I attended high school in the San Jose, California area in the early 1980's,
and I remember a (smallish) outbreak of a strange illness, in which
people developed measles-like spots on their bodies.  This condition
seemed to last only a few days, and I don't recall anyone reporting any other
symptoms.  I seem to recall reading somewhere that this was believed to have
been viral in nature, but I don't know for sure.

However, I have been curious since then about this.