| borrelia burgdorferi and the causative agent of human granulocytic ehrlichiosis in deer ticks, delaware. | during the 1998 hunting season in delaware, 1,480 ticks were collected from 252 white- tailed deer; 98% were ixodes scapularis, a significant increase from the 85% reported in 1988. ticks were tested for borrelia burgdorferi and the causative agent of human granulocytic ehrlichiosis. infection rates remained stable in new castle and kent counties, but increased from <1% to 8% in sussex county. | 2000 | 10905979 |