Phylogenetic Analysis of Spread of Hepatitis C Virus Identified during HIV Outbreak Investigation, Unnao, India

An HIV outbreak investigation during 2017-2018 in Unnao District, Uttar Pradesh, India, unearthed high prevalence of hepatitis C virus (HCV) antibodies among the study participants. We investigated these HCV infections by analyzing NS5B and core regions. We observed no correlation between HIV-HCV viral loads and clustering of HCV sequences, regardless of HIV serostatus. All HCV isolates belonged to genotype 3a. Monophyletic clustering of isolates in NS5B phylogeny indicates emergence of the outbreak from a single isolate or its closely related descendants. The nucleotide substitution rate for NS5B was 6 x 10(-3) and for core was 2 x 10(-3) substitutions/site/year. Estimated time to most recent common ancestor of these isolates was 2012, aligning with the timeline of this outbreak, which might be attributable to unsafe injection practices while seeking healthcare. HIV-HCV co-infection underlines the need for integrated testing, surveillance, strengthening of healthcare systems, community empowerment, and molecular analyses as pragmatic public health tools.

Automated summary

An investigation into an HIV outbreak in Unnao District, Uttar Pradesh, India from 2017-2018 revealed a high prevalence of hepatitis C virus (HCV) antibodies among the study participants. Analysis of HCV infections showed no correlation between HIV-HCV viral loads and clustering of HCV sequences, regardless of HIV serostatus. The outbreak was traced back to a single isolate or closely related descendants, with all HCV isolates belonging to genotype 3a. The estimated time of most recent common ancestor for these isolates aligns with the outbreak timeline, suggesting unsafe injection practices during healthcare seeking as a possible cause. The presence of HIV-HCV co-infection highlights the need for integrated testing, surveillance, strengthening of healthcare systems, community empowerment, and molecular analyses as practical public health tools.