"Thanks for listening," reads the message on the album's back cover, ". . . and remember, scientists here at Fiddle Fever Laboratories are working 'round the clock to discover and develop new and more virulent strains." The record is Fiddle Fever's newly released "Waltz of the Wind"; the scientists are musicians Russ Barenberg, Matt Glaser, Molly Mason, Evan Stover and Jay Ungar; and their virulent strains have sprung out of Appalachian, Cajun, Celtic, Scandinavian and southern jazz fiddling traditions. They fiddle today at Glen Echo Park's Spanish Ballroom, at a double performance -- in concert this afternoon and with caller Bob Dalsemer at the regular Sunday night dance.

The 5-year-old Fiddle Fever is a part-time band -- an arrangement that allows the members to pursue individual musical paths. Jay Ungar, the group's main organizer, says "we have found, in traveling and performing together, that we all really like each other; but if it was the only band for each of us, it would probably fall apart. This particular band can't answer all the members' musical needs. Our musical interests are different."

A Fiddle Fever concert may kick off with a Swedish walking tune, to which they fiddle and march in procession through the audience and up onto the stage. But where the music goes from there is a matter of intuition: "We know what we are going to start and finish with," says Ungar, "but then we depart from there, depending on the audience and the atmosphere."