A new study by researchers at the University of Wisconsin used a genomic analysis of strains of the Herpes Simplex Virus type-1 (generally associated with cold sores) from around the world to see if they tracked with general theories of human migration. HSV-1 works particularly well for this kind of study because it is easily spread by physical contact as well as easy to collect.
Co-author Curtis Brandt explains what they found:
"The viral strains sort exactly as you would predict based on sequencing of human genomes. We found that all of the African isolates cluster together, all the virus from the Far East, Korea, Japan, China clustered together, all the viruses in Europe and America, with one exception, clustered together," he says.
"What we found follows exactly what the anthropologists have told us, and the molecular geneticists who have analyzed the human genome have told us, about where humans originated and how they spread across the planet."
In general, the paper suggests that the data “supports the “out of Africa model” of human migration with HSV-1 traveling and diversifying with its human host”. There was one North American derived strain which they found was related to the East Asian family of the virus. They estimated the “divergence time” between this strain and its relatives as around 15,000 years which corresponds “with the estimated time period in which the North American continent was populated from Asia, approximately 15,000 years BP.”
In other words, the first arrivals on the North American continent may have brought their cold sores with them.