D Is for Delta: A Primer on Hepatitis D Virus
D Is for Delta: A Primer on Hepatitis D Virus
HDV infection always occurs in conjunction with HBV infection. Transmission is parenteral, and many infected individuals are intravenous drug users or recipients of multiple blood products. Associations with poor hygiene and intrafamilial spread have been noted. Perinatal transmission is uncommon. Although sexual transmission of HDV can occur, it is less likely than the transmission of HBV alone.
HDV infection has an incubation period of 28-140 days, with typical onset of symptoms at 3-7 weeks. The virus is not cytopathic, and hepatic injury is thought to be related to immune-mediated cytotoxicity of infected hepatocytes. Viral load does not correlate with the abnormal aminotransferase levels of infected patients.
The spectrum of disease with HDV infection can range from asymptomatic infection to fulminant hepatitis. Fulminant hepatitis is more likely with simultaneous coinfection with HBV and HDV than with HBV infection alone. The severity of clinical outcome may also vary on the basis of the genotypes of the infecting HBV and of HDV. Chronic hepatitis from coinfection of HBV and HDV is uncommon and is more likely to develop from superinfection with HDV in an HBV-infected patient. Superinfection often results in histologically progressive disease, and as many as 80% of superinfected patients will develop cirrhosis in 5-10 years. Chronically HDV/HBV-infected patients may also be at increased risk for hepatocellular carcinoma.
Onset and Clinical Course of Hepatitis D Infection
HDV infection always occurs in conjunction with HBV infection. Transmission is parenteral, and many infected individuals are intravenous drug users or recipients of multiple blood products. Associations with poor hygiene and intrafamilial spread have been noted. Perinatal transmission is uncommon. Although sexual transmission of HDV can occur, it is less likely than the transmission of HBV alone.
HDV infection has an incubation period of 28-140 days, with typical onset of symptoms at 3-7 weeks. The virus is not cytopathic, and hepatic injury is thought to be related to immune-mediated cytotoxicity of infected hepatocytes. Viral load does not correlate with the abnormal aminotransferase levels of infected patients.
The spectrum of disease with HDV infection can range from asymptomatic infection to fulminant hepatitis. Fulminant hepatitis is more likely with simultaneous coinfection with HBV and HDV than with HBV infection alone. The severity of clinical outcome may also vary on the basis of the genotypes of the infecting HBV and of HDV. Chronic hepatitis from coinfection of HBV and HDV is uncommon and is more likely to develop from superinfection with HDV in an HBV-infected patient. Superinfection often results in histologically progressive disease, and as many as 80% of superinfected patients will develop cirrhosis in 5-10 years. Chronically HDV/HBV-infected patients may also be at increased risk for hepatocellular carcinoma.
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