AN UNEXPECTED RESULT FROM BURNING VEGETATION TO REDUCE LYME-DISEASE TRANSMISSION RISKS

The risk for human infection with Lyme disease appears linked to the a bundance of infected vector ticks, principally Ixodes dammini Spielman , Clifford, Piesman & Corwin, in the eastern United States. Habitat de struction by burning, although not well studied, has long been conside red as an effective alternative to synthetic insecticides as a means o f reducing tick populations. We evaluated the effect of a single sprin g burning of the woodland understory on the transmission risk of Lyme disease spirochetes (Borrelia burgdorferi Johnson, Schmid, Hyde, Steig erwalt & Brenner) on Shelter Island, Long Island, NY. Following a burn in early April 1991, the abundance of nymphal I. dammini was 49% lowe r in the burned portion of a woodlot compared with the unburned portio n. However, risk of encountering nymphs infected with B. burgdorferi r emained similar in both burned and unburned woods. It is suggested tha t burning vegetation may disproportionately kill deer-derived rather t han rodent-derived nymphs, significantly reducing tick abundance witho ut affecting transmission risk.