Just throw it out there, during a lull, when the two of you are bullshitting about whether the new Accounts Receivable Officer is a whore or just sleepy or whether either of you have ever known a heroin addict. When he or she is taking a bite of a sandwich, say it loud.
"I don't know. Sometimes it feels like if someone even brushes past me on the elevator I'm never gonna stop throwing up."
Your officemate might be unsure he or she heard right. Clarify.
"I just feel like people are diseased."
Why have you been shutting your officemate out for so long?