中华硬蜱、越原血蜱和青海血蜱经期传播莱姆病螺旋体的实验研究

Ability of Ixodes sinensis Teng, Haemaphysalis yeni Toumanoff and H. qinghaiensis Teng (Acari: Ixodidae) to transmit Borrelia garinii transstadially

以实验室培育的非感染中华硬蜱、越原血蜱和青海血蜱刺叮人工感染 2 1天的阳性KM鼠 ,利用分离培养和PCR方法检测蜱对莱姆病螺旋体Borreliagarinii的保持能力以及体内螺旋体对敏感动物的感染能力。中华硬蜱、越原血蜱和青海血蜱非感染幼蜱均可以通过吸血获得莱姆病螺旋体 ,然而 ,它们在饱血、消化、蜕皮和再次吸血过程中对莱姆病螺旋体的保持能力差异很大。只有中华硬蜱可以保持活的莱姆病螺旋体直至蜕化为下一发育阶段 ,蜕化后仍携带莱姆病螺旋体并对敏感KM鼠有感染能力。而越原血蜱和青海血蜱对莱姆病螺旋体的保持能力不能跨越消化、蜕皮阶段 ,蜕化后这两种血蜱不再携带莱姆病螺旋体 ,因此 ,这两种血蜱不具备经期传播能力 ,作为莱姆病媒介的可能性不大。中华硬蜱于幼蜱到若蜱以及若蜱到成蜱两个阶段均具备经期传播莱姆病螺旋体的能力 。

To determine the ability of Ixodes sinensis Teng, Haemaphysalis yeni Toumanoff and H. qinghaiensis Teng to transmit Borrelia garinii as potential vector of Lyme disease in South China, transstadial transmission of the spirochetes by the three species was studied in the laboratory. Results showed that the three tick species could acquire active Lyme spirochetes by feeding on infected KM mice. However, only I. sinensis could maintain active spirochetes during molting, with subsequent developing stages infectious to normal KM mice. H. yeni and H. qinghaiensis maintained spirochetes not longer than the period of blood digestion; after molting, no spirochetes were detected in the both species. Therefore, the possibility of either H. yeni or H. qinghaiensis to be the vector of Lyme disease was small. The successful transmission of B. garinii in I. sinensis during both larva to nymph and nymph to adult periods in the laboratory indicated that it might be the potential vector of Lyme disease in South China.