Piesman J, Oliver J R, Sinsky R J
Centers for Disease Control, Fort Collins, Colorado.
Am J Trop Med Hyg. 1990 Apr;42(4):352-7. doi: 10.4269/ajtmh.1990.42.352.
Lyme disease spirochetes (Borrelia burgdorferi) multiplied rapidly in larval Ixodes dammini, reaching a mean density of 2,735 spirochetes/tick on day 15 post-repletion. A 5-fold drop in spirochete levels occurred during the subsequent premolting period. Recently molted nymphs contained a mean of less than 300 spirochetes/tick. Following nymphal repletion, spirochete multiplication renewed, reaching a mean abundance of 61,275 spirochetes/nymph on day 75 post-repletion. A 10-fold drop in spirochete abundance occurred again when ticks molted to the adult stage. Tick-derived spirochetes proved to be infectious when greater than 10(4) spirochetes were inoculated ip into hamsters (4 of 4 animals infected). Inocula of 10(3-4) spirochetes were not always infectious (8 of 23 animals infected), and inocula of less than 10(3) spirochetes were insufficient for establishing infection (0 of 8 animals infected).
莱姆病螺旋体（伯氏疏螺旋体）在达敏硬蜱幼虫体内迅速繁殖，饱血后第15天平均密度达到2735条螺旋体/蜱。在随后的预蜕皮期，螺旋体数量下降了5倍。刚蜕皮的若蜱平均每蜱含螺旋体不到300条。若蜱饱血后，螺旋体再次繁殖，饱血后第75天平均丰度达到61275条螺旋体/若蜱。蜱蜕皮至成虫阶段时，螺旋体丰度再次下降10倍。当将超过10⁴条螺旋体经腹腔接种到仓鼠体内时，蜱源螺旋体被证明具有传染性（4只接种动物全部感染）。接种10³⁻⁴条螺旋体并不总是具有传染性（23只接种动物中有8只感染），接种少于10³条螺旋体不足以引发感染（8只接种动物均未感染）。
