The species specificity of several important human viruses restricted the development of informative animal models for studies of viral pathogenesis and immunity. Prof Dr Amit Kapoor's group used viruses infecting wild rats to develop informative lab animal models for their human homologs. Amit believes that studies of viruses in their fully immunocompetent natural host are highly relevant for understanding the host-virus interactions that determine the nature of virus infection, immunity and pathogenesis. For example, he and his team used an HCV-like virus infecting wild rats (RHV) to develop lab mouse and rat models that are now used by several groups interested in characterising immunity, persistence and pathogenesis of HCV. His lab is using this rat-HCV-like virus to define immune correlates of protection against chronic HCV infection. The team showed that RHV mirrors HCV hallmarks like hepatotropic infection, evading immunity to develop life-long persistence, and slow-progressing liver disease (see their publications in Hepatology, Science, Journal of Virology, Nature Communications, and Plos Pathogens). Thus, the RHV-rat model is helpful for testing proof-of-concept vaccination strategies to prevent chronic HCV infection. Amit and his team recently developed rat and mouse MHC tetramers to study rat-HCV-specific T cells, their phenotype, function, and fate during acute and persistent infection. In addition to conventional cell phenotyping and functional assays for T cell analysis, their lab routinely uses bulk and single-cell RNA-seq to gain new insights into the nature of liver responses and immunity associated with virus clearance and persistence in the liver. They are extending their work to develop animal models for other human viruses that lack an informative and tractable animal model, like GBV-C or human pegivirus, TTV, and hepatitis E virus.