Apollo Rising: Acute Conjunctivitis Outbreak in India, 2022

Abstract

Purpose: The purpose of this study was to identify pathogens associated with the 2022 conjunctivitis outbreak in Tamil Nadu, India. Methods: This prospective study was conducted in November 2022. Patients with presumed acute infectious conjunctivitis presenting to the Aravind Eye Clinic in Madurai, India, were eligible. Anterior nares and conjunctival samples from participants were obtained and processed for metagenomic RNA deep sequencing (RNA-seq). Results: Samples from 29 patients were sequenced. A pathogen was identified in 28/29 (97%) patients. Coxsackie virus A24v, a highly infectious RNA virus, was the predominant pathogen and detected in 23/29 patients. Human adenovirus D (HAdV-D), a DNA virus commonly associated with conjunctivitis outbreaks, was detected in the remaining patients (5/29). Hemorrhagic conjunctiva was documented in both HAdV-D and Coxsackie virus A24v affected patients but was not the predominant clinical presentation. Phylogenetic analysis of Coxsackie virus A24v revealed a recent divergence from the 2015 outbreak. Conclusions: Coxsackie virus A24v and HAdV-D were cocirculating during the 2022 conjunctivitis outbreak in Tamil Nadu, India. Clinical findings were similar between patients with HAdV-D and Coxsackie virus A24v–associated conjunctivitis. As high-throughput sequencing technologies become more readily available and cost-effective, unbiased pathogen surveillance may prove useful for outbreak surveillance and control.