Snake wins, since he can snap her neck without being seen.
But anyways, Snake will also win in a head-on fight, the only thing Zamus has is her Paralyzer, Snake has TONS of ways to deal with her, Claymore mines are set up in a second, which hinders Zamus' swift movements, but his guns like the M9 paralyzer and his .45 are more than enough to take Zamus down. One shot from the paralyzer and she's dead due to neck-snapping or Stinger/RPG action, 2-3 shots from the .45 and she's dead, one bare-hand fight and she's dead, severly injured or asleep, which can follow up with dead in time.
The only good thing for Zamus is that she has her Paralyzer, which she can use to stun Snake and then beat him up for 1 second, and after that, Snake's CQC abilities are more than enough to gain the upper hand. Snake can take more hits than Zamus can, the beatings he received in that 1 second are not enough to take him down.
As for health, Zamus can't regenerate or anything, she has to kill enemies to gain health or ammo, Snake just get's packed for the fight and takes plenty of Rations with him, which he barely has to use.
Snake wins
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