In intact ecosystems, like healthy forests, viruses and their wild hosts interact in a delicate balance. But when humans interfere, they can expose themselves to unknown viruses.

When humans modify landscapes, it encourages interactions between people and wildlife and can ...

There are three dominant models of viruses that seem to complete each other.

• The "virus first" model suggests that simple forms of viruses existed before cells and may have provided the raw material for the development of cellular life.
• "Escape" or p...

• Viruses exist through symbiosis - an intimate association between two forms of life.
• Viruses can only reproduce inside living cells where they turn the host's cells into virus-making copying machines.
• Once the viral information becomes integrated into a host's genome, it b...

In 1938, Helmut Ruska, a German physician and biologist, saw the potential of the electron microscope in the application to the field of biology. Helmut collected images, including the variola virus (which causes smallpox) and presented images of the virus particles at a meeting of the Medical So...