How does one get stomach flu? other than getting it from someone who already ha!

How does one get stomach flu? other than getting it from someone who already has one?

You use the term "stomach flu". To be precise it means to have Influenza with abdominal symptoms. You only get the "flu" from another person( its a respiratory virus infection). However, you may be wrong with the terms and you really have abdominal infections that come from other viruses, bacteria, and even parasites/protozoans. These are gotten from contaminated foods and liquids ( even water), from touching fomites ( door knobs, table tops, store shopping carts, etc), and even airborn microscopic amounts of feces ( be careful with diapers, etc.).