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The overwhelming majority of DNA viruses found on human skin have never been described before, a new study has found.

Using mapping techniques to isolate virus-like particles from skin swabs in 16 healthy participants, a team from the University of Pennsylvania found that around 95 percent of skin-dwelling viruses are uncharacterised -- essentially 'viral dark matter' who presence is felt, but whose character is uncertain.


The team made its breakthrough by analysing material afresh, and using new techniques for isolating virus-like particles, without depending on previously existing databases.

The material the teams found "had features of viral genetic material but no taxonomic classification", said senior author Elizabeth A. Grice. "There has been a real need for a better understanding of these viruses, given their potential effects on our skin cells as well as on our resident bacteria." "Until now, relatively little work has been done in this area, in part because of the technical challenges involved. For example, a skin swab taken for analysis will contain mostly human and bacterial DNA, and only a tiny amount of viral genetic material -- the proverbial needles in the haystack."

The microbes that live on, and in, the human body, can be instrumental in both remaining in good health and in causing diseases. The most common infecting virus found by the researchers was the human papilloma virus -- which has been linked to some types of skin cancer. The research also found that viruses are location based. From samples from the palm, forehead, armpit and other areas, the team found, for example, that viruses are more diverse in areas that are intermittently exposed and covered, like the crease of an elbow.

The research also established a baseline for future studies of healthy skin, and included the development of a set of virus analysis tools that are now available to scientists for further research into human viruses. The University of Pennsylvania team who conducted the research are now using their methods to study the variability of skin viruses, and are also analysing virus response to factors such as drug use and radiation.