Integrative transnational analysis to dissect tuberculosis transmission events along the migratory route from Africa to Europe

Abstract Background Growing international migration has increased the complexity of tuberculosis transmission patterns. Italy’s decision to close its borders in 2018 made Spain new European porte entrée for from Horn Africa (HA). In one first rescues migrants this region at end 2018, was diagnosed eight subjects, mainly unaccompanied minors. Methods Mycobacterium isolates these recently arrived were analysed by Mycobacterial Interspersed Repetitive-Unit/Variable-Number Tandem Repeat (MIRU-VNTR) and subsequent whole genome sequencing (WGS) analysis. Data compared with those collections other countries receiving HA a strain-specific PCR applied fast searching common strains. Infections cellular model performed assess strain virulence. Results MIRU-VNTR analysis allowed identifying an epidemiological cluster involving three cases Somalia (0 single-nucleotide polymorphisms between isolates, cluster). Following detailed interviews revealed that two had shared same migratory route most trip spent long time detention camp Libya. To confirm potential en cases, we searched HA. MIRU-VNTR, WGS applied. The identified 12 Eritrea soon after their arrival Netherlands, Belgium Italy. Intracellular replication rate did not reveal abnormal Conclusions Our study suggests pan-susceptible strain, which caused least 15 Somalian Eritrean four different countries.