There are some that had been modified to release endorphins!

>"When we first heard Soviet scientists were inserting the endorphin gene [for euphoria] into plague," says Dr. Henry Heine, a former U.S. Army bacteriologist, "we were appalled. That they would purposefully engineer the Y. pestis bacteria to behave this way... to make you want to go out and socialize... this was some horrifying stuff."

> . . .

> Former assistant secretary of defense Andy Weber agrees. "I grew up thinking Reagan’s phrase ‘Evil Empire’ was an exaggeration," he tells us. "Then I learned what the Russians were doing [with biological warfare]." He pauses for effect. "It was evil."

The accounts are from Annie Jacobsen's notes in "Biological War".

Jacobsen is also the author who claimed that the Roswell event was a Soviet plot to sow panic with an actual Nazi flying saucer piloted by genetically-engineered midgets, so I'd like to see a reputable source. (Having said that, bacteria upregulate selected interleukins to reduce inflammation, so maybe this is a game of telephone based on some actual Soviet effort to increase virulence, just not "euphoria.")

Reminds me of a David Brin short story.