Most people harbor herpes simplex virus type 1 (HSV-1), frequently as a strain acquired from their mothers shortly after birth and carried for the rest of their lives. The genomes of two distinct strains of the virus that causes the common lip cold sore, HSV-1, have been identified within an individual person.
This achievement could be useful to forensic scientists for tracing a person's history. The research also opens the door to understanding how a patient's viruses influence the course of disease. The research by an international team led by Moriah L. Szpara, assistant professor of biochemistry and molecular biology at Penn State University, will be published in Virology.
The new discovery was made with the help of a volunteer from the United States. The research revealed that one strain of the HSV-1 virus harbored by this individual is of a European/North American variety and the other is an Asian variety - likely acquired during the volunteer's military service in the Korean War in the 1950s.
Earlier research by the same team has demonstrated that the geographical origin of HSV-1 can be predicted, as well. Since Asian, African, and European/North American varieties of the virus exist, and the virus is often acquired early in life, the research implies that a personal strain of HSV-1 can reflect a person's origin. Another implication is that two individuals who have identical strains of HSV-1 are more likely to be related than those who have different strains.
"Using similar genetic fingerprinting of HSV-1 could help flesh out a person's life story, adding an extra layer of genetic information not provided by our genomes alone. Forensic virology could be on the way in the same way in which we use genetic fingerprinting of our human DNA to locate perpetrators at the scene of a crime and to help trace the relatives of unidentified bodies," Gatherer said.
"We're working on better ways to sequence viral genomes from ever-smaller amounts of starting material, to allow identification and comparison of samples from diverse sources," said Szpara, who also is affiliated with Penn State's Huck Institutes of the Life Sciences. "Deep sequencing of viruses like HSV-1 will provide a better view of the viral genetic diversity that individuals harbor, and will provide valuable information about how that influences the course of disease."