Scientists at Northern Arizona University are studying an anthrax outbreak among heroin users in Europe.
They sequenced the genomes of sixty anthrax samples from infected heroin users, following an outbreak of the potentially deadly disease. More than 100 people fell ill with “injectional anthrax” in Scotland in 2009 and 2010 and sporadic cases continue throughout Europe.
Health officials assumed the outbreak was related to a single batch of heroin contaminated with the bacteria that causes anthrax. Now, DNA analysis shows at least two contamination events took place.
“That provides some urgency to it,” says Paul Keim, director of NAU’s Center for Microbial Genetics and Genomics, and a researcher at TGen North in Flagstaff. “You can’t just ignore this event as a one-off event that’s never going to happen again. It is going to happen again.”
Keim says traditional methods of tracking diseases wouldn’t work in this case. The two disease clusters appeared in the same regions and overlapped in time. Only by sequencing entire genomes could the researchers find subtle differences in DNA.
“If it was fast food restaurant that had an E. coli or norovirus contamination, then we would be able to track back where they got their lettuce, where they got their hamburger,” Keim said. “In this case you can’t do that, so this tool becomes one of the few that you have to track it down.”
Keim thinks a likely explanation is contamination from water at the source of the heroin production.
The study appeared in the November issue of EBioMedicine.