The 16th-century mummy of a Korean child that was found in that country with
relatively preserved internal organs has been the basis for an Israeli-South
Korean discovery of a unique genotype of the hepatitis B virus that is common in
Southeast Asia.
The team, which conducted a genetic analysis on a liver
biopsy, could use their discovery to study the evolution of potentially fatal
chronic hepatitis B and help understand the spread of the virus, possibly from
Africa to East Asia.
It also may shed further light on the migratory
pathway of hepatitis B in the Far East from China and Japan to Korea as well as
to other regions in Asia and Australia, where it is a major cause of cirrhosis
of the liver and liver cancer.
The Israeli and Korean scientists reported
their reconstruction of the ancient hepatitis B virus genetic code – is the
oldest full viral genome described in the scientific literature to date – in the
May 21 edition of the journal Hepatology.
The mummy was found in a small
family estate in an area that is undergoing reconstruction. It underwent
many tests including laparoscopy (keyhole imaging using an optic fiber and tiny
video camera inserted into the abdomen), during which the biopsy sample was
taken.
Carbon 14 tests of the mummy’s clothing suggest that the boy lived
some 500 years ago during the Korean Joseon Dynasty. The viral DNA sequences
recovered from the liver biopsy enabled the scientists to map the entire ancient
hepatitis B viral genome.
Using molecular genetic techniques, the
researchers compared the ancient DNA sequences with contemporary viral genomes
disclosing distinct differences. The changes in the genetic code are believed to
result from spontaneous mutations and possibly environmental pressures during
the virus evolutionary process. Based on the observed mutations rates over time,
the analysis suggests that the reconstructed mummy’s hepatitis B virus DNA had
its origin anywhere between 3,000 to 100,000 years ago.
The hepatitis B
virus is transmitted through the contact with infected body fluids – from
carrier mothers to their babies, through sexual contact and intravenous drug
abuse.
According to the World Health Organization, there are over 400
million carriers of the virus worldwide, mostly in Africa, China and South
Korea, where up to 15 percent of the population are carriers of the virus.
Although it can kill, there are effective vaccines given to babies that – due to
universal immunization of Israeli and South Korean infants against the virus –
has lead to a massive decline in the incidence of infection.
The
scientists are from the Hebrew University of Jerusalem’s Koret School of
Veterinary Medicine, the Robert H. Smith Faculty of Agriculture, Food and
Environment; the Hebrew University’s Faculty of Medicine, the Hadassah Medical
Center’s liver unit; and Dankook University and Seoul National University in
South Korea.
The lead researchers were Dr. Gila Kahila Bar-Gal of the
Koret School, Prof. Daniel Shouval of the liver unit; Dr. Myeung Ju Kim
of Dankook; Dr. Dong Hoon Shin of Seoul National University; Prof Mark Spigelman
of HU’s parasitology department; and Dr. Paul Grant of University College
London.