibiotics treatment. His best corrected visual acuity in the left eye was count fingers at three feet, and the slit lamp examination showed 3+ conjunctival injection, a circular central corneal ulcer 3.2 mm in diameter, stromal thinning, and an anterior chamber with white cells, flair, and 0.1 mm hypopyon. A cornea punch biopsy identified microsporidial organisms with some features suggestive of Vittaforma corneae. After treatment with topical voriconazole and oral itraconazole for eight weeks, the patient had complete resolution with no recurrence for over 12 months of follow-up. To our knowledge, this is the first reported case of successful treatment of microsporidial stromal keratitis with antifungals.

Clinical Features, Risk Factors, and Treatments of Microsporidial Epithelial Keratitis

OBJECTIVE

To report the clinical manifestations, risk factors, and treatments of microsporidial epithelial keratitis in Thailand.

METHODS

Twenty eyes of 19 patients were diagnosed and the clinical presentations, risk factors, and management were analyzed.

RESULTS

Of 19 patients, six patients (32%) had no apparent risk factors. Predisposing factors included soil exposure (6/19, 32%), water contamination (6/19, 32%), and eye liner (1/19, 4%). Twelve cases (63%) were detected in the rainy season. All cases presented with disseminated, punctated, elevated, epithelial keratitis. Corneal scrapings with Gram-chromotrope staining were positive in all patients. Moxifloxacin 0.5% eye drops were given and all 16 patients experienced complete resolution. Three recurrent cases were resolved with only topical moxifloxacin without corneal scraping or swabbing.

CONCLUSIONS

Predisposing factors were not found in some patients; thus, corneal scraping with staining should be considered in cases having a high index of suspicion. The incidence is increased during the rainy season; therefore, clinicians should have more awareness during these times. Debridement with topical moxifloxacin eye drops, without any systemic medication, may be an effective treatment. Corneal scraping or swabbing may not be required in recurrences.

Treatment of microsporidial keratoconjunctivitis with repeated corneal swabbing

PURPOSE

To report the effect of repeated corneal swabbing in patients with microsporidial keratoconjunctivitis.

DESIGN

Retrospective noncomparative case series.

METHODS

Sixteen eyes of 14 healthy patients with microsporidial keratoconjunctivitis were diagnosed based on the detection of microsporidia in corneal scrapings using Gram stain, the modified Kinyoun acid-fast stain, or both. Polymerase chain reaction plus gene analysis of the microsporidian 16S ribosomal RNA had been performed in 10 patients who sought treatment between 2010 and 2011. Some of the lesions were scraped for procurement of specimens. The remaining lesions were wiped off gently by cotton swabs. Repeated swabbing was performed if infection persisted or new lesions were observed at follow-up. To prevent secondary bacterial infection, 0.3% norfloxacin or 0.25 % chloramphenicol were prescribed.

RESULTS

The mean age was 52.2 years. All patients had the characteristic disseminated, punctate, slightly elevated, white epithelial lesions. The denser white lesions could be removed easily after gentle swabbing, and most epithelium remained intact. The 10 cases with positive polymerase chain reaction results were all identified to be Vittaforma corneae. The mean number of corneal swabbing was 3.3, and the mean disease resolution time was 6.6 days. No patients had recurrence or loss of visual acuity at last follow-up.

CONCLUSIONS

Repeated swabbing effectively can eradicate corneal epithelial microsporidial lesions in approximately 1 week. It is easy to perform, less painful, and more acceptable for the patients.