A microbial threat unlocked by heat
In the summer of 2016, the Yamal Peninsula experienced an extreme heatwave, with temperatures reaching as high as 34-35°C (95°F). This anomalous heat thawed the region's permafrost, the layer of permanently frozen ground that covers vast areas of Siberia. The thaw reached a layer of soil containing reindeer carcasses from a major anthrax outbreak in 1941. That earlier event killed thousands of animals, creating a subterranean graveyard of infected remains.
The bacterium responsible, Bacillus anthracis, has a survival mechanism: it forms spores. These highly resistant, dormant cells can survive in harsh conditions, including being frozen in soil for centuries. When the 2016 thaw exposed a 75-year-old carcass, dormant spores were released back into the soil, water, and onto vegetation. The local reindeer herds, which had not been vaccinated against anthrax since 2007, were left vulnerable. The cancellation of the vaccination program created a large population of susceptible animals, led to for a rapid spread of the disease.
The 2016 outbreak and its aftermath
The reactivated bacteria spread quickly. The outbreak Killed more than 2,350 reindeer, a blow to the indigenous Nenets people, for whom reindeer herding is a central part of their economy and culture. The infection did not stop with the animals. A 12-year-old boy died from the intestinal form of the disease, and dozens of other people were hospitalized. In total, 72 nomadic herders, including 41 children, were taken to the regional hospital in Salekhard.
The government response was massive. A quarantine was established, and more than 200 specialists from Russia's military corps for chemical, radioactive, and biological protection were dispatched to the region to manage the crisis. They worked to decontaminate the area and dispose of the thousands of infected reindeer carcasses by incineration. A widespread vaccination campaign for both the remaining reindeer and local people was launched to contain the spread. The event on the Yamal Peninsula shows how climate change can affect public health, demonstrating that ancient pathogens preserved in permafrost pose a risk as the Arctic continues to warm at an accelerated rate.