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‘Forensic virology’ reveals two HSV-1 strains in one patient
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Researchers using so-called “forensic virology” determined that a patient from the United States had two distinct strains of herpes simplex virus type 1, or HSV-1, originating from two different continents.
The findings by Moriah L. Szpara, PhD, assistant professor of biochemistry and molecular biology at Pennsylvania State University, and colleagues might have implications for forensic scientists in the tracing of a person’s history, according to a news release.
HSV-1, which causes the common cold sore, is widespread in humans. It frequently is acquired by people from their mothers shortly after birth and persists for a lifetime. Coupled with the existence of different strains from Africa, Asia and Europe/North America, this means that a personal strain of HSV-1 can reflect a person’s origin, the release said. Further, identical strains of HSV-1 in two people could mean they are more likely to be related than those who have different strains, the release said.
“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,” study researcher Derek Gatherer, PhD, lecturer in the division of biomedical and life sciences at Lancaster University in the United Kingdom, said in the release. “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.”
Strain comparison shows similarity in DNA identity
The researchers used genomewide comparative sequence analysis to compare an isolate of HSV-1 called KOS63 with a more virulent strain known as KOS79, reportedly isolated from the same volunteer on separate occasions.
They found that KOS63 and other previously sequenced KOS variants used as a comparison shared an average of 99.2% DNA identity and clustered most closely with Asian strains. They observed that KOS79 was as different from KOS63-like strains (DNA identity of 98.5%) as an unrelated HSV-1 strain that was included as an out-group, and that it clustered most closely with North American and European strains. In addition, the evolutionary distance between KOS79 and the other KOS variants suggested it is a distinct and unrelated strain, the researchers wrote.
“It’s possible that more people have their life history documented at the molecular level in the HSV-1 strains they carry,” Gatherer said in the release.
The research also may allow scientists to understand how a patient’s viruses influence the course of the disease, according to Szpara.
“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,” she said in the release. “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 the disease.” – by Gerard Gallagher
Disclosure: The researchers report no relevant financial disclosures.
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