Unraveling the genetic code of the viruses we carry could provide a map of our travel history, suggest researchers who found genetic evidence of two distinct strains of the herpes virus that causes cold sores in a single individual.
Writing in the journal Virology, the international team says the finding could also aid understanding of how a patient’s viruses influence the course of disease.
Herpes simplex virus type 1 (HSV-1) is very common worldwide. Most people acquire the virus, which gives rise to lip cold sores, from their mothers shortly after birth and carry it for the rest of their lives.
Using genomic analysis, the researchers identified two distinct strains of HSV-1 in a single volunteer from the US.
They found that one strain is of European/North American origin, and the other originates from Asia – most likely picked up during military service in the Korean war in the 1950s.
One of the researchers, Dr. Derek Gatherer, a lecturer in the Division of Biomedical and Life Sciences at Lancaster University in the UK, says:
“It’s possible that more people have their life history documented at the molecular level in the HSV-1 strains they carry.”
The authors also note that they developed a particular type of genomic test for rapid identification of the HSV-1 strains. The test – called PCR RFLP – uses enzymes isolated from bacteria that attack specific molecular fingerprints in the viral genome.
The team had shown in earlier work that it is possible to locate the geographical origin of HSV-1 and that distinct Asian, African and European/North American varieties exist. Since the virus is usually picked up early in life, it follows that a personal strain can reflect a person’s origin.
- HSV-1 is mainly transmitted by mouth-to-mouth contact to cause oral herpes, but it can also cause genital herpes
- Globally, more than half of people under the age of 50 (3.7 billion, 67%) have HSV-1
- Rates of infection are estimated to be highest in Africa (87%) and lowest in the Americas (40-50%).
The research also implies that two people with identical strains of HSV-1 are more likely to be related than people who have different strains.
Information hiding in the genetic fingerprint of HSV-1 could help flesh out a person’s life story and provide information that is not present in their own DNA, Dr. Gatherer explains, adding:
“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.”
Senior author Moriah L. Szpara, assistant professor of biochemistry and molecular biology at Pennsylvania State University, says they are working on better ways to identify virus strains from ever-smaller amounts of starting material. This should make it easier to identify and compare samples from diverse sources.
She also notes that as improved genomic analysis helps reveal more of the genetic diversity of viruses like HSV-1, it may also offer valuable information about how that influences the course of disease.
In 2010, Medical News Today learned how another study suggested analysis of bacteria we leave on objects we touch may also have promise as a forensic tool.