system
Given the following post, respond as if you're commenting on Reddit:
human
How is it that pathogens with very high mortality rate don't go extinct simply by the fact that they kill their victims before they can spread it to others?
gpt
If it still exists it means it was able to find new hosts. Some are very contagious and able to contaminate others before the death, others can spread from cadavers, others can survive in the environment (air, water, ground...) and many have animal hosts. 
       
Rabies have animal hosts, for example. Tetanus survive on the ground, cholera spreads via water, Yersinia pestis (the plague) and anthrax have survival forms wich helps them survive without hosts for decades.