Five years ago, after a reindeer died of anthrax infection, its body was preserved in the frozen soil near the Arctic circle  Not long ago, a boy died of anthrax infection  Some scientists speculate that global warming began to melt the permafrost in the Arctic Circle, and anthrax bacteria made a comeback  At the same time, some ancient viruses For example, the pathogens of smallpox and black death may also be buried in these permafrost
Scientists are extremely worried about this
If the pathogen has not come into contact with humans for a long time, our immune system will not be prepared for it