VIRAL INFECTIONS: CHARACTERISTICS OF HEPATITIS VIRUSES AND LABORATORY DIAGNOSIS OF THE DISEASES THEY CAUSE

Abstract

Background: Viral hepatitis, primarily caused by hepatotropic viruses (HAV, HBV, HCV, HDV, and HEV), represents a major global public health problem, leading to acute and chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC). Objective: To analyze the key virological characteristics of the five main hepatitis viruses and to describe the contemporary laboratory diagnostic methods used for their identification and clinical management. Methods: A narrative review was conducted based on peer-reviewed literature and international guidelines from databases such as PubMed, Scopus, and WHO reports. Results: Each hepatitis virus exhibits distinct structural, genomic, and transmission characteristics. HAV and HEV cause acute, self-limiting enterically-transmitted infections. HBV, HCV, and HDV (a defective virus requiring HBV) cause parenterally transmitted chronic infections. Laboratory diagnosis relies on a combination of serological assays detecting specific viral antigens and antibodies (e.g., HBsAg, anti-HCV) and molecular methods (PCR, qPCR) for viral nucleic acid detection, quantification, and genotyping. Conclusion: Accurate differential diagnosis of viral hepatitis is critical for appropriate patient management. A stepwise laboratory algorithm utilizing serology for initial screening followed by molecular confirmation and monitoring is the cornerstone of modern diagnostics.