Memory stick Trojan?

Does anyone know if there's a malware or virus program that only infeects/ replicates via memory sticks? My niece has been warned at school that she needs to check her USB stick for anything unusual and delete it. School network infected, apparently. I want to help her to get rid if she has it, but don't have any details.

Probably a variant of Conficker. One of the infection methods is via USB sticks.

http://en.wikipedia.org/wiki/Conficker

Nothing specific, and it depends on what she has on the pen drive. Any malware that spreads via infected files could potentially spread via any removable media (e.g. floppy disks, pen drives), so removable media should always be checked for malware when going from one machine to another.

In reply to a post by GeoffB:

Does anyone know if there's a malware or virus program that only infeects/ replicates via memory sticks? My niece has been warned at school that she needs to check her USB stick for anything unusual and delete it. School network infected, apparently. I want to help her to get rid if she has it, but don't have any details.

There are - they can only spread by autorun or someone running the app (see link)- suggest you look at disabling Autorun