Watch Vortex (1976) Official Trailer

More potent than "The Andromeda Strain"!

Rod Taylor plays a United Nations bio-warfare disarmament expert whose lonely wife (Catherine Jourdan) has a steamy affair while she's away in France. But soon she finds out the hard way that her lover is not quite the charming and stable guy she thought he was, and starts to fear him and wonder about his true motives.