"Our Neural Chernobyl"
This story was written by Bruce Sterling, and was first published in The Magazine of Fantasy and Science Fiction in 1988. In a bizarre future, free from AIDS and genetic diseases, everyone can be a human genome hacker. One such hacker/scientist, while trying to find a way for the human body to become a cocaine-producing factory, engineers a virus that enriches the dendritic connections of mammalian brains. This virus seems to produce eccentric, absent-minded geniuses, but most humans are apparently immune to this neural Chernobyl (though the reader should be aware of the possibility of an unreliable narrator). Instead, it is animals that suffer the most obvious changes as a result of this virus, leading to more intelligent dogs and cats, as well as a culturally-aware raccoon society.
Read more about this topic: Hackers (anthology)