Earlier this month, an outbreak of anthrax in northern Russia caused the death of a 12-year-old boy and his grandmother and put 90 people in the hospital. These deadly spores – which had not been seen in the Arctic since 1941 – also spread to 2,300 caribou. Russian troops trained in biological warfare were dispatched to the Yamalo-Nenets region to evacuate hundreds of the indigenous, nomadic people and quarantine the disease.
Americans are likely to associate anthrax with the mysterious white powder that was mailed to news media and US Senate offices in the weeks following 11 September 2001. The bacteria – usually sequestered in biological weapons labs – killed five people and infected 17 others in the most devastating bioterrorism attack in US history.
But in Russia, the spread of illness was not the result of bioterrorism; it was a result of global warming. Record-high temperatures melted Arctic permafrost and released deadly anthrax spores from a thawing carcass of a caribou that had been infected 75 years ago and had stayed frozen in limbo until now. This all suggests that it may not be easy to predict which populations will be most vulnerable to the health impacts of climate change.
In 2013, the National Academy of Sciences hosted a forum on the influence of global environmental change on infectious diseases. In his keynote speech, Dr Jonathan Patz stood in front of a large slide of a mosquito and warned: “Global warming’s greatest threat may also be the smallest.” The forum focused on many causes of disease, from fungi, bacteria, viruses and mold spores, to vectors like bats and mosquitoes. Climate change can exacerbate the spread of infectious disease by changing the behavior, lifespans and regions of diseases and their carriers.