Stonebridge apparently get botulinum poisoning from an artillery shell but you can't deploy it this way. It's theoretical release vectors are by aerosol or by poisoning water sources. It would be almost completely ineffective if fired in a shell like that. It also doesn't look anything like the yellow liquid shown coming out the shell.
Michael's symptoms are not consistent with botulism. The blurred vision and breathing difficulty are correct but he is missing all the other more obvious symptoms and has a fever which botulism does not cause.