全沟硬蜱、森林革蜱及嗜群血蜱经卵传播新塔拉塞维奇立克次体的检测研究

STUDY ON THE TRANSOVARIES TRANSMISSION OF CANDIDATUS RICKETTSIA TARASEVICHIAE IN IXODES PERSULCATUS,DERMACENTOR SILVARUM AND HAEMAPHYSALIS CONCINNA( ACARI: IXODIDAE)

本研究旨在明确新塔拉塞维奇立克次体是否可以在全沟硬蜱、森林革蜱及嗜群血蜱3种媒介蜱中经卵传播。以在东北林区采集的牛寄生饱血雌蜱为样本，在实验室条件下人工培育，以获得3种蜱的不同时期的形态，并使用PCR方法检测各虫态中新塔拉塞维奇立克次体的感染情况，从而研究新塔拉塞维奇立克次体在蜱生活周期中的传递规律。共采集牛寄生饱血雌蜱91只，其中全沟硬蜱14只，森林革蜱55只，嗜群血蜱24只。新塔拉塞维奇立克次体感染率为85．71％，5．45％，12．50％。卵的最低感染率分别为全沟硬蜱（2％）、森林革蜱（1．3％）、嗜群血蜱（1．1％），幼蜱的最低感染率分别为全沟硬蜱（5％）、森林革蜱（1．7％）、嗜群血蜱（2．2％）。且3种蜱雌蜱、卵、幼虫均检测到的新塔拉塞维奇立克次体，序列比对一致。感染的幼蜱均可通过叮咬使小鼠感染，三种蜱都能经卵传播新塔拉塞维奇立克次体。全沟硬蜱感染率高可能是东北林区新塔拉塞维奇立克次体的主要媒介蜱。

To verify the transovaries transmission of Candidatus Rickettsia tarasevichiae in Ixodes persulcatus, Dermacentor silvarum and Haemaphysalis concinna. Engorged ticks were captured from cattle in North-eastern forestry area and reared under appropriate laboratory conditions to obtain larvae of threes tick species. Infection of Candidatus R. tarasevichiae were validated through PCR assays to detect the transovaries transmission of Candidatus R. tarasevichiae. A total of 91 engorged ticks were captured, including 14 L persulcatus, 55 D. silvarum and 24 H. concinna and after laying eggs, they were tested via PCR assays with Candidatus R. tarasevichiae infection rate of 85.71% , 5.45% and 12.50% respectively. The minimum infection rate in eggs for each tick species were 2% for L persulcatus, 1.3% for D. silvarum and 1.1% for H. concinna, while the minimum infection rate in larvae were 5% , 1.7% and 2.2% respectively. The sequences obtained from primary female ticks, eggs and lavae in each tick species were identical to each other and also to the Candidatus R. tarasevichiae sequence. Infected larvae were also able to infect mice. Transovaries transmission of Candidatus R. tarasevichiae were identified in I. persulcatus, D. silvarum and H. concinna. The transmission rate in I. persulcatus was the highest among three species, from which a deduction could be made that I. persulcatus are the predominant vector for Candidatus R. tarasevichiae in northeastern forestry area in China.