Hendrik N. Poinar
A recent DNA analysis of 450-year-old mummified remains belonging to a small child in Naples, Italy, revealed that the child — who was thought to have the oldest evidence of smallpox in Medieval remains — actually had hepatitis B virus infection.
Hendrik N. Poinar, PhD, evolutionary geneticist at the McMaster Ancient DNA Centre and Michael G. DeGroote Institute for Infectious Disease Research at McMaster University, and colleagues said this new information will help shed light on the evolution of HBV, which infects approximately 350 million people worldwide, resulting in an estimated 1 million deaths each year.
“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,” Poinar said in a press release. “The more we understand about the behavior of past pandemics and outbreaks, the greater out understanding of how modern pathogens might work and spread, and this information will ultimately help in their control.”
The mummified remains of a small child buried in the Basilica of Saint Domenico Maggiore in Naples, Italy. Previous analysis of the 16th century remains had suggested the child was infected with smallpox, in what had been believed to be the earliest dated evidence of the virus. Advanced sequencing techniques now suggest the child was actually infected with hepatitis.
Source: Gino Fornaciari, University of Pisa
According to the researchers, data on the origin and evolution of HBV are limited.
“Given its global prevalence and the presence of related viruses in other mammals, including nonhuman primates, it is commonly believed that the virus has existed in human populations for many thousands of years,” they wrote in PLoS Pathogens.
The mummified child, approximately 2 years of age, was exhumed from the sacristy of the Basilica of Saint Domenico Maggiore in Naples between 1983 and 1985. An initial analysis revealed the child had a vesiculopustular rash on the arm, body and face, indicating a possible smallpox infection. Electron microscopic imaging supported this evidence, according to Poinar and colleagues.
In a more recent analysis, however, the researchers used advanced sequencing techniques and DNA testing to examine small tissue samples of the child. The researchers found no evidence of Variola virus — the agent of smallpox — but instead, DNA fragments showed the child was infected with HBV.
“Given our results, a new interpretation is that the child was not suffering from smallpox at the time of death, but rather Gianotti-Crosti syndrome caused by HBV infection,” Poinar and colleagues wrote. “Gianotti-Crosti syndrome is a rare clinical outcome of HBV that presents as a popular acrodermatitis in children between 2 and 6 years old.”
The researchers reconstructed the ancient HBV genome and classified the virus as a D3 subgenotype, which is common in the Mediterranean region. Phylogenetic analyses further revealed that the ancient strain closely resembled modern HBV genotype D strains. Because of the similarities, Poinar and colleagues investigated the possibility that the remains were contaminated. However, they reported that the damaged patterns of the HBV sequence indicate that it is an authentic virus from the 16th century. These findings, they concluded, suggest that HBV has changed little over the last 450 years, “in turn implying that HBV has a long evolutionary history in humans.”– by Stephanie Viguers
Disclosures: The authors report no relevant financial disclosures.