Varela-Stokes A S
Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA.
J Wildl Dis. 2007 Jul;43(3):376-81. doi: 10.7589/0090-3558-43.3.376.
Amblyomma americanum is an aggressive ixodid tick that has been implicated as a vector for several bacterial agents. Among these is Ehrlichia chaffeensis, which causes human monocytic (or monocytotropic) ehrlichiosis. In this study, experimental tick transmission of E. chaffeensis from infected lone star ticks to deer was revisited, and the question of whether it would be possible to re-isolate the organism from deer was asked, because this had not been done previously. Here, we were able to transmit a wild strain of E. chaffeensis from acquisition-fed lone star ticks to white-tailed deer. Ehrlichia chaffeensis was re-isolated from one white-tailed deer on multiple days during the infection and from another deer on one day during the infection. Peak rickettsemias for E. chaffeensis-infected deer were 17 DPI with acquisition-fed ticks and 14 DPI with needle-inoculated deer. This study supports the role of the lone star tick and white-tailed deer as vector and reservoir host for E. chaffeensis, demonstrating culture re-isolation of E. chaffeensis in deer infected by experimental tick transmission for the first time.
美洲钝眼蜱是一种攻击性很强的硬蜱，被认为是多种细菌病原体的传播媒介。其中包括恰菲埃立克体，它会引起人类单核细胞性（或嗜单核细胞性）埃立克体病。在本研究中，重新探讨了恰菲埃立克体从受感染的孤星蜱到鹿的实验性蜱传播情况，并提出了是否有可能从鹿身上重新分离出该病原体的问题，因为此前尚未进行过此类研究。在此，我们成功地将一株野生型恰菲埃立克体从饱血的孤星蜱传播给了白尾鹿。在感染期间，从一只白尾鹿身上多次重新分离出恰菲埃立克体，从另一只鹿身上在感染期间的某一天也分离出了该病原体。恰菲埃立克体感染的鹿的立克次体血症高峰分别出现在用饱血蜱感染后的第17天和用针接种感染后的第14天。本研究支持孤星蜱和白尾鹿作为恰菲埃立克体的传播媒介和储存宿主的作用，首次证明了在通过实验性蜱传播感染的鹿中重新分离培养出恰菲埃立克体。
