Epidemiology and Long-Term Consequences of Hepatitis Delta Virus Infection in the Yucpa Indians of Venezuela

Abstract

To define better the epidemiology and clinical impact of hepatitis delta virus (HDV) infection among hepatitis B virus (HBV) carriers in less developed countries, the authors prospectively studied a cohort of 216 Yucpa Indian HBV carriers in Venezuela. HBV carriers were followed regularly between 1983 and 1988 by physical examination, laboratory testing for liver enzymes and HBV and HDV markers, and epidemiologic history. Among the cohort, 74 (34%) were initially positive for HDV infection, and 35 additional persons became infected during the study. Risk factors for new HDV infection included living in southern Yucpa villages; being young adults (15-19 years) or young children (1-9 years), and living in a household with a person with acute HDV infection. Persons with HDV infection were at high risk of developing chronic liver disease; 56% of HDV-infected persons had moderate-to-severe chronic liver disease at the end of the study compared with none of the HBV carriers without HDV infection. Mortality rates were 6.9% and 8.8% per year, respectively, among initially HDV-positive HBV carriers and those with new HDV infection, because of rapidly progressive chronic liver disease and fulminant hepatitis; mortality was significantly lower in HBV carriers without HDV infection and in non-HBV carriers. HDV superinfection is a devastating disease in HBV carriers in tropical South America. Prevention of HBV infection with hepatitis B vaccine is the best available tool to reduce the impact of this problem.

Co-evolution of KIR2DL3 with HLA-C in a human population retaining minimal essential diversity of KIR and HLA class I ligands

“…The Yucpa descend from Asian migrants who arrived in Alaska approximately 15,000 years ago and peopled the Americas through population expansion and southward migration (14). During the approximately 750 generations following the initial bottleneck (13) of population contraction and expansion caused by epidemics of infectious disease, most recently an epidemic of combined hepatitis B and D (19). We have defined the system of KIR and HLA class I ligands in the surviving Yucpa population.…”

“…In the recent past, the Yucpa population expanded from 1,500 in 1960 to 10,000 in 2001. Epidemics of measles and malaria in the 1960s, were followed in 1979-1981 by an epidemic of combined hepatitis B and D that caused considerable mortality of the young (19). The 61 blood samples we studied were donated in 1993 by survivors of this epidemic (20).…”

Chronic hepatitis B

“…The availability of HBV vaccines and public health education on prevention of transmission of HBV infection has led to a significant decline in the prevalence of HDV infection in the past decade. 88,89 HDV infection can occur in two forms. The first form is caused by the coinfection of HBV and HDV; this usually results in a more severe acute hepatitis with a higher mortality rate than is seen with acute hepatitis B alone, 87,90 but rarely results in chronic infection.…”

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

“…Serologic markers for HBV infection have been found at rates of 25 to 83% among Amazonian peoples in Bolivia, Brazil, Peru, and Venezuela. [1][2][3][4][5][6][7][8][9] A study of the Waorani, an indigenous people of the Amazon basin of Ecuador, reported antibodies to the Hepatitis B core (HBc) in 74% of people living in three villages, but none of those living in a fourth community. 10 Infection with hepatitis D virus (HDV) can only occur in individuals who are also infected with HBV.…”