Here is a little something from one of MS's own FAQ's Will the virus impact my Macintosh if I am using a non-Microsoft e-mail program, such as Eudora? If you are using an Macintosh e-mail program that is not from Microsoft, we recommend checking with that particular company. But most likely other e-mail programs like Eudora are not designed to enable virus replication. Implying that Outlook is designed to replicate viruses.
Macro virii the FAQ is talking about is a Microsoft application based macro. If the program can understand the macro, it will replicate there.
Will the virus impact my Macintosh if I am using a non-Microsoft e-mail program, such as Eudora? If you are using a Macintosh e-mail program that is not from Microsoft, we recommend checking with that particular company.