Yabsley Michael J, Murphy Staci M, Luttrell M Page, Little Susan E, Massung Robert F, Stallknecht David E, Conti Lisa A, Blackmore Carina G M, Durden Lance A
Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602, USA.
Vector Borne Zoonotic Dis. 2008 Aug;8(4):491-503. doi: 10.1089/vbz.2007.0240.
We investigated the experimental susceptibility and natural exposure of raccoons (Procyon lotor) to five tick-borne pathogens of human and veterinary importance, Ehrlichia canis, E. chaffeensis, E. ewingii, Anaplasma phagocytophilum (ApVariant 1 and Ap-ha HGE-1 strains), and Borrelia lonestari. Infections were assessed by polymerase chain reaction (PCR), indirect fluorescent antibody (IFA) testing, and/or culture isolation methods for at least 30 days postinoculation (DPI). Two E. chaffeensis-inoculated raccoons seroconverted and were transiently PCR positive. One raccoon was culture positive. Laboratory raised Amblyomma americanum nymphs fed on a third infected raccoon failed to become infected. Two A. phagocytophilum (HGE-1)-inoculated raccoons became PCR positive and seroconverted. Both remained positive for at least 74 DPI. In contrast, raccoons inoculated with A. phagocytophilum (Ap-Variant 1) were only transiently PCR positive and only seroconverted with low titers. No evidence of infection was observed for E. ewingii- and B. lonestari-inoculated raccoons. Only one E. canis-inoculated raccoon was PCR positive 3 DPI. Serologic testing of wild raccoons from five populations (3 infested with ticks) in Georgia and Florida showed antibodies reactive with E. chaffeensis in the 3 tick-infested populations (range of 30%-46%), E. canis in the same three populations (8%-23%), A. phagocytophilum in a single raccoon from Florida (12%), and Borrelia spp. in all 5 populations (8%-53%). All raccoons were PCR negative for tick-borne pathogens. These data suggest that raccoons are likely not important reservoirs of E. canis, E. ewingii, or B. lonestari. However, raccoons are experimentally susceptible and naturally exposed to E. chaffeensis, and these data support the previous finding that raccoons may be involved in the natural history of A. phagocytophilum.
我们研究了浣熊（北美浣熊）对五种对人类和兽医具有重要意义的蜱传病原体的实验易感性和自然暴露情况，这五种病原体分别是犬埃立克体、查菲埃立克体、尤因埃立克体、嗜吞噬细胞无形体（ApVariant 1和Ap-ha HGE-1菌株）以及孤独疏螺旋体。在接种后至少30天（dpi），通过聚合酶链反应（PCR）、间接荧光抗体（IFA）检测和/或培养分离方法评估感染情况。两只接种查菲埃立克体的浣熊血清转化，且PCR呈短暂阳性。一只浣熊培养呈阳性。以第三只感染浣熊为食的实验室饲养美洲钝眼蜱若虫未被感染。两只接种嗜吞噬细胞无形体（HGE-1）的浣熊PCR呈阳性且血清转化。两者在至少74 dpi时均保持阳性。相比之下，接种嗜吞噬细胞无形体（Ap-Variant 1）的浣熊仅PCR呈短暂阳性，且仅以低滴度血清转化。未观察到接种尤因埃立克体和孤独疏螺旋体的浣熊有感染迹象。仅一只接种犬埃立克体的浣熊在3 dpi时PCR呈阳性。对来自佐治亚州和佛罗里达州五个种群（其中3个种群有蜱虫寄生）的野生浣熊进行血清学检测，结果显示在3个有蜱虫寄生的种群中，浣熊体内有与查菲埃立克体反应的抗体（范围为30%-46%），在相同的三个种群中有与犬埃立克体反应的抗体（8%-23%），在来自佛罗里达州的一只浣熊体内有与嗜吞噬细胞无形体反应的抗体（12%），在所有5个种群中都有与疏螺旋体属反应的抗体（8%-53%）。所有浣熊的蜱传病原体PCR检测均为阴性。这些数据表明，浣熊可能不是犬埃立克体、尤因埃立克体或孤独疏螺旋体的重要储存宿主。然而，浣熊在实验中对查菲埃立克体易感且自然暴露于该病原体，这些数据支持了之前的发现，即浣熊可能参与了嗜吞噬细胞无形体的自然传播过程。
