Background

Molecular diagnostics such as pathogen-directed PCRs have transformed testing for ocular infections since the late 1990s. Although these assays remain important diagnostic tools for samples with low biomass, the lack of diagnostic range motivates alternative molecular approaches for ocular infections. The aim of this study was to determine the performance of a high-throughput RNA sequencing approach, RNA-seq, to detect infectious agents in ocular samples from patients with presumed ocular infections.

Methods

We compared the performance of RNA-seq to pathogen-directed PCRs using remnant nucleic acids from 41 aqueous or vitreous samples of patients with presumed ocular infections. Pathogen-directed PCRs were performed at the CLIA-certified Stanford Clinical Virology Laboratory. RNA-seq was performed in a masked manner at the Proctor Foundation at the University of California San Francisco. Percent positive and negative agreement between the two testing approaches were calculated. Discordant results were subjected to orthogonal testing.

Results

The positive percent agreement between RNA-seq and pathogen-directed PCRs was 100% (95% confidence interval (CI): 78.5%-100%). The negative percent agreement was 92.6% (95% CI: 76.6%-97.9%). RNA-seq identified pathogens not on the differential diagnosis for 9.7% (4/41) of the samples. Two pathogens solely identified with RNA-seq were confirmed with orthogonal testing.

Conclusions

RNA-seq can accurately identify common and rare pathogens in aqueous and vitreous samples of patients with presumed ocular infections. Such an unbiased approach to testing has the potential to improve diagnostics although practical clinical utility warrants additional studies.

Background

Viral conjunctivitis (pink eye) can be highly contagious and is of public health importance. There remains significant debate whether SARS-CoV-2 can present as a primary conjunctivitis. The aim of this study was to identify pathogens associated with outpatient infectious conjunctivitis during the COVID-19 Delta surge.

Methods

This prospective study was conducted in the spring and summer months of 2021. 106 patients with acute conjunctivitis who presented to the Aravind Eye Center in Madurai, India were included. One anterior nasal swab and one conjunctival swab of each eye were obtained for each enrolled patient. Samples were subsequently processed for unbiased metagenomic RNA deep sequencing (RNA-seq). Outcomes included clinical findings and codetection of other pathogens with SARS-CoV-2 in patients with conjunctivitis.

Results

Among the 13 patients identified with human coronavirus RNA fragments in their swabs, 6 patients had SARS-CoV-2 infection, 5 patients had coinfections of SARS-CoV-2 and human adenovirus (HAdV), 1 patient had a coinfection with human coronavirus OC43 and HAdV, and 1 patient had a coinfection of Vittaforma corneae and SARS-CoV-2. 30% had bilateral disease and symptoms on presentation. Petechial hemorrhage was noted in 33% of patients with SARS-CoV-2 infection. No patients with SARS-CoV-2 or SARS-CoV-2 and HAdV infections had subepithelial infiltrates on presentation. All patients denied systemic symptoms.

Conclusions

Among the patients presented with conjunctivitis associated with human coronavirus infection, over 50% of the patients had co-infections with other circulating pathogens, suggesting the public-health importance of broad pathogen testing and surveillance in the outpatient conjunctivitis population.

Background

Seasonal outbreaks of infectious conjunctivitis remain a public health issue. Determination of outbreak etiologies in the context of a worldwide pandemic may provide useful information to guide public health strategies. The aim of this study was to identify pathogens associated with outpatient infectious conjunctivitis during the COVID-19 Delta surge.

Methods

This prospective study was conducted from April 2021 to September 2021. All outpatients presenting to the Aravind Eye Center (Madurai, India) with signs and symptoms consistent with acute infectious conjunctivitis were eligible. Three swabs were obtained from each participant: one from each conjunctiva and one from the anterior nares. Samples were processed for metagenomic RNA deep sequencing (RNA-seq).

Results

Samples from 106 study participants were sequenced. The most common presenting symptoms were tearing (86%) and itching (71%). Preauricular lymphadenopathy was present in 38% of participants. 20% of participants had close contacts with similar symptoms. Systemic symptoms such as coughing, runny nose, vomiting or diarrhea were uncommonly reported. 60% of all participants used some medicated eye drops upon enrollment. 75% of study participants demonstrated infection with human adenovirus D (HAdV-D). 11% of conjunctivitis was associated with SARS-CoV-2. 15% had no definitive pathogen detected. 8% of all participants had codetection of more than one pathogen on RNA-seq.

Conclusions

During the COVID-19 Delta surge in India, HAdV-D was the most common pathogen associated with infectious conjunctivitis. SARS-CoV-2 was the second most common associated pathogen. Seasonal surveillance may be necessary for the determination of emerging and reemerging pathogens responsible for infectious conjunctivitis.