Dumler J S, Bakken J S
Department of Pathology, University of Maryland Medical Center, Baltimore, USA.
Clin Infect Dis. 1995 May;20(5):1102-10. doi: 10.1093/clinids/20.5.1102.
The ehrlichioses are emerging zoonotic infections that are caused by obligate intracellular bacteria in the genus Ehrlichia. Two human ehrlichioses occur in the United States: monocytic ehrlichiosis (HME), which is caused by Ehrlichia chaffeensis that infects mononuclear phagocytes in blood and tissues, and granulocytic ehrlichiosis (HGE), an infection of granulocytes that is due to a phylogenetically distinct organism. Both infections cause undifferentiated fever with leukopenia, thrombocytopenia, and elevations in serum aminotransferase levels. Rash is an infrequent sign, and vasculitis is exceedingly rare. Severe or fatal ehrlichiosis is associated with secondary or opportunistic infections and delayed therapy. Ticks are the likely vectors, and deer are the likely reservoirs. HGE is associated with Ixodes species ticks and Lyme disease, a finding suggesting concurrent infection. In cases of HME, ehrlichial inclusions (morulae) are rarely detected; however, they are often seen in neutrophils of patients with HGE. A clinical diagnosis is confirmed with use of the polymerase chain reaction during the infection or by serology during convalescence. Therapy with doxycycline is highly efficacious.
埃立克体病是一种新发的人畜共患感染性疾病，由埃立克体属专性细胞内细菌引起。美国有两种人类埃立克体病：单核细胞埃立克体病（HME），由恰菲埃立克体引起，该菌感染血液和组织中的单核吞噬细胞；粒细胞埃立克体病（HGE），是粒细胞的一种感染，由一种系统发育上不同的病原体引起。两种感染均导致无特异性发热，并伴有白细胞减少、血小板减少和血清转氨酶水平升高。皮疹是不常见的体征，血管炎极为罕见。严重或致命的埃立克体病与继发或机会性感染及治疗延迟有关。蜱可能是传播媒介，鹿可能是储存宿主。HGE与硬蜱属蜱及莱姆病有关，这一发现提示可能存在并发感染。在HME病例中，很少能检测到埃立克体包涵体（桑葚体）；然而，在HGE患者的中性粒细胞中常可见到。在感染期间通过聚合酶链反应或在恢复期通过血清学检查可确诊临床诊断。强力霉素治疗非常有效。
