Mycobacterium tuberculosisOutbreak Strain of Danish Origin Spreading at Worrying Rates among Greenland-Born Persons in Denmark and Greenland

ABSTRACTTransmission of Mycobacterium tuberculosiscontinues at high rates among Greenland-born persons in Greenland and Denmark, with 203 and 450 notified cases per 105population, respectively, in the year 2010. Here, we document that the predominant M. tuberculosisoutbreak strain C2/1112-15 of Danish origin has been transmitted to Greenland-born persons in Denmark and subsequently to Greenland, where it is spreading at worrying rates and adding to the already heavy tuberculosis burden in this population group. It is now clear that the C2/1112-15 strain is able to gain new territories using a new population group as the “vehicle.” Thus, it might have the ability to spread even further, considering the potential clinical consequences of strain diversity such as that seen in the widely spread Beijing genotype. The introduction of the predominant M. tuberculosisoutbreak strain C2/1112-15 into the Arctic circumpolar region is a worrying tendency which deserves attention. We need to monitor whether this strain already has, or will, spread to other countries.