Someone gets an alert about a deadly E-mail virus, and since the mail has been sent some computing company or military address, they decide that it must be true, coming from such an authoritative source, and they forward it to their entire department, or to an entire organization. Time for a reality check. E-mail messages are text. E-mail is transmitted as text. Text is simple data one byte per character.
Text is like an inert object.
You can manipulate it, but by itself, it will take no action. Attachments to E-mail messages can be programs, however, while they are being transmitted over the Internet, they are sent as encoded text. It certainly cannot operate through your E-mail program. Reading an E-mail message might do harm to your psyche, but it can't, on its own, harm your hard drive. Programs of undetermined origin might be infected with a computer virus.