Hepatitis B Evolution Revealed From a Mummy

Scientists have sequenced the complete genome of an ancient strain of the Hepatitis B virus (HBV), shedding new light on this deadly, complex pathogen.

This finding is based on genomic data extracted from the mummified remains of a small child buried in the Basilica of Saint Domenico Maggiore in Naples, Italy.

Little is known about HBV’s origin. But, this discovery confirms the suggestion that HBV has existed in humans for centuries.

Hepatitis B is a liver infection caused by the Hepatitis B virus. Hepatitis B is transmitted when blood, semen, or another body fluid from a person infected with the Hepatitis B virus enters the body of someone who is not infected.

"These data emphasize the importance of molecular approaches to help identify the presence of key pathogens in the past, enabling us to better constrain the time they may have infected humans," explains Hendrik Poinar, an evolutionary geneticist with the McMaster Ancient DNA Centre and a principal investigator with the Michael G. DeGroote Institute for Infectious Disease Research.

Using small tissue samples of skin and bone, scientists were able to tease out tiny fragments of DNA and then stitch together pieces of genetic information to create a much more complete picture.

While viruses often evolve very rapidly, researchers suggest that this ancient strain of HBV has changed little over the last 450 years and that the evolution of this virus is complex.

While the team found a close relationship between the ancient and modern strains of HBV, both are missing what is known as a temporal structure.

In other words, this phylogenetic pattern indicates that the genotypes of HBV diversified long before the 16th century, and enables comparison of potential pathogenic similarities between modern and ancient HBV.

The Centers for Disease Control and Prevention (CDC) report that for some people, hepatitis B is an acute, or short-term, illness. But for others, it can become a long-term, chronic infection. Chronic Hepatitis B can lead to serious health issues, like cirrhosis or liver cancer.

The risk for chronic infection is related to age at infection:

• approximately 90% of infected infants become chronically infected
• compared with 2%–6% of adults.

Approximately 70 percent of persons with chronic HBV infection in the United States are foreign-born, and the prevalence among foreign-born persons is 3 to 5 percent, compared with 0.3 percent in the general population.

The best way to prevent Hepatitis B is by getting vaccinated.

Two single-antigen HBV vaccines and two combination vaccines are currently licensed in the United States:

Single-antigen hepatitis B vaccines:

• ENGERIX-B
• RECOMBIVAX HB

Combination vaccines:

• PEDIARIX: Combined hepatitis B, diphtheria, tetanus, acellular pertussis (DTaP), and inactivated poliovirus (IPV) vaccine. Cannot be administered before age 6 weeks or after age 7 years.
• TWINRIX: Combined Hepatitis A and hepatitis B vaccine. Recommended for persons aged ≥18 years who are at increased risk for both Hepatitis A virus and HBV infections.

The CDC Vaccine Price List provides the private sector hepatitis vaccine prices for general information, and vaccine discounts can be found here.

Vaccines, like any medicine, can have side effects, says the CDC. You are encouraged to report negative side effects of vaccines to the FDA or CDC.

"The more we understand about the behavior of past pandemics and outbreaks, the greater our understanding of how modern pathogens might work and spread, and this information will ultimately help in their control," says professor Poinar.

The findings are published online in the journal PLOS Pathogens. Wade Hemsworth, Manager, Media Relations, McMaster University, hemswor@mcmaster.ca

Funding: ECH and HNP are funded by grant GNT1065106 from the National Health and Medical Research Council, Australia (https://www.nhmrc.gov.au/). ECH is funded by grant GNT1037231 from the National Health and Medical Research Council, Australia (https://www.nhmrc.gov.au/). ZPR is supported through an Australian Postgraduate Award (https://education.gov.au/australian-postgraduate-awards). HNP is supported by McMaster University (http://www.mcmaster.ca/), and through a National Sciences and Engineering Research Council of Canada Canada Research Chair (http://www.nserc-crsng.gc.ca/index_eng.asp).

The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript. The researchers did not disclose any conflicts of interest.