Forty people were infected and a 12-year-old boy died after contracting anthrax after an outbreak in northern Siberia last month that was allegedly caused by a thawing reindeer carcass.
Twenty-four people remain in hospital, and at least 2,300 reindeer have died in the outbreak, the Siberian reports.
Officials in Yamalo-Nenerts region declared a state of emergency and the families of reindeer herders in the region were relocated around 60 kilometres away from the “infection hotspot,” the BBC says. The Atlantic reports that the infected animal carcasses will be burned and uninfected animals will be vaccinated.
Studies say the disease, which hasn’t been seen in the region for 75 years, came from the carcass of a dead reindeer, which is where the “zombie” nickname comes from. The carcass thawed when the permafrost in the region thawed during record-high temperatures this summer. Some regions in Siberia have seen temperatures up to 35 C — six degrees higher than average, Climate Change News reports. Russia’s Global Climate Change Institute reports that July was the hottest month ever recorded.
A 2011 study says anthrax spores can “remain viable” for up to 105 years in permafrost.
“As a consequence of permafrost melting, the vectors of deadly infections of the 18th and 19th centuries may come back, especially near the cemeteries where the victims of these infections were buried,” it reads.
Permafrost normally thaws between 30 and 60 centimetres deep into the ground, but this year it went as deep as a metre in some regions, the deputy director of the Permafrost Studies Institute, Mikhail Grigoriev, said.
That means unknown cattle graves in Russia’s northern regions have a high probability of coming to the surface, he said, meaning there’s a high risk of “zombie” anthrax outbreaks happening over and over.
Researchers in the area say the anthrax outbreak should serve as a warning that other diseases could be lurking in the permafrost, like smallpox.
Experts from the Novosibirsk State University examined the grave sites where victims of an 1890s smallpox outbreak were buried in permafrost on the Kolyma River.
Viable traces of the disease were not found, but some “fragments of its DNA” were noted, prompting a call for another investigation into the situation.
“This type of research should go on,” Sergey Netesov, chief of the biotechnology, microbiology and virology lab at the university, told the Siberian.
“The Yamal outbreak is a reason enough to finance research into the diagnostics and prevention of exceptionally dangerous infections.”