Burkot T R, Piesman J, Wirtz R A
Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases, Fort Collins, Colorado 80522.
J Infect Dis. 1994 Oct;170(4):883-9. doi: 10.1093/infdis/170.4.883.
The presence of outer surface protein A (OspA) as a marker for Borrelia burgdorferi in Ixodes scapularis ticks was monitored with an OspA antigen-capture ELISA. The OspA ELISA, with a sensitivity of 30 spirochetes (8 fg), was not affected by the presence of either recently blood-fed or flat tick homogenates. Median spirochete equivalent levels as high as 16,000 in larvae, 55,000 in attached nymphs, and 10,000 in unfed adults were observed. Estimates of OspA doubling times ranged from a maximum of 140 h in larvae to as short as 17.5 h during nymphal attachment to the host. Spirochete equivalents in nymphs fell by 3 x 10(4) spirochete equivalents (54% of total OspA) in the last 12 h of attachment to mice but rose after detachment. Each OspA-positive I. scapularis nymph, regardless of spirochete equivalent density or length of attachment, successfully transmitted B. burgdorferi to a mouse.
采用外表面蛋白A（OspA）抗原捕获酶联免疫吸附测定（ELISA）监测肩胛硬蜱中作为伯氏疏螺旋体标志物的OspA的存在情况。OspA ELISA的灵敏度为30个螺旋体（8飞克），不受近期饱血蜱或空蜱匀浆的影响。观察到幼虫中螺旋体等效水平中位数高达16,000，附着若虫中为55,000，未进食成虫中为10,000。OspA倍增时间估计范围从幼虫中的最长140小时到若虫附着宿主期间的最短17.5小时。若虫附着小鼠的最后12小时内，螺旋体等效物减少了3×10⁴个螺旋体等效物（占总OspA的54%），但脱落后又上升。每只OspA阳性的肩胛硬蜱若虫，无论螺旋体等效密度或附着时间长短，都成功地将伯氏疏螺旋体传播给了小鼠。
