Know Your Enemy
The microorganisms that have shaped human history — their biology, transmission mechanisms, and the catastrophes they've caused. Select a pathogen class to explore.
Virus
Virion
Size: 20 – 300 nm
Threat Profile
Viruses are the ultimate minimalist parasites — stripped-down genetic code (DNA or RNA) wrapped in a protein shell called a capsid. They cannot reproduce independently; they hijack living host cells, forcing them to manufacture thousands of viral copies. This makes them immune to antibiotics and extremely difficult to treat. Their rapid mutation rate allows them to evolve resistance and cross species barriers, triggering pandemics.
Threat metrics
Mechanism
A virus binds to specific receptors on a host cell, injects its genetic material, and reprograms cellular machinery to replicate itself. New virions are assembled and released — often destroying the host cell in the process.
Case Fatality Rate
% of infected who die — untreated or worst case
All Types — Threat Comparison
Relative danger profile per pathogen class
Data note: Threat metrics are relative estimates based on historical outbreaks and peer-reviewed literature. Case fatality rates vary significantly by strain, healthcare access, and treatment availability. Source: WHO, CDC, UNAIDS, IAEA.