https://www.selleckchem.com/products/l-histidine-monohydrochloride-monohydrate.html tory bacterial infections are the most frequent and occur early after admission. Respiratory infection is associated with advanced liver disease, severe hepatic encephalopathy and a need for a nasogastric tube, orotracheal intubation for endoscopy or esophageal balloon tamponade. Bacterial infections develop during hospitalization in close to 20% of patients with acute variceal bleeding despite antibiotic prophylaxis. Respiratory bacterial infections are the most frequent and occur early after admission. Respiratory infection is associated with advanced liver disease, severe hepatic encephalopathy and a need for a nasogastric tube, orotracheal intubation for endoscopy or esophageal balloon tamponade. Rat hepatitis E virus (Orthohepevirus species C; HEV-C1) is an emerging cause of viral hepatitis in humans. HEV-C1 is divergent from other HEV variants infecting humans that belong to Orthohepevirus species A (HEV-A). This study assessed HEV-C1 antigenic divergence from HEV-A and investigated the impact of this divergence on infection susceptibility, serological test sensitivity, and vaccine efficacy. Immunodominant E2s peptide sequences of HEV-A and HEV-C1 were aligned. Interactions of HEV-C1 E2s and anti-HEV-A monoclonal antibodies (mAbs) were modeled. Recombinant peptides incorporating E2s of HEV-A (HEV-A4 p239) and HEV-C1 (HEV-C1 p241) were expressed. HEV-A and HEV-C1 patient sera were tested using antibody enzymatic immunoassays (EIA), antigen EIAs, and HEV-A4 p239/HEV-C1 p241 immunoblots. Rats immunized with HEV-A1 p239 vaccine (Hecolin), HEV-A4 p239 or HEV-C1 p241 peptides were challenged with a HEV-C1 strain. E2s sequence identity between HEV-A and HEV-C1 was only 48%. There was low conservation a combination of methods, we showed that HEV-C1 is highly divergent from the usual cause of human hepatitis (HEV-A). This divergence reduces the capacity of existing tests to diagnose HEV