Conjunctivitis can be surprisingly difficult to diagnose correctly, considering its telltale signs and symptoms don’t always correlate with any one specific etiology.1 In fact, one study found clinicians can be wrong about the underlying cause as much as 50% of the time.2 An international team of researchers think they have found a way to solve this problem—with gene sequencing.3
The team applied an analytical approach called metagenomic RNA deep sequencing (MDS) to conjunctival swabs from patients with presumed infectious conjunctivitis and used masked data interpreters to identify the pathogens causing the clinical presentations.3
They found the analysis identified pathogens in 12 of the 14 patient swabs. Most of them (10 of 14) were positive for human adenovirus, while the remaining two were identified as a fungal species, Vittaforma corneae. The team then independently verified the findings using a CLIA-certified laboratory for the adenovirus samples and a pathogen-PCR test for the fungal etiologies. The researchers noted the technique can reliably identify both common and rare pathogens causing conjunctivitis.3
“The unbiased nature of metagenomic RNA deep sequencing allowed an expanded scope of pathogen detection, including fungal species not commonly associated with acute conjunctivitis,” they said in the study. The sequencing may also prove useful for identifying the pathogen when the load is too low for direct identification.3
1. Kanski JJ. Clinical Ophthalmology: A Systematic Approach. 6th ed. Edinburgh: Butterworth-Heinemann/Elsevier; 2007.
2. Azari AA, Barney NP. Conjunctivitis: a systematic review of diagnosis and treatment. JAMA. 2013;310(16):1721-9.
3. Lalitha P, Seitzman GD, Kotecha R, et al. Unbiased pathogen detection and host gene profiling for conjunctivitis. Ophthalmology. April 3, 2019. [Epub ahead of print].