Molecular analysis of acute hemorrhagic conjunctivitis in a tertiary care hospital, Kalburgi district, Karnataka 2023.

INTRODUCTION

Viral infections are the predominant cause of acute hemorrhagic conjunctivitis (AHC) across the globe. From July to August of 2023, a large-scale conjunctivitis outbreak was witnessed in India, affecting a large number of individuals. The present study was initiated to identify the causative agent responsible for the AHC outbreak in Kalburgi district of Karnataka state.

METHODOLOGY: Conjunctival and throat swabs were collected from AHC patients from a tertiary care hospital in Kalburgi from August to September 2023. After total viral RNA extraction from all the samples, reverse transcriptase PCR was performed using 5' non-coding regions of the enterovirus (EV) genome. The positive samples were further subjected to PCR using EV type-specific primers of Coxsackie A-24 variant (CA24v) and enterovirus-70 (EV-70). EV negative samples were also tested for human adenovirus. Five representative CA24v-positive samples were subjected to partial sequencing and phylogenetic analysis.

RESULTS

Thirty-three AHC patient samples were included in the testing and analysis. EV was detected among 54.5 % (18/33) of the patients and all were found to be CA24v, while no EV-70 or human adenovirus was detected. Partial 3C-proteinase sequencing revealed that the CA24v strains from Kalburgi were closely clustered and had 99 % sequence identity with CA24v strains reported from China in 2023. However, the Kalburagi strains were 90.3-93.2 % identical to previously reported Indian strains.

CONCLUSION

To summarize, CA24v was identified as an etiological agent responsible for the recent acute hemorrhagic conjunctivitis outbreak in Kalburgi. The CA24v strain detected was closely related to the currently circulating Asian strains.