Dr Derek Gatherer, an infectious disease specialist at Lancaster University, admitted he was not surprised with the findings.
He said: 'This is much as we would expect. All viruses accumulate mutations, but few of them are of much medical consequence.
'They are valuable in tracing the origins of infection chains. It looks like Iceland has imported quite a few infections from other European countries.'
Allan Randrup Thomsen, a virologist from the Department of Immunology and Microbiology at the University of Copenhagen, said the results described by the team 'make good sense'.
Professor Thomsen said: 'It is interesting with the 40 specific variants that fall into three clusters that can be traced back to specific sources of infection.'