User blog comment:JackBigbossMGS3/Snake Over the Years/@comment-4117012-20110801213446

Solid, Liquid and Solidus were designed to live a certain amount of years depending on their importance and abilities. Solid and Liquid were twins, so they'd live an equal amount of life. Naomi Hunter Injected Solid Snake (David) with Fox-Die virus circa 2005 before he went to Shadow Moses island as the revenge of killing her brother (Gray Fox). David supposed to be dead by that time, but his "fate" let him live for a couple of years. It's kinda unclear that David is dying from his Genes or Fix-Die. BUT i think if he'd die from a hear attack that shows it's Fox-Die. About nanomachines, they have diffrent functions, for example some of them are used for musscle relaxation, controling body temperature, decreasing the need for food in mission times, etc. which David used in MGS (because of the damn cold weather of Alaska) and MGS4 (because of his age). the other function includes the whole Patriots business, that would mean... CONTROLING MINDS.