Compounds represented by formula I:or pharmaceutically acceptable salts and solvates thereof, wherein R1, X, Y, Y1, and Z are as defined herein, are useful for treating flaviviridae viral infections. The strip has a generally arcuate or concave cross-section and is configured for being coiled into a spiral from the proximate end to the distal end for placement between adjacent spinal vertebrae, such that upon formation of the coiled shape, the teeth on a first edge engage one of the vertebrae, and teeth of an opposite, second edge engage the other of the vertebrae. The sonde is generally shaped as a discus or saucer, a clay pigeon or skeet, for deployment by applying a spin and directional velocity to the sonde. In other embodiments the specialized results are available to all users.