Virushepatitis

Viral hepatitis refers to liver inflammation caused by infection with hepatitis viruses. The main human pathogens are hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). Transmission routes differ: HAV and HEV are typically spread by the fecal-oral route, often through contaminated food or water; HBV, HCV, and HDV are primarily transmitted via blood, sexual contact, or from mother to child, with HDV requiring HBV coinfection.

Clinical presentation ranges from no symptoms to acute illness with fever, malaise, anorexia, abdominal pain, jaundice, and elevated liver enzymes. HAV and HEV usually cause an acute, self-limited illness, whereas HBV, HCV, and HDV can become chronic infections, potentially leading to cirrhosis and hepatocellular carcinoma. Chronic infection is most common with HBV and HCV; HDV can cause severe disease in coinfection or superinfection.

Diagnosis relies on laboratory testing for viral markers along with liver function tests. Serology detects specific antibodies or antigens (for example, anti-HAV IgM, HAV RNA, HBsAg, anti-HBs, anti-HBc IgM/IgG, anti-HCV with HCV RNA, HDV RNA). PCR is used for RNA viruses. Imaging and elastography may assess liver architecture and fibrosis; liver biopsy is less common today.

Treatment depends on the infecting virus. Acute HAV and HEV infection usually require supportive care. Chronic HBV is treated with nucleos(t)ide analogs such as entecavir or tenofovir; chronic HCV is often curable with direct-acting antivirals. HDV treatment centers on interferon-based regimens and adjunctive therapies. Vaccination provides strong prevention for HAV and HBV; vaccines for HEV exist but are not widely used globally. Prevention also includes safe food and water practices, blood-safety measures, and harm-reduction strategies to reduce transmission.