Nicholson W L, Castro M B, Kramer V L, Sumner J W, Childs J E
Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
J Clin Microbiol. 1999 Oct;37(10):3323-7. doi: 10.1128/JCM.37.10.3323-3327.1999.
Dusky-footed wood rats (Neotoma fuscipes) and Peromyscus sp. mice (P. maniculatus and P. truei) were collected from one site in Placer County, one site in Santa Cruz County, and two sites in Sonoma County in northern California. Serum or plasma samples from 260 rodents were tested for antibodies to the agent of human granulocytic ehrlichiosis. Of these, samples from 25 wood rats (34% of those tested) and 10 (8%) Peromyscus sp. mice were found to be seropositive, but only those from one site. PCR assays targeting the groESL heat shock operon were conducted on all seropositive specimens and a subset of seronegative blood specimens. Ehrlichial DNA was identified in 17 (68%) of the 25 seropositive wood rat blood samples and in 1 of the 10 (10%) Peromyscus sp. specimens. None of 40 seronegative blood samples was PCR positive. Both seropositive and PCR-positive animals were collected during each trapping period. One male tick out of 84 Ixodes pacificus adults collected was PCR positive; samples of Dermacentor occidentalis nymphs and adults were negative. Nucleotide sequences of amplicons from three wood rat blood specimens and from the single PCR-positive tick differed by one and two bases, respectively, from a sequence previously obtained from Ehrlichia equi. At one site in Sonoma County, wood rats had a concurrent high prevalence of seropositivity and PCR positivity, while other sigmodontine rodents collected at the site were only occasionally infected. We suggest that dusky-footed wood rats serve as reservoirs of granulocytic ehrlichial agents in certain areas of northern California. The tick species involved in the transmission of granulocytic ehrlichiae among wood rats remains unknown.
暗色足林鼠（Neotoma fuscipes）和白足鼠属小鼠（P. maniculatus和P. truei）采自加利福尼亚州北部的普拉泽县的一个地点、圣克鲁斯县的一个地点以及索诺马县的两个地点。对260只啮齿动物的血清或血浆样本进行了人粒细胞埃立克体病病原体抗体检测。其中，25只林鼠（占检测数的34%）和10只（8%）白足鼠属小鼠的样本呈血清阳性，但仅来自一个地点。对所有血清阳性标本以及一部分血清阴性血液标本进行了靶向groESL热休克操纵子的PCR检测。在25份血清阳性林鼠血液样本中的17份（68%）以及10份白足鼠属标本中的1份（10%）中鉴定出埃立克体DNA。40份血清阴性血液样本均未出现PCR阳性。在每个诱捕期都采集到了血清阳性和PCR阳性动物。采集的84只太平洋硬蜱成虫中有1只雄性PCR阳性；西方革蜱若虫和成虫样本均为阴性。来自三只林鼠血液标本和单个PCR阳性蜱的扩增子核苷酸序列与先前从马埃立克体获得的序列分别相差1个和2个碱基。在索诺马县的一个地点，林鼠同时具有较高的血清阳性率和PCR阳性率，而在该地点采集的其他鼠科啮齿动物只是偶尔被感染。我们认为，在加利福尼亚州北部的某些地区，暗色足林鼠是粒细胞埃立克体病原体的储存宿主。在林鼠之间传播粒细胞埃立克体的蜱种仍不清楚。
