Work

Molecular Epidemiologic Investigation of an Anthrax Outbreak among Heroin Users, Europe

Year: 2012

Type: article

Abstract: In December 2009, two unusual cases of anthrax were diagnosed in heroin users in Scotland.A subsequent anthrax outbreak in heroin users emerged throughout Scotland and expanded into England and Germany, sparking concern of nefarious introduction of anthrax spores into the heroin supply.To better understand the outbreak origin, we used established genetic signatures that provided insights about strain origin.Next, we sequenced the whole genome of a representative Bacillus anthracis strain from a heroin user (Ba4599), developed Ba4599-specifi c single-nucleotide polymorphism assays, and genotyped all available material from other heroin users with anthrax.Of 34 case-patients with B. anthracis-positive PCR results, all shared the Ba4599 single-nucleotide polymorphism genotype.Phylogeographic analysis demonstrated that Ba4599 was closely related to strains from Turkey and not to previously identifi ed isolates from Scotland or Afghanistan, the presumed origin of the heroin.Our results suggest accidental contamination along the drug traffi cking route through a cutting agent or animal hides used to smuggle heroin into Europe.B acillus anthracis is a gram-positive endospore- forming bacterium that causes the disease anthrax in livestock, wildlife, and humans.Because of its hardy spores, B. anthracis can survive for extended periods in the environment, a trait that likely contributed to the successful global spread of this organism (1).The mostly dormant life cycle of B. anthracis and its relatively recent emergence as a pathogen have resulted in a genome that is highly clonal, with little genetic variation among even the most distantly related strains (2-4).Anthrax is most commonly contracted by exposure to contaminated animal products, such as skins, wool, or meat; its symptoms vary in severity depending on the route of infection.Cutaneous anthrax, the most common manifestation of disease, accounts for 95% of cases, whereas pulmonary and gastrointestinal anthrax are much less common and follow inhalation or ingestion of spores, respectively.Inhalational anthrax is rare but particularly deadly, with up to a 90% fatality rate (5).In 2000, a novel form of cutaneous anthrax, termed injectional anthrax, was proposed after anthrax was diagnosed in a heroin "skin popper" (one who injects the drug beneath the skin, rather than into a vein) from Norway on postmortem examination (6).Injectional anthrax symptoms are more severe than those of cutaneous anthrax and are typifi ed by severe soft tissue infection at the injection site, which can progress to septic shock, meningitis, and death (7).The origin of anthrax in the Norwegian heroin user was never identifi ed, although contaminated heroin was suspected (6).This case was the fi rst to demonstrate this previously unrecognized route of B. anthracis infection.

Source: Emerging infectious diseases

DOI: 10.3201/eid1808.111343