Kidd Linda, Hegarty Barbara, Sexton Daniel, Breitschwerdt Edward
TheScripps Research Institute, Department of Immunology, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
Ann N Y Acad Sci. 2006 Oct;1078:400-9. doi: 10.1196/annals.1374.079.
Rocky Mountain spotted fever (RMST) is an important cause of morbidity and mortality in people and dogs in the United States. Disease manifestations are strikingly similar in both species, and illness in dogs can precede illness in people. R. rickettsii has been identified as a Select Agent by the CDC as a Category C priority pathogen by the National Institute of Allergic and Infectious Diseases because it is amenable to use as a bioterror agent. The clinical and temporal relationship of naturally occurring diseases in dogs and people suggests that dogs could serve as sentinels for natural infection and bioterrorist attacks using this organism. Recognizing genetic modifications in naturally occurring disease agents in order to distinguish them from intentionally released agents are priorities put forth by the NIAID. To determine whether the rickettsiae naturally infecting dogs is the same as those that infect persons in a given geographical region, we characterized rickettsial isolates obtained from three dogs and two persons diagnosed with RMSF in North Carolina. Portions of three genes (ompA, rrs, and gltA) amplified by PCR were cloned and sequenced or directly sequenced. Reactions were run in duplicate in forward and reverse directions. Gene sequences were aligned with known sequences deposited in GenBank and with each other. Sequences of the 5' region of the ompA gene were 100% homologous with a tick strain (Bitterroot) of R. rickettsii for all five isolates. Sequences of the rrs gene were 99.8 99.9% homologous with a tick strain (Sawtooth) of R. rickettsii. rrs gene sequences from one dog and the two persons was identical. Sequences of one dog isolate differed from these by one base pair. Sequences from another dog isolate differed by two base pairs. Sequences of the gltA gene are pending. This confirms on a molecular level that R. rickettsii causing naturally occurring RMSF in dogs in North Carolina is highly homologous to R. rickettsii that causes the disease in people in the same region. Sequence data will be deposited in GenBank, thereby providing genetic information regarding naturally occurring R. rickettsii.
落基山斑疹热（RMST）是美国人和狗发病及死亡的一个重要原因。两种物种的疾病表现极为相似，而且狗的患病可能先于人的患病。立氏立克次体已被美国疾病控制与预防中心确定为特定病原体，被美国国立过敏与传染病研究所列为C类优先病原体，因为它适合用作生物恐怖制剂。狗和人自然发生疾病的临床及时间关系表明，狗可以作为自然感染和使用这种病原体进行生物恐怖袭击的哨兵。识别自然发生的病原体中的基因修饰以便将它们与故意释放的病原体区分开来，这是美国国立过敏与传染病研究所提出的优先事项。为了确定自然感染狗的立克次体是否与在特定地理区域感染人的立克次体相同，我们对从北卡罗来纳州三只狗和两名被诊断为落基山斑疹热的人身上分离得到的立克次体进行了特征分析。通过聚合酶链反应（PCR）扩增的三个基因（ompA、rrs和gltA）的部分片段被克隆并测序或直接测序。反应在正向和反向两个方向上重复进行。基因序列与GenBank中保存的已知序列以及彼此进行比对。对于所有五个分离株，ompA基因5'区域的序列与立氏立克次体的一个蜱虫菌株（比特鲁特）100%同源。rrs基因的序列与立氏立克次体的一个蜱虫菌株（锯齿）99.8% - 99.9%同源。来自一只狗和两个人的rrs基因序列相同。来自另一只狗分离株的序列与之相差一个碱基对。来自另一只狗分离株的序列相差两个碱基对。gltA基因的序列待定。这在分子水平上证实，在北卡罗来纳州自然引发狗患落基山斑疹热的立氏立克次体与在同一地区引发人患该病的立氏立克次体高度同源。序列数据将存入GenBank，从而提供有关自然发生的立氏立克次体的遗传信息。
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