Norwegian-African large Lineage 3 M. tuberculosis cluster

Immigrants from the Horn of Africa constitute the largest group of TB patients in Norway, making up a third of all TB cases in the country over the last decade. One particular genotype-cluster strongly associated with people originating in this region has been identified regularly over a 20-year period. Here we apply transmission modeling methods to whole-genome sequence data to estimate the times at which individual patients were originally infected. By contrasting these estimates with time of arrival in Norway, we estimate on a case-by-case basis whether individual patients were likely to have been infected before or after arrival.