Identification of coxsackievirus A-24 GIV C5 strain as the cause of acute hemorrhagic conjunctivitis outbreak in Hyderabad, India in 2022.

Viral infection is frequently the cause for acute hemorrhagic conjunctivitis (AHC) epidemics. AHC can result from adenoviruses, with enterovirus 70 and coxsackievirus A24 being the primary agents. AHC was initially identified in Ghana in 1969, caused by enterovirus 70 and leading to a global pandemic. Since 2000, outbreaks of AHC linked to coxsackievirus A24 variant have been documented in Spain, Pakistan, Singapore, India, Korea, and China. A sudden surge of conjunctivitis cases reported in October 2022 in and out of the Hyderabad region. This infection presented with usual symptoms of redness of the eyes, discharge, pain in the eyes and crusting. Occular swab samples from 110 patients were collected in order to identify and characterize the virus that was causing the epidemic. We examined adenovirus, enterovirus, COVID-19 and Herpes Simplex Virus by using commercially kits available at the hospital. Conserved regions in the enteroviral 5'-UTR and VP2 gene were analyzed further for characterization of serotype at the National apex laboratory. None of them was found positive except Enterovirus in 16.36 % (18/110) of the patients. From enterovirus-positive samples, the coxsackievirus A24 was observed in all 18 positive samples. These clinical isolates constitute a new lineage cluster associated with genotype IV-C5, according to additional sequencing of the full-length VP2 genes and subsequent phylogenetic analysis. In conclusion, the current outbreak of acute haemorrhagic conjunctivitis in Hyderabad, India was traced to the coxsackievirus A24 strain GIV C5.

Emergence of Recombinant Subclade D3/Y in Coxsackievirus A6 Strains in Hand-Foot-and-Mouth Disease (HFMD) Outbreak in India, 2022.

Coxsackievirus-A6 (CV-A6) is responsible for more severe dermatological manifestations compared to other enteroviruses such as CV-A10, CV-A16, and EV-A71, causing HFMD in children and adults. Between 2005 and 2007, the recombinant subclade D3/RF-A started to expand globally, and a CV-A6 pandemic started. The study aimed to conduct whole-genome sequencing (WGS) of an isolated CV-A6 strain from currently circulating HFMD cases from India in 2022. Gene-specific RT-PCR and sequencing were used to perform molecular characterization of the isolated virus. Confirmation of these isolates was also performed by transmission electron microscopy and WGS. Among eleven positive clinical enterovirus specimens, eight CV-A6 strains were successfully isolated in the RD cell line. Isolates confirmed the presence of the CV-A6 strain based on VP1 and VP2 gene-specific RT-PCR. Sequences of isolates were clustered and identified as the novel CV-A6 strain of the D3/Y sub-genotype in India. The studies revealed that the D3/Y sub-genotype is being introduced into Indian circulation. The predicted putative functional loops found in VP1 of CV-A6 showed that the nucleotide sequences of the amino acid were a remarkably conserved loop prediction compatible with neutralizing linear epitopes. Therefore, this strain represents a potential candidate for vaccine development and antiviral studies.