David Brin The Giving Plague

Not all villains succeed at being evil. Not all diseases deserve the word plague. Fate can be ironic indeed. The chilling short story, The Giving Plague, follows microbiologist Forry, a self-proclaimed cynic, jealous of his "boy wonder" colleague who discovers a unique virus that could change humanity. Transmitted by blood donations, the virus manipulates humans toward altruism and charity. Forry decides that he will do anything to take credit for this discovery.until a more deadly alien virus infects the human race, forcing him to wrestle with his own inner demons.

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