Project Summary/Abstract HEV is an emerged zoonotic pathogen. It infects nearly 20 million people annually, resulting in approximately 70,000 deaths yearly (2). In the U.S. the virus is believed to be endemic to swine herds with the virus making its way into the commercial food supply (3, 4). Genotype 3 HEV is increasingly being seen as a pathogen afflicting immunocompromised populations including those with HIV, cancer, and solid organ transplant (SOT) recipients (5-9) and mortality can reach up to 30% in pregnant women (10) . Currently chronic HEV patients are treated with reduction of immunosuppression risking organ rejection in SOT patients or with ribavirin therapy. There have been reported incidents of ribavirin failure both during and post treatment leading to poor patient outcomes and ribavirin is contraindicated during pregnancy (11-13). Additionally, single nucleotide variants (SNVs) have been identified from ribavirin treatment failure that enhance HEV replication (14). New therapeutics that specifically target HEV, are amenable to treating at risk populations, and prevent complications such as organ rejection while combatting the emergence of new ribavirin resistant HEV strains are essential to improving outcomes in HEV patients. Emerging technologies such as CRISPR/Cas13 which can specifically target and degrade viral RNA along with liver targeting nanoparticles may be an ideal tool to treat HEV infections. Our proposal will test rationally designed CRISPR RNA targets for efficacy using a newly developed cell culture system from our laboratory followed by studies on efficient liver targeting of the therapeutic using cutting edge lipid nanoparticle technologies in a natural host pig model. If successful, these new technologies could be placed into clinical trials as new therapies to combat HEV infection.