After the upload and another seeder happens and that seeder has a virus that force writes its self on to a file would that seeder unknowingly infect the next down loader in line.
yes you have answered your own question
that is why torrents and any seed is questionable , next time never ever download a file to ur hdd save to desktop and use scan with by right clicking on ur mouse or touch pad --- trust nothing or we will see u here again. no downloaded file from an unknown seed is safe and why someone would suggest that is stupid