Anthrax among heroin users in Europe possibly caused by same Bacillus anthracis strain since 2000

Injection anthrax was described first in 2000 in a heroin-injecting drug user in Norway. New anthrax cases among heroin consumers were detected in the United Kingdom (52 cases) and Germany (3 cases) in 2009-10. In June 2012, a fatal case occurred in Regensburg, Bavaria. As of December 2012, 13 cases had been reported in this new outbreak from Germany, Denmark, France and the United Kingdom. We analysed isolates from 2009-10 and 2012 as well as from the first injection anthrax case in Norway in 2000 by comparative molecular typing using a high resolution 31 marker multilocus variable-number tandem repeat analysis (MLVA) and a broad single nucleotide polymorphism (SNP) analysis. Our results show that all cases may be traced back to the same outbreak strain. They also indicate the probability of a single source contaminating heroin and that the outbreak could have lasted for at least a decade. However, an additional serological pilot study in two German regions conducted in 2011 failed to discover additional anthrax cases among 288 heroin users.