赣州市5例恙虫病调查报告

5例病人均有发热及典型的焦痂体征，焦痂率达80％，恢复期血清抗体阳性，对强力霉素高度敏感。发病时间为6、7月份。男女均有发病，以农民为主，均有野外作业史，呈散在流行。调查首次证明赣州市有恙虫病的存在，流行病学特征明显。     

恙虫病东方体在无生命培养基内生长的研究

目的　恙虫病东方体 (Orientiatsutsugamushi;Ot)被认为属专性细胞内寄生。特别是制备大量抗原培养难的问题 ,是近一个世纪以来人们渴望解决的难题。为证实是否能在无生命培养基生长。方法　用Vero -E6个单层组织细胞培养OtJL - 90株与标准Gilliam株 ,在合适时取该培养物接种于Ⅲ号无生命固体培养基培养 ,置 36℃ (± 1℃ )培养 18- 2 4h。结果　可见生长一群无色透明或半透明光滑、湿润、圆形或枫叶样小菌落 ,并产生一种难闻的臭味。两种方法培养物分别做了生物学性状鉴定、形态染色、小白鼠致病力、血清学特异性间接免疫荧光检测。各株Ot经两种培养获得培养物特性基本一致。结论　Ot能在细胞内生长也能在无生命培养基内生长 ,解决了Ot大量抗原培养难的困扰。     

应用PCR技术检测恙螨体内恙虫病立克次体动态和经卵传递的研究

本文应用聚合酶链反应技术检测恙虫病立克次体实验感染的恙螨体内立克次体的动态变化，通过人工腹腔接种而感染的恙螨成虫，恙虫病立克次体至少能在其体内生存３６０天和经卵传递４代；通过未食幼虫叮咬病小鼠而感染的恙螨，经饱蚴、若蛹、若虫、成蛹和成虫阶段，恙虫病立克次体检测均呈阳性，至少能在成虫期体内生存２７０天和经卵传递１代。     

恙虫病东方体Sta56抗原的原核表达、纯化及其在间接ELISA中的应用

目的　构建含恙虫病东方体sta5 6基因的重组表达质粒 ,在E .coli中表达Sta5 6重组抗原 ,纯化后用于间接ELISA检测恙虫病。方法　从含有恙虫病东方体Karp株sta5 6基因的重组质粒TOPO sta5 6扩增出截短的sta5 6 ,定向插入pET30a载体 ,转化大肠杆菌BL2 1(DE3) ,IPTG诱导表达 ,用SDS PAGE及Westernblot进行分析 ;采用电洗脱方法纯化重组抗原并应用于间接ELISA检测恙虫病。结果　以截短的sta5 6基因片段构建了重组表达质粒pETOt95 7,重组的Sta5 6抗原可在E .coli中以融合蛋白的形式有效表达 ,SDS PAGE显示了一条相对分子质量 (Mr)为 4 0 .3× 10 3 的蛋白表达带 ,West ernblot证实该融合蛋白能被恙虫病患者阳性血清所识别。电洗脱纯化的重组抗原应用于间接法ELISA检测恙虫病 ,与间接免疫荧光法IFAT比较 ,其敏感性和特异性分别为 91.7%和 76 .5 %。结论　在大肠杆菌中表达的Sta5 6重组抗原具有免疫反应性 ,纯化后可用作免疫诊断试剂。     

Development of a Scoring System to Differentiate Severe Fever with Thrombocytopenia Syndrome from Scrub Typhus

Severe fever with thrombocytopenia syndrome (SFTS) and scrub typhus are disorders with similar clinical features; therefore, differentiating between them is difficult. We retrospectively collected data from 183 SFTS and 178 scrub typhus patients and validated an existing scoring system to develop a more sensitive, specific, and objective scoring system. We first applied the scoring systems proposed by Kim et al. to differentiate SFTS from scrub typhus. Multivariable logistic regression revealed that altered mental status, leukopenia, prolonged activated partial thromboplastin time (aPTT), and normal C-reactive protein (CRP) level (≤1.0 mg/dL) were significantly associated with SFTS. We changed the normal CRP level from ≤1.0 mg/dL to ≤3.0 mg/dL and replaced altered mental status with the creatine kinase (CK) level. The modified scoring system showed 97% sensitivity and 96% specificity for SFTS (area under the curve (AUC): 0.983) and a higher accuracy than the original scoring system (p = 0.0308). This study’s scoring system had 97% sensitivity and 98% specificity for SFTS (AUC: 0.992) and a higher accuracy than Kim et al.’s original scoring system (p = 0.0308). Our scoring system that incorporated leukopenia, prolonged aPTT, normal CRP level (≤3.0 mg/dL), and elevated CK level (>1000 IU/L) easily differentiated SFTS from scrub typhus in an endemic area.     

Scrub typhus strikes back: Are we ready?

