Delta hepatitis: molecular biology and clinical and epidemiological features

Abstract

Hepatitis delta virus, discovered in 1977, requires the help of hepatitis B virus to replicate in hepatocytes and is an important cause of acute, fulminant, and chronic liver disease in many regions of the world. Because of the helper function of hepatitis delta virus, infection with it occurs either as a coinfection with hepatitis B or as a superinfection of a carrier of hepatitis B surface antigen. Although the mechanisms of transmission are similar to those of hepatitis B virus, the patterns of transmission of delta virus vary widely around the world. In regions of the world in which hepatitis delta virus infection is not endemic, the disease is confined to groups at high risk of acquiring hepatitis B infection and high-risk hepatitis B carriers. Because of the propensity of this viral infection to cause fulminant as well as chronic liver disease, continued incursion of hepatitis delta virus into areas of the world where persistent hepatitis B infection is endemic will have serious implications. Prevention depends on the widespread use of hepatitis B vaccine. This review focuses on the molecular biology and the clinical and epidemiologic features of this important viral infection.

An outbreak of fulminant hepatitis delta in the Waorani, an indigenous people of the Amazon basin of Ecuador.

“…9,15 Of interest, both of these patients were young children. The remainder of the individuals with HDV had a serologic pattern that was consistent with HDV superinfection of a chronic carrier of HBV.…”

“…5,6,15 The availability of hepatitis B vaccine, the early lack of serologic data, and the difficulties involved in traveling to remote villages led to the initial decision to vaccinate all the Waorani while simultaneously investigating the cause of the outbreak and the prevalence of HBV infection. Teaching was repeatedly done in every village regarding methods to limit the spread of HBV.…”

“…11 Superinfection of HBV carriers with HDV, or simultaneous infection with HBV and HDV, has been found to cause fulminant and sometimes fatal hepatitis. [4][5][6]9,[12][13][14][15] Evidence of HDV infection has been found in various South American groups in which HBV infection is endemic 1,[3][4][5]7,16 and not in others. 2,8 To our knowledge, HDV infection has never before been reported in Ecuador.…”

Seroprevalence of viral hepatitis in Tanzanian adults

“…Hepatitis delta virus also contributes to the disease burden among individuals infected with hepatitis B virus, upon which it is dependent for replication (Polish et al 1993). The importance of a sixth hepatitis virus, hepatitis G, is less certain (Yashina et al 1997).…”

Study on seroprevalence of hepatitis delta in a regional hospital in western Turkey

“…Detection by polymerase chain reaction (PCR) indicates acute infection as well as ongoing infection. Loss of HDV-RNA is usually accompanied by a progressive decrease in anti-HD IgM titers [8]. The first choice in treatment is interferon, but response to treatment is 10% to 30% [9,10].…”