Mutations can result in viruses that infect cells, but can't copy themselves without help from other viruses - now it seems these cheats may outnumber normal viruses in a third of influenza cases, red ...

AI designed new bacteriophages that killed E. coli in lab tests, promising advances but raising safety concerns.

A virus found lurking inside a deadly fungus may make the microbe even stronger and harder to kill when it infects people.