Scrub typhus has struck back, albeit with renewed vigour, impacting areas with previously known endemicity as also impressing newer expanses. It is not surprising, therefore, that Scrub typhus has emerged as a leading cause of public health concern globally as well as in India, but are we ready to take on the challenge?Over the last decade, there has been a global increase in the number of outbreaks of Scrub typhus, be it the military occupied areas or the civil population at large. The innumerable outbreaks of Scrub typhus, although disconcerting, have nonetheless contributed phenomenally towards better understanding of the dynamics of scrub typhus. There have been significant contributions to awareness of the disease amongst medical professionals, scrub typhus as a cause of Acute Undifferentiated Febrile Illness (AUFI) and newer clinical manifestation – Acute Encephalitis Syndrome (AES), availability and advances in diagnostics and management, man-vector-pathogen interactions, new records of Leptotrombidium species, newer vectors and Orientia species.Antigenic diversity and the varied clinical presentation of scrub typhus, absence of scrub typhus surveillance system and a lack of political will to recognize the disease as one of the important reemerging public health problem are areas seeking concerted deliberations and actions so that the challenges posed by scrub typhus can be addressed.     

应用PCR／SSCP分析恙虫病东方体分离株基因型的研究

目的：对分离自辽宁、吉林地区的6株恙虫病东方体目的基因进行分析研究,并与国际参考株进行比较,方法：经PCR／SSCP检测,呈现2种不同的单链构象图说：HCAa9202株、HCAp9203株及HCM9501株图谱与Gilliam参考株相同,而KDCt9402株、KDCp9403株及KDCt9404株的图谱则与Karp参考株相同。结果：辽宁、吉林地区恙虫病东方体分离株至少存在2种型别。结论：应用PCR／SSCP方法分析恙虫病东方体基因型,简便,经济、省时、结果准确。     

高湖纤恙螨叮刺和经卵传递恙虫病东方体的研究(英文)

目的研究高湖纤恙螨叮刺和传播恙虫病东方体(Ot)的能力。方法螨叮人传病试验是将2只未食高湖纤恙螨幼虫放在受试者(笔者本人)的前臂屈侧上,罩上透明塑料小盖,在解剖镜下观察螨的活动。经卵传递Ot试验是将20～40只高湖纤恙螨未食幼虫放在1只小白鼠耳中3～5 d,每天观察鼠的情况,病鼠或死鼠予以解剖,镜检Ot。结果恙螨叮人20 d后使人患恙虫病并从血中分离到Ot。鼠体经卵传递Ot试验亦获得成功。阳性鼠均有典型症状、显著病变,并检出Ot。结论结果表明高湖纤恙螨可作为恙虫病的传播媒介。     

mNGS协助诊断无焦痂型丛林斑疹伤寒1例

丛林斑疹伤寒是由恙虫病东方体感染引起的一种急性人畜共患传染病。临床表现为发热、皮疹、淋巴结肿大,被叮咬部位出现特异性焦痂和溃疡是该病诊断的最主要依据,没有焦痂和溃疡的患者往往很难识别。本文报告1例54岁男性患者,以发热、淋巴结肿大及全身多个脏器损伤为主要临床表现,因无特征性焦痂,且经验性使用抗菌药物效果不佳,给诊疗带来困难。病例标本送宏基因组二代测序(mNGS)明确病原体为恙虫病东方体。换用左氧氟沙星及阿奇霉素治疗后患者症状很快好转,最终痊愈出院。mNGS已被证明比传统培养方法更敏感,在早期诊断恙虫病方面优于传统临床方法,尤其是对于没有典型焦痂的患者。     

恙虫病东方体56kDa抗原基因片段在不同载体的表达

目的 构建恙虫病东方体56kDa表面抗原基因(sta56)片段在不同载体的重组表达质粒，在E．coli中表达sta56重组抗原并比较不同表达系统对sta56的表达效果。方法 从含有恙虫病东方体Karp株sta56基因的重组克隆，扩增出不同长度的截短的sta56片段．定向插入pPROEX HTb及pET30a载体，转化大肠埃希菌DH5a或BL21(DE3)，IPTG诱导表达，应用十二烷基磺酸钠—聚丙烯酰胺凝胶电泳(SDS-PAGE)观察重组蛋白表达情况。应用蛋白印迹(WB)方法分析重组抗原的活性。结果 成功构建含sta56不同长度片段的重组表达质粒pHTbOt957、pHTbOt498、pHTbOt342和pETOt957、pETOt498、pETOt342，各重组子均可在E．coli中以融合蛋白的形式有效表达，SDS-PAGE显示各表达重组子表达不同分子量的重组蛋白，WB证实各重组蛋白均能被恙虫病患者阳性血清所识别。结论 恙虫病东方体Karp株sta56基因可在大肠埃希菌获得高效表达，pET30a对sta56的表达效果优于pPROEX HTb；重组蛋白具有免疫反应性，纯化后可用作免疫诊断抗原。