Table 1.

Viruses in humans

Co-evolution of viruses with humans	Acquisition from animals, now permanently established	Temporary residents, occasional zoonotic transmission
α β γ herpesviruses Papilloma + polyoma Hepatitis B	Measles HIV Smallpox Human Influenza A H3N2 Influenza B RSV	Rabies Ebola Lassa Hanta Nipah SARS H5N1

RSV, respiratory syncytial virus; SARS, severe acute respiratory syndrome.