His viruses were created under controlled conditions and none reached the outside. He was reluctant to publish his findings but did so to warn the world of the threat to computers. Macro viruses are specific to Microsoft products and use the macro language available in Word and Excel to do damage to your machine and files. A worm is a program which replicates and spreads, but does not attach itself to other programs. Unlike a virus, it does not require a host to survive and replicate.
Worms usually propagate over a network of computers.
The AutoStart Worm is a little different. It is a faceless background application that takes advantage of the AutoPlay feature in QuickTime 2.5 and higher to install itself. A clean install of the MacOS enables the CD-ROM Autoplay by default. So if you haven't checked your settings yet, you are probably open to this kind of infection. A Trojan Horse is a program which appears to do something useful, yet additionally does something destructive behind the scenes.