I was born and raised in Longview (LHS class of 1964) and my dad still lives there, at 82. MOST disturbing.
I've got friends with family there myself. I'm not a doctor, and I don't play one on TV, but I have been studying food-borne illnesses at culinary school. I'm thinking it may be a toxin mediated infection.
Which one? I don't know.
I would suspect that they are looking for (in order of what I think they might be) E-coli 0157:H7 or a variant; clostridium perfringens; or bacillus cereus.
Prayers for the families.
/john